Cam Housing Oil Leak

[PittsburghKevin]

The cam housing on the passenger side is leaking. It is currently very minor, not losing much. Not filling up the spark plug holes.

Little oil on the backside as well.


I had planned to replace the gaskets and have them at my side. But, now I am debating whether it is leaking badly enough to do anything. (Cowardice setting in.)

I have pretty mediocre mechanical skills, but good attention to detail. Last night, I consulted the "elder statesman" who thought they should be replaced and that timing was a tough job. Torquing it properly would be a problem, ensuring a good seal would be a problem.

So I wandered around the forum but don't have a good feel for whether:
a) How much I should expect these to leak and whether I will be mucking more up by replacing them. (I don't think anything should leak ever, but that is me.)
b) How hard it would be to get the timing right again and everything back together.

I know others have asked questions in this vein -- if I missed an important thread please tell me!

[engineerted]

I would wait untill your next timing belt change. Timing the engine is not that difficult if you have all in the correct info. I find the most difficult is geting the old gasket material off the cam boxes.

Ted

[PittsburghKevin]

Ted,
Hmm. I had it figured backwards then. I was thinking this was a good opportunity to replace the timing belt since I don't know its heritage. The PO had the car 17 years and I have all his bills and there was no mention of replacing the timing belt. I had figured it ought to get done.

[bwilson27]

It doesn't look too bad.

[So Cal Mark]

the leak doesn't look too bad as mentioned, but if you don't know how old the belt is it should be replaced. I'd suggest replacing the front seals at that time. You might find the cam seals leaking and allowing the oil to blow back around the cam housing

[manoa matt]

The original Fiat cam box to head gaskets are notorious for weeping oil. Later they changed the design of the cam box to head gaskets to include a preformed silicone bead around the gasket surface like modern gaskets. I don't think any of the usual vendors carry them, but I know Guy Croft does.

If you are replacing those gaskets you will also need to adjust the valves after its back together and the gaskets have settled.

[PittsburghKevin]

Matt, out of curiosity, when did they change the design, any idea of the year?

From what Mark said, it looks like I'll be doing some work when the car gets back from the welder.

Thanks for the feedback!

[lordxenu]

I've got the same leak going on, on the passenger side cam box. It's not very bad, the most you can see is a wet spot on the block, it's not pooling up anywhere or anything.

I've actually went ahead and bought all the belts, and head gasket set...I guess you have to replace all that stuff when you take the cam boxes off?

I'm assuming you have to completely dismantle the valvetrain? Or will the camboxes come right off leaving the valvetrain in tact until you put the cams back on?

[manoa matt]

The newer type gaskets were on 80's and 90's Fiat models that only sold in Europe, hence why they are so hard to obtain in the states.

It's generally not the practice to apply RTV silicone to the cam box to head gaskets for several reasons. Extra silicone will squish out while torquing down the cam box. It could clog up the oil passages to the bearings. The extra thickness from the silicone will alter the valve clearances, but these will need to be adjusted anyway after replacing the gasket.

On the other hand I have heard of guys using two gaskets, or no gasket and only RTV. However these were to compensate for valve work or to get a specific valve clearance and not to stop oil leaks.

You do not have to completely dissassemble the valve train. Just remove the bolts or nuts that hold the cam boxes on. Be carefull as you remove the cam box from the head as the cam buckets will want to drop out the bottom of the cam box.

[PittsburghKevin]

I am going to tackle it this weekend. Plenty of new things to learn. I'll post how successful I am.

[So Cal Mark]

couple of tips; get a 99 c turkey baster to suck the oil out of the cam boxes before you remove them. Once the bolts are out, sort of roll the cam box away from the engine. That way you won't have the buckets fall out and get mixed up. Put cardboard under the car to catch the excess oil that runs down the side of the engine

[zachmac]

...valve clearances, but these will need to be adjusted anyway after replacing the gasket.

On the other hand I have heard of guys using two gaskets, or no gasket and only RTV. However these were to compensate for valve work or to get a specific valve clearance and not to stop oil leaks.

Why would a simple dissasembly and re-assembly with clean gaskets require a valve clearance adjustment if they were in spec to begin with? Same cams, same bearings, same shims. The adjustment band width is is 3 thousands. Are you assuming a new versus old gasket will change clearance by that amount of greater?

[lordxenu]

...valve clearances, but these will need to be adjusted anyway after replacing the gasket.

On the other hand I have heard of guys using two gaskets, or no gasket and only RTV. However these were to compensate for valve work or to get a specific valve clearance and not to stop oil leaks.

Why would a simple dissasembly and re-assembly with clean gaskets require a valve clearance adjustment if they were in spec to begin with? Same cams, same bearings, same shims. The adjustment band width is is 3 thousands. Are you assuming a new versus old gasket will change clearance by that amount of greater?

Well I guess if you're going to break the engine down that far, you might as well do the necessary maintenance instead of having to do it later.

At least that's my take on it.

[manoa matt]

Yes the tolerances can change for several reasons. The new gasket may be thicker or thinner than the old one. The gaskets wil compress slightly when torqued down. The gaskets are made with a steel core sandwitched between layers of a thermosetting material that is supposed to bond to the mating surfaces. After the engine goes through a couple of heat cycles the thermosetting material will reduce in thickness slightly. All of these factors can add up and throw the valve clearances out of spec.

I've been told the exhaust valve stems tend to stretch more than the intake valve stems resulting in reduced valve clearances.

Aside from the cooling system I would say the valve clearances are the second most neglected routine maintenance procedure. Most mechanics and owners don't have the special tools or the knowhow required to perform the adjustments. Getting them all within specifications will let the motor run smooth and strong.

[htchevyii]

According to Guy Croft, the gaskets compress .002-.003" in the 24 hours after torquing. I used Hylomar sealent on the gaskets on mine and so far so good.