Oil Leak and a Stripped Fastener

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James Learmonth
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Oil Leak and a Stripped Fastener

#1 Post by James Learmonth »

My 65 C Coupe just returned from a 2500 mile road trip with a coating of oil on every surface in the engine compartment. I don't mean a oil sheen but really coated. Oil used on the trip, 2 quarts. Cursory inspection reveals nothing to me. Pulley seal, No, the pulley and fan belt have almost no signs of oil. Crankcase ventilation doesn't appear to be leaking, vent hose from the oil filler can to the right hand K&N filter no leaks. Still suspect is the rubber seal at the top of the oil dipstick. But this seems to be to large an amount of oil for this.

While checking for leaks and loose fasteners I discovered that the right side rear bolt holding the generator stand to the timing cover was loose. First attempt to tighten this bolt revealed that it would turn with little effort but would not tighten. Stripped.
The steel screw still has all of its threads with about the last half inch filled with Aluminum alloy. No telling how long this has been going on although I confess that I last removed the generator stand a little over a year ago in the process of converting to 12V electrics. Say 7000 miles trouble free.

Is it safe to drive with only 3 fasteners on the generator stand?
Can this timing cover be repaired using Helicoil or Timecert thread replacement?
If so, Which is the preferred method?
Can this repair be made without removing the timing cover?
Can this repair be made by someone with modest mechanical ability?
Does anyone have a C timing cover in good condition that is surplus to their needs?

Driving this car in normal daily urban traffic, rarely over 50mph, this engine remains normally oil free. That 3000 to 4500rpm for a full tank of gas followed by another one seems to be where this gusher begins.

All thoughts welcome.

Jim Learmonth
65 C Coupe 221316
Houston, TX

Geoff Fleming
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Re: Oil Leak and a Stripped Fastener

#2 Post by Geoff Fleming »

You might try removing the loose stud, cleaning it,( and the hole it came out of), with brake cleaner, then, when dry, use red Locktite and let it set overnight. This should maintain it for a long time.
It does sound like you've used quite a bit of oil...I would suggest you keep looking for leaks, just in case it is more than the generator stand bolt.
As far as driving the car with only three nuts holding the generator, it shouldn't be a problem.

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Jim Nelson
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Re: Oil Leak and a Stripped Fastener

#3 Post by Jim Nelson »

Last week I saw an oil cooler on a test stand that had a pinhole leak in it that resulted in the condition you described. Couldn't even see the leak, but you could feel the air escaping under pressure. Don't know if that's your issue, but strange things have been known to occur. Pushrod seals are another possible culprit, though there are a number of spots where oil can escape.

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Martin Benade
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Re: Oil Leak and a Stripped Fastener

#4 Post by Martin Benade »

If you are lucky the stripped bolt-hole might still have a few more threads left at the bottom. Then a longer bolt and loctite could help, but check your length carefully to get it just right.
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Dick Weiss
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Re: Oil Leak and a Stripped Fastener

#5 Post by Dick Weiss »

James,

Hard to imagine that much oil leaking from an upper bolt/stud on the generator stand. You could use some JB Weld epoxy to bond the stud in place and not require another 3rd piece.

Check the vertical cheesehead screws (1-on each side of the intake manifolds holding the horizontal side plates)--if they get loose or missing, oilo will find its way out and it'll look like the valve cover is leaking beloiw the plate(s); also it'll look like the pushrod seals are leaking, but the O-rings on the long headbolts (they're above the pushrod tubes) could be 'aged' over the years and can be replaced w/o an engine teardown.

Finally, are you sure about the pulley and its seal not leaking--the underside of the lid clean?

Dick

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Mike Smith
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Re: Oil Leak and a Stripped Fastener

#6 Post by Mike Smith »

Last week, I fixed exactly the problem you describe

I used a Time-cert (which I really prefer over Helicoils) - `Do it once Do it right`

However be aware that there are a number of places on the motor where the tinware screws can enter chambers where oil is present and oil WILL leak past the screws.

I cannot remember each one and it can be different from case year to case year - Stick your preferred sealer on any screw that goes into a blind hole

One other problem I had on my own car many moons ago was a small longitudinal split in the Hex Nipple on the Oil Filter container - although the nut almost covered the split the amount of oil it discharged over the motor was extraordinary. Enough to think that I had blown an oil cooler.
Mike Smith (Essex - UK)

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Steve Hatfield
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Re: Oil Leak and a Stripped Fastener

#7 Post by Steve Hatfield »

Mike Smith wrote: be aware that there are a number of places on the motor where the tinware screws can enter chambers where oil is present and oil WILL leak past the screws.
Amen, brother.
My leak had all the appearances of a failed pulley seal so I was contemplating a speedy until I could further justify dropping the engine, when (as the Maestro often said,
"and lo and behold..!"
I discovered a loose pulley shroud 6mm bolt (10mm ATF) just visible looking straight down. Bingo!
So apparently these stubby little bolts do go all the way the through the third piece ('62 S-90). Either that or some Turkey at one time or another forced a longer bolt through to the oil cavity (as Maestro warned us in his video).

While this leak in no way replicates yours, it taught me to check everything, and often to keep these old gals happy.

Steve
Steve Hatfield
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Albert Tiedemann
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Re: Oil Leak and a Stripped Fastener

#8 Post by Albert Tiedemann »

Steve Hatfield wrote:
Mike Smith wrote: be aware that there are a number of places on the motor where the tinware screws can enter chambers where oil is present and oil WILL leak past the screws.
So apparently these stubby little bolts do go all the way the through the third piece ('62 S-90). Either that or some Turkey at one time or another forced a longer bolt through to the oil cavity (as Maestro warned us in his video).

Steve
Tapped holes at this location are not designed to be through. I have not seen though holes in the third piece at this location [maybe 50 or so engines] This is also a fairly shielded area. It would require quite a bit of force to break though the remaing thickness at the bottom of the hole and the fastener is likely to break under the torque to generate that much axial load.
Albert Tiedemann, C356C
"The Hermit"

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Mike Smith
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Re: Oil Leak and a Stripped Fastener

#9 Post by Mike Smith »

Ab,

Not sure if we are crossed purposes here

The 3rd Piece I worked on last week had already been bodged and one of the Generator Stand Holes did go right through.
This was probably caused by the guy before me drilling the hole deeper to take a looooooooong stud in this hole

With regard to tinware screws - on EARLY engines the tapped holes in the heads (the ones that support the side tin) do go right through into the Rocker Area and will often leak unless you use a sealer

Late engines have blind holes - EXCEPT that the same turkey who had nearly turned the 3rd piece into scrap had also managed to break through one of these blind holes by winding in a bolt that was too long
Mike Smith (Essex - UK)

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Dave Wildrick
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Re: Oil Leak and a Stripped Fastener

#10 Post by Dave Wildrick »

Mike wrote:
[Late engines have blind holes - EXCEPT that the same turkey who had nearly turned the 3rd piece into scrap had also managed to break through one of these blind holes by winding in a bolt that was too long]

On both of my C coupes, these cylinder head holes go all the way through, and I use sealer on the threads of the screws that go there to prevent leaks. I seem to recall Harry Pellow mentioning this as a potential spot for small oil leaks.
Dave Wildrick
Houston, TX
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Vic Skirmants
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Re: Oil Leak and a Stripped Fastener

#11 Post by Vic Skirmants »

Ab was referring to the pulley shield bolts. I totally agree with him. Then we seem to have gone offtrack with every other bolt in a 356 engine.

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