building destroked 3400

[bjornmk1]

hey forced firebird.
I misunderstood your question about the gasket.
the brown circle you see is from the factory gasket.

the engine had only 18 miles on it when it had a wrist pinn stuck....

[ForcedFirebird]

hey forced firebird.
I misunderstood your question about the gasket.
the brown circle you see is from the factory gasket.

the engine had only 18 miles on it when it had a wrist pinn stuck....

No, I was asking about the ports .

Maybe I'm a little lost, but if you are using a 2.8 crank and 3400 pistons, wouldn't the pistons be really far down in the bore if you used 5.7" rods? The 2.8 had the wristpin location .3" lower in the piston so the same rods could be used in the 3.1 and 2.8 with a longer stroke. This would mean you needed 6" rods to get the piston back at the top of the bore at TDC.

[bjornmk1]

You're right about that.
I planned on using the ford cosworth pistons that I had.
that would work fine with that 2.8L crank.

BUTT....since I bought these puppy's for some few $$$
I changed my mind and wanna go the 3400 way.

I am talking to a guy from arias to find out more on those
pistons and they seemed to be made for NA using 200hp nitrous.
according to beeri(arias contact) the pinn's are to thin on wallthickness.
however the upper part(above the top ring)is beefier than a standard piston
so I plan on removing some material there to get towards 9:1 compression.

we'll see if I can get some pinns from arias or elsewhere.
info on this would be apreciated !!

Bjorn

[bjornmk1]

BTW you can watch all pics on my build on photobucket
under futurefiero.

I now have to decide wether to go with a 3400-3.1 crank or with 6"rods.

[bjornmk1]

arias has the pins I need for those forged puppy's
they are 19$ a piece.

think I'll go with that.

[bjornmk1]

in order to get a CR of 8.6 I will need to:

have the block and heads shaved .105 in total.
I checked the threadholes in the block for depth so the headbolts
will still fit properly.
.100 on the block itself is not wise so I will have about .037 shaved from the heads and about .068 from the block itself.

[IsaacHayes]

Will that work or is that too much for the heads? What about the intake manifold lineing up? Sounds like a head ache!

[bjornmk1]

well isaac,

it looks like the heads would take .05 max or so without warping I guess.
I'm not so sure on the block though...but it's iron and no aloy...

[Superdave]

iirc .020" is max for the heads.. any more than that is really risky

[bjornmk1]

sure ...according to the GM manual.
but I think that's only cause of the fitment issue of the intake.
I think the heads can take more than .020

[bjornmk1]

to the shop

tomorrow I'm gonna take the block
to my machinist for machining the decks
and have hin put a sleeve in cylindr nr.5
(where UNFORTUNATLY the pistonpin got stuck)

and if I have some sparetime this week...
I'll flow my other head and replace the valvespring
with the ls6 ones.

I'm also leaning towards using the mls headgaskets from the shop here.
they will probably do a better job sealing the heads than
the severe duty fellpro gaskets.

Gotta check my budget

[ForcedFirebird]

The MLS gaskets are re-usable, aren't they?

[bjornmk1]

I wouldn't re-use them.
the sealing between the layers will be gone.

[1988GTU]

IIRC I'm pretty sure you can buy that sealant to reapply it as necessary.
http://www.scegaskets.com/products/titan.html They are the ones with the sealant I speak of.

[bjornmk1]

maybe you can do that.
but those type of gaskets are ussually layers that are riveted together
one way or the other.

so one should seperate and clean each layer.

I would buy new ones for sure.
just my 2 cts.