Boring a 3.4 *****.040"**** safe?

[whiteThunder]

i was going to bore my block .030", but with a huge cam, will i benefit more from boring .040" over? I was reading an old post by oil pan, and he said that it is safe, can anyone tell me for sure if it is safe? what about this bore with say 50-75 shot of nitrous? What will my compression be like after?

[StudlyCamaro]

the ammount of volume you are going to gain by going .040" over isnt much, personally i wouldnt bother comprimising my block for the 2 or so cubes...

your CR will be affected by the pistons you choose to place in the motor

[viper98885]

Originally posted by StudlyCamaro:
the ammount of volume you are going to gain by going .040" over isnt much, personally i wouldnt bother comprimising my block for the 2 or so cubes...

your CR will be affected by the pistons you choose to place in the motor

I agree...boring the engine .040 over will not yield any true power. The main purpose is just to recondition the cylinder walls. .020" or .030" over would be just fine.

[Jerriko]

There is not enough material to safely bore that much on a 3.4. .040 over is iffy at best.

[oil pan 4]

It is safe but not worth it.
If you bore it .040'' and some thing hapens (realy think about it, with a nitrous engine) and you have to bore it again you will be boring to .050 or .045'' That's over 1mm off each wall. That would push it on a nitrous engine.
I have seen 2.8L-3.1L blocks have been bored up to .080''-.090'' on an all motor race car, no power adder. I don't think they were built to last a long time.
The cylinder walls on the new hemi engines are done by some new casting methoid and the walls are .100'' to .110'' thick that is a little over 2.5mm.
3.4L block walls are 4.5mm thick.

[Jerriko]

Originally posted by oil pan 4:
It is safe but not worth it.
If you bore it .040'' and some thing hapens (realy think about it, with a nitrous engine) and you have to bore it again you will be boring to .050 or .045'' That's over 1mm off each wall. That would push it on a nitrous engine.
I have seen 2.8L-3.1L blocks have been bored up to .080''-.090'' on an all motor race car, no power adder. I don't think they were built to last a long time.
The cylinder walls on the new hemi engines are done by some new casting methoid and the walls are .100'' to .110'' thick that is a little over 2.5mm.
3.4L block walls are 4.5mm thick.

No, it is not safe. Please don't suggest that it is. We are talking about daily drivers on nitrous, not race engines.

[whiteThunder]

Ok, guess i'll stick to .030" (my original plan and some speedpro pistons). Thanks for all the advice, i really respect all of your input. One last question, with my rebuild, i was thinking will putting new pistons(not forged)in really be that beneficial, (it will cost me!) or should i just leave it alone. btw my car has 82,000 miles on the clock.

[JohnD.]

If you're gonna spend the money to replace them and plan on running nitrous then go ahead and replace them. Put in some forged higher compression pistons.

[whiteThunder]

will they really help a cam and head setup? i mean the car runs great now, i don't know what compression is like, but just was more power. so i decided on a full rebuild but am now having second thoughts? i though the larger pistons will help tame a huge cam?

[StudlyCamaro]

will a forged piston yeild more power over a cast or hypersplosive piston?, no, however they can take more heat and not break

and i have no idea where this "a large piston will tame a cam" thought is coming from

[Harry94]

I thought it was more compression helped to tame bigger cams not larger diameter pistons. When I was looking at cams the manufactures always wanted you to have more compression with the more radical cams.

[JohnD.]

I would either build it to run a big cam well or to run nitrous well.

[viper98885]

One of the main benefits of the forged aluminum pistons is the fact that the are lightweight and have a low "bob" weight (weight put on the crank at the top and bottom of the stroke). This will allow the engine to rev faster. The Ross flat-top pistons will offer a 10.0:1 compression ratio over the stock 9.0:1 compression. I have 2 sets of Ross flat-top pistons here that I am giving away at a helluva deal if anyone is interested. I have one set that is standard bore and one that is .020 over.

[whiteThunder]

are the speed pro pistons hyperplosive lightweight, or not really? Also, what are you asking for the .020 over Ross pistons?

[TraviepooCmro]

Hey man, what are you asking for the stock bore pistons?