Loss of compression

[Remdogg]

Hoping someone can help me. The other day my engine started to miss a bit. I got it home and did a compression test. Cylinders 3 and 4 were low on compression so I put a bit of oil in the cylinder and it read really good compression so I'm guessing its ring/piston wear not valves.

Can anyone tell me what is the most straight forward conversion would be to fit a Turbo Diesel, 5 speed and diffs. If I'm going to spend money on it I may as well do something that will get better mileage.

[Remdogg]

Just thinking. My car never blew any smoke at all and still doesn't so wouldn't that say my ring aren't worn?. Could it be a head gasket. There is no water in the oil or the other way around but could it be leaking from cylinder to cylinder since it is just cyl 3 and 4?

I might just be clutching at straws.

Very sad I was meant to be going away in a couple of days but at least it didn't happen while I was away.

[G60michael]

Remmdog, My 1966 and 78 G60 seen to have very Good Compression,Pus they were sitting for about 3 years Before I Got them. I say it is possible the head gasket is Ruined between Cylinders 3 and 4 and when ever comes onto compression stroke it is being pushed into the adjacent Cylinder and leaking ,hence low on compression.

Keep The original Motor, it getting hard to find original G60 these day most are starting to have V8 and other engines Fitted

[Remdogg]

Cheers for the reply. Fingers crossed its the head gasket. It just doesn't make sense to me that it doesn't blow smoke so the rings should be good so its making me think head gasket.

[RiverPatrol]

In extreme cases it could even be something as simple as readjusting the valves. If the valve adjustment is off it is possible that one of the valves is slightly open on the compression stroke.

I would just be surprised if it were the rings. I have rebuilt one of these engines that had 97,000 miles on it. The rings, pistons and cylinder walls were all still within factory specs. I replaced the rings (which were cast iron) with standard size, not over size. With normal use these engine just don't wear out the rings very fast.

Good luck.

[Remdogg]

Well got the head off today. There wasn't anything obvious but the gasket was a fairly new looking ACL monotorque but the was some discolouration between the cylinders. The head bolt were fairly easy to undo, a lot easier than any head I have taken off before so I'm hoping the owner before might have done a shit job . The bores aren't scratched up and the lip on the bore is minimal so fingers crossed it will be the easy fix. I just have to wait 2 days for a head gasket to come in. Painful wait especially with the wifie on my back.

On the bright side my winch turned up today, excited!

[miksum56]

Well got the head off today. There wasn't anything obvious but the gasket was a fairly new looking ACL monotorque but the was some discolouration between the cylinders. The head bolt were fairly easy to undo, a lot easier than any head I have taken off before so I'm hoping the owner before might have done a shit job . The bores aren't scratched up and the lip on the bore is minimal so fingers crossed it will be the easy fix. I just have to wait 2 days for a head gasket to come in. Painful wait especially with the wifie on my back.

On the bright side my winch turned up today, excited!

Check head surface for flatness with edge of something like a steel rule. A head shop will do this if you don't like the look of your valves and decide to do a valve job. To save a few bucks you could rent a valve spring compresser and check at least the middle exhaust valves yourself. (One head I've pulled had a burnt ex. valve that you could see, it was not round anymore but ovaled).
Make sure you follow proper head bolt tightening sequence. Use a good click style torque wrench and don't forget to retorque after a tank of gas or 2. My 2 cents

[Remdogg]

Yeh I'm taking it to a head shop today to check it as I don't have anything that is true to check it.

Do you recommend a re torque on and monotorque head gasket, I was thinking of doing it just because the head bolts didn't seem tight enough on removal. I know another important thing is to lubricate head bolts thread and bolt head to get then right pressure.

Thanks for ya 2 cents.

[miksum56]

Yeh I'm taking it to a head shop today to check it as I don't have anything that is true to check it.

Do you recommend a re torque on and mono head gaskettorque, I was thinking of doing it just because the head bolts didn't seem tight enough on removal. I know another important thing is to lubricate head bolts thread and bolt head to get then right pressure.

Thanks for ya 2 cents.

No problem and your welcome. I don't quite understand your question...Do you recommend a re torque on and mono head gaskettorque????

[Remdogg]

Well monotorque head gasket is meant to only need to be tensioned once but the one that was on there was a monotorque gasket but the bolts didn't seem to be tight enough so either a re torque is needed or they never did the bolts up correctly.