3.2 SS Camshaft Choice - Elgine 306 - 288 - 102
 

I'm about to assemble a 3.2 SS motor that was an abandoned project from it's previous owner.

The spec of the motor is

3.0SC case, crank and rods
98mm barrels and JE Pistons 10.5:1 Compression
"big port" heads using 993 intake valves
TWIN PLUGGED
45mm ITBs
1 & 5/8 stainless headers

The engine came with a set of Elgin 306/288 cams with a 102 lobe centre.

I've never used these cams and am looking for advice.

I have used the Webcam 464/465 (pretty much a Mod S) on similar motors before and always happy with the result.
These Elgin cams have a little more intake duration and a LOT more duration on exhaust.. I'm not sure the resultant effect these would have.

Not looking to build a race engine that lives between 5500 and 8000, rather looking for a fun street motor that punches hard from 3k to around the 7k mark.

Will the Elgin cams do this?

Also considering
DC40
DC43
http://forums.pelicanparts.com/uploa...1679122345.jpg

Given the amount of static compression you quote, these Elgin cams should work well for you application. Than much duration will bleed off dynamic compress so this cam needs all it can get. Fuel quality could become an issue.

hi Henry
my concern is that perhaps this is a cam better suited to a track environment.
The plan for this motor is a fun street car. Our "premium 98" fuel here seems to pose no issue.

Some people are running over 10:1 compression on single plug, where this one will be twin plug... which I might have ommitted from my post... I'll go back and amend!!

Twin plug or not, dynamic not static compression is the important factor to consider. Long duration cams delay the closing of the intake valve and substantially reduce the dynamic compression ratio of an engine compared to the static compression. Your 10.5:1 theoretical compression is a static calculation. Camshaft choice directly affects dynamic compression.
Volumetric efficiency will determine cylinder pressures. Camshafts, port size, exhaust scavenging, intake configuration [fuel delivery] as well as piston dome configuration are all important influences. Given your specs, I believe the Elgin cams will function well for you application. Aggressive, definitely....Others may have a different view....oh well.

Henry sent you shipping info

A quick note about cam selection and early 911 engines.
In over 35 years of building these air cooled hot rods [400+], rarely has anyone every come to me to say, "damn that snappy power isn't my thing".
On the other hand, quite often when a customer picks the "conservative" cam because "they aren't racing" the first question is "what would it cost to change the cams?"

Most of the high performance street car 3.2 SS engines we build us DC60, DC62 and DC65. Of course are mostly MFI engine.

The cams we're using in our new 11.2:1, 3.8 with Motec and our bespoke ITB street engine will be running DC43x-109 Cams.

Rpm quotes in table
 

Good evening,

The cam info here is interesting, where did the data for the RPM peaks come from? I have never seen it before.

Thanks in advance for the reply.

i got it from here... https://supertecperformance.com/pages/how-to-select-a-porsche-camshaft

I'm not expecting it to be 100% accurate, but hoping it's a reliable method for comparing cams on paper.

Good morning,

Thanks for sharing your where the info came from.

Well there's a glowing endorsement. lol

Don’t whimp out and go with milder cam. That SS deserves that much duration you have or more. I run an 80 grind cam on 100 LC in mine and it’s not too much. Great pull from 3,000 on up

I have DC-85 cams in my 3.2 SS motor that's twin-plugged and has 10:1 or better pistons ( 98mm) . I run PMO 46 carbs, and aside from a little stumble from 2800 to 3000, it's a really strong motor. It has no real issues on the street.
From what I've been told the DC85 is the 'second-largest' cam you can put in a motor like this. My only reason for changing the cams would be if it were the cause of the stumble between 2800 and 3000 rpm. Car goes back to Mayo's on Monday for some jet-tweaking and installation of a hand throttle , as it runs cold and the idle takes a while to rev up at first start.