Le Mans camshaft

[Scott Calabro]

Has anyone had any success with this grind with webers, on an 11 to 1 C/R 289 ?

Or would the stock 289 solid lifter high perf cam be better with webers?

Or a modern solid roller?

This will be mated to a UN1-26 (or UN1-13 haven't decided yet) in a replica '40

Thanks,
Scott

 

[Gary Kadrmas]

Scott,

Back when I was putting my 289 in my Cobra back together, I decided to go all out, and REALLY build a killer. A partial list of parts included the Lemans cam and 12.5:1 pistons. The heads were already worked over by Chet McFallo, the original owner of the Cobra, and the person that changed the street CSX-2075 into a Private Dragon Snake.

Some people here will probably laugh at this, but please keep in mind this was done over 33 years ago. Back in 1972-74, Ford High Performance Parts were starting to get hard to find. Not having the wisdom of years and years of racing history, and since I was only 20 years old at the time, I may have made some decisions that were somewhat off, but today, I would make very few changes if I were to do it over today.

Please note: If you are going to run 12.5:1 pistons with todays gas on the street, think again. I tried to make it work, and finally got disgusted. The snout opening on a Cobra is small, and I was always having concerns about the temp gauge running hotter than I would have liked. I ended up removing them, and installing flat tops to lower the compression.

LeMans Cam: At the time, I was unable to find a LeMans Cam from Ford anywhere. I ended up getting it through Cobra Performance/Gordon Gimble in Sacto California (now long out of business). It was a regrind I am sure, and the specs off of the cam card are:

Intake Lift: 510 degrees Exhaust Lift: 510 degrees
Intake Duration: 318 Exhaust Duration: 304 Degrees
Intake: .020 Exhaust: .025
Intake opens: 52 degrees Exhaust opens: 82 degrees
Intake closes: 86 degrees Exhaust closes: 42 degrees
94 degrees of overlap: Intake & exhaust valves open at the same time

In the beginning, I ran dual four Holley 465cfm vacuum secondary carbs, and later switched to Weber 48IDA's. The Webers were VERY responsive, but at the time, I still had drag race 5.38:1 gears in the rearend. It made for screeming acceleration. Anyone running Webers will attest to what its like to flush 8 toilets at the same time. I eventually went back to the Holleys, and I am very happy with that decision.

As far as the LeMans camshaft, I would recommend it to anyone for the best all around camshaft. It delivers good low end, and very good high RPM performance. The idle is a little lumpy, and makes for a 800-900 RPM idle. But damn, sure soulds good!epper: epper: epper: epper: epper: epper: epper:

Hope this helps. Let me know if you have any questions.

 

[Scott Calabro]

Hi Gary !

Thanks for the advice. The engine has 5.4 in. rods. coated Ross flat pistons & I plan on using AFR 180 heads angle milled down to 48 cc to obtain the high C/R.

Both cams are advertised for sale on the Holman & Moody website.

I don't see detonation on pump gas (93) as a problem in a light car, as the generous overlap will bleed off cyl. pressure at low rpm. Especially on the Le Mans grind.

No way would I attempt 12.5 to 1 on pump gas !

Primarily I was wondering which cam would be better with the weber setup on a primarily street driven replica.

Thanks and hope your doing better !

Best,
Scott

 

[Gary Kadrmas]

Scott,

You would be happy with the LeMans grind. Make sure you compare the specs of the cam I listed. Not saying anything negative about cam suppliers, but its best if you see if the specs are what they are, not just a name of a cam put on a box.

 

[Rick]

Wouldn't the cylinder pressure be bled off by the duration? Consequently wouldn't that cam, (Lemans) require or be better suited to a higher static compression than 10:1?

 

[Jac Mac]

Scott,

With your 5.4 rod the piston is going to be 'parked' @ TDC for longer, therefore with the 'Le Mans' cam which has a fairly hefty amount of overlap you will probably have to cut/deepen the valve pockets in the pistons & at a shallower angle to stock since you intend to angle mill the heads. Personally I would use a Roller of around 290 advertised duration & choose the 050 timing after working out how much compression I could obtain without having to mess with valve pockets etc. Lobe centers around 107/108 for shorter road circuits- wider for any good mileage on the road.
I dont know how good your USA 93 octane fuel is, but I would not attempt any of the above on the 91 we have here, even our 95 would be marginal, you have to remember most modern stuff that can run on 93 etc has a computer that adjusts timing etc to suit engine load all the time. In your car YOU are the computer- will you be able to anticipate & react to detonation etc in time to prevent any damage?

Jac Mac

 

[Scott Calabro]

Jac Mac,

Thanks for the input. I thought that with the piston @ TDC for a "long" time it cooled off more due to its close proximity to the cyl. head? I have selected a Ross piston that will accomodate the long rod and has deep pockets. I can't recall the piston P/N off-hand though. I'll post it so you can advise.

I am betting that the combination of light car, low/close ratio box (UNI-26), long rods, small combustion chamber, coated flat pistons, "0" deck, and lots of overlap will get me buy on 11 to 1 C/R and good 93 Sunoco.

If I have to mix some Av-Gas in on hot days I'm OK with that, as a it is easily available to me at work.

I really want that wicked sounding idle (hopefully around 1200 rpm) and upper RPM power. I know I'll have to trade some driveability.

Best,
Scott

 

[Scott Calabro]

Jac Mac,

Ross pistons P/N 99826, with their P/N EPC 104, top and skirt coatings.



Cheers,
Scott

 

[Jac Mac]

The cooling benefit is only one of several things that occur with the long rod .
The 'Wicked Sounding Idle' is going to be somewhat subdued by the longer rod as with the piston ' parked ' for a larger part of the overlap period it does not assist the expulsion of the exhaust gas or help draw in the fuel mixture to the same extent as a shorter rod of the std 289. ( In other words the large overlap that you hope is going to bleed off some compression is going to be negated somewhat by your longer rod choice ) Also the crossover exh system of the 40 will flatten out the sound compared to a cobra with side pipes.

Those Ross pistons will possibly require valve clearance work ,if you angle mill the heads, at the point where the notch blends onto the piston top. Since any machine work will remove some coating you might want to rethink this.

Jac Mac

 

[Scott Calabro]

Many thanks Jac, I will take it under advisement.

Enjoy your weekend.

Regards,
Scott

 

[Rick]

Where is a good source for a Lemans spec flat tappet cam? There have been a very few show up on EBAY. Are any there other reliable sources?

 

[Scott Calabro]

Hi Rick,

You can get the genuine article from | Holman Moody| or an almost exact replica from Crower Cams. They currently have them for sale on special for 60 bucks in the "Garage Sale" section on the website.
P/N 15002. I just bought one last week, they only had a few left. The specs are as follows;

@.050" tappet lift....
Intake
opens 23 BTDC
closes 51 ABDC

Exhaust
opens 59 BBDC
closes 15 ATDC

108 deg Lobe Sep.

Duration @ .050" 254 both sides

Lobe lift .337 both sides

Best,
Scott