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Valve clearance on a mystery bbc
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DRR Trophy
posted
On a bantam altered I bought, it has a solid flat tapet cam, aluminum AFR 325 heads checking around with a feeler gage they around 24-32 thou, was maybe thinking 30intake 32exhaust maybe? Wound be safe? The po thought the lift was around .660
Thanks in advance
 
Posts: 16 | Location: SO-CAL | Registered: January 08, 2008Reply With QuoteReport This Post
DRR Sportsman
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You are asking about valve lash correct?

If yes, I would think .030-.030 hot would be close enough.
 
Posts: 875 | Location: Illinois | Registered: July 27, 2006Reply With QuoteReport This Post
DRR Sportsman
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.30 sounds like alot to me


"Just Shut Up and Race"

Brian Martin
Martin Racing
5.66 @121.55
 
Posts: 731 | Location: Va.Beach .Va | Registered: August 03, 2005Reply With QuoteReport This Post
DRR S/Pro
Picture of wideopen231
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Agree sounds like a lot . I know some manufactures spec close to that,but then as old TF racer told me once they love it when you beat up valvetrain. If me I would consider .020 hot to be high side ,but just my opinion.


http://www.schooledbyscotty.com/
Only the stupid know too much to learn something new.
Chris McBride

deplorables saving america one vote at a time
 
Posts: 1441 | Location: Greensboro NC | Registered: May 24, 2011Reply With QuoteReport This Post
DRR Sportsman
Picture of FootbrakeJim
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The last solid flat-tappet cam I used, (Comp # 11-608-5, .637" lift), the hot lash spec was .018" Int, and .020" Exh.

The Comp solid roller I replaced it with, (11-693-8, .652" lift), lash spec is .020" Int & Exh.

That being said, I have seen cam cards with up to .030" lash, but it sure seems like a noisy, valve-train pounding deal to me...
I think you'll find most any solid cam will be happy and live in the range of .020-ish.


Dan "Jim" Moore
Much too young to feel this damn old!!
 
Posts: 521 | Location: Dallas, TX  | Registered: December 05, 2002Reply With QuoteReport This Post
DRR Sportsman
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Don't confuse me with an engine expert.
But, I set my BBC roller at .022 cold.
It has been good that way for many years.
 
Posts: 201 | Location: Justin, TX | Registered: July 18, 2013Reply With QuoteReport This Post
DRR Trophy
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Sounds about right Mike .Set mine at .020 cold turns into .025 hot
 
Posts: 16 | Location: canada | Registered: January 21, 2017Reply With QuoteReport This Post
DRR Trophy
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My roller is 26 hot with 1.75 rockers
 
Posts: 148 | Location: nc | Registered: February 20, 2014Reply With QuoteReport This Post
DRR Sportsman
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My last flat tappet was an Isky around .620 lift. It was .030-.030. I would think the flat tappet cams would want a bit more lash than the rollers. That being said, I am out of the loop on modern flat tappet stuff but if I was going to err on a flat tappet, I would err towards more not less. Just my.02
 
Posts: 875 | Location: Illinois | Registered: July 27, 2006Reply With QuoteReport This Post
DRR Pro
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quote:
Originally posted by cj92345:
On a bantam altered I bought, it has a solid flat tapet cam, aluminum AFR 325 heads checking around with a feeler gage they around 24-32 thou, was maybe thinking 30intake 32exhaust maybe? Wound be safe? The po thought the lift was around .660
Thanks in advance
. I assume you have no clue on actual cam specs? My thoughts,.......since the tightest you measured was .024, I would start with .025 on both and makes some runs for a base line. Then reset to .022 and get a few runs for a comparison. Performance should give you the mystery answer.


Fellow racer and servant of the Lord of Lords
John 14:6
"Creekside Racing Ministry"
MFI system, ProCharger Non-intercooled [6.02 @ 229 or 3.91/660' soft tune and killing power above 6K rpm]
Ron Clevenger
 
Posts: 1000 | Location: Visalia, Calif. 93292 | Registered: November 23, 2000Reply With QuoteReport This Post



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