I was curious if the L98 is a 90 degree V8 because the 88 4.5 liter Cadillac engine is 90 degrees and I'm investingating the possiblity of putting my old L98 crank in that to increase the stroke from 3.3" to 3.5". If anybody knows if that is possible that would be great too.

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'89 Formula 383 TPI

 

Greg,

Almost all V-8s I've ever encountered were a 90° arrangement.

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Later,
Vader
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"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

 

That sounds like a Hell of an undertaking.

Do the Mains Lineup ?



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60 Ranchero - Project ( Money Hole )
85 Z28 LG4 - Daily Driver
**Mods**
MSD Superconductors
14" Open Element
KYB all around

 

Aint gonna happen....

Look into the 4.9 rather than trying to mess with anything else. FYI the 4.5 is a bored out 4.1, and the 4.9 is a stroked 4.5. That give you an idea? Other than that I'm keeping my mouth shut.

 

I kinda thought all V 8's were 90 degrees but that is something that nobody talks about so I wasn't sure. Thanks.

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'89 Formula 383 TPI

 

Every V8 I've ever seen is a 90 degree block. The reason for this that a 8 cylinder engine fires every 90 degrees thats why they can put 2 rods on the same journal. If look at alot of V6's are 60 degree block for the same reason. The ones that are 90 degrees like the 4.3 have stepped rod journals which makes them weaker. On a V6 you can run a non stepped crank like on the Buick odd fire but then you can't have even fireing order, when the engine is an odd fire they don't run very smooth. V10's are 72 degree block because they fire every 72 degrees. Which is another reason a V10 will make more horse power than an identical V8 plus run smoother. The V10 has more overlaping power strokes. So thats why V8 blocks are 90 degrees.

 

What does stepped journals mean on the 4.3?? How does that make it weaker? My sister has a 94 Blazer with that engine, I don't recommend anyone buying one because they break too much!

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'89 Formula 383 TPI

 

If you look at the rod journal on a V8 two rods go on the same journal. But in the 4.3 to keep it an even fire and still make it work with the 90 degree block the had to step the rod journals. It's kind of hard for me to explain with out a picture.

 

oh, ya, now that I think about it I see what you mean. so each connecting rod has it's own journal on the 4.3 The journals next to each other are not exactly next to each other. Where as the V8's are exactly next to each other. got it, I can see how that would definetly be weaker.

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'89 Formula 383 TPI

 

While you are correct in the fact the a V8 fires every 90', you are wrong on the reason for which the SBC (or any other "90'" V8) is termed a 90' block. If this statement where correct in anyway, then why are there 60' and 90' V6s. You just blew your theory. The degree designation is for the banks seperation angle (much like intake/exhaust lobes and LSA). If you look at the block the right bank is 90' apart from the left bank, hence a 90' block. Nothing to do with the crank and timing. Also, can't remember which, but some exotic/race cars had different angled blocks.

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George P. Lara
1994 Z28 LT1 T56
1984 Z28 High Output
Member: SCCA, SCFB, SC3GFB
Chevy Info --> MadMike's

 

MRZ28HO yes they are called 90 degree blocks because the banks are 90 degrees apart. But I explained why they are 90 degrees apart, and that has to do with the fact that they do fire every 90 degrees which means you can have an even fireing order. And if V6 block is a 60 degree block than it can have an even fireing order because a V6 fires every 120 degrees. If the V6 is a 90 Degree block than it either has to have an odd fireing pattern like the odd fire buicks, or it needs a offset rod journals like the 4.3.
If you ever look at an inline 4cyl you will see that the journals are 180 degrees apart and thats because 4cyl fire every 180 degrees. This is the way most cranks and blocks are designed and if thay are not then they are either odd fire type motors or they have offset rod journals.