Case through-bolt leakage

[totle]

Just noticed that my 79 930 started to leak oil. After cleaning up oil and then started up again, it Looks like it is leaking from one of the case through-bolt.

How is it possible that it starts to leak from here of a sudden?
Case was split 4 years ago and the O-ring was replaced

[Catorce]

It happens, although that is the largest leak I have ever seen from a case through bolt. This is why you use permatex black on those AS WELL as using an O ring.....

The way i would fix it is remove the shroud, pop the engine air baffle off from the top, then remove the oil return tube by destroying it in the process, replacing it with a collapsible. Then undo the offending bolt and re-oring as well as putting on black permatex.

It's going to be an ugly job, but that is a nasty leak.

[scootergt3]

you can't remove the bolts without taking the cylinders out. also, I know Waynes book says to use permatex, but that's a disaster waiting to happen.

[Catorce]

If he is on the nut side, then he can just remove the nut. That's what I was saying. I have used permatex on my builds for years. No issues.

What disaster might await, pray tell.

[totle]

It's on the bolt head side :-(

I also thought it was a major leak for a o-ring, and it has gotten worse I think.

Have you aver seen any cracks in the block around the bolt ?

Could it be what we are seeing? Hope and pray for only o-ring and not any cracks

[Catorce]

Originally Posted by totle

It's on the bolt head side :-(

I also thought it was a major leak for a o-ring, and it has gotten worse I think.

Have you aver seen any cracks in the block around the bolt ?

Could it be what we are seeing? Hope and pray for only o-ring and not any cracks

The only time I have seen a crack in that spot is when a rod directly impacted the inside of the case: i.e: total engine failure. I have a case like that, and it's not pretty - you would know if it was that because your motor wouldn't run....

Ok, it's on the bolt head side. Loosen the nut on the other side, pound out the bolt a half inch, inspect the O ring. If you get lucky it's intact, and you permatex the bolt head and push it back in and call it a day.

If the o ring is chewed up or missing, you need to decide whether this is something you want to pull the motor to fix, because there is no easy way to do so without removing the cylinders. At least you won't have to split the case.

Sucks, I know.

If it were me, I would try sealants first. Not the most correct method, but hey...

[totle]

I will try to pull the bolt out a bit and use sealant

Temporary fix for this season in Norway. Plan is to do a complete engine rebuild during winter

[WERK I]

Have you ruled out the cylinder base gasket?

[Lapkritis]

What method did you use during the last rebuild for the o-rings? There are some recommended assembly greases that cause the o-rings to lose strength over time... And instructions that don't include beveling the case when using the o-rimg weakening grease.

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[totle]

I have been examining a bit more.
Looks like it is coming from the base gasket.
I re-torqued the arp cylinder bolts, but still leaks

I will now remove the engine and take left bank apart to track down leakag and replace base gasket

This is the temp fix until I do a complete tear down next winter

I hate oil leaks

[Henry Schmidt]

Originally Posted by Lapkritis

What method did you use during the last rebuild for the o-rings? There are some recommended assembly greases that cause the o-rings to lose strength over time... And instructions that don't include beveling the case when using the o-rimg weakening grease.

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What a tool....

You've been slapped over and over about your claims of "o-ring failure do to o-ring lubricant" without a single example to prove your noise and still you repeat it.....

truly sad.....just another example of your attempt to be relevant.

[Henry Schmidt]

Originally Posted by totle

I have been examining a bit more.
Looks like it is coming from the base gasket.
I re-torqued the arp cylinder bolts, but still leaks

I will now remove the engine and take left bank apart to track down leakag and replace base gasket

This is the temp fix until I do a complete tear down next winter

I hate oil leaks

Of course more information would be helpful but from what you say (leaking at the cylinder base) and what I can see, it looks like the cylinders are an aftermarket billet product. It is possible that the quality of cylinder might be an issue.

[Lapkritis]

If the cylinder base was leaking then there should be oil at the lowest point of the circle from gravity. Cylinder bottom looks dry and that's a lot of oil...

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[DRACO A5OG]

OP, if on the bolt side, do yo know if the holes were chamfered? Factory o-rings were a bit smaller in diameter unfortunately those are NLA.

[WERK I]

totle,
Do you have any build information on that engine. Like Henry said, those cylinders look aftermarket. They're not LN's or Mahle's, that's for sure. Were the engine case bores enlarged for cylinders? Do you know if displacement of engine was increased? Those cylinder base gaskets look thicker than any .25 or .50 mm base gaskets.
Also, have you removed the lower valve cover to see if any head studs are broken or head stud nuts loose for that cylinder?

[totle]

I took the cylinders apart anf found a faulty base gasket.
Cylinder are JBR steel cylinders. JE Pistons. Bare gasket is 1mm copper gaskets. ( to get correct CR)

I was running hot when my fan belt tore off during a track event last autumn. I had some laps before I noticed.
Cylinders and pistons are fine, No harm there.
Base gasket on cyl #1 had slipped out a bit and was the cause of the leakage.
Replaced all base gaskets on cyl #1-3 since that side was off.

Engine is now back in the car. Some wired left to connect before startup again :-)

[Catorce]

Excellent! Way better than a through bolt leak!!!!

[JFairman]

Put a thin smear of Green Curil T or Blue Hylomar on the base gasket and mating surfaces before installing and it shouldn't leak oil.
Those two sealants never dry so when tightening the head studs a little sealant may squeeze out and then you can clean that off easily with wash Lacquer thinner, Toluene, or Acetone on a rag.

Then you know there's enough sealant in there to hopefully make a lasting seal after the motor goes through heat cycles and cools off again and again down the road.
Best to use new copper base gaskets since they get squished a little and they're not expensive.

[DRACO A5OG]

WooHoo

[totle]

Engine started up and no oil leaks :-)