Performance Engine Rebuild Page 4

Page:     Prev 1 2 3 4 5 6 7 8 9 Next

All the images below are thumbnails. Clicking on them will bring up the bigger images.

HP Books How to Rebuild Your Small Block Ford
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".
HP Books How to Rebuild Your Small Block Ford
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.
Cleaning the Mains
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.
Mains Bearings
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.
Dropping in the Crankshaft
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.
Mains Bearings
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.
Torque the mains
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.
Crank Installed
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.

Page:     Prev 1 2 3 4 5 6 7 8 9 Next
Mail to Mike Mail me!
Back Back to Mike's home page! Valid HTML 4.01!

Last updated: Mon, Feb 18, 2002.
Copyright © Mike vanMeeteren, 2002.