2 bolt or 4 bolt
Thread Starter
Teching In
Joined: Apr 2008
Posts: 42
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2 bolt or 4 bolt hi there, i might be doing a rebuild this winter and im going to be making about 400RWHP and putting down 100 shot once and a while. i have a 2 bolt right now is that good enough or should i go with the four bolt. i want to do this build once and right. thanks matt
they made 4 bolt mains on lt1 blocks...well some of them..if you cannot find one you can have a machine shop or race shop transfer your bottom end to 4 bolt main..it would def be a positive thing if your runnin 400 rwhp.. you will be revving your car high and will want a stronger bottom end...
The 2bolt will hand no trouble handling 400rwhp and a 100shot.
There are a lot of H/C guys pushing 100 and 125 shots on stock bottom ends.
If you are rebuilding, you should at least consider installing studs.
They're relatively cheap and easy to install.
Forged pistons would be a wise investment as well for an N20 car.
4-bolt splayed mains will run you $600-900 for parts and labor.
They'll handle a whole lot more abuse than a 2bolt will though.
If you have the cash and plan to build the bottom end
so you don't have to come back and do it later, the 4-bolt is the way to go.
There are a lot of H/C guys pushing 100 and 125 shots on stock bottom ends.
If you are rebuilding, you should at least consider installing studs.
They're relatively cheap and easy to install.
Forged pistons would be a wise investment as well for an N20 car.
4-bolt splayed mains will run you $600-900 for parts and labor.
They'll handle a whole lot more abuse than a 2bolt will though.
If you have the cash and plan to build the bottom end
so you don't have to come back and do it later, the 4-bolt is the way to go.
TECH Apprentice
Joined: Apr 2007
Posts: 331
Likes: 0
From: Tempe, Az
The 2bolt will hand no trouble handling 400rwhp and a 100shot.
There are a lot of H/C guys pushing 100 and 125 shots on stock bottom ends.
If you are rebuilding, you should at least consider installing studs.
They're relatively cheap and easy to install.
Forged pistons would be a wise investment as well for an N20 car.
4-bolt splayed mains will run you $600-900 for parts and labor.
They'll handle a whole lot more abuse than a 2bolt will though.
If you have the cash and plan to build the bottom end
so you don't have to come back and do it later, the 4-bolt is the way to go.
There are a lot of H/C guys pushing 100 and 125 shots on stock bottom ends.
If you are rebuilding, you should at least consider installing studs.
They're relatively cheap and easy to install.
Forged pistons would be a wise investment as well for an N20 car.
4-bolt splayed mains will run you $600-900 for parts and labor.
They'll handle a whole lot more abuse than a 2bolt will though.
If you have the cash and plan to build the bottom end
so you don't have to come back and do it later, the 4-bolt is the way to go.
I would sooner start with a 2 bolt block than pay a premium for a 4-bolt. Reason being by the time 4 bolt is genuinely a good idea you are going to want aftermarket caps and fitting aftermarket caps to a 4-bolt block is not much less work than it would be to fit them to a 2-bolt block.
Really though as covered most guys are way too quick to think they need this.
Really though as covered most guys are way too quick to think they need this.
I would sooner start with a 2 bolt block than pay a premium for a 4-bolt. Reason being by the time 4 bolt is genuinely a good idea you are going to want aftermarket caps and fitting aftermarket caps to a 4-bolt block is not much less work than it would be to fit them to a 2-bolt block.
Really though as covered most guys are way too quick to think they need this.
Really though as covered most guys are way too quick to think they need this.
But I do have complete light weight rotating assembly.. Trending Topics
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Teching In
Joined: Sep 2008
Posts: 13
Likes: 0
Just a note, your options would be...
2 bolt
4 bolt straight
4 bolt splayed
If you can find an LTx block that has 4 bolt straight caps then that should be just fine. But if your gonna get it done, go with the splayed caps. It really isn't that big a deal to do.
2 bolt
4 bolt straight
4 bolt splayed
If you can find an LTx block that has 4 bolt straight caps then that should be just fine. But if your gonna get it done, go with the splayed caps. It really isn't that big a deal to do.
wishing they had done it right the first time. It's not cheap by any means,
but with the motor apart, it's a hell of a lot easier to do it right the first
time than to have to rebuild later.
This seems especially true for N20 cars who fail to recognize the intense
pressure put on the bottom end when they hit that little red button.
I do agree that it's certainly not needed for a 500rwhp setup.
It's when you decide that a 125 shot isn't big enough anymore and start
messing with 175, 200, ......
(similiarly with N/A setups converted to S/R and F/I who decide to take "just one more step" with the boost level)
Fortunately, it's a lot easier to go back and fix mistakes in the valvetrain
than to rebuild the shortblock. That is, assuming it doesn't fail in the mean time.
Cheap pushrods, weak springs that can't handle RPM, excessively strong springs on cast cams.
It's all about doing it right the first time around.
Man, I wish someone had kicked me in the *** 8 years ago and taught me some of this stuff.
People very rarely stop at their modest goals, so you have to ask yourself where you really see your car in the future.
I once said my car will be just bolt-ons...then I was not happy with only running ~12.8s on motor. I thought about throwing just a baby cam in it like the 219, but then got a sweet deal on some used ported heads. Had a bit larger cam groud for it and ran 11's NA on stock shortblock, which made me content for some time...now the whole thing is torn down and I am going to a pretty radical high CR 383 - which is a splayed 4bolt. That is because even though it will be ran with a custom grind NA cam for now, who knows if I get the itch in the future to change cams and throw a 200+ shot of nitrous at it? Might as well be ready if the desire arises in the future...
I would have saved tons if I had thought everything through and really thought about what I wanted before hand, and saved up to go forged stroker right off the bat.
If you plan on keeping the car, and can afford it, go for the 4-bolt IMO. Who knows what you may dream up in the future for the car.
I once said my car will be just bolt-ons...then I was not happy with only running ~12.8s on motor. I thought about throwing just a baby cam in it like the 219, but then got a sweet deal on some used ported heads. Had a bit larger cam groud for it and ran 11's NA on stock shortblock, which made me content for some time...now the whole thing is torn down and I am going to a pretty radical high CR 383 - which is a splayed 4bolt. That is because even though it will be ran with a custom grind NA cam for now, who knows if I get the itch in the future to change cams and throw a 200+ shot of nitrous at it? Might as well be ready if the desire arises in the future...
I would have saved tons if I had thought everything through and really thought about what I wanted before hand, and saved up to go forged stroker right off the bat.
If you plan on keeping the car, and can afford it, go for the 4-bolt IMO. Who knows what you may dream up in the future for the car.
i plan on doing a similar build in the near future. an di just wanna make sure either of these caps will work.
http://store.summitracing.com/partde...art=ESP-C4102S
http://store.summitracing.com/partde...w=1&N=700+150+
http://store.summitracing.com/partde...art=ESP-C4102S
http://store.summitracing.com/partde...w=1&N=700+150+
When I had my 383 built, it was a little more to go to 4 bolt splayed caps, NON billet, and I felt better having it. Cranks dont often snap, but will help with bearing deflection under heavy loads.