Question : Honing question for a 3.4L PR

[npdimonte]

Hi,

I'm new to rebuilding and have a question on honing my 3.4L. How much can I hone before I need to replace the pistons with larger pistons? If I have to replace the pistons, whats a good source for them?

FYI: 3.4L is for a '88 Fiero GT project.

Thanks,
Nick

[pocket-rocket]

You said 3.4l, so I'm assuming RWD and not the FWD 3400.

http://60degreev6.com/content.php/128-3-4L-(Gen-1)-Specifications

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[Superdave]

why are people calling it a 3.4 PR all of a sudden? Is it a Fiero forum thing?

It's easier to denote it as either an iron head 3.4 (gen 1) or an aluminum head 3400 (3.4L) Gen 3.. or even as a FWD (Aluminum head) engine or RWD (iron head) engine.


Honing doesn't remove much material if done correctly, it's just there to create a surface for the rings to break in to. Honing for too long can distort the bore and you'll have all kinds of problems. Chances are that you'll also have to ream the ridge at the top of the cylinder. If it's too bad you'll break the top rings and the pistons.


Take it to a machine shop and have them measure the bore, roundness and cylinder taper. They'll tell you if it's OK just to hone/re-ring or if it needs an overbore to get the cylinders round/clean again. This is a good place to spend your money, don't cheap out and assume everything is ok.

[carbon]

It probably is a Fiero forum thing... random new users say all kinds of things, like 3400DOHC and 3.4 PR. They also tend to consider Gen 2 and 3 AL heads as the same animal.

Not everyone does it, mind you, but I got tired of, and I think some negs(forum member ratings) from, pointing out the differences all the time. Like, "Shut up fat kid! We don't care!"

[pocket-rocket]

Honing doesn't remove much material if done correctly, it's just there to create a surface for the rings to break in to. Honing for too long can distort the bore and you'll have all kinds of problems.

Take it to a machine shop and have them measure the bore, roundness and cylinder taper. They'll tell you if it's OK just to hone/re-ring or if it needs an overbore to get the cylinders round/clean again. This is a good place to spend your money, don't cheap out and assume everything is ok.

^^^ This.

I'll admit, I made the dumb mistake of assuming when I didn't have the correct measurement tools once. Luckily it was one of our cars and not one I was working on for someone.

I assumed since it sounded fine when it broke down (timing belt) that cylinder to bore clearances were fine and just broke the glaze off the bores. Come to find out they weren't and the thing had piston slap and used oil after that. Most likely it wasn't as quiet as I thought before hand since it wasn't my daily, but my wife's, but in the end it was a big lesson learned.

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