piston info/gasket info/crank info

[dohcfiend]

does anyone know if they make 40 over forged pistons for the 3.4 dohc? i know they make 40 over i seen it on a site be4, but i thnk they were hyper...(forgot how to spell it)pistons.

also this will be the kicker does anyone have any info on copper or steel headgaskets?(or something very hard to blow, so i won't have to worry about replacing ever again) with stock thickness?

i have heard of nitriding cranks to increase strength. would it be worth the $$$. me i am thinking 3 things. forged 40 over pistons + crank strengthening + bulletproof headgasket = extra displacement and 100 shot.

40 over will make it a 3.5l right?

i need some input on this. am i going too far? will this be a recipe for diasaster or low et's?

if every1 thinks it is a bad idea, (seeing how u guys have alot more experience than me) i will take the advice.

except for the head gaskets. if they are out there i will put them in.

[4spdz34]

if i remember correctly the 91-95 head gaskets are of a fiber compound and the 96-97 are metal. try those

[Streetrodder83]

Generally the rule of thumb when running N2O, is no more than half the engines total power. Now, if you do a fresh rebuild using the stock parts you shouldn't have a problem with a 100 shot. Now, running forged pistons on the street is a double edged sword. Sure you have a stronger piston, but at the expense of your cylinder wall. A forged piston expands more, meaning you have to run a larger piston to wall clearance. So when they are cold piston slap occurs wearing away at the cylinder wall. Hypereutectics control expansion better, reducing the piston to wall clearance. The amount of power you are going to be making shouldn't be a problem for a hypereutectic piston. You would be better off sticking with the stock head gasket, then to put in a copper headgasket. Unless, you plan on not driving the car much. Yes coppers are strong, but if you are constantly running your car they will become brittle. They are meant strictly for a racing application. Where their required use is short. With what you are doing you should be alright with the stock parts, so long as you stay out of detonation with the N2O.

[SappySE107]

100% agree. The added displacement on our engines really isn't worth the price to bore them out. Its a minimal gain and thicker cylinder walls never hurt anyone. If you want to go crazy, do a 150+ shot. The crank will be fine as long as you control detonation. If you are going to do anything, deburr and polish the crank. Shotpeen is you wanna go the extra mile. Nitriding is a term I have heard but dont know the full extent of. Any surface hardening will help the crank out though. Balancing and cleaning up the cast marks will strengthen it enough though really. Only for balls to the wall applications do you really need to go overboard on the crank modifications.

[brian89gp]

if i remember correctly the 91-95 head gaskets are of a fiber compound and the 96-97 are metal. try those

That is some of the best news I have heard, if it is true. Gotta head down to Orielly's and check it out.

[dohcfiend]

metal gaskets are good. the reason i was asking is that i have been told that the cylinder pressure from the 50 shot was the cause of the gasket failing. and then i can't get the rear cam bank off.
i had a guy come over from the local machine shop and he didn't have any ideas. so the next step is to remove the engine.
if i am doing that i was curious abut the guts while i have it out.
as far as n20 goes i have read and was told that it was only safe to 30% engine hp with stock timing. which would be 70hp. i figured i would be safe with a 50.

so u are saying the internals can handle a 100?

and it was not detonating at all with the 50, and it only ran lean for about 2 runs until i got some colder plugs. and the 2 runs was about 3 weeks ago.

yea, metal head gaskets rule i am getting those for sure.

well, on that note, the only way i am going to increase the spray is if i can find a n20 retard box.
u guys know of any for these motors?

thanx for the info on the gaskets.ltr.

[SappySE107]

The MSD DIS-4 will work for retarding spark via RPM switches. Id like to see some pictures of the 96 gaskets though if you get a set. I doubt they are any different than the felpro set I have for 91-95.

[Streetrodder83]

The felpro numbers are the same for both engines. Studding the block will offer slightly better clamping. If you are only going to race this car then go with a copper gasket. But, if you intend to drive this car on the street do not use them when they become brittle they start to lose their ability to seal. If you are going for race only, put them in, but if you are going to be doing any street driving you'll be changing head gaskets quite often. At the power levels you are at right now there is no need for them. The head gaskets you already blew were probably on the verge of going as it was the N2O finished them off

[dohcfiend]

yea, you are probably right maybe the person that told me was jealous or something. not a race only car. copper=bad, steel=good.lol.

studding? sounds expensive(arp ain't cheap), but i guess boring is too. i think it is $50 a cylinder.

lastly, since i will have the motor out soon what bottom end mods do you recommend?
i am thinking new rings.

[4spdz34]

all the 96-97 engines i have torn down at the dealer or seen tore down had the metal head gaskets. u might only be able to get them from the dealer.

[Streetrodder83]

What you do now depends on the funds you have and where you want to go with it performance wise. Having the block blue printed would atleast get everything into factory spec what you do from there is up to you. But, having the rods shot peened and beam polished, and also having the crank polished and shot peened would be good ways to strengthen up the bottom.

[dohcfiend]

after considering all of your input and actually getting prices on these procedures. i think it will be best to leave the bottom end alone for a while. it would cost me around $600 to go to just hyper 40 over pistons. $200 to bore+$180 for pistons and the good rings are around $200 aren't they?it would have been more for forged i bet.

i was also thinking of the reliability i was sacrificing by going up on the n20. i admit it i was bitten by the hp bug and it temporarily took away my common sense.

also i didn't take into account the design limits of the engine block. like i could have beefed up the bottom end but i would still have stock mains.

on a positive note i found someone that will polish the head ports for $75. i figure it doesn't take alot of skill to polish the ports so i might go with that, a stall, the metal head gasket, an ud pulley, and the 13* mod and maybe i will notice an improvement. i will have to get back to the bottom some other time(maybe), being how i am running out of bolt-ons(well other than a 96 intake to be ported, but i will cross that bridge when i come to it).

i do have a goal however i mentioned it on one of my 1st post 300 n/a flywheel hp. after i get this i will be happy.

how many to the wheel hp will it take to have 300 engine hp? ex. 300 engine hp measured on a chassis dyno would be 275 hp.

after i get the motor back together i will take it to a dyno and measure n/a hp and n/a+n20 hp. of course i have to find a damn hoist 1st.ltr.peeps.

[SappySE107]

I wouldn't bother with polishing. Its not good for the intake and polishing alone isn't gonna do shit for the exhaust.

[dykz34]

It would take approx. 240whp to be 300 at the crank.

[Dave]

I'd at least replace the bearings, deglaze the cylinders, and put in a set of fresh rings, at that time you can measure the cylinders and see if they are out of spec, also measure the piston skirts, if you're running N2O that can damage the whole piston, even if you ran lean only a couple times.

I'd say blowing the head gasket would either be from running too lean, or bouncing off the rev limiter, wich in turn can cause an overly rich or lean condition.

I'd look at the total seal gapless top ring, since you're naturally aspirated, might be something to think about.