individual runners camshaft

PERUCH · #1 (**permalink**) 06-04-2002, 03:06 PM

Who help me to find the right person or camshaft company to design individual runners camshaft which works with 48IDA's,thankx,Bernie

Jeff Frigo · #2 (**permalink**) 06-04-2002, 04:21 PM

Bernie:

I don't think you need a special cam for Webers. The camshaft should be designed around the style of engine you have or want(comp. ratio, rpm, streetability, cylinder head flow, etc.)

Maybe I don't understand your question.

Mr.Fixit · #3 (**permalink**) 06-05-2002, 09:23 AM

You can get away with a tiny bit more duration on an individual runner intake, so the rumor says. I recommend not taking this into account when selecting the cam, so many other variables with the motor are much more important. So get the cam that your motor wanted with a single 4bbl intake, get that sorted out, then you may find a tiny bit more power moving away from that cam.

PERUCH · #4 (**permalink**) 06-05-2002, 10:54 AM

Thank you gentlemen for your replies,but nobody answer to my question.Last week after 38 pulls in dyno room have find 441HP at 7100,350 torque at 5200(289 engine 10.8cr,stock rockers,early GT40 ported heads)respectable results,so,a friend of mine have the same specs but 452 HPand 385 torque at 4700 with impressive linear torque from 4000to 5200,dyno guy said these high figures came from the cam and this cam came from american cam company on special order.Help me to find the right person which are able to solve this problem,thank you again,Bernie

zimmy · #5 (**permalink**) 06-05-2002, 12:44 PM

Peruch:

I also have had a custom cam produced for my 48 IDAs. The cam needds to have much less overlap than standard type cams. I had great luck with David Generous at Cam Techniques in FL. www.camtechniques.com. He was recommended by Inglese and he builds a lot of cams for restorations, etc. Give him a call.

Zimmy

PERUCH · #6 (**permalink**) 06-05-2002, 04:04 PM

Zimmy,
Thank you for your post,I speak with David Generous about IDA's camshaft ,on the phone he knows particularity camshaft design,regards,Bernie

Mr.Fixit · #7 (**permalink**) 06-05-2002, 04:34 PM

The machine shop I used to work for got all their custom cams for sprint car motors (mechanical F.I. 8-runner intake)from Ultradyne mostly because their willingness to spend time with the engine builder to sort out the right specs for that particular combo. So many variables, too hard to generalize recomendations.

Cal Metal · #8 (**permalink**) 06-17-2002, 08:03 PM

About 225 duration @ .050 lift is about the limit for duration with a Weber system. Reversion is the next problem you will face if you get too deep. Avoid split duration cams, as well.

RICK LAKE · #9 (**permalink**) 07-07-2002, 07:46 PM

Hi Cal Dave S. runs 58 webers and is running alot bigger cam than 225 duration at 50 lift . He will not say what is in it but it is bigger than 650lift, 235 duration at 50 lift and the car turn 7000 rpm. It runs low 10.20' in the heat of the day, and short shifts too. It idles at 900 rpm with no problems. Kuntz builds some 680 lift 238 duration with a set in 48 ida's His red line is 6800 rpm. The carbs run out of flow. Hey Bernie Did you have your cam degreed and checked befor it was installed. Check the cam card for the centerline and that it was set right Good Luck Rick Lake

Cal Metal · #10 (**permalink**) 07-09-2002, 06:56 AM

Rick:

Lift is not an issue with the Webers. 235 @ .050 is within the parameters. I have seen guys use 245 @ .050 and appear to be OK. Sometimes the lack of RPMs is due to an air correction jet which is too large or limited choke size,

Mike Braddock · #11 (**permalink**) 07-09-2002, 02:37 PM

Jeff,

I don't think you need a special cam for webers, but rather the webers allow you to run a bigger cam than you usually would without sacrificing tractibility. Case in point is one of my friends in Titusville, FL named Don Parnell who has a Contemporary with a 351C. He's running 12.5:1 compression, webers and a Comp Cams 292H (I think) bumpstick. On pump gas. The engine pulls strong from 3k rpm and he turns it to 7500. Yes it has a wicked sounding lope, as he's running 244 duration at .050". He swapped over to a holley 4V carb setup while rebuilding the webers and as expected the motor just coughed a sputtered with the common plenum and weak booster signals. I would not have believed it if I hadn't ridden in the car and witnessed how tractable the motor was. He hasn't had it on a dyno but he estimates 500 hp. Buy my point is it's the webers which let him run such a large duration cam (it's only got about .550" lift), which allow him to run such high compression on a "street" motor. So cam selection is very important for individual runner induction systems. Of course, as you said, all of the other engine (and vehicle) specs must able be taken into account as well.

Bernie, those are impressive numbers from your 289. Please let us know how it works out when you talk with that company and what kind of cam specs they recommend. Are you planning to keep the compression the same?

Mike

PERUCH · #12 (**permalink**) 07-09-2002, 03:16 PM

Mike,
My 289 work very well with 10.8 CR,stock rockers (FIA rules),GT40 early heads fully ported 255/202 at.600,245/200 at .550.I spoke with two different companies both different but the approach and the results are quiet the same:
First is David Generous from Camtechniques,the other are Buddy rawls (www.wighat.com/fcr3/ impressive site about camshaft,sometimes difficult to understand but very clever.
About my camshaft specs:
260°@.050 inlet
255°@.050 exhaust
My E/I ratio is very high at low lift average 92% atleast up to .300 lift cylinder pressure is compromise because the exhaust flow begins too early and loose some velocity and scavenging potential and need reducing the exhaust seat duration will achieve is holding the cylinder pressure a little longer,it will also reduce overlap.This should produce better inlet filling and cylinder pressure potential,which will boost VE,and therefore torque in the lower RPM ranges,regards,Bernie