Just for interest's sake - Weslake SB Chevy 4-valve heads

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SchmidtMotorWorks
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Re: Just for interest's sake - Weslake SB Chevy 4-valve heads

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Paul Kirk wrote: Fri Feb 05, 2021 5:10 pm Just out of interest I should mention that I was seriously involved with developement of that engine for the owner who had the most success with it in a speedway saloon, (Roy Grainger).
It was then sold on to 2 different Jet Sprint competitors.
Bruce Bellis imported from Aust, it was originally put together by Sydney mechanic Peter Molloy, (I'm reasonablly sure) but I don't think it was used in Aus. Bruce tried to race it (twice) in a circuit car but had too many problems and only did a few laps in practice at both events.
If there is some interest in details of the engine or the racing history of it I can put pen to paper.
Contact me on paul.kirk@xtra.co.nz, unless I recieve alerts from this site.
PK.
Do you remember what the problems were?
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Re: Just for interest's sake - Weslake SB Chevy 4-valve heads

Post by jsgarage »

Schmidt Motor Works wrote-
-Do you remember what the problems were?-

Hazy recollection with the decades, but with Gurney's multi-valve aluminum heads, I recall something about flexy combustion chambers leading to cracking. Not sure if the post referred to his 3 or 4 valve heads. OEM Ford Boss (iron) heads had the same problems in NASCAR, sorta-fixed by 'posting'. IMHO there's more to designing cylinder heads than monster port flow. Certainly is beyond me!
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Re: Just for interest's sake - Weslake SB Chevy 4-valve heads

Post by Paul Kirk »

Btw I'm refering to the Westlake 4 valve heads for Chevrolet, not the Gurney Westlake Ford heads.
PK.
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Re: Just for interest's sake - Weslake SB Chevy 4-valve head

Post by Paul Kirk »

lada ok wrote: Tue May 13, 2014 5:53 pm we have a couple of early model ford mustangs that run 302" motors with weslake heads down here in NZ ..... these cars run in open saloon car tarmac ... they would still be in the winners circle .... can someone add to this ?
They'll be Gurney Westlake heads, (Ford) Not Westlake heads, (Chev).
PK.
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Re: Just for interest's sake - Weslake SB Chevy 4-valve head

Post by Paul Kirk »

140Air wrote: Thu Nov 06, 2014 10:56 am
shoedoos wrote:Pinched from a website in New Zealand....

http://www.theroaringseason.com/showthr ... lour/page3

Some details re Weslake 4 valve Chev 350, ex Bellis-----
... the valve lift was quite low.....The weakness with the engine design was the angles of the pushrods especially the inlets. Even thought they were 3/8 diameter hardened chrome molly tube they still flexed excessively as evidenced by the contact markings, yet when turning the engine by hand there was plenty of clearence!
....PK.
Thanks for this reference.

Paul indicates that there were (crippling) valve train issues. Flexing pushrods, very low lift and still breaking springs are telltale. The fact it produced a lot of power even with these issues also says a lot.

I think that parts breakage in pushrod designs is often an indication of oscillations, other than and in addition to spring surge, in the system.
Giday....
The inlet pushrods flexed due to their angle from lifter to rocker, in efect they were moving sideways as well as up and down, this combined with incorrect rocker geometry on inlets caused harmonics in the springs which broke. Interestingly once we got the geometry better (not perfect), and different springs, we didn't break any more springs, and Roy got a lot of racing pleasure from the engine. From memory the car was geared for around 6 grand or less.
Btw I see on here some pics of the engine and it looks like the pushrods are on normal angles, but the heads are not on the block in those pics and whoever took the pics just had the rods sitting on the followers in an upright position, when assembled the inlet pushrods were on a much greater angle.
PK.
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Re: Just for interest's sake - Weslake SB Chevy 4-valve heads

Post by AUTOMAN »

Had a set myself and never installed.

70lbs and 15lbs for the covers!

Airflow was horrible.

cliff
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Re: Just for interest's sake - Weslake SB Chevy 4-valve heads

Post by shoedoos »

dominion1.jpg
just in case anybody has some spare disposable...

https://reno.craigslist.org/pts/d/reno- ... 64225.html

dominion.jpg
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