you have a few choices and what you find will dicated what you do
if it was a rope seal engine, the crank will be knurled at the seal surface.
if it still has a visible knurled pattern to drive oil back into the motor you should put in a rope seal, a rubber seal is not going to last long as it has a knurl style pattern on its lip which will ware off on the knurled crank pattern.
the best rope one i found was an ACL/permaseal seal off a holden V8. its part number is HN022 its made of fatter rope than the rest, they work
bit of a pig to fit
but here is the method
https://youtu.be/kSQWlnvAIbI
other options are the 2 piece neoprene/rubber seals made by just about everyone, for small block v8
fit one of them if there is no knurl or it is worn away.
if it has worn away then the diameter of the crank at the seal surface is going to be wrong.
the seal will have been made for a standard diameter on the crank. it has the correct amount of crush built in only if the surface it is sealing against is standard. a worn rope seal surface will be a smaller diameter
you could try getting the crank re knurled but the likelihood cracking is high on a crank that has worked hard and is in its final treated state.
if the block has ever been line bored to correct an issue with the crank main caps then 99% sure the job won't have involved recentering the seal housing. rope seal copes with this, rubber doesn't particularly well. too much crushing by crank on one side and not enough on the other
or indeed if it was a rope seal motor to start with they won't have given a second thought to the seal housing concentricity as it doesn't really matter with rope.
anyway rubber seals
so
put seal in housing and do up to torque
measure crank at seal surface
measure seal inside diameter.
seal needs to be squished a specific distance by the crank to work
(I can't remember how much for a 2 or 2.5 inch bore i do have it written down so can find it)
if it isn't going to be squished the correct amount
take it out
you will need to shim the bottom of the seal housing and cap with thin sliver of metal.
layer of silicone
stick in the metal sliver same width as bottom of seal "trench" and ending about 1mm from the junction between block and cap at both sides. form it first, before gunging it in.
more silicone
put seal on top
press it in and wipe up the silicone mess
put in crank.
repeat same exercise in the cap
do not glue the seal halves together
leave it for 24 hours to set
take out crank
put cap back on
check bore size of seal in relation to diameter of crank if its within the proper range all good
take off cap
put in crank
super glue or silicone ends of seal
smallest wipe of silicone on the mating surface of the cap, tiny.... do not let it block off the tiny return paths from the bolt hole to the inside of the motor.
if yours has rubbery bits in the seal pack for sealing this bit use them instead
put cap back on
do it up
leave it for 24 hours.
or you could try the not very easy
sump off
lower the crank a few mm on the caps
pull out old seal
try to feed new seal in
hope for the best....
might work ....
its a job i have to do as well
last time i had it out i couldn't get an ACL rope seal from Oz as ACL had just gone Under/bankrupt and permaseal wasn't a name i knew at the time i used a standard gasket set one....it worked for the first couple of 1000 miles
I'll have to put in a buick v6 seal or modify a pontiac one from BOP engineering as nobody makes a rubbery one for mine
i just can't be arsed at the mo.
i wouldn't bother with lead free heads unless you need heads..
if you stick with the cast iron heads put stainless valves in. if the exhaust seats have recessed get inserts put in.... you don't need to for the inlets,
would be odd to have seat recession on the inlets anyway, and if there is enough left on the perimeter of the valve head and they don't rock in the guides use em again. depends what you want to do.
its the exhaust valves and seats that suffer.
dave
