e85 446 10.8:1 decent 906s, 1050 carb,headers. (I know big carb but the plan is T.F. heads and 512/528 stroker in the future) Conventional wisdom for gas was to run a big duration to bleed off some dynamic compression? Since corn squeezins' can handle much higher compression would it not be an advantage to strive for a profile that would keep the dynamic compression as high as possible?

So my question is what centerline, opening and closing events would I be looking for?

Or am I just overthinking this and just go with a tried and true 108*
250-260 degree type stick? (solid flat)

Thanks,

mo

If you are going to run only E85 it makes sense to optimize for E85, which means keep the compression up.

I have the old (heavy) 2295s and plans are to go stroker in the future with 13:1.Yes this is a dedicated e85 build since living in the midwest we have about 10 places that carry the stuff within 15 miles from home.

The future plans to stroke it (or just build another based on a low deck) is why I'm going with the 1050 (4150) e85 carbs ain't cheap so I might have to jet down for the 446.



I be prepared though for future plans eh? I ran this old hog for years with the 2295s and and old .471/.474 Hemi cam.

It did not like pump gas and racing gas is lots o' dollars and not available locally.

I have Crane iron 1.6 and am for sure going solid flat tappet on this build.
There was some write-up about e85 camming that you could go 10* or more bigger than pump gas?
Just thinking when choosing a cam there may be something better to shoot for,,,,,,,,,,,,,,,,,,,,,,,,,,or not?

Cam doesn't care what the fuel is. Carb, Compression & timing does.

The intake closing event has a direct effect on dynamic compression. An optimized cam in this case will most assuredly be different for E85 vs gasoline.

So what. 268 cam has different IVC then a 272, or retard the cam to close the valve sooner. With 13:1 you're gonna have a high DCR anyways.

It is 10.8:1 now (13:1 is in my dreams)


I will look more closely at the intake closing events a little more. I am trying to digest an article by Vizard so perhaps something will become of that?

Well with performance cams, you are going to find that the bigger the cams duration, the later the intake closes. Which essentially bleeds of more DCR.

Only sure fire way is to raise the compression. And with E85, raise it a lot.

Not always, get a wide lobe separation and it'll be a better fit. Don't be getting no old school cams though.

With 10.8 CR and pump gas I expect you would be fighting detonation and wanting a high duration cam with higher LSA. With the E85, detonation should be under excellent control so a cam that builds more torque and cylinder pressure is beneficial.

FWIW I think 260 degrees is too much for your combo... the standard port heads will run out of flow at moderate RPM anyhow so you just loose useful mid range torque with high duration. I'll suggest 240-250 @ 108 LSA.

If it is a dedicated drag engine with high stall converter, ignore the above comment.

Looking at a Howards 254/260, too much eh? I can tolerate loosing some on the lower end. NOT a dedicated strip car, more of a get it out and play toy? '69 Coronet 3.23 most of the time (I have a complete 4.57 pig also)No fiberglass stuff so 3800-3900#. High stall 11" probably flashes ~3000 with the old Hemi cam (284 what's that 237*)

That old hydraulic had some lope but I think I would like just a bit more.
I have read many places a solid needs 10 more degrees than a hydraulic?

So looking at it that way, 240 solid would be a "smaller" cam than the old
284 hydraulic. I see you are making sense, but,,,,,,,,,,,,,,,, some people just need a hammer to the head to get it?

I looked at the Hughes cams, but they seem like a whole bunch of lift for the duration, especially with 1.6 rockers (measured a bit more than that)
Well thanks for the help, I will continue my quest.

I wouldn't hesitate to use a cam like your thinking with 106 to 108 LSA and install it at 102 to 105 intake lobe center One of the best HP and torque producing 906 iron headed pump gas stock stroke 440 motors I built had a Reed cam with 101 LSA(installed at 99 ILC) similar duration like your thinking and .560 lift with 1.5 ratio rockers That racal had a bunch of tire spinning bottom end and it would not quit pulling hard up to 7000 RPM according to the customer
Back when I first started learning about camshafts we would use a close (104 to 108 )LSA on the automatic cars and a wider(110+) LSA on the stick shift cars, the thinking was and is the closer LSA help the bottom end, below 5000 RPM, and the wider LSA move the peak power up above 5000 RPM That still applys for me BTW, my bracket motor(505 C.I., 14.3 to 1 comp. ratio) runs on pump E85 with a 108 LSA solid roller cam installed at 106 ILC, runs good, last a long time after I got the rocker arm situation worked out on the Eddy M.
M.W. Victor heads
Make sure your fuel system will provide enough volume(30% more needed at least than for gasoline) for running on E85

Thanks Mr. Cab,

that Howards cam comes with a 4 degree advance ground in according to the specs LSA 108* ICL 104*.

If I go this route I'll check it and perhaps put it in at 102*?

As another reference, I really like the 243@.050/108 LSA MM lobe cam in my 496. It is a lowdeck with ported Ed heads. It is well matched to a 3.23 rear and OD 5 speed. With EFI tuneup it made 592 HP/687 ft lb on the dyno.

Nice Torque number!

That cam have a nice chop?

The old street Hemi grind had a decent lope,,,,,,,,,,, until officer friendly persuaded me to put pipes out past the bumper.

It took away alot of that cams character. Going 3 inch with ultraflos now. (To the bumper)
I know I need to use my sense on choosing a cam, but hearing a super choppy cam sure does strike a primal chord in me. ( and many others it seems)

Numbers like that don't lie, what is the mm lobe? Mopar .904 specific?

Thanks

Yes... the 243@.050/108 CL has a nice chop. The MM (Muscle Motors) lobe is the most aggressive possible with a .904 lifter. At that duration, .55" lift with 1.5 rockers is pretty good for a FT. Some consider this profile a bit risky on the street. That said, I put 15k miles + extended road track runs on mine before freshen. At freshen the cam was re-usable but did show some wear. Hot oil and many runs over 6k RPM may have contributed (need an oil cooler for extended road track time). For safety, I replaced it with the same profile... this time with nitriding.

All that torque/cylinder pressure can contribute to detonation. With moderate 10.2 CR, tight quench and aluminum heads my setup works fine. I think it would work fine in yours also with E85 to manage detonation.

That Howards stick has 254/260* and .550/.555 lift with 1.5s I have old Crane 1.6s ( they measure a bit more than that).

I was thinking on a 1050 Quick fuel 4150 as I might go 500 and trick flows in the future? I figure get it bigger and tune it down for now and I will be set for future endeavors? (e85 carbs ain't cheap)

The diff in price is only ~100 more for the 1050 vs the 850/950. Yes I plan on staying with a 4150 since the car has the ramcharger set-up.

Degree it to get the intake lobe center where you want it, it might end up at 101, 103 or 105 instead of 102, 104 or 106 depedning on the timing set, camshaft pin and crankshaft keyways One degree camshaft timing differences doesn't normally make a bunch of difference at the track or on a engine dyno Once you have the ILC where you like make sure and check the exhaust lobe center to verify that the cam is ground on the LSA that the cam card says it is , not all of the cams are ground correclty If the cam is ground on a 108 LSA and you install it at 104 ATDC on the intake lobe center the exhaust lobe center should be in at 112 BTDC If it is off more than one degree on the LSA send it back and have them grind you one on the correct 108 LSA

Do you find very many cams that are not ground correctly?
I will go through the time to check it out. Thanks for the heads up on checking an exhaust lobe too.

Never thought of checkin' both?