DC30 or DC40 Camshaft?

[OCG911T]

Soliciting advice on a camshaft grind for my 2.4 short stroke build.

I’m torn between the DC30(mod solex) and DC40(mod s) grinds.

Car will mostly be street driven and I want longetivity and reliability in the build.

2.2T case with original non counterweighted crankshaft
Casework at Ollie’s with case savers and bypass mod
ARP hardware throughout
87.5mm LN Nickies with JE Pistons
2.4 liter with 9.5:1 compression ratio
Webers from a 67S with enrichment tubes 32mm Venturis and S setup
Stock 2.2 heads (will keep 32/32 ports if DC30 or open to 36/36 if DC40 selected)
Single plug with Bosch distributor recurved to match cam grind
Stock 5spd transmission
Fender mounted oil cooler
Upgraded oil pump
91 octane fuel (93 is hard to find in Maine)

Does anyone have experience with a similar build with either of these camshafts?

How does the car drive? powerband, horsepower, torque, carb settings, etc.?

Thanks,
Oliver

[Henry Schmidt]

I am a huge fan of the DC40. The build you're proposing could easily produce 170RWHP with 36mm ports and DC40.
That power comes on early and makes great power (2.4S type power) @ 6400 rpm.

[OCG911T]

Henry,

What is the powerband? Is 6400 rpm the sweet spot or it’s max hp? I am nearly certain I will go with the DC40 but am only concerned I will need to regularly wind the engine up into the 7k range to stay in the powerband with a non-counterweighted crankshaft.

Thanks again!

[Iciclehead]

I have a DC35 cam, not yet in the car, albeit on a 3.4 with twin plug/ITB's.....according to Mr. Doherty is is a compromise between the two, may be a consideration for you? I realize the smaller displacement would make a material difference...

Dennis

[OCG911T]

Thanks for the input, Dennis.

I’ll ask John next time I email him if the DC35 could be a good option. He suggested the DC40 and the DC30 to begin with and the only reason I am hesitant about the DC30 choice is detonation can occur with the higher compression ratio and lower octane fuel.

So far I have a few sources who are all suggesting the DC40 for my particular build. If it was going to have a little less compression the DC30 would be a no brainer for the powerband I am looking for, but I won’t complain about the more powerful DC40 grind if my engine build can take it anyway.

Hopefully this won’t be my last build and next time I will go with a DC30 on a 2.5 or 2.6 short stroke with a lower compression ratio.

Oliver

[horizontallyopp]

Oliver,

I have no input for you but certainly interested to see the outcome of your build. I am building up a 2.2 SS (maybe 2.35SS if I went with the same pistons you indicated) on a counterweighted 66 mm crank but want to stick with carbs, single plug ignition and CR below 9.5:1. I went with the DC30 with 2.2T smaller port (T/E) heads to get the power band down a little for more low end drivability. Unfortunately my engine rebuild is stalled due to a house move, so I haven't got it put together yet to give you any advice!

Best of luck!
Keith

[OCG911T]

Keith,

Good luck with your build. I almost went with a 2.3SS build as well, but then found the 87.5mm LN Engineering P&C’s fit the 2.2 case spigots without machining (at least they are supposed to..) I think in retrospect I would have special ordered pistons to target a 9.0:1 CR and gone with a DC30 grind to keep the powerband lower, like your proposed setup. However, with all the casework and hardware upgrades I will probably be very happy with the higher CR and DC40 grind. It will be interesting to see what the CR turns out to be once measured... I definitely want to stay single plug and am limited by the premium unleaded available in Maine.... I believe an air/fuel mixture gauge is in my future the keep an eye on potential lean or detonation issues.

Cheers,
Oliver