4 bolt main or 2 bolt main?
Team Owner
Joined: Mar 2000
Posts: 83,381
Likes: 87
From: Boston, MA
Re: 4 bolt main or 2 bolt main? (britvette)
2-bolt in all L98s. Corvette didn't see 4-bolt in a C4 until the LT5 came out in 1990 and then the LT1 in 1992. You're going to have to make a hella lot of HP to break your 2-bolt.
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Drifting
Joined: Jul 2000
Posts: 1,661
Likes: 4
From: Phoenix, Arizona
Re: 4 bolt main or 2 bolt main? (TheStef)
All L98s were 2-bolt mains. So was the x-fire in 84. GM parts manual lists same part number for caps 84-91 and says "2 bolt." Also, the "4-bolt" mains in the LT1/LT4 only had 4 bolts on 2-4 - #1 & #5 were 2-bolts.
Drifting
Joined: Mar 1999
Posts: 1,931
Likes: 1
From: Norcross GA
Re: 4 bolt main or 2 bolt main? (britvette)
The casting's used in the 60's were weaker than those used now (80's). i.e. Big TQ needed a 4 bolt setup. Monster engines of years gone by.
Today you can make big TQ on a 2 bolt w/o a too much of a problem. Going to a 4 bolt will help the bearings last longer. Is it worth the expense,... depends on how much TQ your talking about. A street engine,... spend your $ else where.
Today you can make big TQ on a 2 bolt w/o a too much of a problem. Going to a 4 bolt will help the bearings last longer. Is it worth the expense,... depends on how much TQ your talking about. A street engine,... spend your $ else where.
Pro
Joined: Dec 2002
Posts: 746
Likes: 1
From: salem or
Re: 4 bolt main or 2 bolt main? (ZylaRace)
For the street: 2 bolt is OK.
The problem is that the 2 bolt caps will move around a bit in the saddles with high revs. If high revs for extended periods it may lead to main bearing failures or crankshaft journal fatigue.
If the torque is too high or if it's applied too suddenly, then you can just plain over stress the cap and break the things loose. This is not the kind of a situation that you'd encounter with your typical street engine L98.
If you're worried about it, then you can have splayed 4 blot caps installed on your 2-bolt block for about 600.00 at your local machine shop. Probeboy not an issue if you don't race and if your street motor doesn't exceed say 350 RWH and 400 RWT. sj
The problem is that the 2 bolt caps will move around a bit in the saddles with high revs. If high revs for extended periods it may lead to main bearing failures or crankshaft journal fatigue.
If the torque is too high or if it's applied too suddenly, then you can just plain over stress the cap and break the things loose. This is not the kind of a situation that you'd encounter with your typical street engine L98.
If you're worried about it, then you can have splayed 4 blot caps installed on your 2-bolt block for about 600.00 at your local machine shop. Probeboy not an issue if you don't race and if your street motor doesn't exceed say 350 RWH and 400 RWT. sj
Melting Slicks
Joined: Apr 2000
Posts: 3,198
Likes: 2
From: Northern CA
Re: 4 bolt main or 2 bolt main? (scorp508)
2-bolt in all L98s. Corvette didn't see 4-bolt in a C4 until the LT5 came out in 1990 and then the LT1 in 1992. You're going to have to make a hella lot of HP to break your 2-bolt.
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Re: 4 bolt main or 2 bolt main? (ANTI VENOM)
My block is a 4 bolt block, but then again, my original L98 engine spun a bearing and made mashed potatoes out of some rods and pistons and swiss cheese out of my oil pan. :mad
I don't know what kind my block is now, just older,
:lol:
I don't know what kind my block is now, just older,
:lol:
