Anyone running Solex cams on higher displacment engines?
 

Putting together a 3.0/3.2 motor.

3.0 Bottom end
98 mm J&E P&Cs with 9.5:1 CR
Weber Carbs (40 or 46)
Single plug electromotive Ignition
Early SC heads with larger 39mm intakes
Larger 3.6L oil pump

Cams?

I have readily available a pair of early Solex grind on 4-lobe cam (Crane cam)

Also considering...

Elgin Modified S-Cam (Intake 296 @.470 lift and Exhaust 270 @.395 lift) with 102 lobe centers and 4.5mm lift at lap)

GE40 cams

Your thoughts?

I had a 2.7 w/ solex cams and I really liked them. The power band was a little tight which made the thing run like a two stroke dirt bike. That particular engine had very small intake ports. I currently run a 3.0 w/ Elgin Mod S cams. The heads are from an '80 but they were opened up by Competition Engineering to approx. that of the 78-79 SC ports. The car pulls nicely and comes on at the upper RPMs but it doesn't have the same snappy feel that the 2.7 had w/ the solex grind but it is certainly fast.

JimZ..

You said...

>>The power band was a little tight which made the thing run like a two stroke dirt bike. <<

I think you mean that RPM range at which the motor appears to produce power is within a narrow range, or did you mean something different.

Sorry, I've never fiddled with 2-stroke dirk bikes, so I don't understand that analogy. Can you explain?

I'm just learning about the effects of cams on the engine, so a little ed-ji-kay-shun is necessary.

Thanks for the reply.

Regards,

yes you are correct. The power was made in a more narrow RPM range. I do recall that I hit the 7300 Rev limiter pretty easily though. I thought that that engine felt very explosive (in a good way.) I liked it better than friends similar 2.7 cars w/ E cams. The 3.0 w/ Mod S cams seems like it needs to be pushed harder to get the same feel. I don't know if it is in the cams or not ...just my observation.

so the E-cams in the 2.7 came on earlier than the Solex.. and the E then leveled out, while the Solex kept on getting stronger .........Ron

The e cam came on earlier and leveled out giving a smoothe feeling. The solex cam came on a little later kept getting stronger and peaked out quickly but really threw you back in your seat.

thanks J

Okay, Jim... so if you had your choice for the ultimate street engine...

E-Cams
S-Cams
Modified-S Cams
Solex Cams

or something else?

I am no expert but alot of factors come into play. Compression, port size, exhaust, displacement etc. I am running a 3.0 w/ 9.3:1 CR and Mod S cams and the motor is certainly strong. I think I would like a little more displacement and a little more compression to give it some more grunt down low. You are proposing a 3.2 w/ 9.5:1 CR so you may be very happy with the Mod S cam. Maybe you can get a little more compression in there? I can tell you this your car will haul a$$ w/ what you are doing.

Gracias for the assistance...

Another thing to consider, it is my understanding that the MOD S cam REALLY needs to have its timing set just right in order to work best.

Actually the Solex and the E cams are virtually identical (if not identical) according to published specs. JMZ's experience is what I would expect of a motor that is port restricted -- basically it ran out of breath at high rev's. If he had ported that engine out to 36 mm's I suspect that he would have picked up some top end HP and it would have felt much more like an RS. BTW, just because it feels faster does not necessarily mean that it was faster, I suspect that the 3.0 with S cams is actually faster, just with a lot less drama.

something about the lobe center is different.

OK - The Solex and the >>Early<< E cams are virtually identical. The '72 on E cams have a wider lobe angle which reduced the overlap slightly, most likely to take into the account that the 2.4E was becoming port constricted at higher rev's.

Early E and Solex were the same. '72 and '73 were different.

Regards,