Unusual Oil Leak After Rebuild, One For The Engine Builders

[vern 0]

After my troubles with the cambelt, I have got the engine running, but it has a persistant oil leak from the cambelt end, it continualy drips if the head bolts are torqued to standard settings, if the bolts are torqued to within an inch of there life, it steadies down to a drip every couple of seconds. The head was checked after I bent all the valves and the block had a slight haircut to get the liner protrousions correct.

Investigations on where the leak is coming from has concluded that it is leaking from the head gasket area, as dry above and wet below the head gasket, this concurs with tightening head bolts reduces leak rate. Unable to confirm exact location as area is hidden by the cam belt cover backplate.

I have upgraded the oil pump with the 7 bar spring and the smaller/larger cog, would this increase in pressure and flow, cause problems with the Cometic head gasket?? forcing oil betwwen the layers, I used a Spesso gasket before the engine rebuild would it be better to use a traditional style head gasket.

Any help would be appreciated as I want to torch the bloody thing

[tony perks 1]

After my troubles with the cambelt, I have got the engine running, but it has a persistant oil leak from the cambelt end, it continualy drips if the head bolts are torqued to standard settings, if the bolts are torqued to within an inch of there life, it steadies down to a drip every couple of seconds. The head was checked after I bent all the valves and the block had a slight haircut to get the liner protrousions correct.

Investigations on where the leak is coming from has concluded that it is leaking from the head gasket area, as dry above and wet below the head gasket, this concurs with tightening head bolts reduces leak rate. Unable to confirm exact location as area is hidden by the cam belt cover backplate.

I have upgraded the oil pump with the 7 bar spring and the smaller/larger cog, would this increase in pressure and flow, cause problems with the Cometic head gasket?? forcing oil betwwen the layers, I used a Spesso gasket before the engine rebuild would it be better to use a traditional style head gasket.

Any help would be appreciated as I want to torch the bloody thing

I had the same thing it turned out to be oil just squeezing past the cam cam on the front, it looked like the head gasket area, so a tiny smear of hylomar on the front edge of the cap and all was well.

 

What kind of finish did the machine shop get on the block surface!, as steel shim gaskets like a ground not milled surface to sit on so you "May" get a leak path down one of the machining marks and isnt the oil feed for the head at the cam wheel end? I too had a 7 bar spring and 26 tooth wheel on my engine but was getting far too much pressure 70psi all the time when hot and nerly 100 cold, so out came the spring and back in with a std one. Now I get 70 cold and 50 when red hot after a stage.

[vern 0]

When you say the cam do you mean the cam seal, as it was dry around that seal, was one of the first things I checked.

You are correct about the oil feed being that end of the block, hence my concern over the increased oil pressure, that could be forcing oil through the gasket. As for the machining, the block was milled as far as am aware, will check on Monday, that was one of my conerns about oil tracking through a milling mark, do you think removing the head gasket and using Hylamar style sealant, or would getting a standard style gasket be better.

[smithy 1]

i think he means the oil is coming out between camshaft cap and cylinder head not through the seal.

 

if it is tracking a milling line i would not use hylomar on a head gasket i would use a standard type gasket instead.

[vern 0]

Update on this, removed head and where the head gasket had left witness marks from the PTFE coating, you could see shiney silver lines from the milling clearly visble. So the oil must have been tracking down the milling marks. Have put a standard head gasket on and all oil leaks cured.

So moral to the story is if using a Cometic head gasket make sure the head and block are surface ground.