[Verdoro 68]

Looking back at my order, that seal was definitely for a 3" main engine.

Thanks for that video. He used a different type of rope seal, but it was still informative. I went back and looked at the instructions that came with the seal. They don't say anything about how hard to pack it, but based on the appearance of the seal, the fact that it rotated, and the way he packed it in that video (and others I watched) I'm pretty sure now that I didn't pack it enough. Seems like it's common to use little bit of RTV in the channel to keep the seal from moving, like Gach said. I installed this one dry. I'll correct both of those issues on my next attempt.

[Sirrotica]

They don't spin often, Probably seen 2-3 in over 50 years of wrenching as my profession.

I like to put a little chassis grease on the seal surface with my finger while I'm assembling it so there is lube as soon as it turns over.

Just little things you pick up when you do it everyday.

[Gach]

Originally Posted by Verdoro 68

Looking back at my order, that seal was definitely for a 3" main engine.

Thanks for that video. He used a different type of rope seal, but it was still informative. I went back and looked at the instructions that came with the seal. They don't say anything about how hard to pack it, but based on the appearance of the seal, the fact that it rotated, and the way he packed it in that video (and others I watched) I'm pretty sure now that I didn't pack it enough. Seems like it's common to use little bit of RTV in the channel to keep the seal from moving, like Gach said. I installed this one dry. I'll correct both of those issues on my next attempt.

I had a feeling it was for 3” main.

[Verdoro 68]

My block is a 3" main 400 so all good there.

I think I know the answer to this, but I'm going to ask anyway just to make sure I'm not making too much work for myself. What's the best way to approach the seal replacement?

I have the assembled block on the stand with everything but the pan and the rear cap on. Feels like a short block disassembly/reassembly while keeping everything in exactly the order it came out is the general approach.

1) The front cover/water pump/fuel pump off
2) Valve train removed
3 The timing set removed
4) Rod caps removed, pistons pushed down in the bore
5) Main caps removed
6) Pull the crank
7) Pack the seal in the block
8) Put everything back where it came from

I've heard of folks using a "sneaky pete" tool to the thread the block side of the seal in while the crank is in place, but how does that make sure the seal is packed appropriately?

[Gach]

Personally I wouldn’t do the sneaky Pete approach. I know its allot of work disassembling everything, but think of the consequences if the sneaky Pete approach ends up leaking.

[Verdoro 68]

I’ve got it down this far, might as well do it right. More work, but not much more than I’ve already done.

[Gach]

I feel for you, hate seeing this kind of thing happen.

[Sirrotica]

Originally Posted by Verdoro 68

My block is a 3" main 400 so all good there.

I think I know the answer to this, but I'm going to ask anyway just to make sure I'm not making too much work for myself. What's the best way to approach the seal replacement?

I have the assembled block on the stand with everything but the pan and the rear cap on. Feels like a short block disassembly/reassembly while keeping everything in exactly the order it came out is the general approach.

1) The front cover/water pump/fuel pump off
2) Valve train removed
3 The timing set removed
4) Rod caps removed, pistons pushed down in the bore
5) Main caps removed
6) Pull the crank
7) Pack the seal in the block
8) Put everything back where it came from

I've heard of folks using a "sneaky pete" tool to the thread the block side of the seal in while the crank is in place, but how does that make sure the seal is packed appropriately?

Don't waste your time with the chinese fingers, and trying to pull the rope seal into the block. If you want the second seal to have a fighting chance, pull the crank, and install it like Pontiac did when they built it. The chinese finger tool may work 50 % of the time, if your lucky. Then you have to pack both ends in, and push short pieces in the ends. You're pretty much adding a lot of failure points. Any time you save will be eaten up doing it twice.

I really wanted the chinese finger to work, and did everything to facilitate it, but I'd never recommend someone use one, the failure rate was too high.

I'm speaking from experience of trying to cheat the process when I worked in a dealership on flat rate, where time is money. I even made a funnel out of copper tubing to try to form the seal as it gets pulled into the groove. No matter what I did I never felt confident that I made a successful repair.

[Verdoro 68]

Originally Posted by Gach

I feel for you, hate seeing this kind of thing happen.

Eh. Just part of the process of a new engine. Considering all the things that can go wrong on a new engine, I'll take it. The irony is how much time and effort I took to make sure the rear main was going to seal - and it was the only thing to go.

I tore everything down today. Everything else looks good! There's a little more wear on the lifter bodies than I was expecting, but nothing that concerns me. I suspect that was the tiny bit of sludge I was seeing on the magnetic oil pan plug. Pack in a new rear main, put everything back where I found it and I should be good to go.

I was trying to get away with leaving the intake and valley pan on but those plans were thwarted when I turned the engine over and dumped some lifters out of their bores. I also dropped a rod bolt deep into the valley pan. Just the universe telling me not to take any shortcuts.

It's actually been a little gratifying to do an autopsy on my first full on engine build and find nothing wrong.

Just waiting on the parts now.

[Gach]

Wow ! You got allot done.. it’ll all be worth it in the end. At least now you know what to do to make new seal work.

[Verdoro 68]

I spent a bulk of the holiday installing the seal and getting everything back together. I was very careful to put everything back exactly where it came from clean, with the specified torque, and lots of assembly lube.

I made sure to take extra care to mold the new seal to the cap and block, used ultra black to stick it in place, and anaerobic sealer between the cap and the block. I'm positive the cause of the failure was not applying RTV to the back of the seal. It clearly says to do in the instructions - Rocky's book says to as well. Not sure how I missed that the first time around with all the attention I paid to the built. I also made sure to lube the seal up really well with red assembly lube as per the instructions. Before I dropped it in I did a smoke test and didn't see any leaks. Then I primed it and let it sit with oil in it overnight to be double sure. Everything was dry

I got it fired it up this afternoon and let it run for a while. I was glad to see the oil pressure the same since I did major surgery. So far no sign of leaks, but the real test will be once I get it back out on the road.

I hope I don't have to do this again for a long time.

[b-man]

Nice work.

Glad you took your time, got everything handled and kept your sanity.

[Verdoro 68]

I may lose my sanity if I see oil under the pan after the next cruise.

I think back to when I first pulled the engine prior to the rebuild and I was afraid to pull a cap off for fear of disturbing something. I’ve come a long way thanks the help, guidance and support here.

[Gach]

You did it right, hey thats how we all learn.

[sdbob]

I think back mistakes,'maybe,' remembering for the next time. Learning by necessity not by instruction. Then a certain time you feel ok I know what I need to do now. The good thing I had a machinist,John Quinn who was very good.very relaxed. Ah the 60s

[Verdoro 68]

Took it for a lengthy cruise to a local cars and coffee this morning which included some freeway time. Ran great all the way. Most importantly - no evidence of leaks when I got home! I hope I'm not jinxing myself, but I'm calling the rear main fixed. I may go as far as putting the inspection cover on the car!

Tangentially - I put an ME Wagner PCV valve on it when I was trying to diagnose the leak and there's a noticeable difference in off idle throttle response and a much more consistent vacuum at idle. I had a general replacement parts store PCV valve on it before and it must have been choking this thing. It was a nice (but spendy) side effect to this endeavor.

Appreciate the input everyone!

[grivera]

Glad it all worked out and the car looks great!

[Gach]

Gorgeous car, so happy to hear your results. Hopefully the hard work paid off

[dataway]

For what it's worth .. .it's been my experience that tearing down and reassembling a decent running engine to fix a relatively minor problem usually leads to an even better running engine with excellent durability. Sounds strange, but you typically find during the process those few other things that might cause problems down the road and address them, you do those couple of things you meant to do the first time, or you do just a bit better job at reassembly because the process is fresh in your mind and you are a bit less nervous and a bit more thorough.

[HWYSTR455]

I have a large, deep well 4WD socket I used to use to pack seals. And just to say it out loud, I never used RTV in the groove, and never filled the holes.

Glad this chapter is closed for you, and you get to enjoy the car!


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