Author Topic: LeMans Cam Valve Lash  (Read 3794 times)

SFM66H

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LeMans Cam Valve Lash
« on: March 25, 2020, 06:37:03 PM »
I did try the search bar here and also on Google, but with mixed to no results, so I'm going to ask Forum 2.0 about the correct valve lash for Ford's C7FE-6250-A LeMans cam in a 289 Hi-Po.

My files say .020 Intake and .025 Exhaust, but I have no confirmation if those are cold settings or not. Can anyone here confirm if those settings are correct and if they are the numbers for a cold valve lash setting?

Thanks,
Kieth
1966 GT350H owner since June 30, 1976

6S1568

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Re: LeMans Cam Valve Lash
« Reply #1 on: March 26, 2020, 11:42:48 AM »
I can't confirm, but I'm still looking through some old spec sheets...... Perhaps you'll hear from one of the engine builders on the Forum.

shelbydoug

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Re: LeMans Cam Valve Lash
« Reply #2 on: March 26, 2020, 12:37:15 PM »
Cam manufacturers always state the hot clearances.

We talked about this here before and everyone has a different method for adjusting valves.

Generally I set them cold. .020/.025 are what I have for that cam also.

Use the Ford shop method of setting each valve at TDC. The distributor rotor will point at each plug wire.

Depending on whether you have aluminum or iron heads determines the cold setting.

First you need to be able to determine zero clearance. I do that by turning the push rod. When you can't turn it with your finger tips, it's at zero. You can't do that with a hot engine. You will get burned.

The Ford Engine plant used the method described in the shop manual.


Aluminum head manufacturers will tell you to deduct .006" from the hot setting. I've had issues with that being too tight. .002 is safer.
I've got AFR aluminum heads and they should be simple but they aren't. They gave me head gasket sealing issues, intake manifold gasket sealing issues and are too tight at -.006"?

My iron Ford heads were childs play by comparison.

On iron heads I add .002 to the clearance spec.


If you are using rail type rocker arms like Jessels, you can't reach the puch rods with your finger tips. With those you need to establish zero clearance with the feeler gauge between the roller tip of the rocker and the tip of the valve stem. It's a go, no go thing that way.

The shaft rocker arms are new to me and are causing half the issues. I'm not sure if they are worth the effort yet? They are a lot of effort to get just right.


If you hear spitting in either the intake (manifold) or the exhaust (headers) you are too tight and the valves are hanging open.
« Last Edit: March 26, 2020, 05:05:25 PM by shelbydoug »
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SFM66H

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Re: LeMans Cam Valve Lash
« Reply #3 on: March 28, 2020, 10:38:31 AM »
shelbydoug,

Thanks for your reply. I've attached here my source for the lash settings of .020/.025 for the C7FE cam and have found that exact same spec in Bob Mannel's "Mustang & Ford Small Block V8, 1962-1969, Vols I & II", Appendix G, Page 2.

But several outside sources have spoken to me about both valves being set at the same lash (and of course that setting varies between those guys too!) but none of them are subscribing to the two books I have that show a different setting for the two different valves.

In my mind, this was a simple question that would have a simple answer. But what I'm finding out is it's like the age old question of what oil is the best. 10 guys, 10 different answers, you know what I mean?

Your reply states that "cam manufacturers always state the hot clearances" - but this chart is not from cam manufacturers. So... would you consider these hot or cold settings?

I need a beer!  :-\   

1966 GT350H owner since June 30, 1976

shelbydoug

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Re: LeMans Cam Valve Lash
« Reply #4 on: March 28, 2020, 11:07:04 AM »
.020/.025 are the Ford specs. Hot.

You generally can add more top end or more bottom end by varying the clearance specs. +/- .004 is about as much as you want to vary. You need to listen for "sputz" in the exhaust. Then they are too tight and not closing completely.



The Ford Performance Book indicates there is an early and a late version of the cam.

For you to have the early version, it would have had to come out of a GT40 MkI. It's possible but very unlikely.

What you probably have is the Ford Service Parts cam.


It's interesting in that many come here attempting to alieveate their stresses and just create more? Having fun yet?


I should also mention at this point that the"LeMans cam" isn't particularly a good grind. I'd recommend that you look at something more current, maybe from CompCams who has some experience with Fords.

It's really kind of a conundrum of a cam. It really will do nothing for you unless you intend to run a 24 hr race at WOT with Webers?

There it's smooth but it gives so much away as a street cam profile.


Look at your head flow characteristics. How does the limited lift on that cam make the heads work? It doesn't have enough lift.


So what, "it's a real Ford 'Lemans cam'". Who cares? No one is going to take it seriously these days.


The listing indicates it fits all Ford small blocks except the 351c. I don't remember it fitting a 351w? I think that engine has a different size bearing lobe? I may be wrong on that? I haven't done one in about 35 years. It also has a different firing order then a 289.

Ford didn't change the 302 to the 351w firing order until the '80s. There would be a firing order mismatch even if you could put it in a 351.

There were some warranty issues with broken camshafts in 68 or 69. The fix was to go to the 351w firing order eventually.

Also, how you "fix" reversion with Webers is generally reduce the amount of overlap. On a Ford that means cutting it down to around 28 degrees total. Some grinders will tell you it's just a late closing intake. I'm not a cam grinder but with 94 degrees of overlap, with Webers that cam has got to throw fuel like a volcano spewing lava?

My point is, I just found some inaccuracies in that chart.
« Last Edit: March 28, 2020, 11:37:02 AM by shelbydoug »
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SFM66H

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Re: LeMans Cam Valve Lash
« Reply #5 on: March 28, 2020, 04:53:04 PM »
Re: The C7FE LeMans cam “not being a particularly good grind” - I would readily concede that. This old dog is willing to try to learn a new trick! And others have mentioned Comp Cams to me. Do you have a part number of the one that you would recommend that I look into?

Thanks
1966 GT350H owner since June 30, 1976

shelbydoug

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Re: LeMans Cam Valve Lash
« Reply #6 on: March 28, 2020, 05:16:18 PM »
Re: The C7FE LeMans cam “not being a particularly good grind” - I would readily concede that. This old dog is willing to try to learn a new trick! And others have mentioned Comp Cams to me. Do you have a part number of the one that you would recommend that I look into?

Thanks

What are you building? A street or a track car?
68 GT350 Lives Matter!

SFM66H

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Re: LeMans Cam Valve Lash
« Reply #7 on: March 28, 2020, 05:50:04 PM »
Oops, that would've helped, 'eh?

Street. Just a stock 1966 GT 350 4 speed...
1966 GT350H owner since June 30, 1976

shelbydoug

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Re: LeMans Cam Valve Lash
« Reply #8 on: March 28, 2020, 06:06:49 PM »
I would recommend this one. If you want a little more lift and duration, switch from 1.6 ratio rockers to 1.7.

https://www.compcams.com/magnum-magnum-muscle-236-236-solid-flat-cam-for-ford-221-302.html

It has plenty of power all the way past 7,000 rpm.

It's a little racier at idle then the 289 hp cam. Mine idles at about 850 hot.

Lots of extra torque right off of idle. People will hear you comming and they stop and look. Greenpeace probably will hate you for it?

It's a solid lifter profile. Nothing fancy to set up. It will work with just about any head that you pick provided it has provisions for solids.
« Last Edit: March 29, 2020, 02:48:44 PM by shelbydoug »
68 GT350 Lives Matter!

SFM66H

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Re: LeMans Cam Valve Lash
« Reply #9 on: March 28, 2020, 07:23:36 PM »

It's a little racier at idle then the 289 hp cam.

Lots of extra torque right off of idle. People will hear you comming and they stop and look. Greenpeace probably will hate you for it?


Thanks shelbydoug - you present very appealing characteristics of this cam. I would enjoy offending Greenpeace if at all possible. I'll run it past my builder for sure. He has already spoken to me of Comp Cams and this may have been the actual one he was referring to. I had LeMans cam blindness at the time...

Thanks again for all the time you have taken to help me with this quandary of mine,

Kieth
1966 GT350H owner since June 30, 1976

Royce Peterson

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Re: LeMans Cam Valve Lash
« Reply #10 on: March 29, 2020, 09:49:50 AM »
The 1967 Ford shop manual gives the specs for hot and cold valve lash on the 289 HP as .018" and .022" respectively. Both intake and exhaust are set at the same specification.


I did try the search bar here and also on Google, but with mixed to no results, so I'm going to ask Forum 2.0 about the correct valve lash for Ford's C7FE-6250-A LeMans cam in a 289 Hi-Po.

My files say .020 Intake and .025 Exhaust, but I have no confirmation if those are cold settings or not. Can anyone here confirm if those settings are correct and if they are the numbers for a cold valve lash setting?

Thanks,
Kieth
1968 Cougar XR-7 GT-E 427 Side Oiler C6 3.50 Detroit Locker
1968 1/2 Cougar XR-7 428CJ Ram Air C6 3.91 Traction Lock

SFM66H

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Re: LeMans Cam Valve Lash
« Reply #11 on: March 29, 2020, 10:07:22 AM »
EXCELLENT - Thanks Royce!
1966 GT350H owner since June 30, 1976

shelbydoug

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Re: LeMans Cam Valve Lash
« Reply #12 on: March 29, 2020, 10:12:30 AM »

It's a little racier at idle then the 289 hp cam.

Lots of extra torque right off of idle. People will hear you comming and they stop and look. Greenpeace probably will hate you for it?


Thanks shelbydoug - you present very appealing characteristics of this cam. I would enjoy offending Greenpeace if at all possible. I'll run it past my builder for sure. He has already spoken to me of Comp Cams and this may have been the actual one he was referring to. I had LeMans cam blindness at the time...

Thanks again for all the time you have taken to help me with this quandary of mine,

Kieth

Well yes. It has often been said that I have the personality of a solid lifter camshaft.

This camshaft was at one time referred to by CC as a upgraded 289 hp cam. You will be much happier with it then the Lemans cam.

Just tell everyone that it is the Lemans cam. How are they going to know?
« Last Edit: March 29, 2020, 10:16:00 AM by shelbydoug »
68 GT350 Lives Matter!

Side-Oilers

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Re: LeMans Cam Valve Lash
« Reply #13 on: March 29, 2020, 02:52:18 PM »
Kind of like wanting Le Mans rods.   A cool sounding name, but there are far better components to run, these days.

Current:
2006 FGT. Tungsten. Whipple, HRE 20s, Ohlin coil-overs, 3.90 gears. 210.7 mph.

Kirkham Cobra. 482-inch aluminum side-oiler. Tremec 5-spd.

Formerly:
1968 GT500KR #2575 (1982-2022)
1970 Ranchero GT 429
1969 LTD Country Squire 429
1963 T-Bird Sport Roadster
1957 T-Bird E-model 3-spd stick

SFM6S087

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Re: LeMans Cam Valve Lash
« Reply #14 on: March 30, 2020, 03:35:01 AM »
And if you're looking for a little extra punch while maintaining a stock appearance you may want to go with a stroker kit. I know a 1966 GT350 that recently won concours gold that has a stroker kit. The judges couldn't tell and the owner planned to drive the car after winning the award.

Just a thought.

Steve