[dv657172]

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

[Dragncar]

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.

[tom s]

Best Gasket CO grafite rope seal.Most of the Pontiac sellers have them.Tom

[dv657172]

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

[Dragncar]

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.

[dv657172]

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

[mgarblik]

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.

[mgarblik]

Pic of Eagle "trench style" oil hole scheme.

[dv657172]

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

[chiefbigb]

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.

[mgarblik]

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.

[grandam1979]

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.

[dv657172]

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

[mgarblik]

Thank you. Eagle absolutely. 2 choices for the oil leak situation. 1. Install a Best Brand rope rear main seal. Pack and trim carefully. 2. Remove the crankshaft and polish the heck out of that seal area with a crankshaft polisher. You don't need to remove the serrations but they need to be polished extremely smooth. Then you can try a new viton rear seal, one or 2 piece. Personally, I would try the Best rope seal. Good luck with it.

[dv657172]

Thanks mgarblik. I think I am going to go with the rope seal and hope for the best

[Formulas]

Eagle crankshafts have had issues in the past with machining and finish
If i was in your shoes i would run my finger over the serrations and make sure they are not to ruff proud or agressive for any seal at all

[Verdoro 68]

Originally Posted by dv657172

Thanks mgarblik. I think I am going to go with the rope seal and hope for the best

I recently went through this with the Eagle crank in my build. I tried a one piece and a two piece BOP seal and both leaked substantially during the tip test. Although I haven't run the engine yet, Graphtite seal hasn't leaked a drop on the stand with the pan full of oil for months which I take as a good sign.

https://forums.maxperformanceinc.com...861242&page=14

[dv657172]

Thanks formula for the advice and Verdoro for the optimism

Formula where do you live in WV, family from between Beckley and Charleston.

[Formulas]

Originally Posted by dv657172

Thanks formula for the advice and Verdoro for the optimism

Formula where do you live in WV, family from between Beckley and Charleston.

Close to Ohio river south of 35 frwy. Gallipolis Ferry hiding out on 10 acres in a log cabin

[dv657172]

Sounds nice, enjoy!