VP MD202B - No compression
- Thread starter Jokani
- Start date
Jcorstorphine
Well-known member
Ignore thought about camshaft gear slipping as that has a key. Not clear how crankshaft gear is secured so back to the manual.
VicS
Well-known member
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Jcorstorphine
Well-known member
So timing gears cannot slip, camshaft and fuel pump timing is correct relative to crankshaft. Even if OP had turned crankshaft through 360, he would be back in same place. If he turned it 180 then timing marks would not line up. If OP had taken off intermediate gear and replaced it 360, would make no difference, Same with camshaft gear, if it was turned 360 then it would still be correct relative to crankshaft.
Going on. If (despite all of the above logic) he had got timing wrong then as this engine has no clearance for valves, he could have smashed a piston into an open valve.
The fact that he could not feel compression on the engine but after a bit of cranking, one of the cylinders was indicating that he now had compression is odd to say the least. Other point is that the engine would not kick over on EasyStart, I would have thought it would have given a cough or something.
To quote famous piece of literature "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."
In the case of the OP posting and the suggestions made it looks as if we have ruled out the impossible e.g. Gear slipping, timings etc then we are left with the improbable so what are we left with.
Valves sticking but has made a dent in piston. Is it possible that this design of engine due to being 120 degree TDC to TDC can rotate with the valves not closing completely due to rust, bent or other trauma.
If the OP cannot find a way forward and there is no compression, then my feeling is to remove rocker box cover and observe valves. Are they closing, do they all move the same. Is there any sign of sticking.
Next would be to take the head off and cross his fingers.
Going on. If (despite all of the above logic) he had got timing wrong then as this engine has no clearance for valves, he could have smashed a piston into an open valve.
The fact that he could not feel compression on the engine but after a bit of cranking, one of the cylinders was indicating that he now had compression is odd to say the least. Other point is that the engine would not kick over on EasyStart, I would have thought it would have given a cough or something.
To quote famous piece of literature "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."
In the case of the OP posting and the suggestions made it looks as if we have ruled out the impossible e.g. Gear slipping, timings etc then we are left with the improbable so what are we left with.
Valves sticking but has made a dent in piston. Is it possible that this design of engine due to being 120 degree TDC to TDC can rotate with the valves not closing completely due to rust, bent or other trauma.
If the OP cannot find a way forward and there is no compression, then my feeling is to remove rocker box cover and observe valves. Are they closing, do they all move the same. Is there any sign of sticking.
Next would be to take the head off and cross his fingers.
Jokani
Active member
Many thanks to all those trying to help me, it is very much appreciated!
I will try and add some further information/clarity, to some of the points raised.
It is a semi-reconditioned engine, specific work detailed on the included cylinders honed, valves relapped etc, but I do not think the rings were replaced. Since fitting it has only been run for 30 mins. The main components should be OK, or at least were.
The valve cover has been removed, the timing looks to be as expected, tappet clearances appear to be correct at 0.20mm
I guess it is possible that the head gasket has blown. But if it has it must have gone in more than one place if, as it appears to now have compression on the mid cylinder No 2.
There are no bubbles in the heat exchanger fluid.
Yep, I had the timing marks verified by someone else.
In the manual it does show a mark on the pulley denoting TDC, mine doesn't have one. This could be due to the fact that I broke the oringinal pulley (see post) and fitted a new one. On closer examination the new pulley doea have a raised circle where I would expect TDC to be, not on the face of the pulley but on the outer rim. This could confirm that the timing is at least roughly correct, or it could just be an imperfection in the pulley and a pure coincidence, it is hard to be sure, and I'm starting to realise that with engines at least it is best not to take everything at face value!
Although not 100% it does look to me as though the timing is correct, at least to the point where it should fire.
The camshaft was not removed, I was intending to remove it, but once I realised that would mean removing the head as well I didn't proceed.
Thanks for all your advice JC, it looks like, taking the head off could be the next step.
Once again thanks everyone for for all the advice, I think it is decision time!
I have missed a whole season of sailing installing this engine and trying to cure subsequent problems. This has mostly been caused by me wanting to fix evertyhing myself, I have learnt a lot, but I think it's time to admit defeat, plus and I am determined not to miss another sailing season next year, and unless I change tactics I could stioll be messing with thei in 12 months.
So, although I spent a lot of time installing new engine, the majority of the time was taken in installing new engine bearers, mounts, diesel tank, control panel etc. I think I could have the engine out and in the back of a van in 4-6 hours, and once fixed, back installed in Gemini in a similar time - This looks like the best way forward to me, it is the only one that guarantees some sailing next year. In the meantime i can get with other jobs.
Now looking for a marine engine, I'll create a seperate post for that.
Thanks again, and once the cause of the problem is known, I will post the details.
I will try and add some further information/clarity, to some of the points raised.
It is a semi-reconditioned engine, specific work detailed on the included cylinders honed, valves relapped etc, but I do not think the rings were replaced. Since fitting it has only been run for 30 mins. The main components should be OK, or at least were.
The valve cover has been removed, the timing looks to be as expected, tappet clearances appear to be correct at 0.20mm
I guess it is possible that the head gasket has blown. But if it has it must have gone in more than one place if, as it appears to now have compression on the mid cylinder No 2.
There are no bubbles in the heat exchanger fluid.
Yep, I had the timing marks verified by someone else.
In the manual it does show a mark on the pulley denoting TDC, mine doesn't have one. This could be due to the fact that I broke the oringinal pulley (see post) and fitted a new one. On closer examination the new pulley doea have a raised circle where I would expect TDC to be, not on the face of the pulley but on the outer rim. This could confirm that the timing is at least roughly correct, or it could just be an imperfection in the pulley and a pure coincidence, it is hard to be sure, and I'm starting to realise that with engines at least it is best not to take everything at face value!
Although not 100% it does look to me as though the timing is correct, at least to the point where it should fire.
The camshaft was not removed, I was intending to remove it, but once I realised that would mean removing the head as well I didn't proceed.
Thanks for all your advice JC, it looks like, taking the head off could be the next step.
Once again thanks everyone for for all the advice, I think it is decision time!
I have missed a whole season of sailing installing this engine and trying to cure subsequent problems. This has mostly been caused by me wanting to fix evertyhing myself, I have learnt a lot, but I think it's time to admit defeat, plus and I am determined not to miss another sailing season next year, and unless I change tactics I could stioll be messing with thei in 12 months.
So, although I spent a lot of time installing new engine, the majority of the time was taken in installing new engine bearers, mounts, diesel tank, control panel etc. I think I could have the engine out and in the back of a van in 4-6 hours, and once fixed, back installed in Gemini in a similar time - This looks like the best way forward to me, it is the only one that guarantees some sailing next year. In the meantime i can get with other jobs.
Now looking for a marine engine, I'll create a seperate post for that.
Thanks again, and once the cause of the problem is known, I will post the details.
Heckler
Active member
Where are you? Would be more than happy to help you strip it and give a definitive answer.
Stu
Jokani
Active member
Hi Stu, I will send you a PM
Heckler
Active member
Hiya Gary
ref our chat, the inlet is no 44, if you have fumes in the cabin, see if they are coming out of the inlet, if so it means bent valves as discussed.
View attachment 61337
Jokani
Active member
Thanks again Stu for taking the time to talk this through. I'll check this out later in the week and report back.
In the mean time, I'll start the search for a mechanic I can take the engine to, should the local idea not come off.
anoccasionalyachtsman
Well-known member
I hate to bang on about the timing, but it appears that the crankshaft mark is suspect. If the camshaft is running 'retarded' by some amount there would not necessarily be valve impacts, but there could be partial compressions.
My next question to the op was going to be whether anything was coming out of the inlet, and skipper_stu seems to think that there may be. Stu favours bent valves - which almost certainly mean cam timing because the valves and their clearances haven't been touched.
So that's two of us that suspect the timing, but I don't think that it means bent valves - and even if the valves have touched, it wasn't running, and there probably won't be any damage other than maybe a bent pushrod.
My next question to the op was going to be whether anything was coming out of the inlet, and skipper_stu seems to think that there may be. Stu favours bent valves - which almost certainly mean cam timing because the valves and their clearances haven't been touched.
So that's two of us that suspect the timing, but I don't think that it means bent valves - and even if the valves have touched, it wasn't running, and there probably won't be any damage other than maybe a bent pushrod.
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olam
Member
Have just picked this thread.
I think the valves lifters are buckets which need to fill with oil if they have been emptied.
This would explain why there is now some compression on no 3 .
you would have to keep spinning the engine(closed sea cock) until the other buckets have taken up the slack too.
We used to have to tow cars down the road in the old days until they regained compression.
If all else looks ok just keep spinning over.
I think the valves lifters are buckets which need to fill with oil if they have been emptied.
This would explain why there is now some compression on no 3 .
you would have to keep spinning the engine(closed sea cock) until the other buckets have taken up the slack too.
We used to have to tow cars down the road in the old days until they regained compression.
If all else looks ok just keep spinning over.
Jokani
Active member
You may be on so something there!
The previous problem was curing an oil leak, so there may be slightly less oil in that there should be, I would not have thought by much, but maybe enough that is having difficulty getting to the lifters.
I was having difficulty understanding why no compression at all, then having some compression of 3, as it seemd strange that it could fix itself, what you say could be the answer,
Skipper Stu touched on this during a call earlier, and said the problem could be something very basic that I had overlooked., this could be it. If it is I will have to hang my head in shame.
Heckler
Active member
These buckets dont have this sort of system with oil in them. The idea of hydraulic lifters (buckets) is that you dont have to keep adjusting tappets. These engines have adjustable tappets.
Stu
anoccasionalyachtsman
Well-known member
I see no buckets.
VicS
Well-known member
#43 in your diagram.
Called "tappets " in the parts lists but AKA as "cam followers"
Some people might call the adjusting screws and locknuts (# 20 and 21 ) the tappets
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anoccasionalyachtsman
Well-known member
Agreed. Not buckets then.
No oil actuation either. If they were hydraulic tappets, which is what I think olam meant, a lack of oil would reduce valve opening and that isn't a problem here.
VicS
Well-known member
Gary
Have you taken the rocker cover off and checked to see of all the valves operate as they should. It'll take 2 full turns of the crankshaft to run through the full sequence of each valve opening and closing once
If the bent valve theory is correct then you should be able to see that some of the valves are sticking down and not closing properly.
If any are bent the rather academic question then is how ?
Got a theory but probably rubbish so wont go into it just yet.
Have you taken the rocker cover off and checked to see of all the valves operate as they should. It'll take 2 full turns of the crankshaft to run through the full sequence of each valve opening and closing once
If the bent valve theory is correct then you should be able to see that some of the valves are sticking down and not closing properly.
If any are bent the rather academic question then is how ?
Got a theory but probably rubbish so wont go into it just yet.
Heckler
Active member
Here is a link for reasonably priced gaskets. http://www.parts4engines.com/perkins100-series-perama-m25-m30-m35/
RichardS
N/A
+1 to all that.
"Bucket" is not a term that is usually applied to hydraulic valve lifters and neither does Gary's engine look like a bucket and shim adjustment to me.
Richard
Jokani
Active member
I did get quite excited about this, and took this morning off work, to travel to the boat and check that there was sufficient oil in the engine. It was slightly down, consistent with the earlier oil leak. Topped of, cranked lot's of times, compression issues are still there. Damn!
The rocker cover has been removed, timing on all cylinders appears to be correct. The Yard Manager although not an engineer, has far more knowlege and experience than me, thinks every is working as it should, and tappets having the correct clearance. Itw as by watching the valves opening and closing that we established that cyliner 2 had at least some compression.
Although I have not 100% confidentlyidentified TDC for cyl1, by watching the valve timings, and with a thumb over the injection hole feeling for compression, the valve and fuel injection timing appear to be correct, for that cyl at least seems to be correct.
Ont thing that I observed that may not be correct, both the oil dipstick and the air intake, appear to have some gas/smoke coming out of them when the engine is cranked over.
Looks like I am back a square one :-(
The yard are now going to engage a local diesel engineering company to take a look, which hopefully will initially take place on the boat.
I will update the post as soon as I have some news.
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