advise on XKE engine issues
Discussion
All, Apreciate some advice on low oil pressure on a series 1 E-type 4.2.
After purchasing a rebuilt series one 4.2 from a Jaguar E-type specialist ,early last month on the way home driving the car for 70 miles ,the oil pressure went from mid 40s down to 0 . odo reading is 27,600 ( taking it that its been once round the clock )
I immedietly parked the car up in a layby and turned the engine off ,( it was sounding very rough ) then contacted the dealer , i talked with the specailist's mechanic who asked to hear the engine running , with mobile phone on he said yes sounds like bottom end issues. they arranged collection and stripped engine down . The conclusion was that a crank bearing had failed and broke up with swarf which blocked the oil pump and resulted in the low pressure reading. ( The original engine had been rebuilt by the previous owner, not the specialist )
The car was covered under the jaguar specialist warranty and repaired with new ground crank , shells etc. Then pressure tested reading on average 23 pressure
I had the car back a week later, and prepared to " run her in" below 2000 rpm for the first 1000 miles.
on start up car would read 40 - 60 pressure then gradually reduce to 20 -30 driving at around 1500 -2000 rpm . after 60 miles the pressure gradually started to drop down to 10 and then 5 , I took the car slowly to a friends house where the reading was reading 0 pressure . Everything off and called the dealer again ,
he explained that it was probably the relief valve that was fitted as a second hand item , ( as a new relief valve was not available at the time of repair).
I find this very worrying that a component fitted by a jaguar specialist was not new and during an engine rebuild on a car purchased and described as "show condition" as a complete rebuild. The car has gone back to the specialist for repair under warranty
looking for advise on what would be the expected running oil pressure be on a rebuilt XKE engine it is the original engine.
So far e-type ownership has not been as expected , 140 miles and two engine failures !!
After purchasing a rebuilt series one 4.2 from a Jaguar E-type specialist ,early last month on the way home driving the car for 70 miles ,the oil pressure went from mid 40s down to 0 . odo reading is 27,600 ( taking it that its been once round the clock )
I immedietly parked the car up in a layby and turned the engine off ,( it was sounding very rough ) then contacted the dealer , i talked with the specailist's mechanic who asked to hear the engine running , with mobile phone on he said yes sounds like bottom end issues. they arranged collection and stripped engine down . The conclusion was that a crank bearing had failed and broke up with swarf which blocked the oil pump and resulted in the low pressure reading. ( The original engine had been rebuilt by the previous owner, not the specialist )
The car was covered under the jaguar specialist warranty and repaired with new ground crank , shells etc. Then pressure tested reading on average 23 pressure
I had the car back a week later, and prepared to " run her in" below 2000 rpm for the first 1000 miles.
on start up car would read 40 - 60 pressure then gradually reduce to 20 -30 driving at around 1500 -2000 rpm . after 60 miles the pressure gradually started to drop down to 10 and then 5 , I took the car slowly to a friends house where the reading was reading 0 pressure . Everything off and called the dealer again ,
he explained that it was probably the relief valve that was fitted as a second hand item , ( as a new relief valve was not available at the time of repair).
I find this very worrying that a component fitted by a jaguar specialist was not new and during an engine rebuild on a car purchased and described as "show condition" as a complete rebuild. The car has gone back to the specialist for repair under warranty
looking for advise on what would be the expected running oil pressure be on a rebuilt XKE engine it is the original engine.
So far e-type ownership has not been as expected , 140 miles and two engine failures !!
fareaster said:
A new engine should be about 60/70 psi hot above 2500 rpm, tickover 20/25. Older engines could drop to two thirds of these values and still be OK. Be aware that the oil pressure gauge/sender unit can be unreliable.
I would disagree about reduced oil pressure as the engine ages, based on personal experience. My engine has done approaching 100,000 miles since the last rebuild and still shows 60psi when hot, dropping to around 25psi at idle. However, I have had the pressure wet gauge tested because the oil pressure senders one buys today are worsethan useless. My car goes off the scale when cold and until I stop, turn the engine off for 20 minutes or so and then continue, when it shows the correct pressure.I am though getting alarm bells sounding reading the OP's post. I'd suggest an independent inspection to check out the engine properly. Pressure relief valves should be available from stock from "the usual suspects" like Manners, Barratts, Robey or Norman Motors. I have to buy parts on an increasingly frequent basis as the car is ageing, like a wheel bearing two weeks back, O ring and exhaust bolts this week and so on, and I have always found parts available somewhere.
lowdrag said:
I would disagree about reduced oil pressure as the engine ages, based on personal experience. My engine has done approaching 100,000 miles since the last rebuild and still shows 60psi when hot, dropping to around 25psi at idle. However, I have had the pressure wet gauge tested because the oil pressure senders one buys today are worsethan useless. My car goes off the scale when cold and until I stop, turn the engine off for 20 minutes or so and then continue, when it shows the correct pressure.
I am though getting alarm bells sounding reading the OP's post. I'd suggest an independent inspection to check out the engine properly. Pressure relief valves should be available from stock from "the usual suspects" like Manners, Barratts, Robey or Norman Motors. I have to buy parts on an increasingly frequent basis as the car is ageing, like a wheel bearing two weeks back, O ring and exhaust bolts this week and so on, and I have always found parts available somewhere.
thanks , can you reccommend an idependent specialist who would check out the engine and an idea of the cost involvedI am though getting alarm bells sounding reading the OP's post. I'd suggest an independent inspection to check out the engine properly. Pressure relief valves should be available from stock from "the usual suspects" like Manners, Barratts, Robey or Norman Motors. I have to buy parts on an increasingly frequent basis as the car is ageing, like a wheel bearing two weeks back, O ring and exhaust bolts this week and so on, and I have always found parts available somewhere.
thanks
Several so-called specialists are little better than back street bodgers and in my opinion one or two well known names fall into this category.
I'm not suggesting that your garage is in this category,rather that not all "specialists" are equal. You may have been unlucky, but so far they haven't covered themselves in glory.
I would suggest that you have the whole car independently inspected by a reputed specialist, not just the engine.
Better still return the car and look for another one.
I'm not suggesting that your garage is in this category,rather that not all "specialists" are equal. You may have been unlucky, but so far they haven't covered themselves in glory.
I would suggest that you have the whole car independently inspected by a reputed specialist, not just the engine.
Better still return the car and look for another one.
Reading this thread and other similar stories makes me think we have a missed opportunity on this forum. I know the mods aren't keen on a name and shame policy for the legal implications attached, but, we could have a recommended thread for specialists with details of work done, cost etc. If certain 'specialists' get no recommendations there would be no legal issue there.
But what about the cams in their shells and the lobes and tappet faces now that the engine has run with low pressure twice, how many miles have been taken from their life and how will they contribute to low oil pressure in the future?
I'd be wanting the dealer to fit a properly rebuilt unit from someone like VSE, whoever just did it obviously didn't do it properly.
To say that a relif valve is not available for a 4.2 motor is lying.
I'd be wanting the dealer to fit a properly rebuilt unit from someone like VSE, whoever just did it obviously didn't do it properly.
To say that a relif valve is not available for a 4.2 motor is lying.
DBSV8 said:
lowdrag said:
I would disagree about reduced oil pressure as the engine ages, based on personal experience. My engine has done approaching 100,000 miles since the last rebuild and still shows 60psi when hot, dropping to around 25psi at idle. However, I have had the pressure wet gauge tested because the oil pressure senders one buys today are worsethan useless. My car goes off the scale when cold and until I stop, turn the engine off for 20 minutes or so and then continue, when it shows the correct pressure.
I am though getting alarm bells sounding reading the OP's post. I'd suggest an independent inspection to check out the engine properly. Pressure relief valves should be available from stock from "the usual suspects" like Manners, Barratts, Robey or Norman Motors. I have to buy parts on an increasingly frequent basis as the car is ageing, like a wheel bearing two weeks back, O ring and exhaust bolts this week and so on, and I have always found parts available somewhere.
thanks , can you reccommend an idependent specialist who would check out the engine and an idea of the cost involvedI am though getting alarm bells sounding reading the OP's post. I'd suggest an independent inspection to check out the engine properly. Pressure relief valves should be available from stock from "the usual suspects" like Manners, Barratts, Robey or Norman Motors. I have to buy parts on an increasingly frequent basis as the car is ageing, like a wheel bearing two weeks back, O ring and exhaust bolts this week and so on, and I have always found parts available somewhere.
thanks
Bozwell who hangs out here occasionally is down in Kent. He's rebuilt quite a few of the Cs & Ds, he rebuilt the engine for E2A.
MPH's friends are in Staffordshire, just outside Bridge North.
RW774 from here is in Essex
The guy I visit has setup shop near Guildford.
The guy I bought my engine from is in Chesterfield
I'm sure others can recommend people.
lowdrag said:
I would disagree about reduced oil pressure as the engine ages, based on personal experience. My engine has done approaching 100,000 miles since the last rebuild and still shows 60psi when hot, dropping to around 25psi at idle. However, I have had the pressure wet gauge tested because the oil pressure senders one buys today are worsethan useless. My car goes off the scale when cold and until I stop, turn the engine off for 20 minutes or so and then continue, when it shows the correct pressure.
I agree. The 3.4 in my XJ6 has a mileage that would get it to the moon and back, yet still shows just under 40psi at idle, failing to 20 - 25 when really hot (stuck in traffic hot). DBSV8 said:
thanks , can you reccommend an idependent specialist who would check out the engine and an idea of the cost involved
thanks
A bit about the reality of XK oil pressure problems. thanks
On the 4.2 series 1 block there are several potential weaknesses that can result in low oil pressure, even dropping to zero. The oil is picked up by a steel supply pipe connected directly to the oil pump. This tube is hung on 2 brackets and I have seen the tube develop hairline cracks around the area of the brackets. It seals into the oil pump with an 'O' ring, as does the supply pipe, and this is one of the most common causes of oil pressure problems; they perish, go hard and stop sealing.
The 4.2 has a larger diameter supply pipe and oil pump and the flange bolting the supply pipe to the block has a 3 bolt flange in place of the older 2 bolt. Between the flange and the block is a paper gasket that frequently shrinks, sometimes to the point where the pipe becomes loose and most of the pressure goes back into the sump! It is vital that the gasket material used in this flange is of very high quality to prevent shrinkage, and the fixings fitted with tab washers.
The pressurised oil goes from the supply pipe straight to the filter housing on the side of the block and through the fabled oil pressure relief valve. If I had a fiver for every time I have heard this valve being blamed for low oil pressure I could retire now to Monaco! It is a dead simple device consisting of a brass shuttle and a coil spring. On the later engines a pressure equalising valve is also fitted, but this is self contained and, in my experience, seldom affects actual operating pressure. If the relief valve is properly seated and the spring healthy, it will not affect your operating pressure.
The oil then goes through the filter and into the block feeding the main crank bearings first and the conrod shells through drillings in the crank. There is a drilling in the rear main bearing that feeds an external pipe leading up to the rear of the cylinder head to feed the camshafts and followers.
When building these engines all of the above has to be spot on or you have a problem!
The only other cause I have ever come across for disappearing oil pressure when hot was a porous block. This is very difficult to diagnose and was really only found at the height of the BL days on some of the late S2 XJs, particularly the 3.4s. The only old Jag I ever found with this problem was a 3.8 Mk X that had done a huge mileage. We had no alternative but to scrap the block and start with a new one.
If you want to send your car up to Glasgow DBS, I would be only to happy to rebuild your engine for you; you can check out my website. I won't comment on the "experts", it's not my style, but my god I have had cars in the last few months in this workshop that have had thousands spent on them with some of the big names and what I found would make your hair curl!
PM me if you are interested. Hope you find this interesting.
Regards,
J
Edited by jith on Friday 5th August 18:05
jith said:
A bit about the reality of XK oil pressure problems.
On the 4.2 series 1 block there are several potential weaknesses that can result in low oil pressure, even dropping to zero. The oil is picked up by a steel supply pipe connected directly to the oil pump. This tube is hung on 2 brackets and I have seen the tube develop hairline cracks around the area of the brackets. It seals into the oil pump with an 'O' ring, as does the supply pipe, and this is one of the most common causes of oil pressure problems; they perish, go hard and stop sealing.
The 4.2 has a larger diameter supply pipe and oil pump and the flange bolting the supply pipe to the block has a 3 bolt flange in place of the older 2 bolt. Between the flange and the block is a paper gasket that frequently shrinks, sometimes to the point where the pipe becomes loose and most of the pressure goes back into the sump! It is vital that the gasket material used in this flange is of very high quality to prevent shrinkage, and the fixings fitted with tab washers.
The pressurised oil goes from the supply pipe straight to the filter housing on the side of the block and through the fabled oil pressure relief valve. If I had a fiver for every time I have heard this valve being blamed for low oil pressure I could retire now to Monaco! It is a dead simple device consisting of a brass shuttle and a coil spring. On the later engines a pressure equalising valve is also fitted, but this is self contained and, in my experience, seldom affects actual operating pressure. If the relief valve is properly seated and the spring healthy, it will not affect your operating pressure.
The oil then goes through the filter and into the block feeding the main crank bearings first and the conrod shells through drillings in the crank. There is a drilling in the rear main bearing that feeds an external pipe leading up to the rear of the cylinder head to feed the camshafts and followers.
When building these engines all of the above has to be spot on or you have a problem!
The only other cause I have ever come across for disappearing oil pressure when hot was a porous block. This is very difficult to diagnose and was really only found at the height of the BL days on some of the late S2 XJs, particularly the 3.4s. The only old Jag I ever found with this problem was a 3.8 Mk X that had done a huge mileage. We had no alternative but to scrap the block and start with a new one.
If you want to send your car up to Glasgow DBS, I would be only to happy to rebuild your engine for you; you can check out my website. I won't comment on the "experts", it's not my style, but my god I have had cars in the last few months in this workshop that have had thousands spent on them with some of the big names and what I found would make your hair curl!
PM me if you are interested. Hope you find this interesting.
Regards,
J
Thanks James ,On the 4.2 series 1 block there are several potential weaknesses that can result in low oil pressure, even dropping to zero. The oil is picked up by a steel supply pipe connected directly to the oil pump. This tube is hung on 2 brackets and I have seen the tube develop hairline cracks around the area of the brackets. It seals into the oil pump with an 'O' ring, as does the supply pipe, and this is one of the most common causes of oil pressure problems; they perish, go hard and stop sealing.
The 4.2 has a larger diameter supply pipe and oil pump and the flange bolting the supply pipe to the block has a 3 bolt flange in place of the older 2 bolt. Between the flange and the block is a paper gasket that frequently shrinks, sometimes to the point where the pipe becomes loose and most of the pressure goes back into the sump! It is vital that the gasket material used in this flange is of very high quality to prevent shrinkage, and the fixings fitted with tab washers.
The pressurised oil goes from the supply pipe straight to the filter housing on the side of the block and through the fabled oil pressure relief valve. If I had a fiver for every time I have heard this valve being blamed for low oil pressure I could retire now to Monaco! It is a dead simple device consisting of a brass shuttle and a coil spring. On the later engines a pressure equalising valve is also fitted, but this is self contained and, in my experience, seldom affects actual operating pressure. If the relief valve is properly seated and the spring healthy, it will not affect your operating pressure.
The oil then goes through the filter and into the block feeding the main crank bearings first and the conrod shells through drillings in the crank. There is a drilling in the rear main bearing that feeds an external pipe leading up to the rear of the cylinder head to feed the camshafts and followers.
When building these engines all of the above has to be spot on or you have a problem!
The only other cause I have ever come across for disappearing oil pressure when hot was a porous block. This is very difficult to diagnose and was really only found at the height of the BL days on some of the late S2 XJs, particularly the 3.4s. The only old Jag I ever found with this problem was a 3.8 Mk X that had done a huge mileage. We had no alternative but to scrap the block and start with a new one.
If you want to send your car up to Glasgow DBS, I would be only to happy to rebuild your engine for you; you can check out my website. I won't comment on the "experts", it's not my style, but my god I have had cars in the last few months in this workshop that have had thousands spent on them with some of the big names and what I found would make your hair curl!
PM me if you are interested. Hope you find this interesting.
Regards,
J
Edited by jith on Friday 5th August 18:05
To be fair to the specialist involved and as it is under their warranty I am giving them every opportunity to resolve the issues they are going to collect the car and perform repairs ,
I spoke directly with their mechanic ( who has said he was not personally responsible for the previous work or oversaw the rebuilt crank ,However he seemed genuinely concerned and said he would personally be rebuilding the engine ).
I have insisted on an invoice of all parts previously fitted prior to the second failure ,crank , shells , bearings etc. diagnostic checks for oil compression etc.
and a list of parts that will be fitted and work performed for this repair with diagnostic checks.
and the engine "run in" for a reasonable time to ensure parts are performing.( 200 miles ? )
After this my expectation is that I will have an E-type fit for purpose and as described "fully rebuild to show condition ",( One of the reasons that i decided to buy from a specialist that only deal with selling E-types and not privately was for this very assurance ). If this is not the case and the car suffers a third failure , then the alternatives would be to reject the car under SOGA, which I sincerely hope will not be the case , will keep you posted on progress
Edited by DBSV8 on Saturday 6th August 07:01
The mechanic didn't rebuild the engine, and yet he was able to diagnose on the telephone that a second hand relief valve was fitted and was the cause of the problem.
If the car is genuinely rebuilt to show standards then you will have paid a substantial price for it. Why is there no supporting documentation for the rebuilds ?
If the engine has failed at such low mileage what about the rest of the car ? Were the gearbox, rear suspension, ancilaries etc. etc. rebuilt during the restoration ? Is there supporting documentation and who carried out the work ? These are the questions I would be asking.
When you have invested tens of thousands of pounds isn't it worth spending a few hundred more on having an independent inspection ? Apart from anything else it will verify that the car has been correctly restored.
If the car is genuinely rebuilt to show standards then you will have paid a substantial price for it. Why is there no supporting documentation for the rebuilds ?
If the engine has failed at such low mileage what about the rest of the car ? Were the gearbox, rear suspension, ancilaries etc. etc. rebuilt during the restoration ? Is there supporting documentation and who carried out the work ? These are the questions I would be asking.
When you have invested tens of thousands of pounds isn't it worth spending a few hundred more on having an independent inspection ? Apart from anything else it will verify that the car has been correctly restored.
Not sure where you are based but I would recommend you talk to Harry at E Type UK in Kent. Also for general advice I would recommend joining The E Type club Forum. Always good advice on there. http://etypeuk.com/forum/
DBSV8 said:
jith said:
A bit about the reality of XK oil pressure problems.
On the 4.2 series 1 block there are several potential weaknesses that can result in low oil pressure, even dropping to zero. The oil is picked up by a steel supply pipe connected directly to the oil pump. This tube is hung on 2 brackets and I have seen the tube develop hairline cracks around the area of the brackets. It seals into the oil pump with an 'O' ring, as does the supply pipe, and this is one of the most common causes of oil pressure problems; they perish, go hard and stop sealing.
The 4.2 has a larger diameter supply pipe and oil pump and the flange bolting the supply pipe to the block has a 3 bolt flange in place of the older 2 bolt. Between the flange and the block is a paper gasket that frequently shrinks, sometimes to the point where the pipe becomes loose and most of the pressure goes back into the sump! It is vital that the gasket material used in this flange is of very high quality to prevent shrinkage, and the fixings fitted with tab washers.
The pressurised oil goes from the supply pipe straight to the filter housing on the side of the block and through the fabled oil pressure relief valve. If I had a fiver for every time I have heard this valve being blamed for low oil pressure I could retire now to Monaco! It is a dead simple device consisting of a brass shuttle and a coil spring. On the later engines a pressure equalising valve is also fitted, but this is self contained and, in my experience, seldom affects actual operating pressure. If the relief valve is properly seated and the spring healthy, it will not affect your operating pressure.
The oil then goes through the filter and into the block feeding the main crank bearings first and the conrod shells through drillings in the crank. There is a drilling in the rear main bearing that feeds an external pipe leading up to the rear of the cylinder head to feed the camshafts and followers.
When building these engines all of the above has to be spot on or you have a problem!
The only other cause I have ever come across for disappearing oil pressure when hot was a porous block. This is very difficult to diagnose and was really only found at the height of the BL days on some of the late S2 XJs, particularly the 3.4s. The only old Jag I ever found with this problem was a 3.8 Mk X that had done a huge mileage. We had no alternative but to scrap the block and start with a new one.
If you want to send your car up to Glasgow DBS, I would be only to happy to rebuild your engine for you; you can check out my website. I won't comment on the "experts", it's not my style, but my god I have had cars in the last few months in this workshop that have had thousands spent on them with some of the big names and what I found would make your hair curl!
PM me if you are interested. Hope you find this interesting.
Regards,
J
Thanks James ,On the 4.2 series 1 block there are several potential weaknesses that can result in low oil pressure, even dropping to zero. The oil is picked up by a steel supply pipe connected directly to the oil pump. This tube is hung on 2 brackets and I have seen the tube develop hairline cracks around the area of the brackets. It seals into the oil pump with an 'O' ring, as does the supply pipe, and this is one of the most common causes of oil pressure problems; they perish, go hard and stop sealing.
The 4.2 has a larger diameter supply pipe and oil pump and the flange bolting the supply pipe to the block has a 3 bolt flange in place of the older 2 bolt. Between the flange and the block is a paper gasket that frequently shrinks, sometimes to the point where the pipe becomes loose and most of the pressure goes back into the sump! It is vital that the gasket material used in this flange is of very high quality to prevent shrinkage, and the fixings fitted with tab washers.
The pressurised oil goes from the supply pipe straight to the filter housing on the side of the block and through the fabled oil pressure relief valve. If I had a fiver for every time I have heard this valve being blamed for low oil pressure I could retire now to Monaco! It is a dead simple device consisting of a brass shuttle and a coil spring. On the later engines a pressure equalising valve is also fitted, but this is self contained and, in my experience, seldom affects actual operating pressure. If the relief valve is properly seated and the spring healthy, it will not affect your operating pressure.
The oil then goes through the filter and into the block feeding the main crank bearings first and the conrod shells through drillings in the crank. There is a drilling in the rear main bearing that feeds an external pipe leading up to the rear of the cylinder head to feed the camshafts and followers.
When building these engines all of the above has to be spot on or you have a problem!
The only other cause I have ever come across for disappearing oil pressure when hot was a porous block. This is very difficult to diagnose and was really only found at the height of the BL days on some of the late S2 XJs, particularly the 3.4s. The only old Jag I ever found with this problem was a 3.8 Mk X that had done a huge mileage. We had no alternative but to scrap the block and start with a new one.
If you want to send your car up to Glasgow DBS, I would be only to happy to rebuild your engine for you; you can check out my website. I won't comment on the "experts", it's not my style, but my god I have had cars in the last few months in this workshop that have had thousands spent on them with some of the big names and what I found would make your hair curl!
PM me if you are interested. Hope you find this interesting.
Regards,
J
Edited by jith on Friday 5th August 18:05
To be fair to the specialist involved and as it is under their warranty I am giving them every opportunity to resolve the issues they are going to collect the car and perform repairs ,
I spoke directly with their mechanic ( who has said he was not personally responsible for the previous work or oversaw the rebuilt crank ,However he seemed genuinely concerned and said he would personally be rebuilding the engine ).
I have insisted on an invoice of all parts previously fitted prior to the second failure ,crank , shells , bearings etc. diagnostic checks for oil compression etc.
and a list of parts that will be fitted and work performed for this repair with diagnostic checks.
and the engine "run in" for a reasonable time to ensure parts are performing.( 200 miles ? )
After this my expectation is that I will have an E-type fit for purpose and as described "fully rebuild to show condition ",( One of the reasons that i decided to buy from a specialist that only deal with selling E-types and not privately was for this very assurance ). If this is not the case and the car suffers a third failure , then the alternatives would be to reject the car under SOGA, which I sincerely hope will not be the case , will keep you posted on progress
Edited by DBSV8 on Saturday 6th August 07:01
Most of the points made above are valid.
However, it is a simple job to undo the plug in the bottom of the filter housing to access the pressure relief spring components. They will drop out complete with spring. Clean thoroughly and refit - a 15 minute job.
Tell me if you discover a piece of swarf/metal that is preventing the pressure relief spring from seating fully ...
However, it is a simple job to undo the plug in the bottom of the filter housing to access the pressure relief spring components. They will drop out complete with spring. Clean thoroughly and refit - a 15 minute job.
Tell me if you discover a piece of swarf/metal that is preventing the pressure relief spring from seating fully ...
jith said:
DBSV8 said:
thanks , can you reccommend an idependent specialist who would check out the engine and an idea of the cost involved
thanks
A bit about the reality of XK oil pressure problems. thanks
On the 4.2 series 1 block there are several potential weaknesses that can result in low oil pressure, even dropping to zero. The oil is picked up by a steel supply pipe connected directly to the oil pump. This tube is hung on 2 brackets and I have seen the tube develop hairline cracks around the area of the brackets. It seals into the oil pump with an 'O' ring, as does the supply pipe, and this is one of the most common causes of oil pressure problems; they perish, go hard and stop sealing.
The 4.2 has a larger diameter supply pipe and oil pump and the flange bolting the supply pipe to the block has a 3 bolt flange in place of the older 2 bolt. Between the flange and the block is a paper gasket that frequently shrinks, sometimes to the point where the pipe becomes loose and most of the pressure goes back into the sump! It is vital that the gasket material used in this flange is of very high quality to prevent shrinkage, and the fixings fitted with tab washers.
The pressurised oil goes from the supply pipe straight to the filter housing on the side of the block and through the fabled oil pressure relief valve. If I had a fiver for every time I have heard this valve being blamed for low oil pressure I could retire now to Monaco! It is a dead simple device consisting of a brass shuttle and a coil spring. On the later engines a pressure equalising valve is also fitted, but this is self contained and, in my experience, seldom affects actual operating pressure. If the relief valve is properly seated and the spring healthy, it will not affect your operating pressure.
The oil then goes through the filter and into the block feeding the main crank bearings first and the conrod shells through drillings in the crank. There is a drilling in the rear main bearing that feeds an external pipe leading up to the rear of the cylinder head to feed the camshafts and followers.
When building these engines all of the above has to be spot on or you have a problem!
The only other cause I have ever come across for disappearing oil pressure when hot was a porous block. This is very difficult to diagnose and was really only found at the height of the BL days on some of the late S2 XJs, particularly the 3.4s. The only old Jag I ever found with this problem was a 3.8 Mk X that had done a huge mileage. We had no alternative but to scrap the block and start with a new one.
If you want to send your car up to Glasgow DBS, I would be only to happy to rebuild your engine for you; you can check out my website. I won't comment on the "experts", it's not my style, but my god I have had cars in the last few months in this workshop that have had thousands spent on them with some of the big names and what I found would make your hair curl!
PM me if you are interested. Hope you find this interesting.
Regards,
J
Edited by jith on Friday 5th August 18:05
Marquis Rex said:
jith said:
DBSV8 said:
thanks , can you reccommend an idependent specialist who would check out the engine and an idea of the cost involved
thanks
A bit about the reality of XK oil pressure problems. thanks
On the 4.2 series 1 block there are several potential weaknesses that can result in low oil pressure, even dropping to zero. The oil is picked up by a steel supply pipe connected directly to the oil pump. This tube is hung on 2 brackets and I have seen the tube develop hairline cracks around the area of the brackets. It seals into the oil pump with an 'O' ring, as does the supply pipe, and this is one of the most common causes of oil pressure problems; they perish, go hard and stop sealing.
The 4.2 has a larger diameter supply pipe and oil pump and the flange bolting the supply pipe to the block has a 3 bolt flange in place of the older 2 bolt. Between the flange and the block is a paper gasket that frequently shrinks, sometimes to the point where the pipe becomes loose and most of the pressure goes back into the sump! It is vital that the gasket material used in this flange is of very high quality to prevent shrinkage, and the fixings fitted with tab washers.
The pressurised oil goes from the supply pipe straight to the filter housing on the side of the block and through the fabled oil pressure relief valve. If I had a fiver for every time I have heard this valve being blamed for low oil pressure I could retire now to Monaco! It is a dead simple device consisting of a brass shuttle and a coil spring. On the later engines a pressure equalising valve is also fitted, but this is self contained and, in my experience, seldom affects actual operating pressure. If the relief valve is properly seated and the spring healthy, it will not affect your operating pressure.
The oil then goes through the filter and into the block feeding the main crank bearings first and the conrod shells through drillings in the crank. There is a drilling in the rear main bearing that feeds an external pipe leading up to the rear of the cylinder head to feed the camshafts and followers.
When building these engines all of the above has to be spot on or you have a problem!
The only other cause I have ever come across for disappearing oil pressure when hot was a porous block. This is very difficult to diagnose and was really only found at the height of the BL days on some of the late S2 XJs, particularly the 3.4s. The only old Jag I ever found with this problem was a 3.8 Mk X that had done a huge mileage. We had no alternative but to scrap the block and start with a new one.
If you want to send your car up to Glasgow DBS, I would be only to happy to rebuild your engine for you; you can check out my website. I won't comment on the "experts", it's not my style, but my god I have had cars in the last few months in this workshop that have had thousands spent on them with some of the big names and what I found would make your hair curl!
PM me if you are interested. Hope you find this interesting.
Regards,
J
Edited by jith on Friday 5th August 18:05
I've started my business back up in Glasgow. You can check out my website from my profile. I've got so many family commitments here, but NO 1 son is doing very well in Chicago. If you're anywhere near, look him up. He has just bought one of the nicest 911s I have seen in a long time. An '86 SC with a 3.2 Carrera sport engine and lots of toys.
Drop me a line if you want his address. Are you still working in the States?
J
hi,
A quick update , i picked the car up from the vendors 2 days ago after the engine rebuild with new high pressure oil pump , new gaskets ,upgraded oil filter to screw on type , and drove the car back from Staffordshire to Dorset , the pressure is reading 58 -60 psi now and running the engine in at below 2500 rpm , so far completed 250 miles and a further 120 miles today , touch wood , she is running smoothly , just need a bit of better weather to enjoy her
thanks
A quick update , i picked the car up from the vendors 2 days ago after the engine rebuild with new high pressure oil pump , new gaskets ,upgraded oil filter to screw on type , and drove the car back from Staffordshire to Dorset , the pressure is reading 58 -60 psi now and running the engine in at below 2500 rpm , so far completed 250 miles and a further 120 miles today , touch wood , she is running smoothly , just need a bit of better weather to enjoy her
thanks
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