Head Gasket or Exhaust Studs Leaking Oil?

[RXTbone]

Looking for a few other opinions before I start down a path... The engine is from a 1980 Spider. I bought it with the understanding that it hadn't ran in 10 years, but turned over and had compression. I've converted from FI to a carb. Engine started up and ran almost immediately. The more the car ran - it began to develop oil leaks on the exhaust side. Though I've never seen a car leak oil from a head gasket - that's what I thought it was doing at first. After some research, I found that these cars can leak oil from the exhaust studs. I pulled the exhaust - pics below.

The more I look at the evidence, based on the oil pattern on the block and gasket (especially the way the gasket has oil soak up over the front port) - I'm inclined to believe the studs may actually be the culprit. Do you agree?

If so, do I just put some RTV on the studs and re-seat them? Is it the stud collar that seals the hole or do the threads alone?

Thank you in advance for any help!

[18Fiatsandcounting]

I agree that there's a good chance that the oil is weeping past the stud threads, but it can be hard to tell as leaked oil tends to "creep" rather than just flow straight down.

Here are the most common sources of leaks on the exhaust side (#1 being most common):

1) Top two studs on the exhaust manifold. These go directly into the pool of oil below the camshaft, so oil can seep past the threads. The lower studs (the other three) go into blind holes so not much behind them to leak.

2) Distributor o-ring, or round its gasket, or the distributor in general leaks (due to bad oil seal in the bottom).

3) Leaking rear cambox cover, the one with the three studs/nuts.

4) Leaking head gasket. Doesn't happen very often, but it can.

-Bryan

[RXTbone]

Bryan,

Your points are quite a bit of help! Based on oil flow, the top two studs on the exhaust don't appear to be an issue - it's the lower three. This causes me to lean toward head gasket.

Thank you for the insight!

[18Fiatsandcounting]

I think you might be right. I looked at the pictures again, and the oil does seem to be appearing on the upper block in 3 places, and those places correspond to the three high pressure oil lines that feed the camshaft.

-Bryan

[RXTbone]

Thank you - that was another question... understanding the design of the head. I questioned the location of the oil jackets. This little project is the gift that keeps on giving!

[RXTbone]

Follow up: So I ordered a head gasket and distributor seal from one of the main Fiat dealers. I received a call from them regarding an order issue - and we started to talk about the head. According to the advisor, they've never heard of a head gasket leaking oil - he was pretty adamant about it. He said the two upper exhaust studs will leak. I told him there was no evidence of a leak on the gasket - he said that the studs will often leak internally. Without thoroughly understanding the casting design of the cambox and head - regardless of if oil can find it's way back into some crevice in the head - it still shouldn't leak beyond the head gasket? In a nutshell - the exhaust stud leak these cars experience are external.

He said the areas I describe as leaking (below the three lower studs) will take on extra oil due to it behind a high-flow area - which in my opinion should also be blocked by a good head gasket.

We also discussed the oil I was using - which was 10W-30 and he said that it was 'water' in these engines. He also said to check the crankcase vent - so the ideas was internal pressure and thin oil. This was actually the only thing that made some sense to me - maybe there is too much internal pressure. If so, I still need to replace a head gasket.

Thank you in advance!

[18Fiatsandcounting]

Well, T-bone, let's just say that I don't fully agree with a lot of what you were told. I'd be happy to discuss over the phone, so send me a PM if you're interested. It would likely be quicker than going back and forth on the forum.

One suggestion that I forgot to mention earlier: Recheck the torque on your 10 head bolts. Using the same sequence as shown in the various manuals, loosen one bolt at a time. Not all the way loose, just crack it, so maybe a quarter turn at most. Then in one smooth motion, retorque to 61 ft lbs and then proceed to the next bolt in the sequence. As you're loosening each bolt, see if any seem unusually loose.

-Bryan

[RXTbone]

Bryan - thanks! May take you up on offer. Your disagreement aligns with mine - plus a dude has to trust his own 40+ years experience working on cars. I already have the exhaust off - I'm just going to keep going. Thanks again for the help!

[18Fiatsandcounting]

Sure thing! By the way, 10W-30 in your engine? Not good for Tucson Arizona in August, but for Kansas in the Fall/Winter, it's totally appropriate for an engine in reasonable condition. Engines with a lot of bearing clearance require somewhat thicker oils (straight 40 weight or 20W-50), but that's just a bandaid for an engine that needs a rebuild.

-Bryan

[RXTbone]

Because I always like to know how things ended if I happen to pull up and start reading a thread... After pulling off the head, I discovered a damaged gasket. At least the garage isn't freezing yet. Thanks again for the input!

[Ics19]

Because I always like to know how things ended if I happen...

Many thanks for the update - It seems I've got the same issue with my "new to me" 2000 While a leaking cam housing base gasket or studs were likely, having cleaned off the oil and re-checked, it's a definite leak from the rear and centre of the head gasket.

Has your new head gasket got a beading run all the way around the outer edge and around the 6 oil holes? The one I've now got ready to fit, has this on both sides - it looks like a red 1/8" bead of RTV. I can't see this on your old gasket, perhaps it's a just a modern thing, but I guess the copper crush rings should really be sufficient on a good day

[RXTbone]

New one has the red bead. Old one, which I believe to be the original, did not (to the best that I can discern). I redid the head on my Ranger last year and the gasket for that one also had the bead. I agree that it's probably modern design and tech...

Good luck on your project!

[18Fiatsandcounting]

T-Bone, thanks for those additional pictures. It does look like you were getting oil leakage past the three oil lines on the exhaust side. You probably know this, but check the block and head for any warping. Is the plan to get the head resurfaced? I'd recommend this with a new head gasket, and heck, by that time you might as well go ahead and get a valve job done. Pay close attention to head bolt torquing sequence as well.

A couple other things. The piston crowns look pretty sooty and oily, which tells me the engine was running rich and/or burning a bit of oil. The cylinder walls look quite shiny, but you might want to see if you can see any evidence of the original crosshatch (a fine diagonal scoring on the cylinder walls, which is beneficial up to a point). If there is no crosshatch, the engine may have been rebuilt at some point and the rings didn't properly seat. Also check to see if there is a ridge up at the top of the bore that you can catch your fingernail on. The color difference that you see in the pictures is fine, but any ridge at the top that catches your fingernail means that the bores have some wear.

Also, that clean area on the piston crown near the intake valve cutout does mean something, but I forget exactly what. I think it has to do with too much fuel coming in through the intake (running too rich).

Post a picture of the bottom of the cylinder head with the valves, if you have a chance.

-Bryan