Last Update 04/04/04
WE MAKE SERIOUS PONTIAC HORSEPOWER
AND WE KNOW MORE ABOUT BUILDING STOCK PONTIAC ENGINES THAN ANYONE.
-FOUR BOLT MAIN CAPS-
This is a two part FAQ. I will reference using stock and aftermarket caps.
Another phone call we get is, "Do you have any 4 bolt caps?
My first reply is, "What is your car and how fast do you want to go?"
If I know you need four bolt caps I'll reccomend aftermarket caps.
Because, trying to use USED four bolt caps 99% of the time will not work.
Why? Many reasons.
#1 The alignment of the main housing bores is super critical.
#2 There's an allowable factory tolerance on every machined part.
Which means - the dowel pin holes are almost always NOT in the same place as your
original caps. I have gone through many different caps until I've found just one close
enough to Re-hone to achieve proper alignment. I've NEVER found a cap
from another block that bolted up to proper torque and was perfect.
The hole must be PERFECTLY round. And, a specific size.
(See my FAQ Rod and Main bearing Clearances page)
So, that brings us to doing the job right from the get-go.
Using after market caps - which are ALL made undersize on the circle, or as
spoken in the machinaist world, the radius, are the best option. Making them undersize allows a machinist to
machine a new perfect circle, and place the thrust area in the right place.
Some people compain that we're too high priced. Well, now you know that all
of our engines recieve this inspection and upgrade.
Most shops cut this operation, and that's how you get cheapie engine rebuilds.
So when wondering if you can buy factory four bolt caps off E-bay and put them on your block
the answer is no! Don't take that risk.