Right cams for carbs?

[JV44HeinzBar]

Hi,
I'm having my 70T's engine rebuilt to 70E specs. I've got the pistons and cylinders already (2.2E), but I've got some questions concerning the camshafts.

What are the benefits of going to an E cam vs retaining the T cam? It's my understanding that the T cam will give me more punch down low & in the middle, while the E cam spreads the power out across the tach.

Also, I came across a set of L cams. What would be the effect of dropping these into my engine vs Ts?

Is there an issue or benefit with using cams designed for MFI vs carbs? My car is using IDE40 Webers.

BTW, I know I don't want to use S cams as the roads near my home don't really allow for that type of driving.

One last thing - When I'm looking at camshafts I noticed that each shaft has a series of numbers. While I think I know what they mean, I'm not 100% sure. For example:

1968 911L spm*, air inj., (lft)901 105 139 00, (rht)901 105 110 05, (in)36.5mm, (out)36.2mm

vs

1969-73 911E 901 105 181 00, 901 105 110 05, 36.58mm, 36.25mm

Could someone explain the numbers in detail? I understand what the 901 probably stands for 911, and I think that the 105 is for the center lobe, but I'm not sure. Anyhow, I'm just guessing.

* Does anyone know what "spm" stands for?

Lots of questions I know, but I want my engine rebuild to be just right for my driving conditions. I should mention my conditions are around town a good bit, but I also have the opportunity to blast around some very nice back roads w/ lots of elevation changes and switchbacks.

Thanks,
Brent

[BURN-BROS]

Hi Brent,

The numbers are casting # used to identify left, right, and bosses for aux equipment.
The 68L cams have identical grinds and the later E cams. Cam timing specs were changed.

The E cams are a nice blend of low speed drivability and upper range performance.

[JT912]

SPM could be Sportomatic? Are ther two pins in the end of the cam that would drive the oil pump? Is this also set up for the smog system drive pulley?

[ratpiper71T]

I'll be taking the same journey with my 2.2 soon., hopefully. I hope then you don't mind if I add to your questions since I was also considering an E cam- now I'm wondering about the solex and mod-s cams how do they compare with the E cams?

[Flat6pac]

Solex is a very nice cam between E and S spec. They are less peaky than the S but more serious than E. I ve always prefered the grind if I could get it.
Bruce

[mskala]

I'm almost through this same thing as well, I say almost because I'm breaking in
the motor. It's a 2.0T case/crank with 2.2E piston/cyl/heads and carbs. I talked
to John Dougherty, who recommended the DC-30, which is his improved Solex cam.
You may want to look into the DC-30.

Keep in mind that the T crank is non-counterweight.

FWIW, the carb setup that is working well so far thanks to PMO, is 32 vent, 55 idle,
135 main, 180 air, F1 tube.

[JV44HeinzBar]

Hi,
I'm looking at a pair of cams now. Can any tell me what the numbers mean exactly?

901.105.139.OR AE1

901.105.110.OR AE2

I was told that these are for a 911E, but I can't find any numbers to verify them to being from an "E".



There appears to be a pin at the end, but I'm not sure. Your thoughts?

I should note that they come from a well respected member, but I want to make sure I'm buying the right set of cams for my driving style; I'm wanting more pickup at the bottom and mid range of rev range.

Brent

[tom1394racing]

Here are some Porsche 911 camshaft specs that will help.

Not yet complete but it does cover the early cams.

[BK911]

if you have the engine apart, you may want to consider adding a 2.4 crank and rods.

[JT912]

The top cam looks like it is set up for the Sporto oil pump. Definately not set up for the air injection (smog) system. I've got some pictures of my '68 cam with both smog and sporto over at Sportomatic cam.
The bottom cam looks like the right bank cam from my engine.

[Tyson Schmidt]

The T cams will not give you more bottom end power than E cams. That's just where T cams make all their power.

E cams will give you similar bottom end power to the T cams but will give a bit more mid range and a lot more top end power.

[rocketreid17]

Did you ever get any further information on these camshafts?
901.105.110.0R AE2 ??

[porschetub]

Originally Posted by mskala

I'm almost through this same thing as well, I say almost because I'm breaking in
the motor. It's a 2.0T case/crank with 2.2E piston/cyl/heads and carbs. I talked
to John Dougherty, who recommended the DC-30, which is his improved Solex cam.
You may want to look into the DC-30.

Keep in mind that the T crank is non-counterweight.

FWIW, the carb setup that is working well so far thanks to PMO, is 32 vent, 55 idle,
135 main, 180 air, F1 tube.

Non-counterweight?,so tell us more