Milling a head for compression?

[Wick]

Heres some FREE HP,I learned this in kart Racing in the 80's.
Put the A on 4 jack stands. Spin a front wheel and time it. How long did it spin?
15sec...1 min...2 min? Now spin the other wheel. Whats the difference in the times?
If you only get 15-30 sec then your using up engine HP to move the car. Get the wheel to spin for 1-2 min. and you will feel the difference. Same thing with tires.
Take your Bicycle and set the air pressure at 15psi and ride it...now up the tire pressure to 40psi and go for a ride...feel the difference? I could take a Kart and give it a push in the garage and it might roll 3ft....remove as much friction as possible and push the kart....across the floor and out the door she would go!
I hope this information is usefull.
Wick

[BRENT in 10-uh-C]

Originally Posted by allison-tech

Knowing my nature( I really should have 9 lives ) I'll be doing some combustion work soon, but 1st, I really like the fact that I can start my eng. w/a crank. Can ya'll still start your HC eng's w/the crank? I also don't want to shorten the life of the babbit, Terry made some good points to ponder, along w/all the other posts.

Lewis, I had a Model A race car once with a head that cc-ed out to about 7½:1 compression ...and I hand cranked it to start that engine because it had no starter. Several of us have run A/B engines with upward of 10:1 CR on babbitt with no adverse effects. The downfall to babbitt (-or inserts) is detonation, ...not necessarily too much compression. I think that port work is not something you can gain on unless you have a flow bench and a manometer to see what you are actually gaining due to the siamesed port. More often than not, you will decrease flow when youstart messing around in there.

Wick, a lot of R&D for our bangers can be attributed to B&S kart racing huh!?!

[Wick]

Yea,Brent I learned alot! I was allways told 10% motor 10% Driver 80% Kart.
Milling Heads,profileing Cams,checking lifters,Flow testing carbs and weighing every moving part! it all added up. Also make sure when your wide open that the carb is wide open too! This can all be used on the Model A.
Wick

[allison-tech]

Brent, very cool car! You or Wick may know a good friend & mentor of mine. When I lived up north, and years ago, I raced go-karts as well, my friend got me into it, he was very good at it and at one time won 1st in IN. He was also my boss, at the time, his name is Arlynn Nofzinger. I was newly married then, and just couldn't afford to do it long, but it was alot of fun! & your right, it taught me alot of things I didn't know.

[Terry, NJ]

Brent, Are you sure about the A manifold being 1.000? Mine was 1.250 and I machined it out .032 to 1 9/32" I was going to take more but the casting was getting awfully thin and I decided not to risk it. Do I have a B manifold? It's now about 2 - 2.5 % larger which will mean very little HP increase, but we work in small percentages sometimes.
Terry

Originally Posted by BRENT in 10-uh-C

Purdy, are you sure the 'B' intake manifold wasn't 1.250" machined whereas the Model A maifold was 1.000" cast? And, doesn't the air flow go up on the square when the diameter increases? In other words, just because the size is 25% larger doesn't mean the airflow increases by 25% as it would be more.

Also, while I agree there was "only 10 horsepower" difference, I would think that a more realistic approach to this mindset would be the thought of the 'B' engine had 25% more power over the A, and the torque level was increased too.

[Terry, NJ]

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Wick. Couldn't agree more! I try to do this with my cars now and then too. See how steep a grade you must go down to accelerate in neutral. . And what's the holdup, cause it's costing me gas mileage! Damn disc brakes, never fully disengage!
Terry

Originally Posted by Wick

Heres some FREE HP,I learned this in kart Racing in the 80's.
Put the A on 4 jack stands. Spin a front wheel and time it. How long did it spin?
15sec...1 min...2 min? Now spin the other wheel. Whats the difference in the times?
If you only get 15-30 sec then your using up engine HP to move the car. Get the wheel to spin for 1-2 min. and you will feel the difference. Same thing with tires.
Take your Bicycle and set the air pressure at 15psi and ride it...now up the tire pressure to 40psi and go for a ride...feel the difference? I could take a Kart and give it a push in the garage and it might roll 3ft....remove as much friction as possible and push the kart....across the floor and out the door she would go!
I hope this information is usefull.
Wick

[Milton]

Originally Posted by allison-tech

Knowing my nature( I really should have 9 lives ) I'll be doing some combustion work soon, but 1st, I really like the fact that I can start my eng. w/a crank. Can ya'll still start your HC eng's w/the crank? I also don't want to shorten the life of the babbit, Terry made some good points to ponder, along w/all the other posts.

Yes, I can crank start my 81 year old engine with my 70 year old arm. The Snyder 5.5 head causes no problems in regards to cranking. In fact, it really lets you know when the compression stroke begins.

[allison-tech]

Thanks Milton, is this a pic. of the snyder combustion chamber?

[sturgis 39]

Originally Posted by 29restorod

At one time someone sold cast ,combustion chamber fillers,that you weled in,to raise compression. I saw them on E-bay one time. Also,low buck racers would just build up weld bead to fill the combustion chamber. I met a guy at a car show with a doodle bug tractor,that had a head, he filled with scrap iron welded in. He said he had been using the tractor since 1950.

I like your signature.

[29restorod]

Wick,we always said it was 1/3-Machine,1/3-driver,1/3-luck. The best driver,with the best kart,could have a lot of bad luck. I did the wheel bearing thing,just like you,new bearings every race,seal lips cut off,and chain lube,instead of grease.

[Terry, NJ]

Once again, I'm new at this so bear with me. Why is it desirable to run SAE 250 (?) (600) weight grease in the rear. Until it gets hot it must be like plowing through peanut butter and surely draining off HP from a engine that hasn't got too much to spare. I know that the 250/600 oil doesn't leak out past the seals. but it seems to me that a better seal could be developed and used that allows for a lighter oil.
Along the same lines, I used a older, Long Fiber grease in my front wheel bearings. After I packed them. they didn't turn so easily either. Perhaps I should have used a more modern moly grease?
Terry

Originally Posted by 29restorod

Wick,we always said it was 1/3-Machine,1/3-driver,1/3-luck. The best driver,with the best kart,could have a lot of bad luck. I did the wheel bearing thing,just like you,new bearings every race,seal lips cut off,and chain lube,instead of grease.

[sturgis 39]

Originally Posted by Tom Wesenberg

If you mill the head at an angle, how are the head studs going to fit the holes? And if you redrill the head stud holes at an angle to match, you still have the head nuts not seating squarely to the head, unless you also mill the top surface for the nuts. Looks like a lot of work for little gain. I'd just buy the new 5.5 head and be done with it. I don't think you could get near 5.5 by milling a stock head.

They make hill side washers that are sloped. I get mine at a local structural steel fabricator. They are mostly used in steel construction because a lot of the standard structural steel members are do not have flat surfaces. The webs and flanges are sloped. McMaster Carr could be a source for hill side washers.

[Milton]

Originally Posted by allison-tech

Thanks Milton, is this a pic. of the snyder combustion chamber?

Yes, it's a Snyder 5.5:1 head from an H&H touring engine. It gives you a fresh start with room to mill beyond the 5.5 ratio if desired.

[Purdy Swoft]

Originally Posted by Terry, NJ

Once again, I'm new at this so bear with me. Why is it desirable to run SAE 250 (?) (600) weight grease in the rear. Until it gets hot it must be like plowing through peanut butter and surely draining off HP from a engine that hasn't got too much to spare. I know that the 250/600 oil doesn't leak out past the seals. but it seems to me that a better seal could be developed and used that allows for a lighter oil.
Along the same lines, I used a older, Long Fiber grease in my front wheel bearings. After I packed them. they didn't turn so easily either. Perhaps I should have used a more modern moly grease?
Terry

Actually, I have at times used 140 and 90 weight gear oil with no problems. the main thing with thinner gear oil is to make sure not to overfill. if you can stick your finger in , bend it at the first joint and touch the gear oil you are good to go. The thing about the seals is the axle usually has a pretty good groove worn in from where the seal contacts. In some cases the seals don't do a lot of good.

[allison-tech]

Looks really good Milton, I think I'm going to go that route, at the same time, I'm now pretty curios as to what I can do w/a stock head. I've got an idea on how to run a HP test, and these heads come off so fast, I just can't resist. I've got 2 dyno's, but they are used for transmissions, not engines, so I thought I could run some hp tests by 1st, making a baseline test by getting my A up to a certain speed, lets say somewhere around 30 mph and hold it steady, using a GPS, for accurrate speed readings, then go full throttle for a designated time & then check my speed at the end of the time limit, lets say 10 sec.'s, and record. Then go back to the shop & take off .025 from the head, and re-run test, doing this up to .100, if this head hasn't been touched yet it sounds like I'd be safe if I stopped there, from what others have said about their experiences, after that I might start playing w/the combustion chamber shape and pattern them from the snyder shape & see excactly where the biggest gains are, I'll use the snyder hc head for a back-up, in case I goof up or degrade performance, that way I can still go driving, what do ya think? Sincerely, Lewis