Head milling
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Mike V. Florida
Well-known member
Until the pistons hit the head. Depends on the block and how much was removed when/if is was decked.
What are you trying to gain?
Put some thought into how much you deck the block. It affects the compression height of the pistons, the amount of "pop-up" and your final compression ratio and clearances.
Ask the machinist to measure the height from the pan rails. Stock is 11.5". There is a fair chance the block has been decked before so it may be less. Find out how much, if at all. Check the pistons to see how far down the rings are from the deck top. Probably no problem there, but check. Check to see how much clearance between the piston top and the head and how much you want to take off. You want .040-.055 clearance, opinions vary, and consider the gasket thickness. Ordinarily not a problem, but you feel better knowing.
Ask the machinist to measure the height from the pan rails. Stock is 11.5". There is a fair chance the block has been decked before so it may be less. Find out how much, if at all. Check the pistons to see how far down the rings are from the deck top. Probably no problem there, but check. Check to see how much clearance between the piston top and the head and how much you want to take off. You want .040-.055 clearance, opinions vary, and consider the gasket thickness. Ordinarily not a problem, but you feel better knowing.
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MikeK
Well-known member
A new block was 11.500 to 11.505" from the pan rail to the deck. A new 11.500 block had the piston tops 0.031 above deck. New A blocks had a minimum of 0.187 metal thickness at the deck to the water, usually a bit more. 80 years of straight water may have rusted quite a bit of that away.
The block you now have may have been decked once or twice already. You need to measure. I've seen well-used blocks resurfaced all the way down to 11.450, but the pistons will be way up and the thickness to water less that 0.125" in places. Scary. Personally, I'd look for another block if the end result would be below 11.470"
If you deck the block yourself, keep in mind the RMS or AA finish directly relates to gasket retention, especially in the siamese areas. Too fine a surface is not good.
The block you now have may have been decked once or twice already. You need to measure. I've seen well-used blocks resurfaced all the way down to 11.450, but the pistons will be way up and the thickness to water less that 0.125" in places. Scary. Personally, I'd look for another block if the end result would be below 11.470"
If you deck the block yourself, keep in mind the RMS or AA finish directly relates to gasket retention, especially in the siamese areas. Too fine a surface is not good.
TerryNJ
Well-known member
It's cost v s gain. I have an that's been cut down about .090-.095 and it works (goes faster) I didn't do this. It would make me nervous yet it could be done for under $100. Buying a new 5.2 head from Snyder's will cost you about $295 + shipping. So if you have the money to spend, Go for it.
Terry
Terry
H. L. Chauvin
Well-known member
FWIW:
Years ago I knew about 5 professional industrial machinist in our small rural area who were in their 20's or so when Model A's came out.
When I got my first Model A in 1958 these seniors all told me the same measurements that they used for removing Model A head material & Model A flywheel material.
They measured the block & the head & would only remove up to 3/16" from the heads & would remove 23 pounds from flywheels to make them weigh 40 pounds.
Where these "supposedly" engine improvement measurements came from I have no idea -- when I told them I had a Model A "Police Head" marked "B" they thought this was a far better head to have rather than milling a stock head.
They had also mentioned Model T milling improvements that they used, but I forgot those measurements & weights.
Again, FWIW, just mentioning one (1) Vintage Model A Milling Religion in only one (1) rural area, which no doubt had dimensions & weights that differed from town to town in the 1930's or so,
Years ago I knew about 5 professional industrial machinist in our small rural area who were in their 20's or so when Model A's came out.
When I got my first Model A in 1958 these seniors all told me the same measurements that they used for removing Model A head material & Model A flywheel material.
They measured the block & the head & would only remove up to 3/16" from the heads & would remove 23 pounds from flywheels to make them weigh 40 pounds.
Where these "supposedly" engine improvement measurements came from I have no idea -- when I told them I had a Model A "Police Head" marked "B" they thought this was a far better head to have rather than milling a stock head.
They had also mentioned Model T milling improvements that they used, but I forgot those measurements & weights.
Again, FWIW, just mentioning one (1) Vintage Model A Milling Religion in only one (1) rural area, which no doubt had dimensions & weights that differed from town to town in the 1930's or so,
Lot's of good info here. Thank you. On my T I decked the block to have nice flat surface for sealing. I work at a machine shop and can use anything I want.
I did not measure the height of the block but I will before it goes back together to see what it currently is. I put the block in our Blanchard grinder and only took off .005-.007" to get a good cleanup.
Someone wanted to know what I was trying to achieve. FREE POWER. anything I can do to make more power without buying more parts is what I like to do.
Porting doesn't look like it will really help like on The T block but I will most likely get in there and cleanup a few areas to flow a little better.
.040 - .055" is a good bit of info I will use.
I had 2 cracks I found after decking so I then Magged the block to make sure I found them all. Pinning and hardened seats before the babbit this week and I will be on my way.
Thanks again for you input.
I did not measure the height of the block but I will before it goes back together to see what it currently is. I put the block in our Blanchard grinder and only took off .005-.007" to get a good cleanup.
Someone wanted to know what I was trying to achieve. FREE POWER. anything I can do to make more power without buying more parts is what I like to do.
Porting doesn't look like it will really help like on The T block but I will most likely get in there and cleanup a few areas to flow a little better.
.040 - .055" is a good bit of info I will use.
I had 2 cracks I found after decking so I then Magged the block to make sure I found them all. Pinning and hardened seats before the babbit this week and I will be on my way.
Thanks again for you input.
TerryNJ
Well-known member
WOW! Having access to a Blanchard is like dying and going to Mod. A heaven! Maybe in time you can answer a burning question of mine. Can you successfully resurface bell housings and flywheel housings, maintaining and restoring flatness and parallelism ?
Terry
Terry
Tom Wesenberg
Well-known member
You will need the lathe to lighten the flywheel, but I just used my palm sander to lightly sand the clutch surface, and the clutch engages very smoothly.
hardtimes
Well-known member
You will need the lathe to lighten the flywheel, but I just used my palm sander to lightly sand the clutch surface, and the clutch engages very smoothly.
Hey Tom,
'used my palm sander'....ha, ha that's funny
! Well, funnier to me than most at this particular time, because I JUST finished a week long 'palm sander' job that would, no doubt, elicit a lot of questions as to ...how did you do that ? I just put my B back together and it runs GREAT
After pondering this 'drastic' action and going against all logic and advice ...well, when people tell you it can't be done...what do you do,eh ?BTW...can you even imagine how 'dangerous' we'd be if , like this gentleman, we had all the equipment and skill that we needed. I'm thinking / dreaming that I'd make 200 hp from a B
TerryNJ
Well-known member
I've done a couple of them and most of the weight is removed of the OD and some off the front ID. I took mine down to about 53 lbs, from 63 lbs. A could have gotten by putting a large champfer in the front, but the Lathe I was using had no compound (????) It wasn't missing,it was never there.
To get really "Rad", you take all of the OD (wall) away so it's flat and no longer a big cup and fit a V8 clutch to it. Bit this is more work than I want to do to . The ten lbs is noticable. Also, It will have to be rebalanced and that is not free, it's cost me about $60. Good Luck!
Terri
To get really "Rad", you take all of the OD (wall) away so it's flat and no longer a big cup and fit a V8 clutch to it. Bit this is more work than I want to do to . The ten lbs is noticable. Also, It will have to be rebalanced and that is not free, it's cost me about $60. Good Luck!
Terri
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