No compression in 2 cylinders
Discussion
This is a 2012 Volvo V50, with a Ford D4162T diesel engine. A month ago, the Cam Belt broke. So, we replaced it, Needless to say the engine didn't start. Next, we removed the rocker cover and found that 2 rockers for cylinders 1 & 4 were broken. They were replaced but, car still would not start, So we did a compression test. Engine had 110 psi in cylinders 1, 2 and 3 and 400psi in 4. So assuming that cyl 4 was OK. We took off the head and replaced the 6 valves in cyls 1,2 and 3. The old valves appeared to be perfectly OK. Got a head kit and put everything back.
Checked compression again and, now we have 40psi in two cylinders, 1 and 4. So next swapped rockers and lifters between cyls1 and 2 and between cyls 3 and 4. But no difference. Still very poor compression in cyls 2 and 3.
So what options are left? Cracked block? We checked that very carefully. it appears to be fine.However, we intend to send it off to be pressure checked.
Broken Piston rings? Highly unlikely. The tops of the pistons were marked but only slightly.
So, has any one here got any ideas? have I missed something?
Checked compression again and, now we have 40psi in two cylinders, 1 and 4. So next swapped rockers and lifters between cyls1 and 2 and between cyls 3 and 4. But no difference. Still very poor compression in cyls 2 and 3.
So what options are left? Cracked block? We checked that very carefully. it appears to be fine.However, we intend to send it off to be pressure checked.
Broken Piston rings? Highly unlikely. The tops of the pistons were marked but only slightly.
So, has any one here got any ideas? have I missed something?
taxi13 said:
This is a 2012 Volvo V50, with a Ford D4162T diesel engine. A month ago, the Cam Belt broke. So, we replaced it, Needless to say the engine didn't start. Next, we removed the rocker cover and found that 2 rockers for cylinders 1 & 4 were broken. They were replaced but, car still would not start, So we did a compression test. Engine had 110 psi in cylinders 1, 2 and 3 and 400psi in 4. So assuming that cyl 4 was OK. We took off the head and replaced the 6 valves in cyls 1,2 and 3. The old valves appeared to be perfectly OK. Got a head kit and put everything back.
Checked compression again and, now we have 40psi in two cylinders, 1 and 4. So next swapped rockers and lifters between cyls1 and 2 and between cyls 3 and 4. But no difference. Still very poor compression in cyls 2 and 3.
So what options are left? Cracked block? We checked that very carefully. it appears to be fine.However, we intend to send it off to be pressure checked.
Broken Piston rings? Highly unlikely. The tops of the pistons were marked but only slightly.
So, has any one here got any ideas? have I missed something?
Instead of DIY....find a mechanic ?Checked compression again and, now we have 40psi in two cylinders, 1 and 4. So next swapped rockers and lifters between cyls1 and 2 and between cyls 3 and 4. But no difference. Still very poor compression in cyls 2 and 3.
So what options are left? Cracked block? We checked that very carefully. it appears to be fine.However, we intend to send it off to be pressure checked.
Broken Piston rings? Highly unlikely. The tops of the pistons were marked but only slightly.
So, has any one here got any ideas? have I missed something?
What sort of crazy person has a cambelt break, then puts another one on and tries to start the engine ? Which will cause even further damage. That is nuts.
And then replaced valves and did not ensure they were all sealing etc before refitting ?
So has the belt been refitted and timed correctly with any hope that it may start ? Did you inspect the pistons and bores for any damage when it was apart ? So there would be no doubt now ?
If not...why not ?
stevieturbo said:
taxi13 said:
This is a 2012 Volvo V50, with a Ford D4162T diesel engine. A month ago, the Cam Belt broke. So, we replaced it, Needless to say the engine didn't start. Next, we removed the rocker cover and found that 2 rockers for cylinders 1 & 4 were broken. They were replaced but, car still would not start, So we did a compression test. Engine had 110 psi in cylinders 1, 2 and 3 and 400psi in 4. So assuming that cyl 4 was OK. We took off the head and replaced the 6 valves in cyls 1,2 and 3. The old valves appeared to be perfectly OK. Got a head kit and put everything back.
Checked compression again and, now we have 40psi in two cylinders, 1 and 4. So next swapped rockers and lifters between cyls1 and 2 and between cyls 3 and 4. But no difference. Still very poor compression in cyls 2 and 3.
So what options are left? Cracked block? We checked that very carefully. it appears to be fine.However, we intend to send it off to be pressure checked.
Broken Piston rings? Highly unlikely. The tops of the pistons were marked but only slightly.
So, has any one here got any ideas? have I missed something?
Instead of DIY....find a mechanic ?Checked compression again and, now we have 40psi in two cylinders, 1 and 4. So next swapped rockers and lifters between cyls1 and 2 and between cyls 3 and 4. But no difference. Still very poor compression in cyls 2 and 3.
So what options are left? Cracked block? We checked that very carefully. it appears to be fine.However, we intend to send it off to be pressure checked.
Broken Piston rings? Highly unlikely. The tops of the pistons were marked but only slightly.
So, has any one here got any ideas? have I missed something?
What sort of crazy person has a cambelt break, then puts another one on and tries to start the engine ? Which will cause even further damage. That is nuts.
And then replaced valves and did not ensure they were all sealing etc before refitting ?
IF & I stress IF what you have done to the valve train is good & has sorted out the issues there then you now need to look elsewhere.
Head itself, block/pistons/rings.
Do a leak down lest & that should help you find where to put your time/money.
When moving engine parts that are deliberately kept apart actually meet it will ALWAYS do major damage to many parts.
So, when I talked about WE, it's me and my (very experienced) mechanic. I have 25 taxis and buses. This is the third time we have had to re-build a head in the last five years and the previous two engines worked fine afterwards. In fact they are both still in use today. Before we changed the old valves we did a leak test. All the valves seemed to be OK. But we went ahead and changed six of them anyway (and, of course, they were ground in and were sealing fine before we replaced the head). After this, we did get our no.1 cylinder one back working. And that's why I wrote to Piston Heads. Why does one cylinder now work, but not the other two. We examined the head carefully and there was no evidence of any cracks. We checked carefully around the injector holes.
So, next on the list is to have the head pressure tested. If that's OK, then it's down to dropping the sump and removing pistons.I would emphasise that the pistons were hardly marked. The tops of the bores and pistons look perfect.
I was hoping that someone here, with even more experience, might suggest something we've missed!
So, next on the list is to have the head pressure tested. If that's OK, then it's down to dropping the sump and removing pistons.I would emphasise that the pistons were hardly marked. The tops of the bores and pistons look perfect.
I was hoping that someone here, with even more experience, might suggest something we've missed!
Edited by taxi13 on Friday 1st May 10:36
Thank you Paintman.
So, a careful check was made of the block, the bores and piston tops.
The head was also checked. It appears unlikely to need a skim. But our next move is have it checked properly and pressure tested. The valves were checked before we changed them and again after we changed them. No difference. They move and seal fine. The guides are OK. The new valves were checked to make sure they were all the same length and exactly the same as the old ones.
As for the rockers (which sit loose, until the cam is bolted down), we've bought a further two (so we have 4 new rockers). They were then interchanged between the working cylinders and the non-working ones. Still no change. 1 & 4 still work OK, 2 & 3 not.
Many of the parts are OEM, but as it happens the head gasket is a genuine Ford part. The head bolting sequence and torquing was carefully done.
What is still puzzling is why we got no.1 cylinder back after changing the valves, but not 2 & 3.
So, a careful check was made of the block, the bores and piston tops.
The head was also checked. It appears unlikely to need a skim. But our next move is have it checked properly and pressure tested. The valves were checked before we changed them and again after we changed them. No difference. They move and seal fine. The guides are OK. The new valves were checked to make sure they were all the same length and exactly the same as the old ones.
As for the rockers (which sit loose, until the cam is bolted down), we've bought a further two (so we have 4 new rockers). They were then interchanged between the working cylinders and the non-working ones. Still no change. 1 & 4 still work OK, 2 & 3 not.
Many of the parts are OEM, but as it happens the head gasket is a genuine Ford part. The head bolting sequence and torquing was carefully done.
What is still puzzling is why we got no.1 cylinder back after changing the valves, but not 2 & 3.
taxi13 said:
So, when I talked about WE, it's me and my (very experienced) mechanic. I have 25 taxis and buses. This is the third time we have had to re-build a head in the last five years and the previous two engines worked fine afterwards. In fact they are both still in use today. Before we changed the old valves we did a leak test. All the valves seemed to be OK. But we went ahead and changed six of them anyway (and, of course, they were ground in and were sealing fine before we replaced the head). After this, we did get our no.1 cylinder one back working. And that's why I wrote to Piston Heads. Why does one cylinder now work, but not the other two. We examined the head carefully and there was no evidence of any cracks. We checked carefully around the injector holes.
So, next on the list is to have the head pressure tested. If that's OK, then it's down to dropping the sump and removing pistons.I would emphasise that the pistons were hardly marked. The tops of the bores and pistons look perfect.
I was hoping that someone here, with even more experience, might suggest something we've missed!
Well you had compression on cyl 4...then after your work you did not.So, next on the list is to have the head pressure tested. If that's OK, then it's down to dropping the sump and removing pistons.I would emphasise that the pistons were hardly marked. The tops of the bores and pistons look perfect.
I was hoping that someone here, with even more experience, might suggest something we've missed!
Edited by taxi13 on Friday 1st May 10:36
So clearly you have caused the problem somewhere.
It's a pretty simple process. Ensure the valves seal after replacing them. Have the head tested if need be. Then the head cannot be the problem.
It should be blatantly obvious if there are any piston concerns from any damage visible on them....which you make no mention of.
After that, maybe hydraulic lifters, and ensuring valve timing is correct. It's not rocket science.
You could do a leakdown test as well as compression, at least that indicate if a cylinder is capable of sealing or not, and/or a smoke test into the cylinder to see where any air escapes the most.
Is that the Peugeot engine, if so Im pretty sure it is like the 1,6 HDI where the cam lobes are pressed onto the shaft and the sudden jolt of a belt breaking and pistons hitting valves can cause the lobes to rotate on the shaft.
If this is the case then valves could be opening and closing at wrong times giving the lack of compression.
If this is the case then valves could be opening and closing at wrong times giving the lack of compression.
stevieturbo said:
taxi13 said:
This is a 2012 Volvo V50, with a Ford D4162T diesel engine. A month ago, the Cam Belt broke. So, we replaced it, Needless to say the engine didn't start. Next, we removed the rocker cover and found that 2 rockers for cylinders 1 & 4 were broken. They were replaced but, car still would not start, So we did a compression test. Engine had 110 psi in cylinders 1, 2 and 3 and 400psi in 4. So assuming that cyl 4 was OK. We took off the head and replaced the 6 valves in cyls 1,2 and 3. The old valves appeared to be perfectly OK. Got a head kit and put everything back.
Checked compression again and, now we have 40psi in two cylinders, 1 and 4. So next swapped rockers and lifters between cyls1 and 2 and between cyls 3 and 4. But no difference. Still very poor compression in cyls 2 and 3.
So what options are left? Cracked block? We checked that very carefully. it appears to be fine.However, we intend to send it off to be pressure checked.
Broken Piston rings? Highly unlikely. The tops of the pistons were marked but only slightly.
So, has any one here got any ideas? have I missed something?
Instead of DIY....find a mechanic ?Checked compression again and, now we have 40psi in two cylinders, 1 and 4. So next swapped rockers and lifters between cyls1 and 2 and between cyls 3 and 4. But no difference. Still very poor compression in cyls 2 and 3.
So what options are left? Cracked block? We checked that very carefully. it appears to be fine.However, we intend to send it off to be pressure checked.
Broken Piston rings? Highly unlikely. The tops of the pistons were marked but only slightly.
So, has any one here got any ideas? have I missed something?
What sort of crazy person has a cambelt break, then puts another one on and tries to start the engine ? Which will cause even further damage. That is nuts.
imagineifyeswill said:
Is that the Peugeot engine, if so Im pretty sure it is like the 1,6 HDI where the cam lobes are pressed onto the shaft and the sudden jolt of a belt breaking and pistons hitting valves can cause the lobes to rotate on the shaft.
If this is the case then valves could be opening and closing at wrong times giving the lack of compression.
So Imagineifyeswill, You hit the nail on the head!!! At first we thought this car had a non-interference engine, as it has the same unit as the Ford Focus 1.6, many of which have non-interference engines. So, we've been to all the trouble of removing the head and changing the valves unnecessarily. If this is the case then valves could be opening and closing at wrong times giving the lack of compression.
Following your advice, we ordered a new camshaft (£80) and compared it to the old one. the cams were miles out!!! The new camshaft worked perfectly.
In this business you're always learning and now, we will know for the future. Many thanks for just giving excellent advice and not not calling us stupid and nuts for any mistakes we may have made. Politeness in these forums goes a long way!
taxi13 said:
imagineifyeswill said:
Is that the Peugeot engine, if so Im pretty sure it is like the 1,6 HDI where the cam lobes are pressed onto the shaft and the sudden jolt of a belt breaking and pistons hitting valves can cause the lobes to rotate on the shaft.
If this is the case then valves could be opening and closing at wrong times giving the lack of compression.
So Imagineifyeswill, You hit the nail on the head!!! At first we thought this car had a non-interference engine, as it has the same unit as the Ford Focus 1.6, many of which have non-interference engines. So, we've been to all the trouble of removing the head and changing the valves unnecessarily. If this is the case then valves could be opening and closing at wrong times giving the lack of compression.
Following your advice, we ordered a new camshaft (£80) and compared it to the old one. the cams were miles out!!! The new camshaft worked perfectly.
In this business you're always learning and now, we will know for the future. Many thanks for just giving excellent advice and not not calling us stupid and nuts for any mistakes we may have made. Politeness in these forums goes a long way!
Really glad it's sorted.
Lot of know it all's on all forums unfortunately.
Didn't know some camshafts are made that way. Every day's a school day 
And thank you for letting us know the result, many don't bother.
ETA Bit of googling and: http://www.jandeengineering.co.uk/camshaftalignmen...
And thank you for letting us know the result, many don't bother.
ETA Bit of googling and: http://www.jandeengineering.co.uk/camshaftalignmen...
Edited by paintman on Wednesday 6th May 20:08
paintman said:
Didn't know some camshafts are made that way. Every day's a school day
And thank you for letting us know the result, many don't bother.
ETA Bit of googling and: http://www.jandeengineering.co.uk/camshaftalignmen...
! Me too for anything smaller than a marine diesel.And thank you for letting us know the result, many don't bother.
ETA Bit of googling and: http://www.jandeengineering.co.uk/camshaftalignmen...
Edited by paintman on Wednesday 6th May 20:08
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