Oil leak crack in side of intake cam housing

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CharlieLong
Posts: 10
Joined: Thu Jun 02, 2022 9:12 pm
Your car is a: 1974 Fiat 124 sport spider

Oil leak crack in side of intake cam housing

Post by CharlieLong »

Seriously overheated engine last summer, (fixed electric issues with cooling fan) began oil leak. Discovered small crack in the intake cam housing. Plan to try JB weld repair. crack is a little below cam height above intake manifold 2nd port. Main question is...does oil actually pond inside the cam housing to cam height? Wanting to clean/prep the aluminum to attempt JB weld but oil doesn't stop seeping out of crack after parked for 5 hours now. Do I need to drain the oil to dry it up?
Nut124
Posts: 748
Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: Oil leak crack in side of intake cam housing

Post by Nut124 »

Yes, oil does pool inside the cam boxes when the engine is running. Once shut down, oil slowly drains back down thru the valve bucket bores clearance. There are two bumps on the outside of the cam boxes. These are the return ports for oil to drain when the engine is running. If you remove the valve cover, you can see these return drains. This is how high the oil will be while running.

I have never seen a cam box crack. How would that ever happen? Can you actually see the oil coming thru this crack?
18Fiatsandcounting
Posts: 3798
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Oil leak crack in side of intake cam housing

Post by 18Fiatsandcounting »

I've never seen a crack in a cam housing either, but I would be reluctant to try to repair it with JB Weld. Suggest just getting a new intake cam housing, and they are readily available on Ebay (search for "Fiat cam housing" or the like) and also at Midwest-Bayless. You could also try a "Wanted" ad on this forum.

The cam housings are interchangeable throughout the model years, although there are some differences for smog-related fixtures. That would depend on which model year you have.

-Bryan
CharlieLong
Posts: 10
Joined: Thu Jun 02, 2022 9:12 pm
Your car is a: 1974 Fiat 124 sport spider

Re: Oil leak crack in side of intake cam housing

Post by CharlieLong »

Yes, oil would come out the crack. Near center and on the side near a mounting stud/nut. Leak started after I overheated it (bad fuse for elec fan) I'm guessing thermal expansion related. Yesterday, I removed the tube between the EGR valve and the manifold for more working room. Used dremel to grind clean and roughen the aluminum and put a coat of JB weld over all the crack area. After a few hours I saw that I greatly reduced the leak but still just one small spot of oil came thru. Must be oil trapped within the crack or maybe it takes days for the oil ponded in there to drain internally? Thought I'd do another coat this morning but maybe I'll wait a little longer. Washed the area again with acetone (carb cleaner) and maybe wait till this afternoon. Your thoughts?
Nut124
Posts: 748
Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: Oil leak crack in side of intake cam housing

Post by Nut124 »

Yes, it can take a day for the oil to seep thru the bucket bores. Some oil will always remain in the low spots at the outside edge of the cam box, where your crack is.

If you really over heated the engine, then head gasket often goes next.
CharlieLong
Posts: 10
Joined: Thu Jun 02, 2022 9:12 pm
Your car is a: 1974 Fiat 124 sport spider

Re: Oil leak crack in side of intake cam housing

Post by CharlieLong »

Thanx! Yep on oil draining. Thought 2nd coat of JB weld cured the oil leak (first did not) but after putting back together and then running it a little, saw that I greatly reduced the amount of leak but still a little oil shows up. last coat was evidently after oil had drained out internally. So far no head gasket issues...no oil in the water or vice versa. Think I'll give it a couple days to drain then try one more coat of JB weld. If it doesn't cure the leak i'll just not park on somebody's nice concrete drive this summer then prolly hire new cam housing installed this winter. Thanx again.
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