FAQ |
Members List |
Social Groups |
Calendar |
Search |
Today's Posts |
|
#1
|
|||
|
|||
Serrations and the lip type seals.
All,
I have a new Eagle crank for my 455 and am planning on using a 1 or 2 piece rear main seal. I keep seeing to make sure the serrations are not too aggressive. This is a very objective statement. What defines aggressive? The Eagle crank doesn’t seem as aggressive as the original crank. Has anyone had a crank shop weld up the area and grind smooth? Any thoughts would be appreciated. Stan. |
#2
|
||||
|
||||
I simply ask the machine shop to polish that spot so as to just remove the sharp edges and provide a smooth surface for the seal to ride on that won't chew it up.
Done that on the last few Pontiac builds and those seals have worked perfectly for me. |
The Following User Says Thank You to Formulajones For This Useful Post: | ||
#3
|
||||
|
||||
The Eagle Cranks are noted for having very rough serrations, and its a problem for any type of seal. I would definitely get the serrations area polished.
|
The Following User Says Thank You to Gach For This Useful Post: | ||
#4
|
|||
|
|||
I have read in the archives that they are rough. Crazy, the eagle is less pronounced and smoother than the original? That’s why I’m curious what aggressive is.
|
#5
|
||||
|
||||
Sharp is probably more of problem than aggressive. If it feels like a nail file, too sharp. Feels "pebbly" but not too tall, probably ok. Basically a lip seal probably does best on a completely smooth surface, but taking it down that far might make it a bit loose?
__________________
I'm World's Best Hyperbolist !! |
#6
|
||||
|
||||
When I was dealing with rear main seals I sent a pic of my Eagle crank to Wade at BOP and he said they looked aggressive. Compared to my factory crank they're definitely more pronounced and frequent so I guess that's what folks mean when they say "aggressive".
After burning up two rope seals, I decided to try the one piece seal but I had the serrations polished before installation. So far so good.
__________________
Ken '68 GTO - Ram Air II 464 - 236/242 roller - 9.5” TSP converter - Moser 3.55 Truetrac (build thread | walk around) '95 Comp T/A #6 M6 - bone stock (pics) |
The Following 4 Users Say Thank You to Verdoro 68 For This Useful Post: | ||
#7
|
||||
|
||||
I can't help but imagine that when looking at factory cranks they are already somewhat polished after running 150,000 miles on a rope which might make them appear "less aggressive"
Just a thought. I've never had an NOS Pontiac crank in my hands to really compare. |
#8
|
||||
|
||||
did you try the ""best Rope seal" ? ^^^^^
i have used on factory cranks and like. BOP 2 piece on my scat cranks on IA2 blocks have a one piece will try on IA2A
__________________
1969 carousel red firebird 455, richmond 5 speed 1964 540 gto 1971 lemans sport convertible 1972 Maverick under slow construction |
#9
|
||||
|
||||
My factory crank is in storage and I don't have any pics handy, but my recollection is that it was quite a bit smoother with less serrations at a different angle than the Eagle.
Yes. I started with those and destroyed two. The first time it rotated in the channel, the second time it melted. I wrote off the failures to installation errors on my part (issues with the way they were packed seemed to be a common assessment) but never really had a definitive answer on why they failed.
__________________
Ken '68 GTO - Ram Air II 464 - 236/242 roller - 9.5” TSP converter - Moser 3.55 Truetrac (build thread | walk around) '95 Comp T/A #6 M6 - bone stock (pics) |
The Following User Says Thank You to Verdoro 68 For This Useful Post: | ||
#10
|
||||
|
||||
Quote:
Thats my experience comparing stock crank with Eagle crank. I can see why there’s been many issues with Eagle. Don’t have a picture of stock crank handy. looking at your Eagle crank, my opinion that was good part of the issues you were having. Now that it polish definitely seems to have helped. |
The Following 2 Users Say Thank You to Gach For This Useful Post: | ||
#11
|
||||
|
||||
Sooooo, the angled serrations are there for some sort of micro-vane pump effect or what.
|
The Following User Says Thank You to Half-Inch Stud For This Useful Post: | ||
#12
|
||||
|
||||
That's what I've been wondering.
__________________
70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Ray Klemm calibrated Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
The Following User Says Thank You to jhein For This Useful Post: | ||
#13
|
||||
|
||||
Quote:
The lip seal on serrations deal would be much less of a pump huh. We could pine for a rear seal that was sprung tight like a front seal. That Remains Mechanically frustrated. Last edited by Half-Inch Stud; 11-17-2023 at 09:52 PM. |
#14
|
|||
|
|||
With all the issues with Eagle and their serrations that makes the choice simple, buy Scat-Molnar and run the one piece.
|
#15
|
||||
|
||||
So you're saying the Scat crank has no serrations, or they are just not as bad as the Eagle? My motor has a Scat forged crank but it was delivered directly to my builder and I only saw it sitting in his shop in the box so I don't l know.
__________________
70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Ray Klemm calibrated Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#16
|
|||
|
|||
Scats are smooth.
|
#17
|
||||
|
||||
Is it this? The crank serrations are "oil return threads" to scoop up any oil that gets past the seal and return it to the engine? Huh. So does that mean that the engineers knew the seals would never really seal and they just had to find a way to make it less noticable?
Scroll down to the diagram of the crankshaft and see that these are referred to as "oil return threads". https://www.theengineerspost.com/cra...-and-function/
__________________
70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Ray Klemm calibrated Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#18
|
||||
|
||||
Is it this? The crank serrations are "oil return threads" to scoop up any oil that gets past the seal and return it to the engine? Huh. So does that mean that the engineers knew the seals would never really seal and they just had to find a way to make it less noticable?
Scroll down to the diagram of the crankshaft and see that these are referred to as "oil return threads". https://www.theengineerspost.com/cra...-and-function/
__________________
70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Ray Klemm calibrated Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#19
|
|||
|
|||
If you are buying a aftermarket crankshaft, there is no reason to use 100 year old rear main sealing tech. Buy smooth.
|
#20
|
||||
|
||||
Really what you don't want to see or feel is a cheese grater. Usually a roll of sand paper or emery cloth will smooth things right down. The sanded down serrations left on the first crank didn't hurt anything, and the serrations on the second crank pictured actually didn't touch the area where the seal rode. The Best Teflon/Graphite seal discolored the crank where it rode.
__________________
Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon in progress. |
Reply |
|
|