Okay guys, got one for you. First, I have not talked to my local machine shop yet. My '41 A needs a head gasket and the front seal repaired. Can the head be milled to increase compression a little? Right now it has flat top pistons and would be put back together with them still in it. But, sometime in the near future I plan on putting the overbore kit in with stepped pistons. If I am able to have the head milled now, will that cause a clearance problem down the road when I do the piston upgrade? Or, if I just do the head gasket now, when I do overhaul it with the overbore/stepped piston kit, can the head be milled any then. I don't want to increase the compression too much now and cause a 30 year old overhaul to start burning oil. This tractor was bough by my grandfather and great grandfather new. It was overhauled about 30 years ago but with the stock piston flat top pistons. It has always been very strong for an A in my opinion. But more power is always nice. Although it hasn't had the cultivators on it for 25 years, the tractor is still worked, and worked hard sometimes. Thanks
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Anonymous-0
Well-known Member
I don't know any real facts about it, but I have 8000ft. high top pistons and a .030 head shave, no problems, runs strong.
gene bender
Well-known Member
You can machine the head and still go with hi-dome pistons. They wont take that much off the head anyway but there still will be plenty of clearence for the pistons later.
If your going to have the Head off its Time to install the New Oversize Kit!
The Inframe Kit (Tisco)from YT mag is around $300 and it Has head, VC , OP , Gaskets with it!
The Steped Head Pistons and Your Head Cut .030 with some Porting and carb Main Jet Enlarged will Give you Close to 30 HP But you need to Give it More Air!
The Easy way is to get a C or Su C air cleaner!
The inlet on a A air cleaner is smaller than the Carb inlet But the C is Larger!
The only Downfall is the Hood needs the Hole Slightly Enlarged (Half Round File) and the top of the C air cleaner is longer and can be Cut off to the A measurement!
No Problem with this Set up It Just Runs Better!
Cliff S
The Inframe Kit (Tisco)from YT mag is around $300 and it Has head, VC , OP , Gaskets with it!
The Steped Head Pistons and Your Head Cut .030 with some Porting and carb Main Jet Enlarged will Give you Close to 30 HP But you need to Give it More Air!
The Easy way is to get a C or Su C air cleaner!
The inlet on a A air cleaner is smaller than the Carb inlet But the C is Larger!
The only Downfall is the Hood needs the Hole Slightly Enlarged (Half Round File) and the top of the C air cleaner is longer and can be Cut off to the A measurement!
No Problem with this Set up It Just Runs Better!
Cliff S
mike1972chev
Well-known Member
Why dont you plan on just doing it all together at one time,like now??? 
If you do mill the head now and just reinstall it,it is not that big of a deal to clearance the new piston "domes" later on,If they would EVEN need to be relieved???
I personally WOULD NOT mill the head ANY more than it needs.No need wasting head material on something that is getting harder to find every day.You might have to mill it again sometime in the future???(Want some "meat"left to work with!)
If you do mill the head now and just reinstall it,it is not that big of a deal to clearance the new piston "domes" later on,If they would EVEN need to be relieved???
I personally WOULD NOT mill the head ANY more than it needs.No need wasting head material on something that is getting harder to find every day.You might have to mill it again sometime in the future???(Want some "meat"left to work with!)
Gotta agree with Mike here.
I personally wouldn't mill it unless it really needed it.
First of all, I can't imagine the horsepower gain would even be noticeable (but the bill will be).
Second, as mike pointed out, they aint making any new ones. Why start machining parts that don't need it? Think long term. 50 years down the road, some other guy might be rebuilding your tractor, the head might need machining -with no material left to correct the problem.
Seems like a waste to me.
In my mind, if your tractor needs more power, what you need is a bigger tractor.
I'm not a fan of trying to make old tractors into something they weren't. A little bump in power isn't a bad thing, but I guess I'm more of a purist.
I use an old tractor for that old-time experience. Tricking out the engine kind of defeats that purpose. I'd rather just drive something newer.
Not saying YOU should or shouldn't do it, but just throwing my 2 cents out there as something to think about.
I personally wouldn't mill it unless it really needed it.
First of all, I can't imagine the horsepower gain would even be noticeable (but the bill will be).
Second, as mike pointed out, they aint making any new ones. Why start machining parts that don't need it? Think long term. 50 years down the road, some other guy might be rebuilding your tractor, the head might need machining -with no material left to correct the problem.
Seems like a waste to me.
In my mind, if your tractor needs more power, what you need is a bigger tractor.
I'm not a fan of trying to make old tractors into something they weren't. A little bump in power isn't a bad thing, but I guess I'm more of a purist.
I use an old tractor for that old-time experience. Tricking out the engine kind of defeats that purpose. I'd rather just drive something newer.
Not saying YOU should or shouldn't do it, but just throwing my 2 cents out there as something to think about.
When you remove the head lay a straight edge across the head to see if it's warped. If it looks I wouldn't have it machined. A new head gasket torqued down evenly starting in the center and work out in both directions. Use 3 or 4 steps starting with 25 ft-lbs until you reach 80 ft-lbs. Set your valves at .017" cold
after the engine is heated up retorque the head
starting with 60 or 70 ft-lbs.
Its easy to run the front wheels along with the steering wheel out from under the engine. You may need to drain and remove the radiator to gain access to the timing gear cover. Its been a long time since I did an A. You need to support the engine well. Check the damper pulley hub for a worn groove caused by the old seal rubbing on it. They have a speedi-sleeve kit to cover that area and a new seal for the cover. Leave the bolts loose on the timing gear cover until the damper is installed. This will allow the seal to center itself. Hal
after the engine is heated up retorque the head
starting with 60 or 70 ft-lbs.
Its easy to run the front wheels along with the steering wheel out from under the engine. You may need to drain and remove the radiator to gain access to the timing gear cover. Its been a long time since I did an A. You need to support the engine well. Check the damper pulley hub for a worn groove caused by the old seal rubbing on it. They have a speedi-sleeve kit to cover that area and a new seal for the cover. Leave the bolts loose on the timing gear cover until the damper is installed. This will allow the seal to center itself. Hal
mike1972chev
Well-known Member
Yea,
Nothing breaks my heart more than taking my Big Block Chevrolet blocks and heads to a machine shop to find out they CANNOT be milled/decked any more because they are at there maximum tolerance already! MAJOR BUMMER
Save room for future repairs,if you can?
Nothing breaks my heart more than taking my Big Block Chevrolet blocks and heads to a machine shop to find out they CANNOT be milled/decked any more because they are at there maximum tolerance already! MAJOR BUMMER
Save room for future repairs,if you can?
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