Printable Version | Subscribe | Add to Favourites
New Topic New Poll New Reply
Author: Subject: Pinto cam choices
flak monkey

posted on 2/3/19 at 07:42 PM Reply With Quote
Pinto cam choices

Looking at cam choices for the pinto I'm building. Total can of worms.

Big valve and ported head, at 10.5:1 compression ratio. It's going to either be running twin 45 DCOE or DHLA or R1 bike carbs.

So
FR33?
RL21?
GTS1
Burton BF63?

Choices, choices...





Sera

https://www.facebook.com/sera.jay666

https://www.facebook.com/SJEAmerican/

View User's Profile View All Posts By User U2U Member
overdriver

posted on 2/3/19 at 10:28 PM Reply With Quote
Not in a position to have undertaken any comparisons but the Piper 285 seems to perform admirably in my Pinto - twin 45 DCOEs but not aggressively tuned - c. 130 - 140 bhp.

Sorry if that throws another worm into the can!

Michael.

View User's Profile View All Posts By User U2U Member
snapper

posted on 3/3/19 at 06:26 AM Reply With Quote
The choice depends on rods and pistons.
I fitted Cosworth rods and V6 Kolbeinschmit pistons but wish I had fitted forged pistons that way I could use a higher compression without worrying.

FR33 is a good choice same as the piper 285
The FR21 is an older version of the FR31 which I fitted to one engine good cam but sluggish below 3500 but WOW when you go above that.
The other cams are considered old now and different from the high duration low lift profiles of yesteryear.

Burtons have a diagram showing that valve lift over ľ of valve diameter is waisted as you get no more flow but I disagree as the longer the valve is open at max flow the more volume you will get in to the cylinders.
Area under the curve.

[Edited on 3/3/19 by snapper]





I eat to survive
I drink to forget
I breath to wee my ex wife off (and now my ex partner)

View User's Profile View All Posts By User U2U Member
Dingz

posted on 3/3/19 at 05:54 PM Reply With Quote
There is a good article on Pinto cams in Dave Andrews old site DVA
I've a flowed injection head, standard valve sizes, bike carbs and a Piper 285. I haven't noticed any tractability problems at low revs which I think may be due to the bike carbs being constant velocity, perhaps it would be more noticeable with conventional sidedrafts. If you are looking for big output figures with Bike carbs I may be tempted to go to the next cam up.





Phoned the local ramblers club today, but the bloke who answered just
went on and on.

View User's Profile View All Posts By User U2U Member
flak monkey

posted on 3/3/19 at 11:20 PM Reply With Quote
Thanks guys.

Also considering the Piper A8 cam, which seems to get a good rap.

I will be going strong with the bottom end on this....





Sera

https://www.facebook.com/sera.jay666

https://www.facebook.com/SJEAmerican/

View User's Profile View All Posts By User U2U Member
snapper

posted on 4/3/19 at 08:42 AM Reply With Quote
Iíve fitted a crank scraper to the high power Pinto which is supposed to give a couple of bhp at high revs.
I also grafted a Cosworth spraybar to an RS2000 oil pickup and found out afterwards that simply notching the rods would have given me the same spray effect





I eat to survive
I drink to forget
I breath to wee my ex wife off (and now my ex partner)

View User's Profile View All Posts By User U2U Member
mcerd1

posted on 4/3/19 at 09:13 AM Reply With Quote
I've also gone with a piper 285 for now (fingers crossed it'll be running soon) - but that might not be aggressive enough for you

how wild are you planning to make this one ?

quote:
Originally posted by snapper
Iíve fitted a crank scraper to the high power Pinto which is supposed to give a couple of bhp at high revs.
I also grafted a Cosworth spraybar to an RS2000 oil pickup and found out afterwards that simply notching the rods would have given me the same spray effect

I don't much fancy notching or drilling the rods so I fitted the whole cossie pickup pipe on mine instead (shortened to suit my sump) - only it's needing a little tweak to work: linky
I reckon its down to it being a brand new one thats never been fitted to an engine before

[Edited on 4/3/2019 by mcerd1]

[Edited on 4/3/2019 by mcerd1]





- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

View User's Profile View All Posts By User U2U Member
IanSouthLincs

posted on 8/3/19 at 10:40 AM Reply With Quote
This is something Iíve not long done. I still have the original engine, ported carb head with 44.5mm inlets and 38mm exhausts, 10.5:1 comp ratio and piper 285 cam. Running twin 40 Weberís, it was (and still is) a very strong pulling engine.
However in the quest for more, Iíve built a forged bottom end with Wossner and PEC equipment 92mm bores, injection head, extensively ported with 45.5mm inlets and 38mm exhausts. Kent RL22 with double valve springs. Running twin 48 Webers and with 11.8:1 comp ratio.
Letís not beat about the bush, Iíve spent quite a bit on this engine and by the hell its quick, not been on a dyno yet and still havenít really pushed it as itís still very new but itís not even thinking about letting up power at 7500rpm. Thereís the obvious big BUT..... I always knew it would be the case and I really donít mind as itís nowhere near a daily drive, IT IS A PIG below 2000rpm thereís nothing there, you have to be very gentle with the throttle otherwise it will bog down. Now I personally love it, as the revs climb the horizon starts to really come at you.
You really must be honest with yourself how wild an engine you can live with, or suits what you use the engine for. Iíll be honest with you if youíre keeping comp ratio to 10.5:1 youíre wasting your time using any more than FR33 or Piper 285, I just donít think anything wilder will work properly and it will actually cost you power.
Hope this helps 👍

View User's Profile View All Posts By User U2U Member

New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content © 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [© 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.