[Sirrotica]

Rich, just a thought here, if you paid to have the rear main installed, then the shop that did the labor to install it should be standing behind it, as in this second time should be a freebie............

Unless they made a waiver at the time, they should be doing the job again at N/C. That's the way I did business in the past, but who knows what kind of excuse people hide behind nowadays. It appears that the leak repair is deficient in quality, therefore it falls in their lap to make it right. When you are a garagekeeper, (automotive repair shop) you have a moral, and usually a legal responsibility to give the customer what they originally paid for.

Now that you own the smoke machine, I'd offer to let them use it to diagnose where the leak is. Unless you and the shop aren't on speaking terms I would think they'd agree to that proposal. Then there's a trust factor if you even want them involved at this point with the repair. The machine doesn't lie the crankcase is leaking without the engine running. As mentioned, crankcase pressure is going to exacerbate the problem.

Just thinking aloud here, but I obviously don't know the complete situation.

[gtorich]

Originally Posted by Sirrotica

Rich, just a thought here, if you paid to have the rear main installed, then the shop that did the labor to install it should be standing behind it, as in this second time should be a freebie............

Unless they made a waiver at the time, they should be doing the job again at N/C. That's the way I did business in the past, but who knows what kind of excuse people hide behind nowadays. It appears that the leak repair is deficient in quality, therefore it falls in their lap to make it right. When you are a garagekeeper, (automotive repair shop) you have a moral, and usually a legal responsibility to give the customer what they originally paid for.

Now that you own the smoke machine, I'd offer to let them use it to diagnose where the leak is. Unless you and the shop aren't on speaking terms I would think they'd agree to that proposal. Then there's a trust factor if you even want them involved at this point with the repair. The machine doesn't lie the crankcase is leaking without the engine running. As mentioned, crankcase pressure is going to exacerbate the problem.

Just thinking aloud here, but I obviously don't know the complete situation.

I hear ya brother, the shop did a re-ring and installed some new parts i had, bop 1 pc rms gasket...........they supplied the new rings , i had all the rest of the parts...........asked about a warrenty, they said unless you had it dyno at the shop for 800 we can warrenty anyting............i gave them all top notch parts, they said we have plently experience with the bop one pc seal, they did a smoke test and said the front oil pan was leaking, they threw on god knows how much silicone on the front of the pan..............seems im seeing a leak in the back. lol.....really dont want to deal with them again, not the type to bad mouth anyone, but im getting there with these boys.............will try another shop.

[78w72]

Originally Posted by lust4speed

Haven't seen this posted, but I look for a starburst pattern of oil on the crank flange. If it is the main seal there will be oil streaks from the center of the crank down the flange. If it is from the pan or other areas the flexplate/flywheel will be coated and streaked but the crank flange will be surprisingly clean. Usually works for me but your mileage may vary...

X2 on this, that last pic with the oil spot shows the crack end is dry, the oil looks to be coming from the rear U seal area on the pan... I dealt with the early style 3 tab rubber U seals leaking 2 times on my stroker build thinking it was the RMS and each time it was the pan U seal, not the rms.

Im a little late to the party here but have talked to Rich about this leak quite a bit, told my story of pulling the engine 2 times to bring back to the shop that did the short block thinking it was the rms, they replaced the 2 piece BOP and installed the pan with a new felpro gasket, I installed the pan the first time that leaked after a short drive about 2-3" spot sitting overnight... got the motor back after the new rms, reinstalled in the car but this time after a couple minutes idling there was a 5-6" spot in 1-2 hours of shut down!

Pulled it again to bring back he said the rms was good, this time I brought the 1/4" cork gasket and explained what I read from Mr P-body & others about using it with Ultra black RTV sealer, got a free dyno/leak test session before bringing it home, still 99% leak free 10 years later using synthetic oil and no additives.

The smoke machine is hard to see where it starts from without being there, its better to look at the very beginning for where the smoke starts from than letting it pour out where its gets all over in a tight space like that.

Heres an idea... if you are still OK with doing the work of pulling the engine, how about pulling the pan yourself & trying the thick cork gasket at the rear then a traditional felpro gasket on the side & front? Then before installing the engine, you can do the tip test where it sits tilted back full of oil for a couple hours or longer. That way the engine doesnt have to leave your garage and you're not paying another shop to replace the rms again only to reinstall the pan with that crappy rubber U seal? Worth $50 for a gasket & a tube of ultra black or grey. I Had to do this 3 times over 1 summer when all along it was the rear pan rubber seal.

Aso what type of oil pan is that? I dont see the slots for the rubber tabs to stick through.

Hope you can get it figured out this time, if I had to make a guess based on my ordeal and yours, it would be the rear pan seal over the RMS.

[gtorich]

Scott, good to hear from you again, the motor is already out, will check to see if i have a vid of the smoke just starting to come out, the pan is a aftermarket pan, think i might put that on the stand and do the cork over the rear of the pan, then do the smoke test again, might be interesting, couple yrs back i did do the tip test, had a small leak, was told thats normal, wont leak when in use. I guess the part that really confusing me is the amount of oil in the bellhousing and flying around on the whole underside of the car............will try as you said, cant hurt.

Rich

[78w72]

Hey Rich, good to hear from you too. The smoke machine would work too, let the RTV set up & fully cure, especially if you do this when its getting colder soon. The website with the write up and pics on doing the rear cork seal isn't up any longer, had lots of good info there, wonder if there are any posts here that explain it good with some pics to show?

I also put a very thin layer smoothed with finger of the rtv on the side & front gaskets, then install the pan before dry but only snug up the bolts so the gasket doesnt squeeze out then let it set up like the instructions on the tube say, then tighten the bolts until they feel tight and the gasket isnt compressing any more. Then let cure at least 24hours. That has always worked for me and never had front or side oil pan gaskets leaks, its always that dang rear rubber seal, the later year 5 tab style with 2 groves are better but the cork is best.

[Dragncar]

Originally Posted by gtorich

The zip, no idea if i have serrations on the crank or not, never saw it, been to 3 different shops, you would think someone might have noticed that. lol................here is a pic a little after messing around with the smoke machine, oil was drained a week or so ago.....I can try to get some better vids, having a hard time with the u tube deal,

Im thinking that last vid might be the best one

I fixed a leak like that once from the outside. I put the car up, drained out the oil. Cleaned it all up with CRC Heavy Duty Degreaser ( far better than Brakkleen) Let it dry. Put a big shop vac on each valve cover with duct tape. Turned them on.
Got some Ultra Grey and put it all over the area with a long flat bladed screw driver. Let the Shop Vacs run for a hour or two. let the silicone dry overnight.
Never got another leak from that spot.

[HWYSTR455]

That looks like a rear main seal to crank leak to me, and seems like it's a big one, but hard to say not being there.

It kind of doesn't matter, regardless, the pan has to come off.

I too would need to know if the serrations are present. That looking like an OE crank tells me they are. I understand that the BOP seal can be used with serrations, but believe you have to knock them down some first.

Personally, I would use a Best rope seal.

At this point, sadly, you probably would be best to pull it. You can inspect other aspects of the build that way too.

Is it a 400 block?


.

[78w72]

I have a 2 piece BOP rms on a stock 400 crank that seals good after going on 16 years, the serrations can be an issue if they are pronounced but on all the higher mile stock cranks ive seen the serrations are worn down quite a bit and my builder said they shouldnt cause a problem when they are like that... if they are still raised and sharp or even if not, cant hurt to knock them down some to be safe.

We are mostly guessing at where the leak is from, but being thats the old style rubber U seal and how dry the crank end is in that last pic on page 3 with the tell tale drop of oil on the pan lip... I still say its the pan seal, mine acted exactly like that. After driving the oil was flung around & being in the rear area of the pan I thought for sure it was the rear main... but it was the pan seal both times.

What kind of pan is that? Doesnt have the rubber prongs poking through, looks like an aftermarket from what I can see in the pic and they must have cut the prongs off the seal which will allow it to move even more than it does with the tabs poking through the holes in stock pans.

If it were mine, I would definitely try replacing the pan gasket before tearing into the engine more or sending it out to pay another random shop to replace what could be a perfectly fine rms. Whatever you decide, hope you get it sealed up!

[grivera]

When you remove the rear main cap, make sure you anaerobic sealer between the cap and block, RMS to edge of the cap where it meets the pan gasket.

https://shop.advanceautoparts.com/p/...SABEgL3AvD_BwE

[JLMounce]

Of the number of times that you had the engine put together, do you recall the shop grinding the crank for the seal at all? This should be a separate charge, or I suppose bundled in with whatever work the crank may have needed.

I had the 1 piece BOP seal done on my engine last year and I have a specific line item charge for grinding the crank specifically for that seal. On some cranks, those serrations are quite deep and if it was never prepped for the BOP seals, that could be why you continually have problems. If that's the case you'd certainly be better off trying to find an NOS asbestos gasket. Or, you can always take the crank out and have it ground, but now you have yet another complete disassembled engine.

From the video I don't know that I saw smoke coming from the pan gasket as much as from behind the crankshaft flange. Certainly hard to tell though.

[78w72]

Originally Posted by grivera

When you remove the rear main cap, make sure you anaerobic sealer between the cap and block, RMS to edge of the cap where it meets the pan gasket.

https://shop.advanceautoparts.com/p/...SABEgL3AvD_BwE

If he just replaces the pan seal, there is no need to remove the main cap... unless of course he or someone can confirm without a doubt its the rms. I'm suggesting trying a new pan gasket with cork rear seal before sending out the motor again & paying lots of $$ when its possible $50 gaskets & a couple hours of work in the garage may fix the leak.

Regarding the serrations on stock cranks, Ive pulled or bought already pulled stock cranks, easily 15-20 over recent years, all from higher mileage engine of 60-80k+ miles and the serrations were not very pronounced or sharp, on my 50k mile original 400 W72 crank it was almost like it had been polished before but was just from the stock rope seal & mileage. Always good to check and knock down if needed, but my 400 with a 2 piece BOP seal is doing very good after 15+ years. Just my experience.

[78w72]

Did a quick search for the cork rear pan seal... found lots of threads where I link to the now dead "pontiac street performance" website that had an excellent write up from Mr P-body.

But I did find a post from Cliff that showed a couple pics of using the cork seal. Mr Pbody stressed using ultra black RTV liberally on the gasket to cap & gasket to pan as well as a bead on the ends where the side rail gasket meets the cork U seal.

https://forums.maxperformanceinc.com...+pan+cork+seal

[gtorich]

Hey thanks guys for the help, i really appreciate it, Scott got the motor on my stand today, much higher and i can flip it upside down and see what is going on, laying on the floor looking upside down was a pita, im gonna change the oil pan gasket just to see whats thats about and do the smoke test again..........i have a bop one pc oil gasket on now, and for some reason i have a spare one also, i did cut the rubber part on the back on that one...........must have done something wrong to order another one, but this time im gonna put the cork gasket i got from butler a few years back on top of that one.

Got a few tips about doing the smoke test, said dont keep letting the smoke getting worse, blow it away and watch better..........ill try that.

Jason, never got a charge on anything i can see about cutting the serrations on the crank, thinking of taking that cap off and take a look..........just to see. lol......i did put an ad in for an original NOS gasket, i think i"ll win the lotto before i find that thing.

Mike, its a 70 455 block, i do have another 70 455 bare block i bought a long time ago, its been bored .030 but without a torque plate, my present block is .035, wondering if i should just move everything over to the other block, im thinking something is just not right with the one i have. lol

Scott, the oil pan is a aftermarket one that i got from Wade at BOP, thinking of looking for a original oil pan that i dont have to fix every hole in the thing.

Once again, couldnt do it without you guys..............been fighting the same issues since the first build in 2010, wow

Rich

[78w72]

Sounds like a plan... just to be sure, do you mean youre going to put the cork pan seal "on top of that one" as in 2 gaskets at the rear pan? I havent used the BOP 1 pice gasket so not very familiar with the. Post pics as you go so people can make sure you set it up right. It's critical to get that area sealed good to prevent leaks there.

[grivera]

Originally Posted by 78w72

If he just replaces the pan seal, there is no need to remove the main cap... unless of course he or someone can confirm without a doubt its the rms. I'm suggesting trying a new pan gasket with cork rear seal before sending out the motor again & paying lots of $$ when its possible $50 gaskets & a couple hours of work in the garage may fix the leak.

Agreed- my advice is assuming he first confirms it’s the RMS leaking.

[HWYSTR455]

On the serrations, you can use a strip of emery cloth to knock them down, it doesn't take a lot of effort. As long as you stay directly on the serrations, there's no risk of effecting any bearing surfaces.

You don't need them for the newer type rope seals either, most are impregnated with a type of dry lubricant, like graphite. The serrations were to hold oil, so the seal wouldn't dry out and stick to the crank, basically.

I probably not go to a used OE pan, it's more trouble than it's worth. Butler has the OE type PRW pans that are baffled, the $125 they charge makes them a no-brainer.

Makes things much easier now that it's on a stand. If it does become obvious it was a pan seal leak, then no need to pull the cap.

Just to say it out loud, don't use a cork end cap gasket along with the rubber one, use one or the other. If the gasket 'spikes' line up and fit in the pan holes, you could mock it up with no sealant and run a smoke test to see if you have a RMS leak. (As well as a pan gasket leak.)

If you didn't have any issues with the engine other than the leak(s), I wouldn't think about moving parts over to another block, could just introduce other issues. But being on a stand you have an opportunity to review the previous work done (or not done).

If you're not comfortable with the engine for whatever reason, think the best approach is to use the spare block and build another short block. A 4.25 stroker rotating assembly many times is less expensive than machine work on an existing rotating assembly. Many kits are already balanced too.

Nice thing about that approach is you can still drive with the existing engine.


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[gtorich]

Ok, took two more vids with the motor upside down to see better today, hope these turn out, i cant figure out that you tube stuff to save my life. Had a email saying dont let the garage fill up with smoke and wonder why you cant see anything, so i blew the smoke away as soon as it came out...........still hard to see, im gonna change the oil pan gasket anyways and take off the main cap to look at the crank.

https://youtube.com/shorts/kg6OWbz5SVQ

[gtorich]

hope this one works

https://youtube.com/shorts/zKf0Nbb0vP0?feature=share

[gtorich]

These pics are where the smoke starts with the pick too pointing at it............i hope im not driving you guys to drinking keeping up with this stuff. lol

[mgarblik]

Originally Posted by grivera

When you remove the rear main cap, make sure you anaerobic sealer between the cap and block, RMS to edge of the cap where it meets the pan gasket.

https://shop.advanceautoparts.com/p/...SABEgL3AvD_BwE

That is 100% correct and an important step. Missed by many engine builders and a major oil leak source. It is spelled out in all the factory service manuals but gets missed. Of course this was in the days before anerobic sealers and they just say sealant. RTV is not the best product for this area. It will not dry between 2 machined surfaces and the viscosity is too high. Anerobic sealer/gasket maker is the stuff to use. Have seen several smoke tests of Pontiac engines with smoke pouring out between the #5 main and the block at the rear. Miss-diagnosed all the time as a rear main leak or pan gasket leak.