I have a few questions on 2.8L engines: 1. Are there any differences in the V6 engines used in automatic vs manual? If so, what are the differences. Can the engine from an auto be bolted in as a direct replacement in a car equipped with a v6/manual? 2. I found a new crate 2.8L and am not sure if it will fit an 87 Fiero. The person who owns it does not have any of the original paperwork, and hence does not have the part number. The casting number on the block is 10065459. According a a reference from GM website, that casting number was used in FWD 1990/3.1, FWD 1987-89/2.8. The owner claims it is a 2.8l. Itcame from the factory with injectors and the bottom half of the intake manufold. Any suggestions to determine if it will fit?
Posts: 213 From: Evans City PA Registered: May 2002
The only difference is the flywheel, I pulled a 2.8 from an auto car to drop in a manual car and all I did was take the flywheel from the manual motor to put on the motor I was dropping in, You just use the engine wiring harness that is already in the manual car.
More importantly, starting in '88 GM changed the way the crankshaft is balanced on the 60° motors such as the 2.8. The '88 up motors are internally balanced and use a neutrally balanced flywheel or flexplate, the '87-down motors need a counterweighted flywheel or flexplate. If you use the wrong flywheel/flexplate destroy the motor in no time.
The flywheel is used on manual transmission cars and the flexplate goes with the automatic transmission. Externally the blocks are the same. It is important to find out what cylinder heads originally came on the motor you're looking at buying (aluminum or iron) because the pistons are different between the two and mixing up the aluminum pistons with the iron heads will give you an unusable compression ratio. The block castings were the same, only the pistons were changed for the aluminum head and iron head motors.
Starting part way through '87 they started using the new block which has a single piece oil pan gasket (easy to spot) however, some were internally balanced and some externally.
If it is actually a 3.1 it will be internally balanced. You can put your iron heads on a 3.1 and it will work pretty well. They all marry up to the bellhousing, but like the man says, you will have to know which flywheel, assuming the engine does not have one already