Cam Guru's

[911ctS]

Forgive me if this has been mentioned here before. I did try a search but it didn't turn up with much. Anyway, I was wondering if anyone knew the difference between the solex cams (66 911 cams) and the 911L cams. Are they the same? If so, then what did the 69' and 70' 911E come with? From BA's book it looks to be a Solex cam, (but in an E ???) so what is a true E cam? Is it from a later E model like the 2.4E? Are there many differnet factory cam grinds out there that BA does not mention on his chart of 911 cams? For instance different variations of E cams or Solex cams for diffenet years. Please shed some light on this subject if you can.
Clint

[camgrinder]

All the 911L cams I have ever seen are the same grind as the 911E which was originally produced as a camshaft for the 901/06 2.0 engine.

[911ctS]

Thanks John, I was hoping you would chime in.
Do you guys at Elgin have a grind that is between an E cam and an S cam? I've heard that your special S grind is a very good compromise, but im afraid that it is still to radical for my 2.4L engine. Currently I have 911 E cams with 9.5 to 1 comp. (its a daily driver) and I'm looking for a slightly hotter cam but dont want to come close to S specs because they're just not practial in a 2.4 for daily street use AND I still have 32mm intake ports. Would you recomend the Solex cam or something else? thanks
Clint

[jluetjen]

911cts;
Here's a post where I posted a comparison of the different cams. I doubt that you will find much of an improvement in your engine if you put a "wilder" cam in. I maintain (although others might disagree) that the 2.4E's are pretty much limited in the creation of additional HP by their 32 mm intake ports. A longer duration cam may prop up the torque curve at higher revs (and thus increase the HP some) but you might lose torque at lower revs where you spend most of your driving time. I suspect that Porsche changed the 2.4E cams by increaseing the lobe angle (and thus reducing the overlap) to keep the performance on par for the 2.4E.

[911ctS]

That was very, very helpful John. Thank you very much!! Ive been looking for one of those charts for awhile now. Dang, I knew there was some odd ball cam variations out there.
After looking things over, my future plans are to get some Solex cams to put in. I currently have 67/68 cams now and I could use my peak torque and HP up just a tad, my car is very light at 2K and the low, low end torque is almost going to waste. Im also planning on going to 34mm port size or possibly get some 2.7 heads to swap out, I think those are 35mm or something. This sould solve some of the breathing problems closer to 7000 RPM.
Thanks for the information and advise.
Clint

[camgrinder]

Clint,
What we call our "Mod-S" cam might be too much for a street driven car. I think a Solex cam ground on 102 lobe centers might be right.
It would have more lift and 10 degrees more duration than the early E cam you have now.

John, I would like to see your chart. I went to the post and it didnt show up. Do you know the late 2.4E cams casting numbers?

[jluetjen]

John;
When I went to the link in my previous post, the chart still appeared. I created it by collecting and cross checking as many different published accounts as I could (since unlike you I'm not in a position to see and measure 100's of cams). I agree that there is still some ambiguity regarding the differences between Solex/Early E/ Later E cams. Try as I might, I have yet to find anyone who has measured and published the measurements for them to clear it up. In the absense of any hard conflicting evidence, I'm going with the factory manuals which describe the Solexes and Early E's as having the same specs with the exception of the MFI drive.
I don't have casting numbers for the 2.4E's.

[camgrinder]

John,
I went to your post with a newer browser and it shows up. Very interesting.
I still doubt the specs on the 901/09 901/11 911 E profile. I believe the little handbook is incorrect. It lists the correct timing setting and the correct lift for a normal "E" but the duration of the Solex type grind.
I noticed Bruce Anderson's book changed between editions. The first edition shows a normal E spec and the second shows it as a Solex type cam.
I think the only way to know is someone with a 901/09 original engine having the camshafts measured.

[jluetjen]

John;
I just went and pulled some of the data from the factory shop manual (as opposed to the little spec. book).

"2000 enging with modified camshaft" as from serial numer 911-001.

Intake:
Opens @ 20 BTC
Closes @ 34 ABC
Lift: .413

Set to 3-3.3 mm (.118-.130 inches ) at TDC

Exhaust:
Opens @ 40 BBC
Closes @ 6 ABC
Lift: .382

901/01 with Solex cams
Intake:
Opens @ 29 BTC
Closes @ 39 ABC
Lift: .413

Set to 4.2-4.6 mm (.165-.181 inches ) at TDC

Exhaust:
Opens @ 39 BBC
Closes @ 19 ABC
Lift: .382

911E (2.0) (From the spec book, the shop manual says very little about the 2.0E)
Intake:
Opens @ 29 BTC (Confirmed with shop manual)
Closes @ 39 ABC (Confirmed with shop manual)
Lift: 36.58 mm

Set to 4.2-4.6 mm (.165-.181 inches ) at 3.00 - 3.30 mm @ TDC

Exhaust:
Opens @ 39 BBC (Confirmed with shop manual)
Closes @ 19 ABC (Confirmed with shop manual)
Lift: 36.25 mm

911E-C (2.2) (Matches the spec book)
Intake:
Opens @ 20 BTC
Closes @ 34 ABC
Lift: 36.58 mm

Set to 4.2-4.6 mm (.165-.181 inches ) at 3.00 - 3.30 mm @ TDC

Exhaust:
Opens @ 40 BBC
Closes @ 6 ABC
Lift: 36.25 mm

It looks like for the 2.2E the factory reverted back to "2000 with modified camshaft" specs.

[RoninLB]

FWIW

a few years ago I bought new E-cams from Stoddard[before Pelican days] and went thru some questions and answers about this same thing. The left cam had the MFI gear drive. I'm still not convinced what I have ? I somewhat believe it's below.

I do have the part numbers if needed.

[camgrinder]

The specs in the picture are what I am used to seeing as a 911-E grind.
If someone wanted the mystery Solex-E grind it would be easy to grind the Solex on a 102 lobe
centers. That would be a good step up on the MFI E cars.

[911ctS]

I was just wondering John..... Isn't the 2.7L S cam a very good core to have for re-grind? Could you grind a true solex cam off of this?
Clint

O ya Ronin, I think those are the cams i have too. What sort of engine config. are you running?

[camgrinder]

The Cis 2.7 S is a decent core for regrinds because the base circle is .100" bigger than the pre 1973 cams.
The Solex grind will not fit on this core. The E grind fits much better but will come out around .060" smaller than the original E cam base circle.
.060" is the total, what the rocker arm sees if 1/2 the reduction and only .030".

[911ctS]

I think I understand what you are saying, but just wanted to make sure.

So basicly what your saying that the lift specs off the cam are going to be about .060 smaller and the specs affecting the rocker or valve will be .030 less that solex spec.

If this is the case.... then is there a core out there (becides the solex itself) that will be a candidate for the solex?

Thanks,
Clint

[camgrinder]

Actually the lift specs dont change at the cam lobe when you reduce the base circles. Lots of things such as duration, lobe centers and rocker ratio can change by altering the base circle, however cam lift does not.
The solex has a very tight lobe center (97 degrees) like an early 911 Carb/MFI S cam. The 911 E had 102 and the later cams use 110 to 113 lobe centers. Moving lobe centers takes more off the base circle than anything.
I think using an E cam and puting the Solex on top with the E lobe centers would be best.
If you have a 2.7litre and wanted a wide power band, Use the solex masters and put it out at 108. with some PMO carbs and 10-1 c/r I would expect an RPM range of 3000-7000.

[RoninLB]

Originally posted by 911ctS

O ya Ronin, I think those are the cams i have too. What sort of engine config. are you running?

In progress,

2.7, rebuilt
E-cam
stock heads
8.5 RS
PMO
MSD, etc.
SSI, Monty