 |
Here's some background to get everyone up to speed. I have an '86 Caprice coupe that shows up in the magazine from time to time. It was a V6 car, but I bought it planning on upgrading to a V8. Later, I bought a 94 9C1 (police package) Caprice from former staffer Terry McGean with the intention of swapping that car's entire drivetrain into my car. In preparation, I wrote an overview article on the LT1 engine that appeared in our January 2008 issue. We had a lot of positive response to that, so Doug gave me the green light to do an LT1 build.
LT1 Caprices are ideal donor cars, because they are plentiful in junkyards. They also came with all the upgrades that some of the early LT1's didn't have (vented Optispark being one of them). Plus, they don't command the higher prices of F- and Y- car parts. I pulled the engine out of the car and took it to JMS racing engines in El Monte, CA for an overhaul. I wanted to put the engine back to stock condition to get a good baseline number before doing any aftermarket parts testing. Here's what we found:    Crank was bad- the thrust flange had worn out. JMS's Mike Johnson said that's a common problem on these engines. A mismatched torque converter can load up the crank, essentially pushing it forward in the block. I got a new stock replacement crank from Scoggin Dickey.
The block, cam, and heads were all in good shape. Awesome for a 250,000 mile police car-turned-taxi cab.
There was too much piston to cylinder bore clearance. I was really hoping to be able to just do a light hone and ring and bearing replacement, but JMS recommended a 0.030" overbore. LT1's came from GM with Mahle pistons, so I got a set of 0.030-over pistons and rings from them. The rest of the bearings and gaskets came from Summit Racing.
The build will continue in the next installment...
John
|
Share This
|
|
|