Valve differences

Ol' Ron said:
Thanks, I printed this info for future use. FYI the amt of material removed fron seat grinding will have little or know affect on spring pressure. Stainsles steal valves are bad for cast guides unless chrome plated. Most aftermarket guides are too oose for the valve. Knurling and fitting the valves to .0005-.001" stem clearance prevents oil contamination of the combustion chamber.
A thin coating of RTV on the guide is all that's necessary cor intake guide seal. Harden seats on the intake valves is un-necessary.
This is most of the valve info I have.
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Ron, I probably didn't explain things very well, so I'll try again.

If I grind the seat 0.020" (verticaly) then the valve sits lower in the block. Since the horseshoe clip rests against the bottom of the deck guide bore, the guide is in the same position as it was before the seat was ground. As the valve sits lower by 0.020" the spring is lengthed by 0.020" also and thereby lowers valve seat pressure requiring shims.

Jim
 
blown49 said:
Ron, I probably didn't explain things very well, so I'll try again.

If I grind the seat 0.020" (verticaly) then the valve sits lower in the block. Since the horseshoe clip rests against the bottom of the deck guide bore, the guide is in the same position as it was before the seat was ground. As the valve sits lower by 0.020" the spring is lengthed by 0.020" also and thereby lowers valve seat pressure requiring shims.

Jim
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Your statement is correct as to where the valve ends up after seat grind.
Measure your spring pressure at the new installed height and as Old Ron says
.020" won't make much of a change that can be determined with the average spring pressure tester (bin there done that)..Shims are sold in .015" .030" .060" only.
What do you require for desired spring pressure and at what height?That is what you should be shooting for without a good way to measure spring pressure you are only guessing at best.After all the fun is over you will come to recognize that the small amounts of change have no real change in spring pressures at such low spring values.

R
 
Your getting it down Jim. If you building a stock engine with stock springs and drop the seats .020 I'd install a .030 shim and call it good. Walt
 
Lawri, I agree. If someone is building a mild street engine with a Max #1 or lower cam I'd use rotators. I believe this will extend the life of the valves. I've had one engine with a max#1 and rotators, for 6Years now. I set the short springs at 45/50 lbs with one .060" shim.
 
Thanks Ron, luckly the eng is still on the stand,so its easy to remove the other style and fit the rotators,as the straight stem valves are already in.
Thanks Lawrie
 
Lawrie, check your installed spring pressure, accually the valve are a differance length between the rotor setup and the single retainer. I have the rotor setup in my 40 - 276, track cam, around 9.5 heads, 4 carbs, T-5, 9in. 3:50 gears. built it 35 yr's ago, over 100 grand on speedo. Walt
 
Walt ,you are on the ball,as after I said I would look at changing them out,I thought about seat pressure too,
Darn, there goes another couple of days work.
Lawrie
 
Lawson Cox said:
Let me skin my ignorance here. Don't all early Fords have hardened valve seats? Isn't that why unleaded gas doesn't matter in the flatheads? Inquiring minds want to know.
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No. I have a '53 block that definately doesn't have hardened seats.

Or did you mean earlier than *BA series of motors?
 
Walt Dupont--Me. said:
Lawrie, check your installed spring pressure, accually the valve are a differance length between the rotor setup and the single retainer. I have the rotor setup in my 40 - 276, track cam, around 9.5 heads, 4 carbs, T-5, 9in. 3:50 gears. built it 35 yr's ago, over 100 grand on speedo. Walt
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Lawrie I believe the installed height of the '51 thru '53 rotator springts id 1.89" as opposed to the '49 thru '50 springs installed height of 2.125". I am going to my office in a kittlle bit and check this info for sure. This should yield a seat pressure of 37 to 41`#,s according to the Ford data sheets.

Jim
 
While on the subject of valves I need a favor. Original Ford valves had a "bump" around the stem under the valve head. This was actually a bump and not an undercut. I have a mushroom type valve with a bump and a '51-'53 valve with the bump. I'm looking for someone on here that may have a '49-'50 valve with a bump I could purchase. Only need one for a project I'm working on. I tried several vendors but no luck.

TIA
Jim
 
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