Lots of mentions of these cams but haven’t found any reference to the rpm range this cam is making its torque at. Trying to zero in on the best torque converter to go with it.
How about posting some timing and lift numbers? Patrick's is history since the company went belly-up, and I'm pretty sure they were just reselling someone else's cam. Just about any high performance cam in a stovebolt engine without some radical cylinder head work is a waste of time and money, and even if you decide to invest in "Improving" the head, it's basic design limits how much of an improvement can be measured on a dyno. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I have the 264 cam and my seat of the pants dyno feels the cam from around 1300 rpm up to 3800 rpm. What it gives at high rpm it gives up some low end torque.
The mild 254 cam probably tops out earlier and may have better low end.
I luckily got a hold of a guy at Patrick’s just before they went belly up and got him to send me the cam specs. This is what he sent me: Patrick’s Mild Cam Specs- Intake and Exhaust Lobe Center Sep - 110.3 Cam Deg Valve Overlap - -.8 Crank Deg
Intake Valve Opening - -.4 ‘BTDC Lobe Center - 110.7 ‘ATDC Valve Closure - 40.8 ‘ABDC Duration - 220.4 Crank Deg Max Cam Lift - .28909 In. Net Valve Lift - .43364 In. Lobe “Area” - 23.14 In * Deg
Exhaust Valve Opening - 40.1 ‘BBDC Lobe Center - 109.9 ‘BTDC Valve Closure - -.4 ‘ATDC Duration - 219.8 Crank Deg Max Cam Lift - .28854 In. Net Valve Lift - .43281 In. Lobe “Area” - 22.99 In * Deg
My specific situation is: 350 miles on a completely rebuilt 235 with the mild cam, dual carbs from Langdon’s, 700r4, 4.11 gear and a 2400 stall B&M Tork Master.
My “seat of the pants dyno” tells me I should be closer to a stock converter, possibly a 2000 stall to achieve my best power delivery. Currently it seems to not necessarily slip but never fully lock and just generally more bark than bite.
I was concerned the “slipping” may be overheating the trans/converter but after checking the fluid today it still looks like it was just poured in.
A torque converter never locks up 100%. The physics of the stator almost doubling the engine torque just before the transmission input shaft begins to turn also causes the best possible RPM lockup to be 90%- - - -100 RPM in- - - -90 out. That's why modern torque converters in transmissions such as the 350C and 700R4, etc. use a single disc clutch inside the torque converter to eliminate the slip during light throttle cruise conditions. No matter what the stall speed is, there's no way to stop all the slip unless you use a locking converter. I'd recommend going back to the OEM converter for the 700R4 and installing the electrical controls to make use of the lockup clutch. It's a simple system which does not require a computer- - - -just a vacuum switch and a "brake on-off" (BOO) switch.
BTW- - - -the first transmission to use a locking converter was a 1949 Studebaker, followed shortly thereafter by the 1955 Packard Ultramatic. There's nothing new under the sun! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I am going to suggest that all of the gain in performance from engine upgrades with a 235 will all be lost with the addition of an automatic transmission. But hey, breaking even ain't a bad place to be.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
"Automatic transmissions are smarter than all drivers and most mechanics!" That was one of Dad's favorite sayings. He was the first man in Nashville Tennessee to work on automatic transmissions, back in the late 1940's and he fixed thousands of them over his lifetime. He had a very good point! It's virtually impossible to get an automatic in the wrong gear, no matter how hard someone tries! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Just to put a bow on this thread for anyone who may search in the future...
I took the car to the local trans/gear shop; the owner who is someone I trust, took it for a drive and said in his opinion the Patrick's 3/4 Mild cam is pretty aggressive. He was shocked that with a 2400 stall converter on it, when you put it in gear, it jumps even with your foot on the brake at 800~ rpm. I'm kind of thinking maybe Patrick's sent me one of the more aggressive cams in error..?
He said the trans is shifting well and at the proper points. He doesn't think changing converters will yield any better results as long as that cam is in there.
Here's a short clip where you can hear it...
Perhaps someone familiar could determine if mild or closer to wild..?
I am going to suggest that all of the gain in performance from engine upgrades with a 235 will all be lost with the addition of an automatic transmission. But hey, breaking even ain't a bad place to be.
I'm inclined to agree with you. My goal was an easy cruiser that looks good and sounds a little sinister. If I were going for a tire shredder I'd obviously have taken the 6 out but I love the novelty of it... I think it just comes down to having expected more peppy responsiveness of it. I know I could get that with a manual trans but, like I said "an easy cruiser". Trade-offs...
Having it driven and verified to be running, shifting and all properly; I'm pretty satisfied with these "throttled" performance expectations.
My carbs and timing were set by my engine builder, local guy who has lots of experience with these engines so I'd be real surprised if it were one of those out of whack.
I can't say yet what my topend details are because I'm still about 45 miles short of my 100 mile break in on that ring/pinion. I'm gonna try to get through that tomorrow with a couple drives with complete cool down in between, then I'll see what's what.
If it moves immediately, the cam is small not large. Big cams are notorious for poor torque off idle. The "2400 stall" converter is rated with the Chevrolet 350 V8's torque at that RPM, far higher than yours, so your stall is less. K = RPM ÷ (T^.5), K equals the engine speed at stall divided by the square root of the torque at that speed. Estimating the V8 torque as about the displacement at 350 ft/lbs, the K value of this converter is about 130. This applied as 200 ft/lbs to your L6 gives 1,800 stall with the same converter. A looser (higher stall) converter will improve low speed response and acceleration, with some loss of mileage and increase in ATF temperature. By comparison a "3500 stall" (with a 350) converter has a K value of about 175, which would stall about 2,500 with your engine. I wouldn't change anything until you have enough miles on it to try WOT.
It sounds awesome! Suddenly I don't care about everything else which may or may not be the best of ideas. I now get it. Now I want one which sounds like that.
Last edited by 52Carl; 08/31/201912:11 AM.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
Jack Clifford, when he was alive, had as much, likely more, experience with camshafts for the 235 Chevy then anyone. I have run a few of them over the years and they were very good cams. I still have one I have never run, Giant size cam, way too big to ever run, from when I was way younger and bigger was always better, lol, so that one will get reground at some point. But jack’s descriptions of his cam grinds I always found to be accurate so here is a page out of one of his old catalogs that might help with assessing what you have.
That being said, I have had very good luck with jerry Cantrell at Schneider cams in San Diego. They are pretty good and if you want a little rumble out of the 235 at idle, give them a play. They will grind you a cam that makes sense for your build, which is particularly important when running an automatic.
It sounds awesome!- - - - - -Now I want one which sounds like that.
Pull one spark plug wire and retard the timing a little- - - - -it's a lot less expensive than killing all your low end torque with too much cam and one too many carburetors. You'll still be able to get away from a stoplight faster, also! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Your cam sounds more radical than the 264 in this engine. See what you think. Dave
Wow, yeah I’d have to agree. Really wish Patrick’s was still around to figure it out with a phone call. Is that 264 available through other suppliers now that Patrick’s is defunct?
Hotrod Lincoln Pull one spark plug wire and retard the timing a little- - - - -it's a lot less expensive than killing all your low end torque with too much cam and one too many carburetors. You'll still be able to get away from a stoplight faster, also! Jerry
LOL, I doubt a stock 235 or 261 for that matter will out pull my little ole farm truck from a stop light...... Winky wink. Dave
Neat thread, perhaps we should take it to the Hipo forum. Swizcore don't want to hijack your post, let us know how it goes after you get the rear gears broke in.
For some more perspective, I have run two cams other than stock in my 235-powered 3800 pickup -- a Howard's M4F "3/4 race" and a Crower "custom special."
The Howard's goes like this: 206 deg. @0.050 intake and exhaust, split overlap at 4 degrees; split timing on the bottom at 30 and 30. This cam is indistinguishable from stock when running 2 carbs and Fenton headers. That's why I pulled it out. It will pull well at 2200 RPM at WOT. No dyno numbers but I would guess that the torque peak is about 2200. The actual grind may not be what's on the card. I didn't degree it when I put it in. Dead smooth idle.
The Crower it considerably hotter and I developed it over the phone with advise of Bruce Crower. Advertised duration 252 deg. Here are the specs at 0.050 lift: duration, 220 @0.50 lift split overlap at 8 degrees split timing on the bottom at 42 deg. I did degree this cam and I installed it 4 degrees advanced, which was as much as I dared to maintain 0.50 valve to piston clearance. I told Dave that I wanted a torque peak around 2800 RPM and I'm guessing it's more like 2950. It will turn up til it runs out of carburation at about 3600. On the road, It pulls hard down to about 2600 when the fire begins to die down and by 2500 it's time to shift down. If you're not in a hurry it will pull down to 1500 without complaint and it's fine around town loaded just shifting the main transmission. With the 3-speed auxiliary I can keep it on the boil between 2600 and 2900 RPM and that cam works well. It idles without a lope but not like stock.
Changing to the Crower cam with no other changes improved the fuel economy significantly, like about 25%, because I'm no longer running way over the peak torque RPM most of the time as before. In overdrive it's turning 2850 at 60MPH. It has noticeably more power at 2800RPM.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
The .050" duration is a better indicator of how hot a cam will feel than nominal duration. The stock cams are really mild (compared to V8), with 220° and up actually making more peak power. IME most aftermarket cams' .050" duration can be approximated by deducting between 30° and 40° from the advertised intake duration (half that from each end of the timing figures). Hot cams with faster ramps should take off closer to 30° (the above Crower is 32°) and mild cams with slow tappet movement more than that.
Pull one spark plug wire and retard the timing a little- - - - -it's a lot less expensive than killing all your low end torque with too much cam and one too many carburetors. You'll still be able to get away from a stoplight faster, also! Jerry
Party pooper! I don't want to drive one, I just want back it out of the garage and annoy my neighborhood.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
Finished the 100 mile break in last night. During that drive I noticed nearing 60mph a shimmy was building. While it was cooling off I decided to double check pinion phasing. I was about 4.5° difference at ride height(105psi front/50psi rear) so I corrected that and took it out this morning. I “stretched her legs” to about 67mph and that pinion correction really helped. At 65mph I was in the 2500rpm range.
Since this is an X-frame car, I’m thinking the little bit of shimmy I still have is at the trans tailshaft/front half of the drive shaft. So I guess I’ll be shimming up the trans at the cross member to correct that.
All in all I’m honestly pretty happy with how she drives, goes and stops now.
Ok, just for clarification exactly what vehicle are you running this motor in?
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
Moved the trans crossmember up to the higher hole set on the frame. It’s about 1” higher and took her for a spin. Smoothed out even more, to the point I was able to run on the expressway at 70 SMOOTHLY. At 70 she’s running about 2900r’s. Chirps 2nd if I’m in it a little but like I said, I went with the 700 for an easy cruiser and I think I’ll stick around 65 on the eway when necessary to hit a show.
Thanks for all the info and experience fella’s. I know this is a truck based site but having gleaned a bunch of knowledge from here on my 55.1 Burb build, I knew there’d be more experience than theory in here and that’s why I brought my car issue in. Much appreciated.
