|
This is the book at no serious engine builder should be without. I've assembled somewhere around
40 engines, half of those small block Fords. I could probably do it with my eyes closed. But
every time I do one of these engines, I still have this trusty book sitting at my side to double
check my work. Not only that, it's a great reference for all the torque numbers. The book is,
of course, Tom Monroe's "How to Rebuild Small Block Ford Engines".
|
|
Not only is it a great reference, it's a good book for the beginner as well. I recommend that
anyone thinking about rebuilding their engine read this book cover to cover, twice. It will help
you avoid a lot of costly mistakes. On top of that, it is a good book for evaluating if you
are capable of tackling a rebuild job yourself, or should farm the work out. Anyway, I opened
the book up to the page on crank shaft installation, just to double check my work.
|
|
The time has come to install the crankshaft. The first thing we want to do before loosening
the main caps is wipe the inside of the mains out (to get the fogging oil off), and then
loosen the main caps.
|
|
Now we install the top half of the main bearing shells into the block. Make sure the bearings
are dry, we don't want any oil on them to throw off our clearance readings. Remember that the
thrust bearing goes on the #3 main.
|
|
We're going to set the crank in the block to check the clearance, but first the passages
need to be cleaned. This is done by simply using the straw with the brake cleaner and shooting
through the passages from the main to the rod journal. Then wipe the journals themselves
down with a paper towel. Now *gently* set the crank into the block. Grab the crank with
two fingers in the hole for the pilot bushing, and a hand wrapped around the snout. Make sure
you're not standing on oil where you could slip. Lower it in carefully, being very careful not
to hit the main studs. Contact with those studs will nick the crank, and you'll be on your
way back to the machine shop.
|
|
Now we install the upper half of the bearings into the main caps. Again the thrust bearing goes
on the number three cap.
|
|
Even though I trust my machine shop completely, I still double check their work. Even the
guy running the crank grinding machine is human, and mistakes are sometimes made. Since I
don't have a full array of machine tools like bore gauges, journal micrometers, etc, I have
to rely on the simple yet useful method of Plastigage. Plastigage is a simple wax strip of
a certain thickness, that you flatten by installing the caps. You then remove the caps and
check how wide the Plastigage was flattened to, which tells you the clearance. The Plastigage
color you want is green, which measures from .001 to .003 inches. My motor is set up for race
clearances, so I want .0025 main clearance. The Plastigage comes in a paper sleeve. Instead
of pulling all the Plastigage out at once, just cut the paper sleeve into sections as wide as
the main journals. Then remove the wax strips, and place one on each main journal. Plastigage
must be used DRY, so make sure there is no oil present on the crank or bearings.
|
|
Now replace the main caps, and torque them to spec. With main studs, the torque setting is
90 ft/#, and I like torqueing that in two steps, stopping at 60 ft/# the first time through,
starting from the center cap and working my way out. Make sure the caps are fully seated before
you start torqueing the caps down. Sometimes a gentle tap with a hammer is required on the
side of the cap to get the cap to sit down on the block. After torqueing the main caps down,
loosen the caps up again, taking care not to spin the crank. If you spin the crank, the
Plastigage will smear, and you have to start over.
|
|
You can kind of see the Plastigage strip here flattened out. The strip was wider than the .003
marking, but not quite as wide as the .002 marking. The main journals are exactly where they're
supposed to be.
|
|
After we Plastigage the mains, the crankshaft is removed. Clean all the wax from the Plastigage
off the crank using a little brake cleaner. Now clean all the bearing surfaces with brake
cleaner. Install the rear main seal in the block. I like to use the method described in the
Tom Monroe book, I've never had a rear main leak using his method. You put a small dab of sealer
on the end of the seal, offset the seal slightly in the groove, and place a small T of RTV between the
cap and block to keep it from leaking. Once the seal is in, put a thin coating of ARP Moly
Assembly lube on all the bearing surfaces. Then drop the crankshaft in again, replace the main
caps, and torque to spec. The next thing you want to do is check crankshaft endplay. Force
the crank all the way forward, and place a feeler gauge between the thrust bearing and the crank.
You should have .005 to .009 clearance.
|
| |
|
|
Mail me!
Back to Mike's home page!
