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Search found 2125 matches

by hoffman900
Sat Oct 01, 2022 6:21 pm
Forum: Engine Tech
Topic: From a solid roller to hydraulic roller
Replies: 85
Views: 1566

Re: From a solid roller to hydraulic roller

This is hitting closer to home Mike. Is there a significant change one way or the other with an aggressive profile like like your EHR series vs your regular hydraulic rollers when taking the same .050" numbers into consideration? That being shorter seat timing yet the same 050" number. Not really, ...
by hoffman900
Sat Oct 01, 2022 1:03 pm
Forum: Engine Tech
Topic: A visual example of the 90 degree crank drawback.
Replies: 14
Views: 454

Re: A visual example of the 90 degree crank drawback.

Here is a good visualization of an 90* crank in the intake manifold with a common plenum: https://www.facebook.com/watch/?v=303159527677911 (Converge CFD model from Roush-Yates) I know the GM Engineers working on the IMSA / WEC / FIA Corvette C8R like the flat-plane crank because it pulls more evenl...
by hoffman900
Fri Sep 30, 2022 1:33 am
Forum: Engine Tech
Topic: Camshaft lobe design by Billy Godbold
Replies: 48
Views: 1770

Re: Camshaft lobe design by Billy Godbold

Billy does make a valid point about soft entry to the acceleration pulse (paraphrasing). Especially on pushrod engines with modern/stiffer valvetrains. I’ll have to find it, but he has said elsewhere that this came about when they flipped an old cam designer’s lobe around and found it worked better...
by hoffman900
Thu Sep 29, 2022 9:58 pm
Forum: Engine Tech
Topic: From a solid roller to hydraulic roller
Replies: 85
Views: 1566

Re: From a solid roller to hydraulic roller

FYI, you can’t compare centerlines of a Harold lobe vs a symmetrical design. As Mike Jones has stated elsewhere, they like to be / or appear to be more advanced than they run.

Honestly, hit the easy button and use whatever Mike will spec out and grind for you.
by hoffman900
Tue Sep 27, 2022 1:44 pm
Forum: Engine Tech
Topic: Camshaft lobe design by Billy Godbold
Replies: 48
Views: 1770

Re: Camshaft lobe design by Billy Godbold

I always thought a graphic style program where you can manipulate the acceleration curve (or any of the curves) at any point would be the most powerful, and obviously it would integrate or derive the other curves, and then have to work backwards. Obviously you would have to know your limits for a gi...
by hoffman900
Tue Sep 27, 2022 10:34 am
Forum: Engine Tech
Topic: Camshaft lobe design by Billy Godbold
Replies: 48
Views: 1770

Re: Camshaft lobe design by Billy Godbold

If some smart guy would only write a follower translation program that would produce valve lift from lobe lift, I would buy him (or her) a beer, and even dinner if it is an her. That's the exact opposite of what we use for design. We design the valve lift curve, and then translate it into the lobe ...
by hoffman900
Mon Sep 26, 2022 2:23 pm
Forum: Engine Tech
Topic: Camshaft lobe design by Billy Godbold
Replies: 48
Views: 1770

Re: Camshaft lobe design by Billy Godbold

I heard today that Billy isn't at Comp Cams anymore? He went out on his own, but I think he's still doing some work for Comp. With how The Edelbrock Group is running things now, I think he saw the writing on the wall. Yeah it appears he’s probably doing his old job but as a contractor (and probably...
by hoffman900
Mon Sep 26, 2022 2:21 pm
Forum: Engine Tech
Topic: Camshaft lobe design by Billy Godbold
Replies: 48
Views: 1770

Re: Camshaft lobe design by Billy Godbold

Great explanation of lobe design ... at least I thought so https://www.youtube.com/watch?v=K1DFrWcvTuc Billy is a brilliant guy evidenced by a PhD in Mathematics. He has often served as a design judge for the Formula SAE competition helping university student engineers learn about engine and camsha...
by hoffman900
Sun Sep 25, 2022 12:40 pm
Forum: Engine Tech
Topic: How much advance for a less than optimal cam ?
Replies: 22
Views: 697

Re: How much advance for a less than optimal cam ?

Assuming that the events below .050” is the same is a big assumption. The engine sees seat-to-seat duration, not .050”. You can’t compare a Mike Jones designed lobes to Billy Godbold has designed lobes to Harold Brookshire designed lobes look at .050. Mike’s cams look smaller at .050” than they run...
by hoffman900
Sun Sep 25, 2022 12:21 pm
Forum: Engine Tech
Topic: How much advance for a less than optimal cam ?
Replies: 22
Views: 697

Re: How much advance for a less than optimal cam ?

Thats because the .050" specs are a accurate way to reference the relative position of the camshaft in the engine and then to move it +/- as desired, with accuracy Moving the camshaft +/- will have a much more profound effect on the engine power curve than does +/- changes in thw rocker ratio. The ...
by hoffman900
Thu Sep 22, 2022 11:48 pm
Forum: Engine Tech
Topic: 128 my take, anybody see it like this ?
Replies: 158
Views: 4166

Re: 128 my take, anybody see it like this ?

Why should our discussions have to become personal and demeaning? We are all adults, if you have a different opinion or view, that is awesome, why can’t we express that thought in a respect way? We have a tremendous community here with some of the most talented and knowledgeable people in this indu...
by hoffman900
Thu Sep 22, 2022 10:45 pm
Forum: Engine Tech
Topic: 128 my take, anybody see it like this ?
Replies: 158
Views: 4166

Re: 128 my take, anybody see it like this ?

D. Vizard claims in his SBC book that he has tested well over 10,000 cam combinations in 40 yrs of cam testing. In another publication, he says the number 19,200 cams. I have no reason to doubt either claim. Has anybody tested more? I know this much: I will take his advice until I find someone who ...
by hoffman900
Thu Sep 22, 2022 11:10 am
Forum: Engine Tech
Topic: Does quench affect power?
Replies: 262
Views: 7505

Re: Does quench affect power?

That's my point it's not 15hp, it's minimal. Set it to .040-.050, and call it a day. Thread over, lol We’re all not building street strip engines here or are interested in that. A bunch of you need to expand your horizons. Why are you even here and posting in this thread? Like, if you guys want to ...
by hoffman900
Thu Sep 22, 2022 10:33 am
Forum: Engine Tech
Topic: Does quench affect power?
Replies: 262
Views: 7505

Re: Does quench affect power?

On anything. The majority of the guys on this site are referring to 2 valve domestic stuff, except for hoffman, who always quotes formula 1 stuff for some reason. Lots of theory for something that is minimal at best. And works the opposite in many cases based on the theory that no one has been able...
by hoffman900
Thu Sep 22, 2022 9:10 am
Forum: Engine Tech
Topic: Does quench affect power?
Replies: 262
Views: 7505

Re: Does quench affect power?

So have we figured out how much it affects power yet? 13 pages, no definitive number, just a bunch of theory and I thinks and it seemed to helps. On what kind of engine? 2-valve wedge at 6000rpm or 4-valve pent roof at 11000 rpm? On anything. The majority of the guys on this site are referring to 2...