3500 crank

[zofo61]

So with all that said...........is the general opinion that the only thing we are changing on the 3500 is using the 3400 rods on an offset crank?

[bszopi]

Thought about this more while taking a shower, and figured out I screwed up the piston deck clearance (went out .075" instead of in). So, with that said, how about these numbers....

And with going with the 3500 heads, it yields 8.12:1.

Now, this assumes that a 3500 piston staying in the block 0.0065", unlike the 3100 where it comes out of the block 0.020". If we use that number, with the 3500 heads, CR is 8.53:1, and with the 3400 heads, it comes out to 9.14:1.

There was a reason I put a big IF at the beginning of my original post.

[bszopi]

Hmm... That's wierd. AHHH... I figured out what's wrong. I copied and pasted only 2 columns instead of all 3, so the stock values are showing up. Hold on, lemme see if I can recreate the numbers I had last night....

And yes, I used 3400 values for the combustion chamber volume and piston volume. Using the 32.4cc volume for the heads, the CR drops down to 11.33:1. I'm not sure of the stock piston dish(dome) volume for a 3500, so that may change things as well.

[ForcedFirebird]

IF I did the math right...

You used the stock bore/stroke for the 3400's? this number would be lower with 32.4cc chambers on the 3500 heads, and the 3500 gaskets have a 3.8" bore.

[El_Diablo]

holy shit.... someone was off, lol

[bszopi]

IF I did the math right...

[El_Diablo]

can someone please figure out the compression of the setup joseph proposed on the last page, im really interested in doing something like that but dont have the mathmatical know how to figure it out

[blkalero]

Why would the crank throws have anything to do with it, other than to clear the piston? Couldn't the pistons be profiled to clear them?

with rod length givin and piston pin placement they didn't clear.
this is why I dont recomend going 10mm. less of a stroke woukld be fine

What is the difference in diameter between the 3400 and 3500 pistons and I assume the 3400 block can take the bore?. Anyone have a line on forged 3500 pistons...............Ive been reserching a top coating as well..............think a little more lift and duration as well.....and would one of Bens regrind stages fit this combo?

Actually I meant to imply you use the 3500 block rather than pay to have a 3400 block preped to fit the pistons and crank. There were two sets of 3500 forged pistons on EBay about 2 months ago for a reasonable price that would have more than restored compression ratio with a .075" shorter compression height.

[Monzsta]

Why would the crank throws have anything to do with it, other than to clear the piston? Couldn't the pistons be profiled to clear them?

[blkalero]

So let's have the gory details.. Where did the block get in the way, any other clearance issues, and what did the pistons cost? There's a 3900 on ebay right now for $1,200... might be time to go hunting..

Being stroked 10mm requires the crank throws to be ground down as well as the block.
looks like there will be enough meat left without hitting a water jacket to clear the longer throw.
Thats kinda where I lost the extra cash to finish.
pistons were $735 I believe with rings. (JE forged) broke down to like $600 for the pistons and $135 for rings.
I went with manley rods forged I beams good for 750hp ish.
I decided on the I beans due to them being lighter than the H beams.

I wanted light and strong. this caused the price to go up I could of goten cheaper rods and saved a few hundred or more. I believe the set of six after mods ended up being close to 900 or more.
if I had to do it over I'd go like 6mm instead of 10

[zofo61]

What is the difference in diameter between the 3400 and 3500 pistons and I assume the 3400 block can take the bore?. Anyone have a line on forged 3500 pistons...............Ive been reserching a top coating as well..............think a little more lift and duration as well.....and would one of Bens regrind stages fit this combo?

[IsaacHayes]

Rods should be good for 350-400 crank HP. Others have dyno'ed 350ish wheel HP before on stock 3400. Pistons are the main thing, but if you have a good tune then you should be good generally.

[zofo61]

Stroke the 3500 crank with an offset grind to the 3400 rod journal size, then use the 3400 rods with the 3500 pistons. Since the rod length difference is .200, and the offset grind should be able to get you ~.125" increased stroke or closeness to the cylinderhead, the pistons will sit about .075" lower in the bore, considering the 3500 crank journal diameter is .250" thicker than the 3400 crank journal and you have to halve the diameter of the circle to get the amount you can offset grind the crank by without adding metal.

Not sure how much it will reduce your compression by but it should be perfect for boosting. Of course you can perfect it with custom pistons to restore the stock piston to deck height but if it isn't necessary it will save you quite a bit of doe.

Now thats the kind of info I needed to get rolling......................now if I am going for around 350 HP to 400 MAX( and thats optimistic) I should be able to use the stock 3400 rods and some forged 3500 pistons.....YES?

Ive been talking to Sappy as well about swapping the 3400 in 2002 Monte with the 3500/.........what would be the main issues with the harnessesand PCMs?..................what would I have to do to the 3500 to stroke it out?....I have one comming and I want to do the most with the 3400 I have and the 3500 thats comming...........remember I have that RSM Blower Kit sitting on the floor as well...........

Stroke the 3500 crank with an offset grind to the 3400 rod journal size, then use the 3400 rods with the 3500 pistons. Since the rod length difference is .200, and the offset grind should be able to get you ~.125" increased stroke or closeness to the cylinderhead, the pistons will sit about .075" lower in the bore, considering the 3500 crank journal diameter is .250" thicker than the 3400 crank journal and you have to halve the diameter of the circle to get the amount you can offset grind the crank by without adding metal.

Not sure how much it will reduce your compression by but it should be perfect for boosting. Of course you can perfect it with custom pistons to restore the stock piston to deck height but if it isn't necessary it will save you quite a bit of doe.