Wanted:. 1986 V6 harmonic balancer

[Fierofool]

If your balancer doesn't, and the engine has the engraved plenum, next thing I would do is to look at the back of the flywheel for the presence or absence of weights and get a balancer to match accordingly. 

[Fierofool]

I have a meeting to go to and didn't have time to read through this, but it might be of some help.

https://www.hagerty.com/articles-videos/articles/2017/11/27/identify-pontiac-engine-blocks

[TopNotch]

Here is page 3-11 of the GM 60-degree V6 Power Manual. This is official GM information. This should end all confusion on the subject.
See especially the second paragraph of the second column.

[PK]

Yes TN, that is the article I referred to earlier.  So very weird why some have the harmonic balancer "weight" and others do not. 

Thanks FF, I will enjoy reading that linky dink.

[PK]

If you can't see the VIN on the block, assuming they used the flywheel that might have been on an engine swap, and your inspection plate is off at the bottom of the bellhousing, you can pull the coil wire and slowly rotate the engine and look for counterweights on the flywheel.  An 88 engine and flywheel won't have counterweights.

Checked just now, I have an externally balanced enjun.

My terrible memory told me the inspection plate would come the whole way off without removing anything but couldn't work out how!??

I also have a small oil leak either from the sump or real seal... Deep joy. :0)

[PK]

If you can't see the VIN on the block, assuming they used the flywheel that might have been on an engine swap, and your inspection plate is off at the bottom of the bellhousing, you can pull the coil wire and slowly rotate the engine and look for counterweights on the flywheel.  An 88 engine and flywheel won't have counterweights.

Checked just now, I have an externally balanced enjun.

My terrible memory told me the inspection plate would come the whole way off without removing anything but couldn't work out how!??

I also have a small oil leak either from the sump or rear seal... Deep joy. :0)

[GTRS Fiero]

So, pre'88.  Someone changed the upper intake plenum.

[PK]

It must have been changed a good while back.  I have had it 20+ years... And that's how long it took before I learnt engraved is not original.

[GTRS Fiero]

Unless some late '86 models got the later plenum.

[Fierofool]

Unless some late '86 models got the later plenum.

That's possible.  Look at the manufacture date on the door decal.  If it was something like late June of 86, that may have happened.  It might even be an 87 engine, which I believe has some improvement on the oiling galleys. 

[PK]

Door date is 03/86 so I guess someone changed plenum. 

[GTRS Fiero]

Does the brake booster port have a threaded bushing that screws into the plenum?

I'm also curious if you have the pre-'88 oil sending unit.

[PK]

This is a great way to get to know your Fiero!  I will try and remember to check next time I am there.

[PK]

I remembered to look bit wasn't sure exactly where/what I'm looking for?

[GTRS Fiero]

Look on pages 10 and 11 of the October newsletter.