Mark et all,
Has anyone compiled a list of unreliable engine builders?
Or is this out of characther?
I think that this is helpfull considering the budget we
are working with often times, and limited track time.
I will be looking soon for an engine builder locally
but the same thing is happening here. Who can you trust?
I would hate to invest any dollar amount and have the
engine builder indicate to me that it was not his fault.
This is ludicrous.
jack
> From mac.overtons@coastalnet.com Wed Sep 11 12:46:34 1996
> X-Info: Submissions to wheeltowheel@abingdon.sun.com
> X-Info: Change requests to wheeltowheel-request@abingdon.sun.com
> X-Info: Authors retain implicit copyright to their material. Obtain
> X-Info: permission from the authors before redistributing messages.
> To: "'vintage-race@autox.team.net'" <vintage-race@autox.team.net>
> Cc: "'wheeltowheel@abingdon.eng.sun.com'"
> <wheeltowheel@abingdon.Eng.Sun.COM>
> Subject: piston to head clearance - LMSC results!
> Mime-Version: 1.0
> Content-Transfer-Encoding: 7bit
>
> Afternoon, y'all!
>
> I thought I might share with you our experience this year regarding piston
> to head clearances. The Chevy power book recommends a minimum
> of .035" for small block chevies, and we run a 355 c.i. small block
> in our Late Model Stock car.
>
> We had a "famous" engine builder build us an engine, and he gave the
> dyno sheets on our engine, which indicate 352 HP. This is VERY
> competitive, and we thought "great! we won't be giving up anything to
> the other racers." I asked the engine builder how he made that kind
> of horsepower, considering the very restrictive rules for NASCAR
> late model stock engines. He told me that he left only a .022"
> piston to head clearance. Now, I figured that this was WAY too
> small of a clearance, but he replied "if the pistons ain't hitting the head,
> you ain't gonna make horsepower."
>
> To make a long story short, the motor blew up on the 11th lap of
> testing one afternoon, with the #1 rod end exiting the block and
> ruining one perfectly good motor, and test day. Upon inspection,
> the tops of the pistons all had a perfectly legible, .004-.006" deep
> impression of the cylinder head combustion chambers. My theory
> was this "banging" into the cylinder head hammered the rod
> bearings and caused the resulting failure, but the engine builder
> basically told me that it wasn't his fault and he wasn't going to
> fix it for free....
>
> we spent $10,000 on the motor and it will cost us another
> $2500 to build another. The heads were Ok, 7 pistons, 6 rods were
> OK, but will need new crank, cam, lifters, block (of course - there
> were holes big enough to put your fist in..), oil pan, pump, etc.
>
> IT just isn't worth it to cut it too close on the piston to head
> clearance, IMHO. Give up the few HP for longevity, that's the
> lesson learned here. As a result, we didn't get to race at all
> in '96, and have to wait until '97.
>
> Cya,
>
> Mark Coffin
> #31 Overton's NASCAR LMSC Monte Carlo - crew chief (but not engine builder)
>
>
|