I am doing a 3.4 swap in my 86 se 2.8 im keeping the 3.4 oil pan. Question is what is the difference between the 85 86 timing cover verses the 87 88 timing cover? Also can i use my 86 timing cover or do i need to purchase an 87 or 88 timing cover? I have looked up part numbers on sites like rock auto.com and they show the same timing cover for 1985 through 1988 part # PIONEER 500189 if i do need an 87 or 88 timing cover does anyone have one for sale that will worknon my 3.4 swap Thanks

The mating surfaces of the front cover/oil pan changed with the later model V6 engines.
Early design had a 45°angled interface, later designs met at a 90° angle.
Your 3.4 pan is 90°, the 85 front cover is 45°.
Be sure to use the 3.4 oil pump and pickup in your swap, not the 2.8 components.

Like mentioned above, the 3.4 V6 oil pan will only work with the later style Fiero V6 timing cover. The Pioneer #500189 appears to be the correct part.

My personal choice would be (and actually was) to get an '87-88 Fiero V6 oil pan and timing cover. You can still use the superior 3.4 V6 oil pan gasket (which is also reusable!). Plus, you don't need to modify the motor mount bracket or bash the pan for clearance. And you'll have more room for exhaust routing. But you will need to trim the baffle, to make room for the 3.4 V6 oil pump. I did it with tin snips. No joke.

[This message has been edited by Blacktree (edited 04-26-2017).]

Is there any issue with using the 85-86 pan and 85-86 timing cover on a 3.1 or 3.4?

quote Originally posted by pmbrunelle: Is there any issue with using the 85-86 pan and 85-86 timing cover on a 3.1 or 3.4?

No problem, that is what I did after making the mistake of mixing the '86 pan with the 3.4L timing cover.

And just so the OP knows his options, you can use the 3.4L oil pan and the 3.4L timing cover with the 3.4L water pump as long as you swap out the metal impeller for the one on the 2.8L water pump. You cannot use the stock 3.4L water pump as it's reverse rotation to the stock 2.8L water pump and will cause overheating. Don't ask how I know this.

Pressing the old impeller off and the new one on is an art that I have not mastered. Once I broke my impeller I gave up. Water pumps are cheap but I didn't have the right tools and just messed things up.

3.4L water pump at the bottom, 2.8L at the top.

[This message has been edited by Hudini (edited 04-26-2017).]

quote Originally posted by pmbrunelle: Is there any issue with using the 85-86 pan and 85-86 timing cover on a 3.1 or 3.4?

No issue, except that the early Fiero V6 uses a crappy oil pan gasket design, which is prone to leaks. The later design is better in that regard.