Do S Cams make sense for me?

[Paul_D]

Howdy. I have a 2.2 T motor that is stock with the exception of Webers and 2.4 E pistons & cylinders that were used when the engine was rebuilt 22 years (but only about 20K miles) ago. The engine runs fine and leak-down test is OK (4 cyls. @ 5%, 2 @ 8%)

I have the engine out while doing some work on the tranny. I'd like love to up the HP of the motor somewhat but I don't want to tear down and dump $thousands into an engine that is basically in good shape. Does it make sense to have the cams welded/reground to S spec, if I'm not prepared to make the other changes/upgrades that should go along with higher revs and HP, at this time?

Things like:
-Head porting
-valve spring upgrade
-counterbalance crank

I'm resigned to the need for additional oil cooling, and I have a good Bosch mechanical distributor from early S on hand, so I should be able to get the ignition curve right. I also have some 34mm venturis for the carbs - which I believe are correct for hotter cams.

But the pistons? Are they a "show stopper"? Am I going to have interference between the 2.4 E pistons and S cams?

Does keeping the T crank and valve springs mean staying with the lower redline of the stock engine? It would seem pointless to have S cams in a rev-happy short stroke motor but not be able to use the full glory of the upper register.

So... new cams, now, more or less alone -or save my sheckels till I can afford the whole enchilada, which may be never?

Thanks to the group for any input or advice.

PS I have Wayne's engine book, so I have some idea of what the full list of recommended 2.2 upgrades consists of, I just can't do it all right now.

[tadd]

redoing a 911 engine is not cheap. Period. That said, there seem to be paths that are less expensive than others . Porsche wanted a sports car and did a lot of good work. That said, there are some nice tweeks out there if one designs within the 'limitations' for lack of a better word.

First is head flow. Head work is expensive. There is lot that can be done, but it costs. So if you build around a stock 36 mm 'S' port life will be cheaper. Thus, do you want small and high reving, or larger and lower? Sporty racer or traffic driver? If you want sporty, build small, say 2.2 with a DC60 cam and the mods to give you 8k rpm (second cost - keep reading). A more relaxed motor would be Gradys 2.8S. 92 mm pistions with S cams kept to below 7300 rpm.

Second is rpm. Getting beyond 7300 gets more expensive. Oil mods, rods, ect. Keeping it below 7300 lets you live with stock parts but for aftermarket rod bolts.

Typically I'm an 'while you are in there' kinda guy.... but given the mag case and its NEED to be resized after splitting that costs I'd only split the case if you must. Once you do split the case, spend the money and get squirters if they aren't installed already. IIRC, its a PIA but the rod bolts/bearings can be changed w/o splitting the case. THat saves the 2k bill for resizing the case.

Bottom line, you may just want to pick up some S cams and try them. On a 2.4 they really aren't that peaky. Just that will make a night and day difference. You might want to check out the 'hot' choice of a DC 44 on 102 LC. Its been used in a few 2.3L motors with great results.

Just some rambling.

tadd

[Paul_D]

Tadd,

Thanks for your suggestions. One question - what does "102 LC" refer to where you wrote "...choice of a DC 44 on 102 LC." ?

-Paul

[tadd]

LC = lobe center or distance between the peak lift in degrees. Big motors 3.6L like 109 ish while the smaller ripping 2.0s use 98 ish.

Just about any modern cam profile will require better springs and retainers. About $800 ish, not too bad.

Another 'cheap' upgrade (IMHO) is to twin plug. Its around $450 to have the second hole added to the heads then you can go with one of the repo distributors or coil pack. Just FYI, the phasing timing (electronic advance) eats caps and rotors on a distributor. Even if you don't have the cash for the ignition, I would recomend getting the twin plugging done while the heads are off. Just put the plugs in and put the valve covers back on. When you are ready, pull the covers and just add leads. Even if you don't up the compression, it will let you run crappier gas at less advance and easily pay for itself over time. Future proof yourself while the motor is appart. Compression is effiency.

tadd

[Steve@Rennsport]

Tadd offers stellar advice here,.....

I would only add that using "S" cams requires a compression ratio that leaves you with some low-end power.

JMHO, but "S" cams are somewhat peaky in engines under 2.7 litres which is a cylinder pressure issue. I would measure your mechanical CR with the pistons you plan on using before settling on a camshaft.

To realize the potential with "S" cams, you'll do better if the heads are opened up and flowed to "S" specification otherwise its a waste of money. Solex cams are another good choice in engines like these.

[Eagledriver]

Solex or E cams would be a much better choice, especially if you don't port the heads. Revs on your motor are more a function of cam profile and spring shim depth than anything else. Use the rev limit for the cams you use (ie 7000 with Solex). Your crank is OK for any of the stock rev limits. Have the valve springs shims set to the cam profile you use as well.

-Andy

[Paul_D]

Very good info, thank you. This forum is great.

I will probably take the advice of using the Solex cam. Each of the incremental costs connected with S level upgrades are not so bad by themselves, but taken together it's clear that it would cost upwards of $10K to do it right, and I'm not prepared to spend that right now.

-Paul

[tobluforu]

Do a WTB in th classified and see if someone has E cams. Then send these along with your rockers to your preferred cam grinder have the cams ground to solex specs, the rockers cleaned up/ground along with new bushings installed. RSR rocker shaft seals are cheap and a no-brainer IMHO.

[kenikh]

Best small bore cam ever with 32mm ports: DC30. Any Solex or E can be reground to this cam. S like top end, E like torque. What's not to like?

Send your cams out for a regrind and call it good.

[911pcars]

But the pistons? Are they a "show stopper"? Am I going to have interference between the 2.4 E pistons and S cams?

Am pretty sure E pistons don't co-exist well with S cam-controlled valves. Refer to Wayne's or B.Anderson's tomes. Still not convinced? While the valves in your E might be a tad smaller in diameter, I'd perform a mechanical test with clay and calipers. You can do this w/o actual S cams in place; use a dial indicator to track a set of valves supported by a pair of lightweight test springs.

Sherwood

[kenikh]

Valve pocket clearance isn't right and the CR is too low on E pistons too accomodate the overlap of the 'S' cam.