• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Oil leaking from distributor on to block.... what am I missing?

JG71B

Well-Known Member
Local time
9:18 AM
Joined
Mar 26, 2017
Messages
754
Reaction score
693
Location
NE OH
I've had this thing apart a couple times and can't figure it out. Oil keeps pooling up right underneath it in the corner of the block, everything's nice and not too tight, holds timing good, easy to adjust, I don't get it, anybody got any ideas? I have no other leaks besides this. It's not coming from the hold down at the Valley Pan either, the inside of the distributor is coated with oil and seems to be leaking out of the small hole in the bottom floor of it. Is there a gasket or an O-ring I'm forgetting about? Seems to be pulling up from the shaft and getting through the top somehow , the cap isn't soaked but the bottom inside of the distributor is. I've read a few times there is a round o-ring and a square o-ring for the base of the distributor to the block , but not sure. Appreciate any help
20240817_120340.jpg
20240817_120349.jpg
 
Chrysler used metal gaskets early and then switched to O-ring in groove below flange at block surface.
Mike
 
I had that problem once except it was on a Hemi so there is no valley pan. It was just impossible for oil to get there. There is no place for oil to come out of that would end up there. It was impossible. After several months I finally figured it out. I had a different problem causing big time crankcase pressure. It was pushing the oil up there from underneath the distributor.
 
I would think positive pressure inside the engine may be the issue too. I would clean or replace the pvc valve first. Second, are you really sure it’s not seeping at the valley plate hold down? It gets a lot of oil splash from the cam and lifters.
 
What gasket or seal do you have between the dust and block? If you find a gasket, ground thr dist housing so it works like it's supposed to. @HALIFAXHOPS , is there some kind of seal inside?
 
the early distributors use a metal gasket at the base
 
Pretty much all the current gasket kits come with a rubber o-ring and a paper gasket for the distributor. My distributor doesn't work with the the o-ring, but the paper gasket with a faint smear of hylomar seals it up nicely...


*Edit*
'CRS' must've kicked in earlier, sorry...my current distributor (Firecore) does use the o-ring as well...it helps the base fit snugly in the block, and uses the paper gasket on the lip. So use both and you should have no leaks...at least from there.

Judging by the puddles at the red arrows in the OP picture it could also be weeping from the valley pan/head junction area.

(Here's a pic of an old Firecore unit I have laying around--mounts like the OEM)
20240818_075004.jpg
 
Last edited:
That’s why you install the o-ring included in that link
 
OP stated he has oil inside the dizzy. So somehow it coming up the shaft into the housing then probably leaking out onto the block. I know I've seen one way grooves on the shafts before, to keep oil from coming up into the dizzy but is there a seal also?
 
I believe there is often a thin washer at the top of the shaft, under the weight base. But whether it is an effective oil seal, I doubt it. And I’m not sure if it’s universal. The spiral groove in the shaft and bushings are the main form of oil control I believe.
 
It could be blowby filling the inside of the housing with oil and it's dripping downward. It's fairly a common problem on units that have significant blowby. Make sure you have a functional PCV system including a breather that isn't plugged, or at least a couple good working open breathers.

If that's all okay, have a look at the collar on the distributor shaft, the one that is held on with a roll pin on the inside....there are a a couple styles that have been used historically.....one style has sort of a built in washer, which acts as a slinger to attempt to keep the inside of the housing cleaner...it's usually made of some kind of plastic (maybe nylon, not sure). The other style is shaped like a cylinder and is usually nylon or plastic, but is sometimes metal on an aftermarket distributor. The type that has the slinger built in may be the solution, or at least it has worked in the past. The factory and Mopar Performance distributors came with both styles over the years. good luck
 
do you have a functioning pcv system?
Digging a little deeper, it has MP aluminum valve covers and I did find that the baffle inside on the passenger side is pretty close to the hole where the breather goes on and looks like it is sitting right on the baffle essentially blocking the breather off. I cleaned everything up and swapped holes with the oil cap and breather so, we'll see if that was cause. Appreciate it
 
Auto Transport Service
Back
Top