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#1
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So as mentioned in a previous post I thought I had a rear main seal leak in my 65 GTO (68 461 engine) race car. I did not build the engine nor do I know much about it although opening up the bottom end added some light.
Question - I have attached 3 pictures. I dont know what a bad rear main seal looks like. What if anything do the pictures tell you? Would hate to pull out a good seal and replace it when it might be just a pan gasket issue or something else. Thanks |
#2
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You have a BOP 2 piece. But also have serrations on the crank.
I would use a BEST seal on a crank like that. BOP lip seals are better with a smooth aftermarket crank. |
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#3
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Is it possible to install the Best Gasket rope seal without removing the crank?
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#4
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Best Gasket CO grafite rope seal.Most of the Pontiac sellers have them.Tom
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#5
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Thanks guys for the quick replies!
So does the hatches mean its a GM factory 455 crank? I have learned the engine has BRC 971 pistons and Eagle CRS-6800 H-Beam connecting rods |
#6
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If its a 68 engine its not a 455. It could have a Eagle stroker crank in the 68 400 block making it a 455 for all intents and purposes. They had the serrations.
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#7
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It is a 400 with a 455 crank, I was just asking if its possible to determine whether someone worked on an original crank or used an aftermarket one. The Eagle crank would make sense as it does have Eagle connecting rods
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#8
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If you post some pics of the crankshaft, that can be determined quickly. A shot of one entire counterweight would do it along with one main cap removed to reveal the oil hole. Eagle crankshafts have a unique oil hole drilling strategy and trough carved into the journal. No other crankshaft brand I am aware of or any OE crankshaft uses this technique.
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#9
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Pic of Eagle "trench style" oil hole scheme.
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#10
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I took the advice and pulled the crank (1st timer) to do it hopefully right the first time.
But,,, when I lifted the crank some of the rod bearings stuck to the crank unknowingly and then fell off so not sure which bearing is for which rod. Big deal or little deal? Do I need to replace them now? Car had about an hour breakin time on a stand before I bought it and I have put 13 passes on it. |
#11
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No problem.
Just make sure they go in the correct way. ![]()
__________________
John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#12
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If you look at the bearings that got mixed carefully, they should have a break-in pattern on them now. It may take a little time, but if you study them carefully, you will be able to match them back up. Also, as mentioned, depending on the brand and series of rod bearings, they may have an upper and lower bearing shell. They will have an L, (lower) or a U, (upper), after the part number on the back of the shell. The upper and lower halves have a chamfer on one edge of the shell and not the other. Most aftermarket crankshafts use these bearings for clearance against the large fillet radius.
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#13
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Concerning replacing the rope seal with the crankshaft in the engine. Yes it can be done and I have done it dozens of times. How does the repair do? Not the greatest IMO. When I worked at the Pontiac dealer as a tech it was a different time. Pontiac engines were well known as oil leakers as well as their cousin, the Oldsmoibile . Small oil leaks were considered "normal" just like a Harley Davidson or a Jaguar. I replaced 13 oil pan gaskets/rear main seals in 1 week at the dealership. Could do them in the car in 2-3 hours. Would take me all day now to do 1. The process was to form a new seal half in the cap first. Then carefully remove it and cut it into 1/2' sections. Then use a specially made brass punch formed from instructions in the factory service manual and gently mash the OLD rope seal into the block groove with this punch from both ends. Then insert the new 1/2" sections in the groove and mash therm in with the punch. You could generally mash 2-3 1/2" sections into the upper groove. Trim the ends with a razor. Then install a new rope seal half in the cap and put the thing back together. That was the "official Pontiac" method for replacing the rear main seal in the car. How did it work? For the time period, pretty decent. It would knock a big leak down to a few drips. That was considered good enough in those days. About 1/2 of them would be leak free. I wouldn't do one this way today unless there was a reason to not remove the engine and really do it correctly.
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#14
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Based on your pic and the ones I attached it would appear to be an Eagle crank, right?
Also attached 2 pics with some number stamping |
#15
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455 crank in a 400 block would require some type of thrust bearing mod. The factory crank would have the part number on it. Aftermarket ones I have seen and used have marking on the front counter weight identifying the manufacturer. Also their part number.
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Be carefull of the feet you step on today.They may be attached to the a$$ you kiss tomorrow. |
#16
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If you could take one more pic straight down of the oil hole, I can tell you. Eagle cranks have oil feed holes that look like a human eyeball. The hole is in the center and it is chamfered on both sides. All the other crankshafts have a scoop type chamfer on the leading edge. On a factoery crank the chamfer is very small and not a scoop at all.
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#17
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Thanks guys for all the thoughts, comments and advice. Crank is out and hopefully the seal will be back in and the bottom half back together next week!
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#18
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Thanks for the historical perspective Mike!
__________________
Anybody else on this planet campaign a M/T hemi Pontiac for eleven seasons? ... or has built a record breaking DOHC hemi four cylinder Pontiac? ... or has driven a couple laps of Nuerburgring with Tri-Power Pontiac power?(back in 1967) |
#19
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With the serrations on the crank that tells you it’s not a stock crank if someone turned one down they wouldn’t put the serrations back. I can’t remember the last time I heard of someone turning a crank down like 20+ years.
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#20
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Here is a pic as requested
Also two somewhat related (easy) questions 1. Is that the correct way to secure the dipstick? (see second pic) 2. The builder laid 4 nuts between the windage tray and main caps to provide more clearance for the crank. Is this correct/proper? Thanks DV |
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