Engine Block strength questions

[h-bot]

From: cossie_REMOVE_647096_THIS_@yahoo.com

Hello,
I'm planning to run lots of boost with a CV engine
and have read accounts of blocks splitting near the
300hp mark, and that some dirt track racers have built block girdles
to overcome this. Does anyone have any details, or could you
point me to some good reading on reinforcement of the Vega block ?
Any nitro-burners on the list ? <grin>

Thanks
Mike




[This is message #10464 by user cossie on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: kiva5198_REMOVE_144543_THIS_@yahoo.com

I have a motor that ran 30% and 50% nitro at Bonneville last season,
10,000 rpm, 9 back to back passes, no problems. It is about 14:1
compression with big cams, aluminum rods, p&p head. There is at least
one member running in the 430 hp range on a sleeved block at @26 psi.
It can be done. Remember it is more stressful on the parts to build a
n/a motor at 300 hp than to build a low compression high boost
intercooled motor at 300 hp. I know there is another one inthe works
right now, we'll see it on the dyno in the future.

Britt
(back to only two n/a CVs, and one high compression boosted Mazda)


--- In <a href="/group/cosworthvegas/post?protectID=219233066105193209050199029077192253163098100009128121188190230091025019053061151110147">cosworthvegas@yahoogroups.com</a>, Mike Vee <<a href="/group/cosworthvegas/post?protectID=219233066112082198015038190036129">cossie@e...</a>> wrote:
> Hello,
> I'm planning to run lots of boost with a CV engine
> and have read accounts of blocks splitting near the
> 300hp mark, and that some dirt track racers have built block girdles
> to overcome this. Does anyone have any details, or could you
> point me to some good reading on reinforcement of the Vega block ?
> Any nitro-burners on the list ? <grin>
>
> Thanks
> Mike




[This is message #10465 by user kiva5198 on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: doctorduke_REMOVE_307932_THIS_@yahoo.com


The Vega aluminum block is certainly weaker than a typical cast iron
block. You have to remember that though it is "high-tech", it was
originally designed for no more than about 125 HP, with no eye toward
modification for racing, so it is definitely not "overdesigned". You
can refer to the first quarter 2001 CV magazine for the article I
co-authored with Mike Hall on the development problems Cosworth had in
the early seventies. The production CV blocks are a little better
than those early blocks and the HD block much better, but once you get
up to the 9000 rev level reliabililty is suspect.

For a boosted engine running lower revs you have to take into account
cooling considerations. If you double the indicated horsepower, you
double the amount ot heat that must be removed from the engine.

Rather than using the aluminum Vega block, anyone attempting a high
boost turbocharged engine should consider the "Iron Duke" block. A
lot of racing parts were built for this engine. Cosworth might still
have some DOHC head conversions and Arias builds an aluminum version
of the block. The Iron Duke block actually had a lot more development
for racing than the Vega block, and it proved out to be a durable
foundation for a high specific output racing engine.

Being as how the Iron Duke engine was used in the '77 Astre rather
than the aluminum 140, the mounting hardware to install it in a H-body
chassis is available.

Duke







[This is message #10472 by user doctorduke on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]