4 bolt main???
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4 bolt main???
I was watching horsepower tv and there was an ad for an edelbrock crate motor that they mentioned was a "4 bolt main block". I guess I spelled all that right, but anyway what does that mean, and what are our motors? just curious 
Lexus Champion
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From: Florida
Originally posted by joel5150
I believe it refers to the main bearing cap bolts and how many are on the motor. I am not sure how many are on our cars.
I believe it refers to the main bearing cap bolts and how many are on the motor. I am not sure how many are on our cars.
Many small block motors only have 2 bolts per cap. If you have 4 bolts per cap, then the motor is stronger and can spin to a higher RPM. Some 2 bolts that have been coverted to 4 bolts will have a splayed design for the 2 bolts that have been added.
I am not sure what the Lexus 4.3L motors have.
Last edited by WhiteTiger; Jul 13, 2004 at 08:28 AM.
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can someone explain or link what exactly that means? I don't have a clue what component we're even talking about other than something in the engine, but I've learned that more is better! Do I6s have bolt mains or just Vs or just V8s? Man I feel like a maroon! 
What we are referring to is the main bearing caps that hold the crankshaft in the engine. Sort of like a U with a holes on each side for the bolt that goes into the block. This holds the bearing and crankshaft. The more bolts, the heavier duty the engine is considered thus the more HP it can take. Old GM engines had 2 bolt mains, but Vetts and heavy duty trucks came with 4 bolt mains for the increased load. See the picture of the GM motor attached. Notice how each of the caps have 4 bolts? 2 on each side. Thus a 4 bolt main engine.
Hope that helps
Lee
Hope that helps
Lee
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Those are 2 bolt mains on the ends as less torque is present there. I believe they were changed to 4 bolts in later years, but someone else familiar with these engines should clarify.
The Lexus V8 has 3 bolts on each end, thus the 6 bolt main. One stout and well built motor. I rebuilt 2 of them so far. One mine (hardly changed oil), and a friends who blew it up with NOS.
Lee
The Lexus V8 has 3 bolts on each end, thus the 6 bolt main. One stout and well built motor. I rebuilt 2 of them so far. One mine (hardly changed oil), and a friends who blew it up with NOS.
Lee
6 bolt mains it is , these 1uz blocks are considered bullet proof.. they are basically race engines that toyota has been running since 1989 in the first ls 400 , tundra v8, landcrusier, lx470, gx470, sc400, sc430 etc etc .. the block design has not changed since then for its been slated bullet proof,, in fact i read a article once were cessna (the small plane builder) was considering using this v8 block for their engines because of the reliablity and also the ability for it to sustain 8-10rpm's for extended period of times without any signs of premature wear...
we have one of the strongest built platforms which it is why i say "its a keeper"
we have one of the strongest built platforms which it is why i say "its a keeper"
(Learn something new every day). 
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