??'s piston cc, gen3 rocker, 3400 lim-uim, headers

[merlot566jka]

ok in another post i asked a few questions that didnt really get answered. it may have been the title of the thread that made people not even look at it. here are the questions in better form....

what is the piston cc for the gen1 (IRON HEAD) 3.4?
what is the piston cc for the DOHC 3.4?
what is the piston cc for the gen3 3.4?
Are ther wrist pin location differences in these pistons?

are the gen3 rockers adjustable? i read that they are not, but cannot confirm. if they are not, when measuring for pushrods how do you know you have the exact length? This is asked because im using gen3 heads on a gen1 3.4. ive never worked on or with non adjustable rockers, so i dont understand how they can be non-adjustable and still work. unless they are perfect length pushrods.

also, ive seen the flow charts for the 2000+ 3400 lim and uim, impressive! but what are the port demensions? do they taper? im in the proccess of ordering these parts from another member, but im in alaska and the car and parts are in VA, so i cannot see for my self.

Last, whats the difference in gen3 exhaust portsvs gen1? as in, can my headers i have now for my gen1 heads be used on my gen3 heads...ive heard some only had to wallow out the exhaust manifold bolt holes on the headers about 1/8in to get them to bolt up...is this true? does any one have some old exhaust manifold gaskets from a gen1 and gen3 you can take comparo pics of for me? i know the ports are different shap, that can be taken care of with a grinder..if they line up!

i appreciate any help....

[bszopi]

From the site CR calculator... (http://60degreev6.com/test.php?do=start)

Piston Dish
Iron Head 3.4 - 8.0cc
DOHC 3.4 (91-95) - 5.0cc
Gen3 3.4 - 27.0cc

Here is a post from an old topic that lists compression heights (and piston dishes, etc): http://60degreev6.com/showpost.php?p...7&postcount=18

The Gen3 rockers are NOT adjustable. Remember, you have to take into account the preload of the hydraulic lifters, which will help if the puchrod is not the exact correct length. Here is a thread discussing how to determine correct pushrod length : http://60degreev6.com/showthread.php...ushrod+preload

Somewhere I have the port dimensions... Ben has them somewhere as well. If I can find them, I'll post them.

As far as the ports for the exh manifolds go, the ports are in the same location, but you just need to widen the bolt holes. Here is a post that talks about it : http://60degreev6.com/showthread.php...t=header+holes

Search is your freind...

[merlot566jka]

wow, thank you very much.

acording to your CR calculator, if you use the 28cc heads from a 3x00 on a gen1 3.4 you get a cr of 10.6 or so. WTF?

not questioning your integrity, but if thats right i dont know what im worried about.

and again thanks for the search stuff. its not the fact that i dont search, i guess i just dont know HOW to search. the searches i do never yeild results like that. i guess im retarded when it comes to searches

[bszopi]

Don't think you plugged the numbers in right...

You have selected to use the following values for your compression ratio calculations:
Bore 3.622"
Stroke 3.307"
Head Gasket Bore 3.75"
Head Gasket Compressed Thickness .040"
Combustion Chamber Volume 28 cc
Piston Dome Volume 8 cc
Piston Deck Clearance .0095"
Displacement 3349 cc
Calculated Compression Ratio 13.45:1

Here is a thread with port dimesnions : http://60degreev6.com/showthread.php...=plenum+design

And as far as searching goes... remember, I've been around here since the beginning (2000?) and try to read every post in every section, so I know what things have been said. And for some common items, I remember specific words to use for the search. One thing you might want to check though... Goto your User CP => Edit Options => Thread Display Options and ensure that Default Thread Age Cut Off is set to "Show all threads". That way your searching will go through the entire site, not just the past year or so.

[merlot566jka]

ehh yeah, today just isnt my day for the computer. i wasnt using my eyes to finger communitcation skills. .0095 for deck clearance. not .095

[merlot566jka]

using 2 head gaskets, greg wagoner in 'High Performance Fieros' did it successfully. yet it doesnt say how long he was successful! can this be done and expect some sort of durability? he also used this with a boosted 3.4pr. and didnt have a problem. i know this isnt suggested, but is there anyreason that it wont work?

the alternative is a headgasket spacer. also in the same book he eventually went to a headgasket spacer with a thickness of .075. this would work perfect with the 3400 head for a cr of 10.1:1 using the alum .060 head gasket. with the .040 head gasket from the iron head it yeilds 10.56 cr.

[ForcedFirebird]

You're hurting quench when you increase the gasket size (best if quench is kept around .040). If you are going to swap heads, it's not that hard to get the pistons out and swap them for 3400 pistons with a large dish.

OR

Look into the 3500 heads, the CR calculator doesn't have the chamber sizes, but they are larger than the 3400 heads.

[merlot566jka]

using 3400 pistons comes with several questions...

dont they have a 'slap' problem?
will i have to change anything, i dont know if the wrist pin is located in different area or what the difference is other than the dish on the pistons.

having said that, i agree with using them (3400 pistons) to lower the cr to an acceptable level. i am having another short block built, and im trying to figure this all out before i order it. i dont wanna screw my self over by ordering something thats going to take excessive work to make it work.

3400 pistons, stock deck clearance, gen3 heads= 9.57
3400 pistons, zero deck clearance, gen3 heads= 9.78
3400 pistons, 0 deck, gen 3 heads, .040 head gasket= 10.31 (BINGO!)

[merlot566jka]

ttt, anyone?

[bszopi]

The piston "slap" you are referring to isn't really a problem. It is due to designed clearances being at the opposite extremes for the block and the pistons (ie, the piston is the smallest it can be, and the block bore is the largest it can be, but both within accepted tolerances). This results in the piston "slapping" when the engine is cold. There is a very good chance you won't have to worry about it.

As far as you CRs go, I'm just wondering how you are planning on getting the zero deck height with stock 3400 pistons.

[merlot566jka]

install pistons, measure piston to deck height, remove pistons, shave the deck of the measured deck to piston....am i missing something here? do these pistons come outa the block at tdc?

[bszopi]

3100 pistons come out of the block .020", but it appears the 3400s stay in the block? Seems odd, but maybe that's right. I never looked at the 3400 in my car, and I only have 2 3100s and a 3500 in my basement right now....

[merlot566jka]

so the cr calc on the site says the deck height clearane is .0065 on the 3400, .0095 on the 3.4 iron head. this means to me the piston is .0095in from the deck at tdc in the 3.4, and .0065 in the 3400...right? using the 3400 pistons in the iron head block they should come to .0065 from the deck at tdc...?? are the 3400 pistons different in demnsions from the 3.4?

[wildchild]

I seen where a guy said he used a set of 3.4 dohc pistons in his 3.4 to raise the compression ratio.

[merlot566jka]

welcome to the forum....

the temptation to be overly rude to youis over-whelming, but ill keep my composure...
u r refering to using the 3400 block with the iron heads. yes many have used the dohc pistons to raise the cr of the 3400/iron head hybrid, mostly in fieros. but im working on an entirely different animal here. ive got the 3.4(iron head block) and im using the gen3 heads. im trying to lower the cr, or find means of making it workable with all factors taken into account. not ryin to bust ur balls, just setting u strait.

that said, ne one else have some insight on this, the piston height of the 3400 pistons used in the 3.4 block?