Has any one got newman p5 camshaft specs timing figures and lift at tbc
Has any one got newman p5 camshaft specs timing figures and lift at tbc
Its all in their data catalogue:
http://www.newman-cams.com/wp-conten...LOGUE-2023.pdf
They seem to be wrong
Or . . . . . . . you haven't got a P5 cam ?Originally Posted by mariors2000
What seems to be wrong?
Manufacturers give cam specs of the CAM itself, checked at a certain (very low) checking height; for instance Kent uses 0.01" or 0.25 mm. Also for the valve lift spec they use a fixed rocker ratio; Kent uses 1.69 for inlet and 1.65 for exhaust. Newman uses 1.58 .
Now as you know the cam / valve geometry on the Pinto engine is somewhat complicated.
Newman states in their catalogue:
Quote: Valve timing on OHC rocker arm engines
These engines are the hardest to set up if you look into our spec sheet we do not normally give left at TDC specification this is due to pivot hights of the valve stem, cam
base circle, and ball stud being variable from engine to engine, as the angle of the rocker arm increase the rocker ratio changes, so with these engines you may have to
accept a compromise of valve timing to cam lift at TDC. Unquote.
So if you are checking the camtiming in an engine you are bound to get different values to what the manufacturers spec.
I'm timing figures are 43 77 77 43 which works out with 107 lsa and 300 degs duration
Newman figures are 33 87 87 33 which are which are wrong cheers mario.
Maybe the newman figures are actually on the camshaft itself cheers mario that's all I can think of
That's what I said.
But yes do not trust all things which are printed.
In the Newman catalogue (see link posted by haz87) the timing of the PH5 cam is 33/87 87/33 and duration is 300 degrees. The PH6 cam is quoted as (also) 33/87 87/33 but has a duration of 310 degrees. So something is not correct. Same values appear in Newman catalogue of 2008.
So only 15 yrs old. They could've changed something unbeknown then.
I gave up many years ago trying to time a camshaft by the grinders timing figures, all’s that it does is give you a massive headache when they don’t match what they say. The best and easiest way’s to set them on equal overlap on number one cylinder on a single cam engine and then adjust as necessary on the Dyno assuming you have enough valve to piston clearance. I have never understood Newman’s figures, their valve opening times appear more like a standard cams figures.
I discussed on another thread regarding the changing rocker ratio of a Pinto and how it was so important to set every cylinder rocker ratio identical to what the camshaft lobe centre was, some posters didn’t believe me.
I have just looked on their currant data sheet Rob and they are still the same figures as Minilite Man quotes.
if cam shaft data sheets really worked we wouldnt need dynos!
I know times have moved on but 50 years ago we had to believe what information the cam grinder gave us on the data sheet was accurate when our engines were built on a tight budget. We had never heard of a Rolling Road, only a static dyno that such likes as the large professional companies had and we could have never afforded to put an engine on one. I don’t even think there were luxuries like vernier wheels, just a small pack of offset dowels to work with on the Ford pushrod and Twink engines.
I remember well back in the 70’s my late Father ringing Cosworth Engineering to find the camshaft timing for a pair of L1’s, a couple of days later a small buff envelope arrived proudly supporting their name on the top, inside was a complete data sheet of all their camshafts at the time. What would be the chance of a World Championship Engine builder dealing with the general public nowadays. I proudly kept that envelope for over 30 years before it got lost.
i suspect that back then someone like cosworth would of actually known where best to time a cam. The thing is we now have almost 1000's of profiles for just a single engine type when in reality there will only be 5 or 6, but a gazzillion variations of said profile, i think its niave to expect radical differences from a small shift in timing or lift. when you look at kents catalog at GTS3 lighting rod cam is a fair bit different to a GTS4 loose surface cam, but a lighting rod has limited modifications, given the same spec engine i dont think there will be a lot of difference in the power deliveries. but then thats what my cam test is aimed at
Last edited by Graham; 01-07-2023 at 07:15.
Kent list no less than 4 cams for various forms of short oval Racing with their Big Daddy being the Ultimate F2 Stock Car cam, the other 3 look very similar profiles. I think I have mention before both the GTS3 their loose surface Rally cam and the GTS4, Tarmac Rally cam both have too much TDC overlap to give good mid range torque, Dyno tests might prove me wrong.
Looking forward to your future tests.
It will be interesting to see what the measured valve lift is on full lift with your cylinder head when you get the Newman 4.75 installed.Will it be more than the advertised lift on their data sheet?
Last edited by Forest_rallying; 02-07-2023 at 13:23.
i usually get advertised lift or even slightly more
The only reason I ask is that Newman are advertising their cams with a different rocker ratios to what Kent’s are although their cams have similar cam lift to their competitors. The 4.75 has 7.94mm cam lift giving an advertised valve lift of 12.03mm. Kent on the other hand have the RL31 cam lift has 7.79mm and valve lift of 12.93mm, the GTS3 having cam lift of 7.97 and 13.20 of valve lift. So in theory the 4.75 in your cylinder head should have more valve lift than the RL31 and similar valve lift to the GTS3. Time will tell.
The 4.75 should be with you tomorrow.
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