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| Pontiac - Street No question too basic here! |
| View Poll Results: Which rear main seal | |||
| Best Gasket braided Teflon/graphite rope seal |
   
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14 | 42.42% |
| BOP 2 piece viton seal |
  
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19 | 57.58% |
| Voters: 33. You may not vote on this poll | |||
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#1
10-31-2019, 08:39 PM
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Rear main seal
Looking at parts here and there as I build my 428. For the rear main I’m between the BOP 2 piece viton and the braided Teflon/graphite rope seal. I’ve used the viton seal in 2 engines I’ve assembled, 1 was dry the other had a tiny drip. I’ve talked to a handful of people who have used the graphite rope seal and not one had a leak or drip.
Of these 2 which seals have you used and have you had success?
__________________
1967 GTO, 432 (428+.030), 4-bolt mains, factory Nodular crank, scat rods, icon dished pistons, Lunati HR 243/251@.050, .618/.622 lift, Edelbrock 72cc round port heads, 10.5:1, offy 2-4 intake, Edelbrock 650cfm carbs, Super T10 trans (2.64 first), BOP 10 bolt w/ Eaton posi and 3.36 gears |
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#2
10-31-2019, 08:44 PM
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Rope seals have worked okay for me, on factory cranks.
With that said, so have the 2 piece BOP's. As long as the crank is polished and knurls removed, the BOP seal does an excellent job. On the other hand, if you have the knurls removed, I wouldn't use the rope seal. Pretty sure the aftermarket cranks I've seen don't come with the knurl like the factory cranks did. |
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#3
10-31-2019, 09:02 PM
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I prefer the Best rope seal on my 3.25 journal engines. Not a drip from one of them. The rope seals that come with the fel pro gasket kits are complete junk. I’m sure the viton seals are nice. Have always questioned how they would seal up good with the grooves cut in the factory crank where the seal rides.
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#4
10-31-2019, 09:34 PM
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Quote:
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#5
10-31-2019, 09:44 PM
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Why no 1 pc BOP choice?Tom
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#6
10-31-2019, 09:47 PM
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guess i’m lucky using BOP one piece seals no problems yet
__________________
2008KRE Q16 Winner 2014 atco raceway doorslammer winner 86 grand am tube car 8.95 @152 455 eheads solid flat tappet cam Hoffman Racing building and racing Pontiacs for 35 years |
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#7
10-31-2019, 10:14 PM
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Im 100% with the 1 pc,50-50 with the 2pc and 100% with the Best Gasket rope.Tom
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| The Following User Says Thank You to tom s For This Useful Post: | ||
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#8
10-31-2019, 11:06 PM
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I will never, never use a rope seal if a lip-type seal is available for the application.
Two exceptions: 1. Sealing machinery that's pumping abrasive material. This obviously does not include the oiling system of a car engine. It might include sealing pumps that move wastewater and the like. Rope seals handle abrasive fluids better than lip seals. 2. Certain Pontiac engines that have the seal groove non-concentric with the bearing saddle. I have heard--but never seen--that some Pontiacs were pretty bad in this regard. A rope seal would adjust for non-concentric machining better than a lip seal. |
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#9
11-01-2019, 04:07 AM
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First time user of the 1 pc BOP seal .. perfect so far ... not even the tiniest drop. Did not have the OEM grooves polished off, but they were pretty smooth already.
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#10
11-01-2019, 06:06 AM
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Yup the one piece seal works perfect even with the grooves on the Crank not polished off, but you do then need 2 people to install the Crank.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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#11
11-01-2019, 08:05 AM
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I have the Viton one piece seal and have had zero oil issues.
https://www.bopengineering.com/beltd...c_topend.shtml
__________________
1967 Pontiac Tempest 2dr HRDTP Coupe 468 C.I. 500 HP 5 speed = FUN!!! 1990 Chevy Suburban R2500 Daily Driver 1986 Volvo DL245 Wagon.. Project car!!! The Burb Files |
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#12
11-01-2019, 08:07 AM
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BOP one piece if the block hasn't been excessively align bored. If it has been worked over a few times, I would use the rope seal.
__________________
71 Formula 433, Splayed cap 400 block, 4" stroke Scat forged crank, 6.8 Eagle rods, custom Autotec pistons. SD 295 KRE D ports, Old faithful hybrid roller, Torker II, Holley Sniper Stealth, Tribal Tubes, TKO 600, 3.73 Eaton posi. |
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#13
11-01-2019, 08:32 AM
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BOP 1 piece for sure.
__________________
"I know just enough to keep me here, but not enough to get me out" |
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#14
11-01-2019, 01:52 PM
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Quote:
I did have a small drip when using the one piece seal on a crank ground smooth, but that could have easily been user error on my part. Sent from my SM-G965U using Tapatalk
__________________
68 Firebird-- Street/Strip - 400/461 Eagle Forged Bottom End & Ross Flat top pistons. KRE 325 CFM D port, Ultradyne 263/271 @.050, .4267 lift. Crower Solid roller lifters and 1.65 stainless rockers. Quickfuel 1000 on Torker2 intake and 2" open spacer. Hedman 1.75" headers. TH400 w/brake. Ford 9" w/3.80 gears & 28x9 Hoosier pro bracket drag radial. Best ET: 1.35 60ft, 6.29 @ 107.20 mph, 9.99 @132.33 mph. 3,300 race weight |
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#15
11-01-2019, 05:55 PM
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I have a 2pc BOP seal in my 400. Tight as a drum. Did a tip test to verify before installation. I will say we never had to do the tip test in the ol' days with the asbestos laden rope seals; they could sure make up for a lot of production variation in that area. However, if you get the BOP type seal right; 2 piece or 1 piece, they do a better job overall.
__________________
 65 Tempest, 400, TH400 86 Fiero SE 2.8 |
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#16
11-01-2019, 06:20 PM
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Have installed several BOP 2-piece Viton seals on several 3" engines. No leaks after years and many miles. Have installed one 1-piece BOP.....no leaks, plenty of service. Also a 3" engine. That said, If I were doing a 3.25" engine, I would use the Best Gasket rope type, as the large journal engine seems to be happier with this type of seal due to the construction and design of the rear main cap and block. So: BOP for the 3" mains, and Best Gasket for the big journal engines.
__________________
Jeff 
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| The Following User Says Thank You to geeteeohguy For This Useful Post: | ||
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#17
11-01-2019, 06:55 PM
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I only have 20 minutes run time on my 467 but I used the Viton 2 piece seal and the tip test and it didnt drip at all
__________________
468/TKO600 Ford thru bolt equipped 64 Tempest Custom. Custom Nocturne Blue with black interior. |
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#18
11-01-2019, 09:34 PM
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The rope seal has worked exceptionally well in a factory crank 400 for the last 8 years and (maybe) 25k miles. Absolutely no leaks. Using the same on a 455 build that will replace the 400.
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#19
11-01-2019, 09:47 PM
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Quote:
GT. |
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#20
11-01-2019, 09:57 PM
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Quote:
__________________
1967 GTO, 432 (428+.030), 4-bolt mains, factory Nodular crank, scat rods, icon dished pistons, Lunati HR 243/251@.050, .618/.622 lift, Edelbrock 72cc round port heads, 10.5:1, offy 2-4 intake, Edelbrock 650cfm carbs, Super T10 trans (2.64 first), BOP 10 bolt w/ Eaton posi and 3.36 gears |
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