Stock 3.0 SC...do I need cams if I want PMO's?
 

Hi,

I'm looking to hot rod my 3.0 SC motor. I'm told Early “S” profile or GE 60 Cams, and 46 mm PMO's would make for a great, responsive motor. Do I need to do them at the same time, or can I do one then the other? Just curious.

Thanks!

You can bolt on the carbs with stock cams no problem. Or you can run those cams with CIS, but I would opt for the carbs first then the cams.

The CIS cams will work fine, but yes get some cams sometime, ignition works wonders also (a big recurve). wow factor- 10+ sound- 10+ fuel mileage- 4 butt dyno- 10+ wallet- empty!
http://forums.pelicanparts.com/uploa...1411448423.jpg
stock 3.0 with crappy Zenith's, loved it!!

Ok, great. 46mm cool? PMO,or does any other company make them? Anything else I need to be concerned with?

fax richard parr at pmo your order form and your concerns, he will call you back and chat at lengths, a real good guy.

Did you say "fax" him? Is he stuck in a 15 year time Warp? :)

A Fax keeps the junk mail and casual questions to a minimum I would imagine. Less distractions in his shop.
Easier than saying serious inquiries only! :)


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Just fax him, it is good to be in the PMO warp. He will call you and with expert advice and follow through.

Great...thanks all!

No, but a pair of DC-40's is a lot of fun!

Mike, what are DC 40's? And...is there a consensus on where to get the cams?

Dougherty Racing Cams

Dougherty Racing Cams

I could be wrong, But I don't think you could run those cams with the stock CIS pistions. From what I've read, valve/piston interference would result due to the CIS piston shape and no valve reliefs.

Also, with the valve overlap, you'll want more compression, or it will be a dog on the bottom end.

Yes, it's the start of the slippery slope. JE 10:5 to 1 CR pistons work very nice with 46mm PMO's. Add headers or SSI's and an M&K and enjoy.

Heh, I know. I think I'm going to go Carbs and S Cams to match my SSI's. That should be a good start.

Well, it's settled. I'm in the market for some 46's. :)

I think the S cams won't clear the CIS pistons.

Check that before or it's not going to be a good surprise.

You are buying carbs?

What kind of time warp are you in? ;)

Michael,

Let's combine much of the information in one place.

You do not need the cams to run carbs. Webers/PMOs will run just fine on a stock internal CIS converted car. However, The cams will not take advantage of the power you can get by running carbs as a fuel system.

There are many great cams for the 3.0. However, you can not run most of these on stock pistons. The piston dome on a CIS car is too tall and the piston will hit the valve on the exhaust side. The cams are more fun because they open the valves further and keep them open longer.

If you want to run an S, -40 or -60 cam you will need new pistons or have large pockets cut into your existing pistons to clear the valve. As you can see this gets to be a slippery slope...

I would start by talking with Richard at PMO. He will set you straight on the carbs. Don't buy yet.

Second call is to a well known cam grinder. John Dougherty, (DR Cams), Elgin, Web-cam, Take your pick. Find a grind that will utilize the carbs ability to handle reversion but also work with the stock pistons.

Third call is back to Richard to tell him what cam you are using.

Don't forget to have your rocker shaft faces refinished to match the new cams. Better yet. Buy a second used set and have them matched.

Cams in a 3.0 make a huge difference. After you have your carbs and cams en route call up Barry Hershon and have your distributor recurved to match the new cams.

You will certainly be pleased.

Rich Paar figured out years ago that the only way to get work done and not spend all day on the phone was to call people on his schedule.

Great guy and great products. It's worth sending the fax!

Thanks JPNovak, et al. Some really great advice for this Carb newbie. And @wayner, lol!
Touche sir...touche.

I built a 3.2SS with 46mm PMO's and S cams. It is a great engine and while the cams give you some decent torque down low the temptation to rev it out is often too great.

I'd like to go EFI but the carbs are still fantastic, as long as you can handle a poor idle while it's cold and difficult starts if you don't drive it all the time.

Ok kids...talked to Richard Parr the other day. Nice guy, and very knowledgable. I totally get the fax thing now, btw. Apparently, EVERYONE calls him and asks him a million questions, so he puts a good barrier of entry in front of them. Smart.

Anyway, I'm getting PMO 46's to start with. I need to measure my intakes to see if I've got 34mm or 38mm. If I've got 34, I'm going to have to bore them out. Any threads on this procedure?

It's not your intakes but rather your intake ports on your heads. It's not something you can do with the heads still on the motor.

For the time being you will have to buy intake manifolds that match your intake ports. Hopefully you have a 78-79 motor or Euro ROW with the large ports.

Also, I think you can probably get away with the larger manifolds for a while, even if you have small ports, it's only a small step. I don't know for sure though.

Gentlemen,
With all due respect to the fine products from PMO, Webers/PMO carbs are a waste of money without a commensurate upgrade to other significant engine parts.

However, carbs do look racy, and if that's the objective, great. Go for it. However, that look will cost $2500-$3500 with only a slight bump (if any) in power. Perhaps better throttle response. Congrats. Not sure how people think carburetors are superior to fuel injection. Maybe being able to tune carbs in their garage with minimal instruments and skill is key. 930 engines use CIS. Should their turbocharger(s) be "upgraded" with a carburetor too?

Other than Webers/PMOs, compatible pistons and more aggressive valve timing completes the correct mix of equipment for more torque and power, but that requires a serious expenditure of budget. Even then, it's more a function of increased volumetric efficiency (i.e. + compression ratio) and better breathing than just dumping more fuel in the engine.

To summarize:
- Aggressive valve timing isn't compatible with CIS pistons due to structural interference
- The benefit of carburetion is limited by CIS piston design and emissions-centric valve timing.
- Weber/PMO carbs look and sound sexy. CIS equipment is complicated and looks clumsy in comparison.
- There is no substitute for cubic inches (or cubic centimeters)

Sherwood

Sherwood, thanks for the input. As the car becomes more and more of a dedicated track machine, My next step will indeed be cams and Pistons. One step at a time though...my CIS has been an absolute mess for over a year now, and I can't wait to ditch it.

Just got done going through your build thread. Impressive! You've done a lot of work to that car and it's certainly deserving a motor that matches it's looks.

From this picture from your thread, it looks to a be a 80-83 US 3.0. It has metal fuel lines and what looks to be the smaller intake runners.

http://forums.pelicanparts.com/uploa...1365990394.jpg

For less money I would put the Bitz EFI kit on there. Tune it and enjoy it. You can still add compression and cams later and then just retune.

Again, I'm trying to get as authentic RSR as I can, without completely breaking the bank. I'm ordering some PMO 46's today. I *do* have the smaller intake runners. (34mm) Richard said he'd swap me out when I did the heads and got the larger bore. I'll do cams and heads sometime next year, perhaps. Any issues with running 46's with the 34mm runners that you know of?

You wont be using the 34 runners, the carbs use manifolds and there should be no issues, they are shaped and come with spacers to cover up the injector notches.

RSR engines used MFI - not synonymous with "not breaking the bank" (however, no clue as to the size of your bank account). Even RS engines used MFI. Completing the look of an "RSR" body is another big ticket item.

46 Webers are over-carbed for a 3 liter factory SC engine and unless adequately compensated with more modest venturis and rejetting, fuel mileage and perhaps throttle response will suffer.

Perhaps shop for the 46 Webers now, then install them with more compatible pistons/cylinders, head, cam and exhaust at a later date? Again, confirm with your checkbook.

Folks on these threads have no hesitancy to spend other people's money.

Sherwood