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Search found 1851 matches

by hoffman900
Sun May 09, 2021 5:30 pm
Forum: Engine Tech
Topic: Cams
Replies: 14
Views: 1073

Re: Cams

My impression if Comp’s low shock design came from them grinding a Harold Brookshire Comp design backwards, and it working better.
by hoffman900
Mon May 03, 2021 12:35 am
Forum: Vintage/Classic/Historical Engine Tech
Topic: I Still Like Pushrods, They're Still Viable
Replies: 71
Views: 1640

Re: I Still Like Pushrods, They're Still Viable

The answer is, Dan Gurney. His car, Eagle His engine, Gurney/Westlake He drove his car, too Although not a American, Jack Brabham was the only other, to do so. But, that is really irrelevant. Penske just didn't knock on enough doors, I guess. Just like his US competitors didn't. He was last competi...
by hoffman900
Sat May 01, 2021 12:45 am
Forum: Vintage/Classic/Historical Engine Tech
Topic: I Still Like Pushrods, They're Still Viable
Replies: 71
Views: 1640

Re: I Still Like Pushrods, They're Still Viable

Perhaps the fact that Penske's sponsors were mostly US companies who had little interest in European racing, did not help matters any. Penske once remarked, "They knock on the same sponsorship doors that we do." F1 is a world wide market. USA sponsors wouldn't matter(although one of his sponsors wa...
by hoffman900
Wed Apr 28, 2021 8:34 am
Forum: Vintage/Classic/Historical Engine Tech
Topic: I Still Like Pushrods, They're Still Viable
Replies: 71
Views: 1640

Re: I Still Like Pushrods, They're Still Viable

Ron, this is a drawing of the Ford, Duratech 3.0, V6. It has a deck height of 8.189. I would be surprised if it was wider than a LS but, I couldn't find a measurement. I've inscribed the 2 red lines, point out what it might look like if it was a SOHC engine. Based on the bore and stroke, the DH cou...
by hoffman900
Tue Apr 27, 2021 4:40 pm
Forum: Vintage/Classic/Historical Engine Tech
Topic: I Still Like Pushrods, They're Still Viable
Replies: 71
Views: 1640

Re: I Still Like Pushrods, They're Still Viable

The way to go is with even flatter chambers than that. Here is the new Honda CBR1000rr-r valve angle: https://www.motorcycle.com/blog/wp-content/uploads/2020/09/197275_2020_HONDA_CBR1000RR-R_FIREBLADE_Valve_Angle-544x388.jpg they stood up the valves on their current F1 engine as well. https://pbs.tw...
by hoffman900
Tue Apr 27, 2021 10:02 am
Forum: Engine Tech
Topic: piston weight
Replies: 81
Views: 7344

Re: piston weight

There is a good Honda white paper from their V8 F1 engine about piston design, and them cracking due to the rpm’s they were running at the time.
by hoffman900
Tue Apr 27, 2021 8:44 am
Forum: Vintage/Classic/Historical Engine Tech
Topic: I Still Like Pushrods, They're Still Viable
Replies: 71
Views: 1640

Re: I Still Like Pushrods, They're Still Viable

I suppose a point could be made in packaging a push rod, over a DOHC but, not a SOHC. We'll have to agree to disagree on this statement. Put a Ford Mod SOHC 4.6 (25" wide, 26" tall) beside a 5.0 pushrod (18" wide, 20" tall}. The SOHC is a huge exterior package for it's displacement and power output...
by hoffman900
Mon Apr 26, 2021 8:36 am
Forum: Vintage/Classic/Historical Engine Tech
Topic: I Still Like Pushrods, They're Still Viable
Replies: 71
Views: 1640

Re: I Still Like Pushrods, They're Still Viable

I think the the packaging thing is overstated. F1 has been using V engines for decades and those guys live and die by packaging ( (for aero and weight) and they are still DOHC designs. Just very compact. Same goes for MotoGP bikes which are mostly V4s now. A finger follower valvetrain can be very co...
by hoffman900
Thu Apr 22, 2021 4:47 pm
Forum: Engine Tech
Topic: Custom race Tri-Y headers going lean
Replies: 33
Views: 1009

Re: Custom race Tri-Y headers going lean

Tuner wrote: Thu Apr 22, 2021 4:20 pm Or, they are improving scavenging and pulling fuel through the cylinder out the exhaust port, in which case (actually any case - same with jetting) playing with collector extension length to find the ideal is an important consideration.
That too.

Really hard to say without more information.
by hoffman900
Thu Apr 22, 2021 3:41 pm
Forum: Engine Tech
Topic: Custom race Tri-Y headers going lean
Replies: 33
Views: 1009

Re: Custom race Tri-Y headers going lean

Abbottracingheads wrote: Thu Apr 22, 2021 2:52 pm If the motor went lean it means the new headers are not pulling on the carb as hard, therefore less signal.
Or they killed reversion and you’re not getting the double fueling effect in those rpm ranges, which you would expect properly built tri-y’s to do.
by hoffman900
Sat Apr 17, 2021 12:40 pm
Forum: Engine Tech
Topic: PolyQuad 4 Valve Head: The Best For Both Torque AND Horsepower With Small Displacement?
Replies: 15
Views: 761

Re: PolyQuad 4 Valve Head: The Best For Both Torque AND Horsepower With Small Displacement?

There are some interesting posts here by a fellow named Logan d about oems implementation of high tumble and its benefits over swirl. About 18 years ago, I was working with a head porter. He took a well proven NHRA Pro Stock head, and redesigned the ports, so the air would swirl, instead of tumble....
by hoffman900
Fri Apr 16, 2021 11:05 am
Forum: Engine Tech
Topic: Big Type 4 VW
Replies: 22
Views: 1041

Re: Big Type 4 VW

There are plenty of air cooled 4 valve heads floating around in motorcycle circles from the 1970s and 1980s.

There are plenty of 911 / 914 Porsches road racing making well above 100hp/L.

The op has liquid cooled heads and “plenty of airflow”, so I think he’ll be good in that regard.
by hoffman900
Fri Apr 16, 2021 10:23 am
Forum: Engine Tech
Topic: PolyQuad 4 Valve Head: The Best For Both Torque AND Horsepower With Small Displacement?
Replies: 15
Views: 761

Re: PolyQuad 4 Valve Head: The Best For Both Torque AND Horsepower With Small Displacement?

A 4 valve head engine will make much more torque and have a flatter power curve than a 2 valve. With more valve area, valve timing can be less. This is what allowed the Ford mod motors to dominate the EMC some years ago before they had to completely rewrite the rules. They also did so with mostly OE...
by hoffman900
Fri Apr 02, 2021 11:50 am
Forum: Engine Tech
Topic: Road Race Track/AutoCross 351w
Replies: 54
Views: 2635

Re: Road Race Track/AutoCross 351w

A few others have touched on this angle, but Auto-X and closed track road racing are vastly different animals IMO engine wise. So is real(?) road racing ever in the mix, or are we focusing mainly on autox? Looks like autocross and track days. For track days, don’t even worry about going faster in a...
by hoffman900
Fri Mar 26, 2021 4:51 pm
Forum: Engine Tech
Topic: Harvey Crane class
Replies: 2
Views: 559

Re: Harvey Crane class

You can observe his website via Wayback machine. http://web.archive.org/web/20090603082847/http://www.harveycrane.com/ The images are floating around. It seemed like a pretty rudimentary program. You could probably learn a lot buying or finding used camshafts and profiling them. There are several NA...