3.1 Block - 3100 SFI heads - ???

[KlingonFiero]

Hi All!

I have been searching and searching and cannot seem to find any real info...

I have a 3.1 block, out of a 1991 Lumina.

I have the Heads, LIM, UIM, Fuel Rail, etc... , from a 1996 3100, this is the SFI stuff .

I have two questions.

1. What Gaskets do I use?

2. What pushrods do I need? Custom? or will the stock 3100 pushrods work? I have seen quite a different ideas on pushrods and am looking for a definate answer...

Thanks alot!

[KlingonFiero]

Oops, I do have one other question...

What are my timing cover options?

Use the 3.1 style? or the 3100 style?

I would really like to use a 1987 2.8 v6 timing Cover (this engine is going into my Fiero and I would really like to keep the acc. the same...)

thanks!

[Guest]

For the intake you would use the matching gaskets to the heads and intake, in this case '96 3100.

Head gaskets you can use from either the 3.1 or 3100, since they are the same gasket.

If you keep the genII (3.1) pistons you can use thinner iron head 3.1 gaskets (or 2.8 ), to be .040" compressed thicknes and bump SCR up to about 9.3:1. The aluminium head gaskets are .060" compressed thickness, and with the 3.1 pistons, 3100 heads and .060" gasket you will get 8.9:1 SCR.

Pushrods will need to be custom, no question.

Front cover will take some work. You can use your Fiero front cover but IIRC will have to block off one coolant port in the front cover where there is a bypass in the genI block, I don't believe the genII block has this coolant bypass.

You will also need to make custom accessory mounts due to the heads having a different bolt pattern in the end of each head as compared to the iron heads. Also the alternator will need to move farther up and rearward to clear the taller heads and valve cover. You might actually be better off swapping over to the genII/III accessory system.

[KlingonFiero]

For the intake you would use the matching gaskets to the heads and intake, in this case '96 3100.

Head gaskets you can use from either the 3.1 or 3100, since they are the same gasket.

Thanks a lot, that is part of what I needed to know...

Pushrods will need to be custom, no question.

Not what I really wanted to hear... I guess I will have to do some searching on that.

Front cover will take some work. You can use your Fiero front cover but IIRC will have to block off one coolant port in the front cover where there is a bypass in the genI block, I don't believe the genII block has this coolant bypass.

You will also need to make custom accessory mounts due to the heads having a different bolt pattern in the end of each head as compared to the iron heads. Also the alternator will need to move farther up and rearward to clear the taller heads and valve cover. You might actually be better off swapping over to the genII/III accessory system.

I will have to take a look at the junkyard tomorrow, I know that the 3.1 (gen II ) has the alt at the top of the engine, this is a problem for the Fiero decklid. I wonder if the third Gen 3100 SFI setup is the same...

Thanks!

[Guest]

Yes the 3100 has teh same mounting location for the alternator, but is more offset to the rear of the vehicle. Use the genII alternator set-up as it's a little tighter to the engine itself. The deck lid IIRC can be cutout to clear the alternator, since, and you'll be able to veryify this, I believe this part of the deck lid is actually a "double" thick area, where there is a space between two layers of the deck lid. I know for a fact that the genII alternator mount has been used in a Fiero.

[KlingonFiero]

I have seen some pics of the Fiero decklid, notched out to clear the alt. Obviously it can be done Just not sure I wanted that look, even as easy at it would be to change the alt. Still need to decide.

Just got back from the J.Y.
Got quite a lot of misc parts I needed to complete this swap, but couldn't get a 3100 Timing Cover.

I had serious problems trying to get the harmonic balancer off of the darn engines.The first one I tried, it came off about halfway, then wouldn't budge
The second one was even worse, it was stuck on so bad that it broke the puller!

I guess I will try the Fiero Timing Cover and go from there... If it doesn't work out, I can always go back to the Junkyard.

Still need to find a source for the custom pushrods...

[Guest]

I have a 3400 timing cover I'd sell you.
Do you have the 3.1 timing cover?

Custom pushrods can be bought from just about any cam manufacturer, poular sources are Crane Cams, Comp Cams, Camotion, etc.

[ForcedFirebird]

Custom pushrods can be bought from just about any cam manufacturer, poular sources are Crane Cams, Comp Cams, Camotion, etc.

The pushrods won't work from the FWD block in a hybrid?

[Guest]

The pushrods won't work from the FWD block in a hybrid?

No, the genIII pushrods are way too short. The genII pushrods are also usually too short. I used genII pushrods on my hybrid, because I also used genI adjustable rocker studs. I however DO NOT recommedn doing it this way, valve train geometry is not ideal, and I was constantly battling loose rocker arms. It would also mean that stamped rockers would need to be used instead of the roller fulcrum rockers used on the '96+ genIII heads.

[ForcedFirebird]

No, the genIII pushrods are way too short. The genII pushrods are also usually too short. I used genII pushrods on my hybrid, because I also used genI adjustable rocker studs. I however DO NOT recommedn doing it this way, valve train geometry is not ideal, and I was constantly battling loose rocker arms. It would also mean that stamped rockers would need to be used instead of the roller fulcrum rockers used on the '96+ genIII heads.

Thanx again

My hybrid is still on hold untill I get this rotatin assy in the 3.1, trying to get a hold of a 3.4 for the EDIS .

[Guest]

Stop calling it "EDIS", unless you plan on installing it in a Ford. :P

[ForcedFirebird]

Stop calling it "EDIS", unless you plan on installing it in a Ford. :P

Sorry, I have two Fords, a Lincoln, a BMW and a Firebird .

Immagine that being a GM fan, just couldn't pass up the deals I got .

[KlingonFiero]

I have a 3400 timing cover I'd sell you.
Do you have the 3.1 timing cover?

Custom pushrods can be bought from just about any cam manufacturer, poular sources are Crane Cams, Comp Cams, Camotion, etc.

I do not have the 3.1 timing cover. I got the heads, etc from a friend. Did not come with the timing cover or accessories.

I am a fairly decent mechanic, I can rebuild most anything, given the parts. Not too good at mixing and matching engine parts though
This is my first experience at this kind of thing.

So, I do not know what the repercussions of using a 3400 timing cover would be.

If it will work... send me an email, dsm56(at)hotmail.com.

I did find something on Crane's website ( I think that is what site I was on...) but they didn't list prices at all...

I did see the custom pushrods on the 60degreev6 store - for $135.00, is that inline with other places???

[Superdave]

http://www.pushrods.net

They did a custom set for my 3500 for $75.

[KlingonFiero]

http://www.pushrods.net


They did a custom set for my 3500 for $75.

Thanks for the heads up!