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Technical => Matt Shaff's Engine Shop => Topic started by: wideopen231 on September 17, 2015, 11:33:26 AM

Title: cam differance for alky
Post by: wideopen231 on September 17, 2015, 11:33:26 AM

 Putting motor together this weekend,well everything except pan and starter ,everything has to be one off with this deal.
  I know the cam I'm instelling is far from optimal. 296 @.050 is about 15* too much duration. Thinking 280 range would be lot closer.  The bad thing is started thinking about cam with alky. reasons alky runs cooler,alky uses about twice as much fuel to air which inturn takes up more of intake tracks capacity. wondering if running little less duration on exhaust will help keep more heat in chamber. also thinking have higher intake duration than exhaust might help with complete filling of chamber on induction.

  Wondering if any here have done testing or read anything on this? Then it could be the age old case of overthinking and forgetting the KISS principal.Either way its going together with too much cam for now.I need to hear it come to life even if needs few things to be track ready.

Title: Re: cam differance for alky
Post by: masracingtd1167 on September 17, 2015, 02:01:09 PM

Chris Have you ever talked to the guy's at Bullet . They might be very helpful with cam advice . Why not have your cam re ground ? I have had very good luck with there stuff. 

Title: Re: cam differance for alky
Post by: digster on September 18, 2015, 07:34:38 PM

+1 Bullet cams have reground several cams for me. Talk to Tim. He's a lot of help and a southern gentlemen to boot.

Title: Re: cam differance for alky
Post by: alkyal on September 19, 2015, 01:32:08 PM

Have known Tim G. for 25 plus yrs. His amount of experience is 2nd to NONE. As some of you know, Tim worked for UD Harold Since day one. Between Tim and Harold, They have ground over a hundred Custom cams for me,both new and Re-Grinds.

Title: Re: cam differance for alky
Post by: wideopen231 on September 19, 2015, 05:37:10 PM

Trick here is the fact its 48*(raised cam) motor.I only have three cams for themall are 296@.050 and I need good amount less duration.Have not called bullet but the 2 company's I called said it would be very questionable getting that much out of it.Next up is these cams are 500 new and if I can sell one off I would be better off then paying to regrind it.

Title: Re: cam differance for alky
Post by: wideopen231 on September 20, 2015, 02:55:21 PM

 found this on drr some good read on this even if oppisite of what i was thinking about on subject.
http://dragraceresults.com/fullstory.cfm?id=2455&type=2&title=BIG_DUKE_CYLINDER_HEADS__ALKY_OR_GAS

Title: Re: cam differance for alky
Post by: roadster27 on September 22, 2015, 11:04:23 AM

comp cam ground me a 116 lc , 277 int , 292 exh  , .800 lift cam for my alcy motor , 502 cu in

Title: Re: cam differance for alky
Post by: wideopen231 on September 22, 2015, 02:05:07 PM

Roadster,

What was performence differance?