Oil Leak Help

[kridgleyud]

Experts ... I need some help!

Bought a rebuilt 218 from and Dodge truck to go into my 1940.  If you followed my build thread you'll recognize the issue.

 

Months ago before winter I put the motor on the chassis, cranked the starter without plugs and had a BAD oil leak from the rear of the motor.  I pulled it back out and replaced the rear main seal (bolt-on type) and new oil pan gasket.

 

This weekend I put her back onto the chassis and tried again ... cranked starter without plugs and what happens ... oil to about 20 psi and nothing higher ... more leaking out of the back.  Pulled her back out with oil this time; into the garage again to see if I can find out where this oil is coming from.

 

Here is the seal i took out last time versus what I replaced it with ...

 

Any thoughts as to other sources for oil coming from the back of the block?  All seals and plugs look intact on the back of the block ... any chance it could be coming from the crank at the pilot bearing? 

[Merle Coggins]

There is a pipe plug in the end of the oil pressure gallery, behind the bell housing. It not be tightened properly? Or the welsh plug at the end of the camshaft bore is leaking? 

Edited June 18, 2018 by Merle Coggins

[Andydodge]

Did you replace/install the small seals on either side of the rear main cap?.....andyd

 

[kridgleyud]

@Merle Coggins  I'll check these while it's out .. .didn't see any signs of oil here last time but I'll definitely look again.

@Andydodge Sure did!  I'm stumped really ... but with her out maybe I'll see something I couldn't before.  

[thebeebe5]

“.....  from the crank at the pilot bearing?”   You mean from where the transmission input shaft goes?   That’d be impossible unless there’s  a severe crack or someone drilled a hole there.   Really unlikely.   I suspect your rear main seal.    The neoprene type requires machining to work properly and be installed with the lip inward towards the engine, not outward towards the crank flange.  Call Egge and get a Best Gasket brand rope seal replacement. Install it in your original seal holder following their directions. 

[BigDaddyO]

Rig it up so you can crank it over (or even better, start 'er up) on the floor and watch to see where it comes from.

 

Edited June 19, 2018 by BigDaddyO
Punctuation.

[halffast52]

could it be possible  your dodge engine had a m6 transmission that shares engine oil with the torque convertor ?just a thought 

Edited June 19, 2018 by halffast52
spelling

[greg g]

The only engine trans combo that shared oil were the one year only (54) Plymouth "Hy drive" and they were fited behind 230's, not 218's.  The often overlooked can shaft seal might be the source.  Have you eliminated the oil pressure gauge hose that runs between the back end of the engine and the firewall. A split one will pump considerable oil in a short time.

Edited June 20, 2018 by greg g

[kridgleyud]

Thanks for the thoughts all.  I've got her on a stand (crate really) so I can look at further.  Plan:

1. Remove pressure plate and clutch disk, use starter and bellhousing to crank and look around ... 

2. Remove bellhousing and starter and flywheel and look at plugs/seals on rear again for wetting

 

@thebeebe5, I was with the understanding that the rope seal in the bolt-on retainer was a direct swap with the newer neoprene seals.  Curious, what machining is required for this seal to work?  The pic shows both .. I did install the flange inward as that's what the manual showed, its just flipped in my pic.

 

@greg g, there is a plug in place of the oil pressure gauge line at block that would normally run to the firewall. ... But, going to re-check all seals and plugs to make sure they're sealing.

[thebeebe5]

20 minutes ago, kridgleyud said:

 

@thebeebe5, I was with the understanding that the rope seal in the bolt-on retainer was a direct swap with the newer neoprene seals.  Curious, what machining is required for this seal to work?  The pic shows both .. I did install the flange inward as that's what the manual showed, its just flipped in my pic.

 

That lip would be distorted if the seal was installed with it towards the engine because it would be pressing against the block.   It needs to be free of obstruction to seal properly.  Believe me, I made every argument to Pat, the machinist at the shop where I’m building my engine, and he just kept shaking his head and telling me it wouldn’t work unless the hole at the back of the block was opened up to allow the lip to extend unobstructed into the block.  He uses the Best Gasket brand rope replacement for all the flatheads he does and they haven’t been coming back, so that’s good. 

Also, another problem I had with that seal was that the ends didn’t meet well on my sample.  And gobbing on silicone sealer wouldn’t have helped the ends mate and keep the oil in.  Called Jeggs (the supplier) and heard crickets on that one.  Tried to leave a negative review on the product and they struck it down, so couldn’t even alert others to the issue.  

[kridgleyud]

@thebeebe5, thanks for sharing this.  It may likely be coming from this seal again ... the rope seal I took out, in my original pic didn't look very good.  I have the best gasket on the way as it's very cheap through EGGE.  I plan to replace is no smoking gun other than this is found.

 

Again, really thankful for the feedback and experience shared and have to trust the word of your engine builder.

[thebeebe5]

Here’s the BG seal compared to a FelPro seal that comes in the full gasket kit.  BG seal is far more firm, and it doesn’t seem to be an actual rope product...  Feels like some kind of graphite fibre.   Just follow the directions closely and you’ll be good. 

[kridgleyud]

Hello all.

I did some investigation as to where this oil is coming from and I found the issue.  The bore into the crank flange for the pilot bearing and trans input shaft is too deep.  Not sure what happened to this crank before I had it, but it was machined out for some reason ... now I'm worried what else I'm going to find.  It's so deep that is broke into the oil passage for the rear main bearing journal.

 

Who in for world would machine anything out of this????

 

Here is some pics of what I see ... picture into pilot bearing bore / picture shining light into bore and looking down at main bearing surface ... you can see the oil passage light up.

 

I'm going to pull the crank out next and take to the machine shop to see what they think ... I'm thinking I'll need to regrind a crank I have in an old motor and replace all bearings to match.  But ... maybe it's possible to plug this area behind the pilot?  That's optimistic ...

[casper50]

wow.  glad that you found the problem anyway.

[kencombs]

Maybe you can have a special pilot bushing machined that has a closed end and install it using a bit of Loctite to seal it.  That would be a lot cheaper than welding/regrinding etc.

[soth122003]

Treat it like a leaking freeze plug and make a patch about .010-.020 thick and the diameter of the pilot hole. use light sealant on the edge of the plug and press it in with a brass drift. then install the pilot bushing and check the  clearances.

 

Joe

[kridgleyud]

Figured I would post the solution I used ... I found a dorman expansion plug that matched the bore ... drove this in with some permatex and it seated nicely.  Re-installed the flywheel, bell housing and starter and cranked her with no load to check oil pressure .... got it now! no leaks!

 

She's going back in the car as soon as my new clutch disk comes in from Nashville and I'll get her started on frame.  Video when all goes well

[kridgleyud]

So the expansion plug in the crank worked out well ... no more leaking from the rear and with plugs out, starter rotating the flywheel I saw the pressure gauge jump right up to 25-28 psi ... BUT!  Also noticed some oil coming from the #3 and #4 cylinders (apparent from the plugs being removed).  After cranking starter like this for a bit on and off ... some small oil drips coming from the headers ... this makes sense if there was oil in the cylinders and being blown out the exhaust valves.

 

I'm hoping this was because the motor was sitting upside down and rotated in that position while I was working through the crank flange and rear seal.  however, I'm starting to not trust anything on this motor anymore and think I should do a compression test to make sure the rings are OK.

 

Am I being paranoid with this, or should I start her up and see if it goes away?  It's never been run to temp or broken in yet, so maybe there's some oil getting by until it's run at RPM and able to get hot ... on the other hand I don't want to ruin anything either.

 

thoughts?