Oil Leak Around Distributer

[lovehamr]

Hi all,

A couple of months ago I pulled the stroker 428 out of my car because I had an oil leak that I thought I'd tracked to the timing cover and a few other things.  Well, I replaced the timing cover seal installed the slinger (I'd left it out during the build), checked bearings etc.  Then I put the lump on a local dyno (had to fab the mount plates myself, all they had was chebbie stuff) and ran 15 or 20 pulls without ever leaking a drop.  I was quite happy with that because I thought I'd fixed my problem.  Then I slipped the thing back into my car and started driving it as much as I could, drove it to work every day last week.  Then I noticed little puddles on the shop floor and thought "WTF!?"  Putt her up on the lift (don't know how I did it all those years without the lift ) and found oil all over the lower front of the engine but none on the balancer.  Long story short, it appears to be coming from the dist to manifold opening.  I'm using and old Mallory YL dist and replaced the rubber seal when I built the engine.  The manifold is a PI that is in pretty good shape and the dist is centered but It doesn't seem that the seal is very compressed.  Before this FE I had only built small blocks, so is there some trick to getting this puppy sealed?  Other than filling the void with The Right Stuff.

Thanks, Steve

[drdano]

I fought this for years on my old 390, but it was due to the dizzy being off-center.  I would have a reducer ring fabbed that would reduce the inside diameter of the hole.  That would be pretty easy and straightforward, wouldn't have to pull the intake.  Someone with a lathe could easily make the ring since the OD and ID center points would be common.  If you had a slight "hat" on the top of the ring, say 1/8" it would locate itself vertically and prevent the ring from falling into the engine.

[ScotiaFE]

There are a few different sizes of the doughnut that fits on the dizzy.
I have a small collection of different ones from over the years of buying gasket sets.
There are taper and square and o-ring, old ones where a felt type.
Possible source for a tighter fit doughnut may be your local engine shop.

[jayb]

That is a common area for leaks on the FE, especially if you can't get the distributor centered in the hole on installation.  I have often filled the gap with gray silicone RTV after the engine was timed and the distributor was in its final position.  Surprisingly with normal RTV (not the Right Stuff) you can still twist the distributor a few degrees to adjust the timing somewhat without breaking the seal formed by the RTV.  The sleeve mentioned in drdano's post is really a better solution, but if you build one of those make sure you design it so it doesn't interfere with the distributor hold down clamp.  I preferred the RTV solution whenever I was running a vacuum pump on the engine, because even with a sleeve you would still see some vacuum leaks at the distributor hole, and the RTV took care of that issue.

[lovehamr]

Thanks guys.  I had thought about using RTV or something but thought that would be a bit TO back-yard-ish.  I had no idea that it was somewhat common.

[hvywrench]

Sounds like you've done your diagnostics so I'm not second-guessing.
My Low Riser 8v has a crack between the dist hole and the threaded hole for the hold down.
Pretty small, doesn't 'leak', but will show oil if not addressed with RTV.
Just another place to inspect.

[lovehamr]

I'll check there to.