Cold Compression Test

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Llew

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65
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Gosport
I have just done a compression test on a 2.25 diesel but had to do it cold as the engine just wont start, when I did have it running a while ago there was vast amounts of smoke, so much that I couldnt stay in garage. My results are.

No.1 28.5 bar
No.2 29 bar
NO.3 28.5 bar
No.4 29.5 bar

Does anyone know if the results are acceptable for a cold engine. I know that the figures fall short of the values in the manual but that is for a hot engine.

Cheers Lew
 
Llew said:
I have just done a compression test on a 2.25 diesel but had to do it cold as the engine just wont start, when I did have it running a while ago there was vast amounts of smoke, so much that I couldnt stay in garage. My results are.

No.1 28.5 bar
No.2 29 bar
NO.3 28.5 bar
No.4 29.5 bar

Does anyone know if the results are acceptable for a cold engine. I know that the figures fall short of the values in the manual but that is for a hot engine.

Cheers Lew
Click to expand...

a reckon the needles stuck on yer tester !
 
Llew said:
I have just done a compression test on a 2.25 diesel but had to do it cold as the engine just wont start, when I did have it running a while ago there was vast amounts of smoke, so much that I couldnt stay in garage. My results are.

No.1 28.5 bar
No.2 29 bar
NO.3 28.5 bar
No.4 29.5 bar

Does anyone know if the results are acceptable for a cold engine. I know that the figures fall short of the values in the manual but that is for a hot engine.

Cheers Lew
Click to expand...

Stick some oil down each cylinder, leave for a while give it a quick spin then do them again. That tests piston/ring wear.
 
Llew said:
I have just done a compression test on a 2.25 diesel but had to do it cold as the engine just wont start, when I did have it running a while ago there was vast amounts of smoke, so much that I couldnt stay in garage. My results are.

No.1 28.5 bar
No.2 29 bar
NO.3 28.5 bar
No.4 29.5 bar

Does anyone know if the results are acceptable for a cold engine. I know that the figures fall short of the values in the manual but that is for a hot engine.

Cheers Lew
Click to expand...

These are very good figures, and suggest that the injection pump isn't doing the job, or the timing is way off.

Unless the GLOW PLUGS are working well these engine may not start from cold. The glowplugs are probably wired in SERIES, so if one goes duff, they all stop working. Make SURE all the plugs are good.

CharlesY
 
Glow Plugs are wired in series but havent checked them yet, i suspect though that one or more arent working. I will start checkiing timing again, last time I checked everything was all lined up in the pump when the small inspection cover was off. I have had the timing chain cover off a while ago and had a look in there but everything seemed alright and the was no excessive slack in the chain and tensioner was working. I will get it running and try advancing/retarding injection pump again.

llew
Cheers for all the help
 
Llew said:
Glow Plugs are wired in series but havent checked them yet, i suspect though that one or more arent working. I will start checkiing timing again, last time I checked everything was all lined up in the pump when the small inspection cover was off. I have had the timing chain cover off a while ago and had a look in there but everything seemed alright and the was no excessive slack in the chain and tensioner was working. I will get it running and try advancing/retarding injection pump again.

llew
Cheers for all the help
Click to expand...

Before you do much else, while the engine is cold, VERY CAREFULLY set all the valve clearances to 0.008" EIGHT thou, 0.2mm.

This is a tiny bit under spec but is good for diagnosis.

If you can arrange it, get the injector spring pressures checked.
Get them set to exactly 125 BAR opening pressure, and if you trust the guy get the injectors opened up and cleaned inside to make SURE the needle in each on is free to move.

Only after you do these things is there much point in trying the timing.

CharlesY
 
I have sent the injectors to be tested, should get them back tomorrow. Checked the glow plugs, number 4 has a dead short on it the others are working, so should explain why struggled to start, also the ballast resistor doesnt seem to be working properly. I am not getting a voltage drop across it. I think the insulation to the bracket may have gone and was shorting through there.

Thanks for all the help
 
sent injectors to diesel tester, one of the nozzles was knackered and spill fuel into engine constantly, just hope that oil wasnt too diluted by this , and one of the others had been set too high, so hopefully when I get them back it will solve some of the smoke problems.

THanks for the offer to test injectors though
Lew
 
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