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Posted

I bought a complete BEST gasket kit for my engine re-build. It included the new type neoprene rubber 2 piece seal.   But there are no detailed instructions on how to install it.

I'm thinking there must be a correct method.  Has anybody done this with success and can post procedure here please ?

I have contacted BEST to ask for help but as yet they have not replied.

 

Posted

No Lamar, it's on my pick up project 401 engine.  I got a BEST gasket kit but it only comes with the new style rubber seal.  I'm 50/50 on whether to use the rope or rubber.

I know Willie has not has success with the rubber style.  Others swear by it, so it's all doing my head in trying to decide which way to go.  I don't want to pull engine after it's all been re-built to fix oil leaks.

Posted

The rubber seal does not work on the 264/322 because of the machined groove in the rear main. However, supposedly the 364/401/425 have been reported with great success to work because the machining of the rear main is consistent. I think the difference between the two is the 322 looks like this: \_/ and the later engines look like this: |_|

  • Like 4
Posted

Rooster, maybe I have them backwards. If it's a 401, it should work. Otherwise, I don't think BestGasket would sell a complete kit with the rubber two piece - the 322 kits come with a rope seal instead.

Posted

They seem to work for some people Benjamin , but not for others.   There has to be a specific method of install for it to be successful.   The rubber piece ends sit proud in the cap groove by about .020" or so.   So there must be a trick to how much to trim ( if any ) and what sealant to use --- if any.   That's the key to it all I reckon.  These seals have a metal wire core so they wouldn't need to have much crush,  if not trimmed to a degree I can't see how they would not buckle under torque ?  The supplier BEST ( and others ) have not got back to me yet , so will wait for help, if not then the new rope seal goes in.  I've had enough of waiting and need to get this all together.

Posted (edited)

Can only share the following from my rebuild thread if you do decide to go the rope seal route and it did sit .015 proud.  There was a shim provided in the BEST kit that was put against the seal and then the seal trimmed with a razor knife along the shim to get the .015.  The engine is still bone dry after a year since the rebuild.

 

Rear rope seal going in, left .015 above the top of the seal and lightly tapped it in.  Ed put a dab of anerobic sealer (doesn't need air to cure) on the side seams, inserted the provided rubber seals along with 2 provided thin rods that are tapped in the side to tighten the side seal up.  Should have taken pics of that.  This set was from Best Gasket, will see how dry this Nailhead is. 

Edited by KAD36 (see edit history)
  • Like 1
Posted (edited)

On most rear main seals that are rubber, there iS a "front" and "rear" side to the seal.  How the thin flange "points", for example.  On many rubber seals, there is ALSO some small knurlings cast into the rubber.  These are supposed to direct oil that got that far BACK into the motor.  In the 1960s, there was a "help??!!" letter to the automotive person in "Popular Science" magazine.  He'd just rebuilt his engine and had a significant rear main seal leak.  Installation was "correct", other than he installed the rubber rear seal halves backward . . . knurlings pointing the wrong way with respect to crankshaft rotation.  That helped the oil get out of the motor, not direct it back into the pan.  Reversed the seal and the leak stopped.  I suspect there should be some pictures of this online, somewhere, or in some online service instructions.  Perhaps in other gasket maker websites?

 

I do like the conversion to a rubber rear main seal from the older rope seal, personally.  But it can be installed the wrong way, unlike the rope seal (although there are some issues with rope seals unique to that type of seal).

 

NTX5467

Edited by NTX5467 (see edit history)
  • Like 2
Posted

The new rubber seal halves come with a diagram to show the correct forward facing lip install.  But that's it as far as instructions go.  Maybe the seal, with it's protrusion on each end is made to suit a number of engines ?   That's where the success is measured I reckon.  How much to trim and where ----- it being a different install procedure than the rope.

  • 3 weeks later...
Posted

… rooster just install the rubber gasket and be down with it … loosen the main bearing caps so you have little crank shaft drop to aid in the install … leave top cap with about an 1/8 inch gasket protrusion, trim the bottom cap but not quite flush and torque the cap down after applying machine oil to the treads of the bolts, torque in 1/2 increments and you will be go to go with a 59 engine regardless is it is the 364 or 401 ….

Posted

Thanks for you advice on this buick man, but it's too late.   After much ( too much ) deliberation / procrastination I've installed with rope seal.  I got NO responses from any of the rubber seal suppliers on multiple requests for correct install procedure.  Not even BEST who supplied the gasket kit without instructions.   So I didn't want to take any chances with getting it wrong.  If the rope leaks ( badly )  at least I then have the option to install the rubber seal as you suggest.  Too hard or not possible to change from rubber to rope without taking engine out and to pieces.   And I ain't doing that again  :o

 

 

  • Like 3
Posted

… that is right what they sat about the rope If the technique is correct and the done properly and you are aware of some of our qualified members that have given you suggestions on how to do just that  … however, with the rope there are various methods and various ways to screw it up … with the rubber if you leave the rubber proud beyond the cap surface about 1/8 inch, there is very little room for " application technique " error and a resulting leak, unlike when "roping"  a crank … so yes if it leaks then go put on your rubber !

  • 3 years later...
Posted

Resurrecting this thread with the same question. The neoprene seal projects above the surface somewhat. Do you trim it it, or let it crush a bit?? I think the answer is trim it. Also, it seems like it would make sense to rotate the seal so the halves ofthe seal are not in line with the halves of the main cap. Anyone? 

Posted

Have not done the rubber seal but thinking about it, it seems less likely to crush than the rope seal (that was .015 high) so flush might be best.  Whether you trim it flush or leave it maybe .005 high try it dry first see how it fits and consider a dab of anaerobic sealer to help ensure it seals.  Good luck

  • 3 months later...
  • 1 month later...
Posted

yep you can put rubber rear seals in the early engines too about half the time.    thanks for the shout out bill.  yeah check out my blog.  www.nailheadbuick.com/blog       i have 50 articles on there now surrounding the nailhead, which i have written.   articles consisting of parts identification.  how to's.  trouble shooting, and specs.    buying parts from me comes with very extensive product support.  i build 15 to 20 nailheads a year.  its all i work on.  all the parts i sell, are the same parts i use on in house builds... so i know what works and what doesnt, first hand.   click on that link and scroll down 40 or so articles.  i have 3 articles on rear main seal installs.  one on rope, one on rubber, and one on the rope, in car, patch job.  also information describing when each one is the best option.  

  • Like 1

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