Just thought I'd update this thread with the latest stuff we've done...

My daughter got all the accessories on the engine today. It's been slow going, just a lot going on... but she got the new alternator, new starter, cleaned up water pump pulley (with new water pump), and the new A/C compressor installed... all with the correct brackets.

I don't know why these pictures came out so badly... but whatever...













Again, if I didn't mention it, this is a 1985 roller-cam block that we're converting to a serpentine system:


ALTERNATOR - Alternator comes from a 1988 Fiero V6, with a 6-groove 1987-1988 L4 Fiero alternator pulley. We use the alternator brackets from the 1984-1986 Fiero engine.

AC COMPRESSOR - We use an A/C compressor from a 1987-1988 L4 Fiero, specifically with a 6-groove serpentine pulley. Brackets come from an 87-88 Fiero. There's one bolt hole missing from the bracket, but it still bolts in perfectly. It really feels like it doesn't need it, but I may weld an "ear" on the bracket to use the other bolt hole (block differences from 1985 and 1988). We can't use the 86 bracket because even though it uses the new compressor, we want to convert to a serpentine system, and the 86 brackets are designed to allow the compressor to be adjusted for belt tension (has a separate belt).

WATERPUMP - There is no difference on the waterpumps for the Fiero from 1984-1988. The only difference is the pulley. The biggest issue is that the pulley is extremely hard to find. This one was given to me off a donor L4 / 87 motor. The one from my 88 was very badly mangled and we couldn't use it.

CRANK PULLEY - The crank pulley from a 1987-1988 Fiero L4 will easily fit a 1984-1986 crank... and it'll just work. But we wanted to incorporate a harmonic balancer to help smooth out the motor a little bit. We found a brand new OEM GM one that was compatible (from like a 1989 Grand Am), and installed it. NOTE: L4 Fieros never came with a harmonic balancer.


She also installed a new starter, which is the much smaller starter from the 3400 V6 in the 1998 Pontiac Grand Am ? (if I remember correctly).

... as you can see, the only bad thing is that you don't get a lot of contact surface on the crank pulley. I don't think it will be a huge issue... particularly because to be quite honest, this is the factory belt routing of the normal "V" belt, which tends to have less grip anyway. It's not ideal... the V-belt L4 Fieros always seemed to squeal. The 87-88 Fieros used a belt tensioner which really improved the contact pattern, and I don't think this was ever an issue for those cars. I'll say in this case, it's a 6-groove pulley (everything is 6-groove) and the V6 Fiero (which does not have a tensioner) is only a 5-groove. So I THINK I'm going to be OK. I'm still looking for potentially a spot to place an idler pulley.

As I mentioned before, the factory belt tensioner will not fit on the 84-86 blocks... the bolt locations just aren't there. GM changed a lot of stuff from 86-87... and that being one of them. The whole block is totally different, so it's amazing that anything bolts up (as you see above).


Just floating some ideas, but I'm thinking either an idler pulley sitting somewhere between the waterpump, compressor, and crank pulley... like, right in the middle of that triangle, so after it goes around the waterpump and compressor, it then sneaks up to an idler pulley, and then back down to wrap around the crank pulley before going back up to the alternator. It gives a bit more meet on the crank pulley... and I could install a stud there... but I may not even need it... so still considering.

[This message has been edited by 82-T/A [At Work] (edited 06-09-2024).]

[This message has been edited by Patrick (edited 06-10-2024).]