oil pressure question
Discussion
I can't seem to find anything wrong with my engine at the moment.
Lost all pressure a few weeks ago. Accusump also discharged itself. Oil pump and drive are fine.
Is the accusump connected to the oil pressure switch? I was wondering if perhaps a faulty pressure switch would cause it to discharge itself.
Is it possible to spin a bearing without it sounding like a bag of nails? Any ideas?
Cheers
Gary
Lost all pressure a few weeks ago. Accusump also discharged itself. Oil pump and drive are fine.
Is the accusump connected to the oil pressure switch? I was wondering if perhaps a faulty pressure switch would cause it to discharge itself.
Is it possible to spin a bearing without it sounding like a bag of nails? Any ideas?
Cheers
Gary
If the Accusump is connected as per factory loom then it is only connected to the ignition.
In this state it will open when the ignition is switched on and close when it is switched off. The valve therefore will be open all the while the engine is running.
Incidentally the Accusump will still charge even if the valve is closed as the engine oil pressure will force past the closed valve. It is designed this way.
In order for yours to discharge the ignition would have to be on and maybe the oil low pressure switch made.
Steve
In this state it will open when the ignition is switched on and close when it is switched off. The valve therefore will be open all the while the engine is running.
Incidentally the Accusump will still charge even if the valve is closed as the engine oil pressure will force past the closed valve. It is designed this way.
In order for yours to discharge the ignition would have to be on and maybe the oil low pressure switch made.
Steve
Hi Gaz
Did you check in any way that you had really lost oil pressure? Maybe by fitting an old type none electrical oil pressure gauge. You could have used this in conjuction with an oil pump priming tool to check for pressure. I always use one after any engine work. The tool fits into an electric drill, you remove the dizzy and drive the oil pump with the drill. After a couple of seconds you will feel the back pressure and the gauge should read. It also means you don't need to crank the engine. You could try it with the sump removed to see if you have really lost oil pressure. You would need to fit an oil filter and feed the oil pump. It would be messy but maybe worth a try. But better than stripping the engine down. If you have lost pressure you might see where the oil is getting out.
Before you do any of that take out the dizzy and check the oil pump drive on the end of it and the cam drive gear. I've had the drive gear strip before which will cause zero oil pressure but this usually causes problems with ignition timing before it fails. How was the car running at the time you lost oil pressure? Make sure you mark the dizzy position before removing it.
I've just stripped mine down, still not impressed by American Speed. End float was 24thou should be a max of 7thou. The Harmonic Damper was also stuck fast even the correct puller would not remove it due to the end of the crank being damaged before it was fitted. I could see the damaged end of the crank looking into the damper. I had to leave it on the crank. It's all going in the bin. Apart from the block.
Let us know how you get on.
Regards Dave
>> Edited by CanAm Dave on Wednesday 28th December 23:41
>> Edited by CanAm Dave on Thursday 29th December 00:18
Did you check in any way that you had really lost oil pressure? Maybe by fitting an old type none electrical oil pressure gauge. You could have used this in conjuction with an oil pump priming tool to check for pressure. I always use one after any engine work. The tool fits into an electric drill, you remove the dizzy and drive the oil pump with the drill. After a couple of seconds you will feel the back pressure and the gauge should read. It also means you don't need to crank the engine. You could try it with the sump removed to see if you have really lost oil pressure. You would need to fit an oil filter and feed the oil pump. It would be messy but maybe worth a try. But better than stripping the engine down. If you have lost pressure you might see where the oil is getting out.
Before you do any of that take out the dizzy and check the oil pump drive on the end of it and the cam drive gear. I've had the drive gear strip before which will cause zero oil pressure but this usually causes problems with ignition timing before it fails. How was the car running at the time you lost oil pressure? Make sure you mark the dizzy position before removing it.
I've just stripped mine down, still not impressed by American Speed. End float was 24thou should be a max of 7thou. The Harmonic Damper was also stuck fast even the correct puller would not remove it due to the end of the crank being damaged before it was fitted. I could see the damaged end of the crank looking into the damper. I had to leave it on the crank. It's all going in the bin. Apart from the block.
Let us know how you get on.
Regards Dave
>> Edited by CanAm Dave on Wednesday 28th December 23:41
>> Edited by CanAm Dave on Thursday 29th December 00:18
Well, thanks for the advice, Steve, Dave.
Keith came over this morning to have a look. (thanks Keith, much appreciated!!
)
He managed to get oil pressure reading on the gauge! He seems to think the engine is fine. Still no regrets on taking it out though. Perhaps the oil pressure relief valve was stuck open? I shall replace with a new one anyway.
Keith was impressed with the build quality of the AS engine!
I will also replace the crankshaft oil seal. Have noticed engine mounting lugs rubbing on chassis mounts, which means the rubber between was not doing anything! I shall grind them down before refitting. Anyone else had this?
Misfiring might have been down to the distributor. It's badly corroded under the cap.
Gary
Keith came over this morning to have a look. (thanks Keith, much appreciated!!
) He managed to get oil pressure reading on the gauge! He seems to think the engine is fine. Still no regrets on taking it out though. Perhaps the oil pressure relief valve was stuck open? I shall replace with a new one anyway.
Keith was impressed with the build quality of the AS engine!
I will also replace the crankshaft oil seal. Have noticed engine mounting lugs rubbing on chassis mounts, which means the rubber between was not doing anything! I shall grind them down before refitting. Anyone else had this?
Misfiring might have been down to the distributor. It's badly corroded under the cap.
Gary
gtr-gaz said:
.......Have noticed engine mounting lugs rubbing on chassis mounts, which means the rubber between was not doing anything! I shall grind them down before refitting. Anyone else had this?.......
Noticed that before the engine was fitted so ground them down as you say.
Steve
gtr-gaz said:
Misfiring might have been down to the distributor. It's badly corroded under the cap.
I noticed that my distributor had a lot of corrosion when I was locking out the advance. As the engine has always been a warm dehumidified garage I was a bit puzzled by this. I wondered if it might have been something to do with moisture condensing there during the flight over...
Spoke to the factory last week about the accusump.
Basically, I had the wrong idea of how it worked. I assumed it was mechanically opened (like a spring, where if the pressure dropped, the spring would open the valve) NOT TRUE
It is wired to the ignition, as Steve.D said. With the ignition on, the accusump will be charged by the oil pressure in the engine. However if the pressure drops, the oil pressure switch makes contact and activates the accusump to pump oil into the engine.
So if the oil light comes on, the pressure gauge is at zero and the accusump has discharged, it does not neccessarily mean you have lost oil pressue. It could be just a blockage in the pressure switch fitting.
(does that make sense?)
Gary
Basically, I had the wrong idea of how it worked. I assumed it was mechanically opened (like a spring, where if the pressure dropped, the spring would open the valve) NOT TRUE
It is wired to the ignition, as Steve.D said. With the ignition on, the accusump will be charged by the oil pressure in the engine. However if the pressure drops, the oil pressure switch makes contact and activates the accusump to pump oil into the engine.
So if the oil light comes on, the pressure gauge is at zero and the accusump has discharged, it does not neccessarily mean you have lost oil pressue. It could be just a blockage in the pressure switch fitting.
(does that make sense?)
Gary
I don't believe the oil pressure switch is in the circuit but I'm more than happy to be proved wrong.
Follow my logic.
In order for the oil light to come on the pressure will be down to around 2-5 psi.
If the pressure switch were to operate the Accusump at this point then it would release oil at maybe 40psi. As soon as the switch reaches more than 5psi it would close the Accusump again leaving you with still only a little over 5psi in the engine.
I believe the Accusump opens when the ignition comes on and closes when it goes off. A sudden loss of pump pressure (surge) will be compensated for by the Accusump being open with a large stock of pressurised oil. A slow fall off of pump pressure (a failing or worn pump) will not be saved by the Accusump as its pressure would also slowly drop.
Steve
Follow my logic.
In order for the oil light to come on the pressure will be down to around 2-5 psi.
If the pressure switch were to operate the Accusump at this point then it would release oil at maybe 40psi. As soon as the switch reaches more than 5psi it would close the Accusump again leaving you with still only a little over 5psi in the engine.
I believe the Accusump opens when the ignition comes on and closes when it goes off. A sudden loss of pump pressure (surge) will be compensated for by the Accusump being open with a large stock of pressurised oil. A slow fall off of pump pressure (a failing or worn pump) will not be saved by the Accusump as its pressure would also slowly drop.
Steve
There is nothing magic going on here, the Accusump is at one end an air reserve that is pressurised as engine oil (also under pressure one hopes) enters the other end. Oil is pushed in when the pressure is greater than that on the air side. So when oil pressure drops below the air side oil will then be pushed back out, the rate of which will be dependent on the engine oil pressure. Also note that the Accusump will charge regardless of the valve state, ie the valve could be shut and it will still charge given the required oil pressure, but none will flow out (good when you disconnect it from the engine!). The system is not connected (as stated above) to any external oil pressure switch or sensor of any type. Having said that, mine is, as my dash controller monitors oil pressure and switches the Accusump electronically at my predetermined oil pressure level.
Gary, do you have an Accusump manual, it makes good reading?
Gary, do you have an Accusump manual, it makes good reading?
Phil, don't recall looking at an accusump manual! Guess I need to sort out all the paperwork I have for my car. It's bound to be in there somewhere!!
I think I was clutching at straws on information from the factory!
It now looks like I definitly lost oil pressure and the engine is stuffed! Took the main bearing caps of the crankshaft yesterday to change the oil seal and was horrified to find most of them badly scored.
It's now in the back of the van and will be on it's way to be rebuilt this afternoon. It's no good me just changing the shells. I need to know what caused it.
Gary
I think I was clutching at straws on information from the factory!
It now looks like I definitly lost oil pressure and the engine is stuffed! Took the main bearing caps of the crankshaft yesterday to change the oil seal and was horrified to find most of them badly scored.
It's now in the back of the van and will be on it's way to be rebuilt this afternoon. It's no good me just changing the shells. I need to know what caused it.
Gary
gtr-gaz said:
Phil, don't recall looking at an accusump manual! Guess I need to sort out all the paperwork I have for my car. It's bound to be in there somewhere!!
I think I was clutching at straws on information from the factory!
It now looks like I definitly lost oil pressure and the engine is stuffed! Took the main bearing caps of the crankshaft yesterday to change the oil seal and was horrified to find most of them badly scored.
It's now in the back of the van and will be on it's way to be rebuilt this afternoon. It's no good me just changing the shells. I need to know what caused it.
Gary
It may have been the other way round. You ran a bearing then lost pressure.
Steve
rossins said:
gary, any further news on the engine?
simon
Well, engine builder (who is probably one of the best (american engines) in the country has it in pieces at the moment. There is not a lot wrong with it. There was some scoring on the main shells. He has put this down to the timing chain rubbing on the block and producing metal filings! This was not obvious to me until it was pointed out, but there is a definite wear line there. AS had ground it down but not enough to clear the chain.
Apart from that, there is some good stuff in it. Must be a first to compliment AS!!
He has suggested it is a bit too race orientated for my needs and is going to price up some alterations to make it more drivable on the street. This will include hydraulic lifters.
All depends on if I will be able to tell the power difference.
Loss of oil pressure he is assuming was due to pressure relief valve getting stuck open, as he cannot find any other cause.
Gary
Be interested to see if the "detune" will help summer cooling problems.
[quote=gtr-gaz
He has suggested it is a bit too race orientated for my needs and is going to price up some alterations to make it more drivable on the street. This will include hydraulic lifters.
All depends on if I will be able to tell the power difference.
[/quote]
Normally the choice of lifter depends on the cam profile. Wild cams (that allow the engine to rev and have high lift) will need mechanical lifters as you have. So there is a good chance you will need to change the cam also if going hydraulic - especially if you with to make it more 'street'.
However there are some good cam/hydraulic lifter 'matched combos' that rev well to 7K - so you dont need to give it all up!
Not sure it will alter any cooling issues
He has suggested it is a bit too race orientated for my needs and is going to price up some alterations to make it more drivable on the street. This will include hydraulic lifters.
All depends on if I will be able to tell the power difference.
[/quote]
Normally the choice of lifter depends on the cam profile. Wild cams (that allow the engine to rev and have high lift) will need mechanical lifters as you have. So there is a good chance you will need to change the cam also if going hydraulic - especially if you with to make it more 'street'.
However there are some good cam/hydraulic lifter 'matched combos' that rev well to 7K - so you dont need to give it all up!
Not sure it will alter any cooling issues
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