[DeTomaso] Compression Ratio Question

[Art Stephens]

Garth,
     The 377 was supposed to be about 10:1 when new.  After crunching some 
numbers,  it looks like the CR could have been as high as 10.5:1 after 
milling the .020 off the heads.  So,  if my CR was actually over 10:1,  I'm 
guessing it was probably going to detonate,  under the circumstances,  even 
if I had no oil getting into the combustion chambers?  Perhaps the engine 
would have survived 1/4 mile blasts for a long time?  But it appears that 
damn Rocky Baroofy character and his lead foot may have been a little too 
much for it?  I have to build this engine to be able to survive,  just in 
case I let that joker drive my car again :-)).

Thanks,
Art



----- Original Message ----- 
From: "Garth Rodericks" <garth_rodericks at yahoo.com>
To: <detomaso at realbig.com>; <artstephens at charter.net>
Sent: Friday, September 21, 2007 11:46 AM
Subject: [DeTomaso] Compression Ratio Question


> Art,
>
>  Your 377 stroker was running 10:1 compression with iron, closed chamber 
> heads, and you
>  believe detonation killed it.  Was the aforementioned CR before or after 
> the additional .020
>  was milled off the heads?
>
>  You want...
>   - 408 stroker Cleveland built with CHI 3V aluminum heads
>   - Max HP
>   - Durability -  I don't want to blow up any more engines due to 
> detonation.
>   - Plenty of compression ratio, 11 or 11.5:1
>   - MSD knock sensor this time around
>
>  My 2-cents, and that's about all it's worth...
>  You're throwing your money away building a high compression engine. This 
> engine will fail in
>  short order the way you want to drive it.  Also, aluminum heads usually 
> increase the
>  liklihood of detonation. So, forget high compression. The knock sensor 
> and in-car timing
>  adjustments are merely band aids for the high CR and pump gas. And you 
> WILL NOT get
>  max HP when you dial it back.
>
>  Build a high HP low compression engine that will be durable and reliable 
> on pump gas. Bob
>  Benson's Pantera has a 411 Windsor Dart block, Brodix heads, Scat crank, 
> steel rods, etc.
>  and makes 550-600 HP with a CR less than 10:1 (I think it was 9.8:1, but 
> I don't recall for
>  sure - Bob?)
>
>  The point is you can make BIG power with a durable low compression engine 
> and pump gas.
>
>  Here's a 9.2:1 CR 2V Cleveland that makes 520 HP on unleaded pump gas:
>  http://www.kostecki.com.au/articles/art_of_power.html
>
>  I think this engine will be much better suited to the way you want to 
> drive your car and will
>  far outlast your proposed build.
>
>  Keep us posted!
>  Garth
>
>
>
>
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