Disadvantages of a reground cam

[BRENT in 10-uh-C]

Originally Posted by Don S

This thread kinda got away from the original question. I got the touring cam from Bill Stipe,complete with the technical information He provided. With the engine described in my earlier post,is the touring cam the best option,or should the 3.78 rear gears be changed to 4.11,or better carburation?Highway speed is no problem,it is just that long hills will slow her down to 30-35 or so in 3rd gear. Thanks again

Happens a lot around here ...and it seems like more so here lately. It's all good though!!


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[Bob Johnson]

I have been doing some investigating of camshafts. I was curious about what regrinds were in certain cars. I built a tool that allows me to measure the lift curves without removing the head. Here are graphs of camshaft lifts for two cars that I measured. The one labeled Regrind #1 was in a car that was lacking power. The one labeled Regrind #2 was in a car which ran very well. Regrind #2 show that to get more lift the duration is increased. Regrind #1 indicates a possible worn lobe and a slight shift of the valve timing.

Bob

[john in illinois]

Don S I have about the same setup as you. Touring,inserted,balanced engine. Stock Zenith carb. ,3.78 gears ,F 150 OD trans, 23 or 26 %.

The engine was built with an unknown touring regrind cam. I had the engine apart,so I decided to put in a new Stipe 330 cam,Which Bill told me would be a good torque cam for overdrive. Boy what a difference that made. It pulled better at all speeds. I was going to put a Weber carb on it and decided that I didn't need it after the cam.

I went to Montana last summer and crossed the Rockies at Helena,6500 ft.
I was able to maintain 40-45 mph in third . I only had to shift to 2cnd one time to get over the top of a hill without lugging.

I think 4.11 gears would make all the lower gears too low in the 4speed. More power would help a lot. If you don't want to change cam,a Weber or some other carb set up might help hill climbing. Good luck,each A engine seems different to tune.

[Don S]

Some numbers regarding the reground cam from Bill.
Intake---Max cam lift--.304 Duration at .016, lash 241deg,cam duration at.050 209Deg
Exhaust numbers are the same except the lash ,which is 241 deg.
Lobe center line is 112 Deg
Exhaust is set up for 10deg btdc and 52deg abdc
Intake is set up for 8 deg atdc and 53 bbdc
Some numbers for the crunchers out there.Comments?

[Don S]

THanks John,it sounds as though we do similar touring trips.I am not ready to tear down my engine at this point as it is running quite well except for the hills.Did you change your valve size with the engine apart?

[Bill Stipe]

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Don, Sorry your having troubles. I will post a dyno test of an engine I think is similar to yours accept you have a 5.9 head and I assume an A carb. The 5.9 head should give you about 2 to 3 HP more acording to tests I have done.
Also on your OD 150 tranny I have the same one in my truck and bought from Dave Wilton years ago and I made sure I purchased the one with the smallest jump in 4th gear over drive the other 2 chioces are too tall to pull with the Model A engine. Also if you are pulling a hill you need to pull out of over drive and run straight through in high gear, you should be able to run 45 to 50 mph yet in third gear. I guess I don't know how steep of a hill you are talking and how long the hill is but you only have about 54 to 57 HP at 2400 rpm and the torque drops off at higher RPMs.

Ford Motor 40 HP @ 2200 RPM and 128 Ft LB @ 1000 RPM
Bill Stipe

www.stipemachine.com

[Don S]

Thanks Bill,I may leave it in 4th a bit too long on occasion. Some of the hills are several miles long,some with swichbacks. I am running a Zenith carb,with only the spark arrestor,no real filter,should breathe ok. Ive run this thread long enough,thanks for your suggestions.

[Smitty]

What does a cam with worn bearing surfaces sound like?

[Purdy Swoft]

I don't see any disadvantage with the reground cams that I run in two of my model A's. It all depends on the cam core and the person that grinds the cam.It is a must to talk with whoever grinds the cam. The cam grinder will give you the specs that are necessary for the core and what other mods may be needed for the desired effect. Compression, gear ratio, carburetion and lifter choice will be the most important consideration. I run a regrind in my roadster with a 317 lift and the duration is 252- 255. I don't have the other specs in front of me now, but the roadster or the speedster have power, pretty much like a modern car. I don't live in mountainous country but there is some pretty good hills and I can accelerate going up any of them. My Super Winfield 3/4 race cams also idle good and will still chick ah lunk with the spark retarded. The 3/4 cams won't idle quite as low as a stock cam with a heavy flywheel , but still idle good. I run 3.78 gears and the original three speed transmission. and I have never needed to down shift on any hill.

[john in illinois]

Don,my engine does have larger intake valves.

[Don S]

Thanks John,larger valves will help. Purdy,you are probably running a downdraft carb? I am trying to stay stock looking for licence purposes

[Purdy Swoft]

Don, no down draft for me. I'm running a vintage Trojan dual updraft manifold with model B carbs. Its not like it came from the factory look but was a period correct accessory. The car looks mostly original, otherwise.