Head milling for compression: What is stock cam lift?

[FarmerJon]

Had an opening on a machine at work, so am grinding an extra head for compression. 

It is a '53 217 head, should be 7.1cr stock.

I am aiming for .060 off, after some research. 

What is the stock valve lift of the '48 and '53 217s? I want to keep an eye on valve clearance while I am cutting.

I DO plan on a final, physical clearance check before installing head, just want some ballpark numbers for now.

 

Top is cleaned up, and .020 has come off the bottom so far.

[squirebill]

My Plymouth  Service Manual that covers 1946 to 1954 in the Engine Data and Specifications Chart gives a valve lift of 3/8 inch. for all models P-15 to P-25 engines.   (217.8 cu.in. piston displacement )

[FarmerJon]

I have a couple manuals at home, but didn't think to grab them this morning.

Ok, looks like I have plenty of space, measured .480 with .020 off, got it takig .020 more now

 

 

ETA, thanks Bill, my reading comprehension is off this morning 

Edited February 8, 2023 by FarmerJon

[47 dodge 1.5 ton]

I have measured (4) 25” engines, all were .375” lift.

[rallyace]

Be careful when milling your head as the valve will stand proud from the head and the valve will lift a tiny bit more than .375" at higher revs. I would allow for the amount the valve stands proud plus the lift plus at least .125" just to be safe.

[Sniper]

1 hour ago, rallyace said:

Be careful when milling your head as the valve will stand proud from the head and the valve will lift a tiny bit more than .375" at higher revs. I would allow for the amount the valve stands proud plus the lift plus at least .125" just to be safe.

 

Too late.  Op is at .480

.375+.125 = .500"

 

Of course the HG is probably .0.60 compressed.

 

Lol

[FarmerJon]

8 hours ago, rallyace said:

Be careful when milling your head as the valve will stand proud from the head and the valve will lift a tiny bit more than .375" at higher revs. I would allow for the amount the valve stands proud plus the lift plus at least .125" just to be safe.

This is a good point, BUT I think that the .125 is a bit much, I will get out to my spare block and measure, but I suspect around .050, about the same as the compressed head gasket.

George Asche says that virgin heads are around 1/2" and that heads could be milled .060 without other modification. 

There is a old chart from a '50s speed magazine that also gives guidelines for head milling and states that .050 is safe ( and brings '53-54 heads to 7.7)

My head measured .510 to start, I now measure .475, so my .050 on the dial of the surface grinder equaled .035 off.

Chamber is starting to get noticeably smaller. 

I will CC what I have, but will likely try to get to .050 Friday. 

I am considering doing some other chamber work, to unshroud valves and sparkplug, but I have to see what my availability is for a Bridgeport. 

You can really see the flats above the valves in the 3d scan. They are around .135 higher than the "belly" of the chamber

 

ETA: looks like performance flathead Ford guys are running .030-.040 valve to head clearance as "safe" and as little as .020. Seems there is some legit disagreement about how much flow comes over the valve.

Edited February 9, 2023 by FarmerJon

[Sniper]

I think the main issue with valve to head clearance at full lift is more along the lines of them smacking into each other rather than flow issues.  The higher the RPM and/or faster the lift speed the more I would worry about that.  Stock cam?  not too worried.

 

If I get a chance I'll cc my Edgy heads, have to get the tools first.

[FarmerJon]

A lot of things to factor. Based on everything I have read on ideal flathead chamber design, the Edgy heads likely one of the best developed. IIRC they should be around a 74cc chamber.

I would be interested in a measurement from the deck to the intake and exhaust clearance, please!

[47 dodge 1.5 ton]

Sniper,  Any way you can get a scan on an “un-touched” Edgy head chamber? Could save the file on here for future reference possibly? 

Edited February 9, 2023 by 47 dodge 1.5 ton

[Veemoney]

When I checked my head before milling it , I first took a measurement on the block with the valves raised to the deck. Then measured the head from deck to valve pocket. I added the thickness of the gasket and clearance to determine how much I could remove safely. For me I wanted the actual clearance of the hard parts rather than assuming from the .500 casting or cc of the head. I probably have the notes but doubt where to start even looking for them.

[Sniper]

39 minutes ago, 47 dodge 1.5 ton said:

Sniper,  Any way you can get a scan on an “un-touched” Edgy head chamber? Could save the file on here for future reference possibly? 

 

I would not even now where to go for that.  Maybe if I lived in a big city there would be somewhere to do that.

[Los_Control]

Just now, Sniper said:

Maybe if I lived in a big city there would be somewhere to do that.

Oh my, I go to the big city once a month .... the next town over that has a Walmart.

@Sniper town has 2 walmarts .... Hard to get bigger then that      

[Sniper]

You know you live in a very small town if you have no DQ, lol.  

[squirebill]

Looking at the photos and seeing the spark plug hole directly above one of the valves ...I'm guessing the ground electrode hanging into the combustion chamber  has been taken into consideration.