Distributor Seal, WTF Am I Doing Wrong?...

**** man, I getting the pop corn, this **** is getting good

 

i dont see how you can have the hold down to tight, even if you had it so tight you bent the holddown and stretched the bolt almost to the point of snapping it still would not cause a leak, have you made sure there is not a big scratch on the underside of the dist. collar? post a few pics of your setup it allways helps.

 

Clean everything, put a single new distributor gasket on the distributor, make sure there are no O rings on it, put in the distibutor, tighten the hold down bolt to about 15-20 ft lbs (tighter than a valve cover bolt, not as tight as an intake bolt). Take the distributor back out, look closely at the gasket. Is it compressed evenly all the way around? or is one side not compressed, or is there a line on it indicating that scratch that budd surmised?

 

Budd's right. The hold down ends end up about midway around the lip on the dist if I'm remembering right. I've seen them so tight I bent a dist wrench trying to loosen them . No leak. I'm curious to know about this phantom leak.

 

Here's a pic of where the pcv is...

Here's the underside of the intake with baffle...


Closeup of the baffle. About 1/8" gap on either side...


PCV valve on top. You can see part of the dizzy mounting boss on the left...


Engine shot showing oil fill tube with breather cap on the front...

 

See pics above. There is no scratch on the intake or distributor mounting surfaces.

 

It is evenly compressed when I don't over tighten it. The gasket from before was curved downward on the hold down side when I removed it. No lines in the gasket other than cocentric rings from the dizzy.

 

First of all the flow of oil goes from the pump to the filter, then up to the left side and back and across the distributor cavity and over to the right side of the engine, so if the dist is loose or the gasket is bad it will leak, I know because I just reset the timing on mine and didn't tighten the dist back down and the oil came out between the gasket and the intake. Big time!!! It drove me crazy to because I didn't make any changes except the timing, but I had never heard of that happening before, but it will leak. Use two gaskets or a thicker gasket and I'll bet it solves the problem.

 

The prongs of the hold down don't quite go halfway around the dizzy lip. Think of it like this. If you apply too much force to one side (hold down side from overtightening), it will lift up the other side, no?

I've got the timing set again and am gonna take it out for a drive. I'll know for absolute sure if overtightening was the problem if it's not leaking when I get back.

 

Thanks for the input. Some have said it won't leak unless there is too much crankcase pressure from not enough venting. I think you and I have shown it will leak from between the gasket and the intake just as you described. I'm pretty sure too loose is just as bad as too tight on the hold down bolt when it comes to a proper seal here.

And you're right about the amount of oil coming out too. It's quite a leak. I did a google search on the netz and it seems like a lot of leaks from the dizzy gasket get blamed on rear main seals. So, it does happen fairly often.

 

Have you taken apart the oil pressure line at the back of the block yet?

That's a huge leak for a distributor gasket. HUGE. You can leave the gasket completely out and it won't leak as much as you describe.

Yes, I know you checked, and double checked, and triple checked. But I'm here to tell ya after 25 years of ****ing around with small block chevies.......Take that fitting apart. Don't just look at it. Holler at me if you want but a bad distributor gasket simply does not leak the volume you describe. Don't care what google says, I've sealed too many chevies to believe that you can confuse a distributor leak with a faulty rear main.

Another thing you may not realize.....oil wicks uphill. Anything leaking that volume on the back of your motor will wet down the distributor gasket. Don't just ***ume because the gasket is wet that's your leak.

Anyhoo, I'm outta here, too much bad juju floating around over a simple leak. Good luck with it.

 

Shifty,

I'd never holler at you, you're trying to help me. Please don't take my words directed at one jerk as directed towards anyone I disagree with. That said, the oil presure sending unit is tight and was never messed with during the swap. Nothing leaked before the swap. The distributor gasket isn't just wet, there is a puddle of oil on the intake and a conveniant little channel for it to run down the back of the intake onto the block and down the ****** pan. There was another post on the last page describing a huge leak from the dizzy hold down being too loose.

I've read plenty of your posts in the past and respect your knowledge and experience. I'm not saying you're wrong. Just saying what I'm describing is possible. If one was to search the web, one could find many instances of a dizzy leaking so bad as to mimic a rear main seal blowout.

Either way, I'll know for sure in a few minutes if it's not leaking after a test run. Be back soon with results.

 

Terd Ferguson... It's a funny name, heh.

Did you get this thing solved on your drive? I'm in agreement with some of the other guys that it seems like you've got too much crankcase pressure. I ran my engine for a couple years without a distributor gasket and it didn't leak. I didn't even know that there wasn't one on there until I took it apart to swap heads!

I personally would be looking that direction, but that's just me. Good luck and I'm really curious about this so post up your results.

 

The other thing I should mention is that if the breathers are blocked it will cause extra crankcase pressure and it will blow out the path of least resistance. I've got a late model (1987) 350 cu.in. with a mid sixties tri-power Offenhauser intake and when I first set it up it was running a little rough so I pulled the hose off the PCV and stuck a bolt in it, well let me tell you after just a few minutes of running it was leaking around the dist. and around the valve cover grommet. So make sure you have plenty of ventilation, both valve covers and the oil fill tube. As for the negative replies, well life's to short to let it bother you, move on and get your problem fixed and go out and have some fun with it.

 

Ok, I'm back from the test run. One problem solved and another found. It is no longer leaking from the distributor. That's the problem solved. It is still leaking, but not nearly as badly. Before, it didn't leak on first start up at idle. After driving a couple of miles, it would leak on the gas and at idle.
Now, it doesn't leak at idle even after driving. It only leaks when you give it gas. But as I said above, it's much slower and not coming from the distributor. I got a mirror and a flashlight and as best as I can tell, it's either coming from the oil pressure sender or the intake manifold itself right at the oil pressure sender. Picture me trying to hold a mirror and a flashlight trying to give her gas at the same time, lol.

So, Shifty, are you listening? You were right and so was I, to a degree. The distributor was leaking likely due to over tightening. But, there is another leak in almost the same spot. At least I'm gaining ground here and have it narrowed down. I'll get it sooner or later.



I might as well ask what would cause the oil pressure sender to leak?

 

leakin from the theads? or the sender itself? factory style sender?

 

I can't exactly tell if it's coming from the sender itself or the seal between the intake and block at that same spot. It could be coming from the top of the sender, the threads or the intake manifold there. It's just an awkward place to see, but the leak is right there at the sender.

The sender is br*** and there is an aftermarket oil pressure gauge. So I'd say it's likely aftermarket. They've both been there since before I bought the truck.

 

ok, is it a br*** fitting with a line goin to the gauge? or a pressure switch with a wire?

 

Br*** fitting with a line going through the firewall.

 

plastic line? if so, its prolly leakin. had it happen a few times myself. replace it with a copper line kit. and retape the threaded fitting into the block with teflon tape.

 

Try removing the fitting and plugging the hole?

 

I'm new to this post and have not read the whole thing but What kind of gaskett did you put in the rear of the intake ie... the rubber ones that came with your intake gaskett kit or did you use permatex (blue glue) but the black kind? this could be where your new leak is comeing from I'm glad you got the dizzy sealed

 

Are you ready for the old (I told you so) lol

Boy, do I feel stupid!! Put a 1/8 pipe plug in the sender hole. I will still bet is is leaking from the silicone seal from the rear of the intake.

 

Not sure if this had been mentioned before or not, but how loose a fit is the distributor housing in the bore on the intake ? Is there an appreciable amount of side play?

 

Yeah, it's a plastic line. I probably bumped it and cracked it or something without noticing when removing or installing the intake manifold.

I'd rather fix it right with a new line. That way the gauge will still work.

I used RTV for the front and rear of the intake manifold. I still can't be 100% positive that it's not leaking from the rear of the intake manifold at or around the oil pressure sending unit, but the sending unit makes more sense. I got a good bead of RTV down and the plastic line of the sending unit seems really fragile.

I'll be the first to admit when I'm wrong, lol. And it very well may be leaking at the rear of the intake. I can't be 100% positive, it's just a hard spot to see. But it's a lot easier to try the sending unit first rather than pulling the intake again.

The distributor is now good to go. Oil is no longer pooling up on the intake manifold. I believe I was severly over tightening the hold down bolt pulling down on one side of the dizzy enough to slightly lift up the opposite side allowing the oil being splashed around in the valley to escape. Think about laying a coin flat on a table and applying pressure to one side. You can flip it over. I think the same principal applies. Right or wrong, oil is no longer coming from the dizzy, no oil is coming out at idle like before, and the amount of oil leaking on the ground now is CONSIDERABLY less and only comes out if you're on the throttle.





And for the record, I can see oil mist and a tiny puff of smoke when you mash the stink pedal. It's just very hard to tell if it's coming from the sending unit or the rear of the intake manifold at the sending unit location. I used a mirror and flashlight from up top and crawled under and can see the mist from both angles.

 

Put a pipe plus in the sender hole and see if it still leaks. If it does it's time to pull the intake off again. Have fun.

This is how you learn and I bet this problem will never happen to you again. Just remember all of the fixes that were give so that you can p*** it along some day.

 

Terd, I'm glad you fixed the dist. leak, but I can guarantee you it wasn't leaking because you overtightened the clamp bolt. You would have pulled the threads out of the aluminum manifold before the distributer base would ever ****. You have two flat surfaces; the manifold and the distributer base are both machined flat so no matter how tight you tighten the bolt its never gonna lift one side. More than likely the new clamp I think you said you installed one somewhere along the way, actually holds the dist. down now.
Also it's OK to put two or even three dist. gaskets under there depending on how thick they are, some are thicker than others and you can stack them.

 

You should take off your oil pan next. Those are fun to get to seal too

 

Seriously, that's why I ask dumb questions sometimes. Sure enough, somebody will search like I did for a solution. Only from now on, there'll be some info cause I asked a dumb question. And you're right, this is how you learn. I've done plenty of stuff to cars, but for whatever reason, never had to remove a distributor before this. Everything's kind of a mystery until you actually do it yourself.

I used to be the same way with electrical stuff. My dad's an electrical engineer, but I never paid attention to his wiring projects when I was a youngster because I thought wiring was "boring" and just never had to use the info at the time. But surprise, it's not quite so boring when you're trying to chase down a short and don't know what you're doing. Thank goodness he was still around to teach me when I really needed it. The most important thing he taught me about wiring is that there's smoke inside, don't let it out.

I've got a lot of experience building/modifying everything from crotch rockets to brit bikes to dirt bikes to high boost twin turbos to 4x4's to road race prepped suspension tuning to scratch building guns (AR's, AK's, full on custom Gov't. Models) to scratch building gigantic fish tanks and stands to hold them. All my stuff has always been heavily modified/customized/home built and I'm definately not prejudiced when it comes to a cetain kind of means of transportation (and this isn't my first old vehicle, or second, or third, or etc.). But there's still some stuff I've not had experience with for the same reasons- I've never "needed" it. I've never welded. I've never built an engine. I've never done any fabrication other than simple stuff. I want to learn all this stuff and this truck will teach me a lot of that (hopefully I won't have to learn to build an engine anytime soon though unless it's for fun, lol.).

That said, it may sound pretty dumb that I didn't know not to crank down on a distributor hold down, but you gotta learn somehow. I've always been a DIY kind of guy and this extends way beyond cars. I always help out when I can from what I've learned the hard way. And you can damn sure bet this won't be my last dumb question.

You may be entirely right. But it didn't leak before with the same old hold down. And I can only ***ume it was tightened properly before I removed it and put the monkey grip on it. Did you see my ****ogy of being able to flip a coin lying flat? And how the gasket was curved downward slightly on the hold down side when I removed the dizzy to check it to see how the gasket was mating to the dizzy and intake? Again, I'm not saying you're wrong. No offense meant.

Haha, done it a couple of times and that's actually something that's never given me a bit of static.



I'm going to get at the oil pressure sending unit tomorrow and see what's up. If it leaks after that, I ***ume it's gotta be the rear of the intake manifold. Either way, my problem is now smaller than it was and will just get smaller still. And I appreciate all the help. That's what makes this place great.

 

Sure, just trying to give you something cheap to help diagnose.

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