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Old 04-08-2019, 07:37 AM   #1
Mulletwagon
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Default Valve Clearance

Planning on adjusting the valve clearance. Should I expect some amount of residual oil to pour out when I pull the cover ? Seeing different recommendations for the intake/exhaust valve lash. Is there a standard clearance that gives acceptable noise and proper valve timing ? Should the clearance be set hot, cold, or warm ? Any recommended technique ?
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Old 04-08-2019, 07:53 AM   #2
larrys40
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Default Re: Valve Clearance

Pull cover when cold. Oil level should have drained down.
There may be a little that comes out but not much. Have some shop towels handy . Clean out valve chamber. If it had non detergent oil in it plan for lots of sludge to be removed .
There will only be adjustment if it has adjustable lifters.
I know rich fallucca at AER sets them all now .012 across the board.
Don’t get too excited if they’re off by a thousandth or two.
Are you doing this because there is noise or problem?
If they are adjustable and have been in for a long while you may find they don’t want to move easy. I hope single lock as opposed to double and have your thin wrenches handy.
All the best
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Old 04-08-2019, 08:00 AM   #3
Kurt in NJ
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Default Re: Valve Clearance

Yes some oil will come out----the sooner after shutoff the more oil there is
Valve clearance is determined by camshaft design and valve material
Original specs are cold engine
If the engine is "original" the valves are adjusted by grinding the stem
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Old 04-08-2019, 08:02 AM   #4
Mulletwagon
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Default Re: Valve Clearance

Thanks Larry. The engine has about 1000 miles on it after a high dollar rebuild contracted by the PO. Got some loud clacking and a mildly rough idle. Build sheet says adjustable lifters. Thinking adjustment is due following the break in.
Cheers
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Old 04-08-2019, 10:40 AM   #5
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Default Re: Valve Clearance

You might contact the previous owner to find out who did the engine and which camshaft it has in it and what the lash should be set at. But my thinking is at least .013-.015" for intakes is good and .017-.020" for exhaust. If I remember correctly a 'B' camshaft calls for .022" exhaust.


I believe the Ford specs for an A shaft is .015" intake and .015" exhaust. The B shaft calls for .015" intake and .022" for exhaust due to some burning problems with the early production vehicles.

Regrinders and new cam makers will have their own lash specs.

I like keeping the valves cool and believe setting them a tad loose is better than a tad tight.

Mine, I believe, has the original camshaft and lifters. The engine was last done in 1961 and the valves were checked when we bought it 1975 [ all .016-.017"] and they haven't moved in all these years. They are quiet.

I've checked/adjusted them on some others. Some have wanted them set to certain specs, some haven't. Some are a PITA to set, some aren't.

Last edited by Patrick L.; 04-09-2019 at 12:33 PM.
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Old 04-08-2019, 03:56 PM   #6
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Default Re: Valve Clearance

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Quote:
Originally Posted by Patrick L. View Post
You might contact the previous owner to find out who did the engine and which camshaft it has in it and what the lash should be set at. But my thinking is at least .013-.013" for intakes is good and .017-.020" for exhaust. If I remember correctly a 'B' camshaft calls for .022" exhaust due to some burning issues.
That seems awfully excessive for tappet to valve clearance as most written stock clearances are given as .010-.012 for all valves. I usually set intake at .010 and exhaust at .012.
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Old 04-08-2019, 06:38 PM   #7
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Default Re: Valve Clearance

J Franklin is right. The exhaust at 17-20 thousands would rattle.
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Old 04-08-2019, 07:29 PM   #8
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Default Re: Valve Clearance

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J Franklin is right. The exhaust at 17-20 thousands would rattle.
Ditto that!
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Old 04-08-2019, 08:42 PM   #9
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Default Re: Valve Clearance

Just don't start it with the valve cover off. Your car, you and your shop will get an oil bath in very short order.
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Old 04-10-2019, 02:19 PM   #10
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Default Re: Valve Clearance

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Last edited by Benson; 04-11-2019 at 11:55 AM. Reason: Several corrections made since original posting
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Old 04-10-2019, 02:30 PM   #11
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Default Re: Valve Clearance

Quote:
Originally Posted by Patrick L. View Post

I like keeping the valves cool and believe setting them a tad loose is better than a tad tight.
I'm not sure that setting them loose keeps the valves cooler. As long as the valves are fully on the seat when the cylinder fires, I don't see how keeping them on the seat longer cools them.

I like to set at the minimum of the factory recommended range. That way I get a little higher lift and a little more performance.

In the "Counter Intuitive" department, I've found more As with loose clearances than tight clearances. You would think as the valve wore into the seat that the clearances would get tighter.
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Old 04-10-2019, 03:08 PM   #12
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Default Re: Valve Clearance

Part of the reason for valve clearance is heat transfer.
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Old 04-10-2019, 09:06 PM   #13
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Default Re: Valve Clearance

A few years ago Snyders recommended a setting of sixteen thousants .016 . The guy that ground my super street 3/4 race Winfield cams said lash should be .016 .This clearance has worked well for me . I don't hear any ticking so far .
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Old 04-10-2019, 09:45 PM   #14
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Default Re: Valve Clearance

I guess it boils down to if you are working on a race engine, B, or A engine, follow the book or the shop that rebuilt it. It's all your choice.
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Old 04-10-2019, 10:17 PM   #15
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Default Re: Valve Clearance

Quote:
Originally Posted by J Franklin View Post
I guess it boils down to if you are working on a race engine, B, or A engine, follow the book or the shop that rebuilt it. It's all your choice.
Partially true.
ALL modern solid lifter common engine cams are designed with a clearance ramp.
Most vintage cams such as the model A/B were designed by the 3 curve method. These have a concentric base circle.(no clearance ramp) The running clearance was originally specified by trial and error. .016 seemed to be adequate for long valve life and low noise.

As a side note, modern HYDRAULIC lifter cams have a concentric base circle also.
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Old 04-10-2019, 10:46 PM   #16
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Default Re: Valve Clearance

http://www.fordgarage.com/pages/stipecamshaftspecs.htm

Stipe touring cams are very close to stock B cam designs,yet stipe uses a clearance way closer than .022 exh,they are down to the .012. His designs are nearly the same as the B cam,Ford recommended .022 to rest the exhaust valve on the seat longer to allow additional cooling.Modern valves handle heat way better,allowing the later designs to make maximum use of the lift for power. Model B parts can be used in a model a engine with great results,side bowl carb and mechanical advance distributor are two of the great advantages designed into the B engine that work great on an A engine..the B cam is another.
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Old 04-10-2019, 10:50 PM   #17
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Default Re: Valve Clearance

Quote:
Originally Posted by Railcarmover View Post
http://www.fordgarage.com/pages/stipecamshaftspecs.htm

Stipe touring cams are very close to stock B cam designs,yet stipe uses a clearance way closer than .022 exh,they are down to the .012. His designs are nearly the same as the B cam,Ford recommended .022 to rest the exhaust valve on the seat longer to allow additional cooling.Modern valves handle heat way better,allowing the later designs to make maximum use of the lift for power. Model B parts can be used in a model a engine with great results,side bowl carb and mechanical advance distributor are two of the great advantages designed into the B engine that work great on an A engine..the B cam is another.
Stipe cams are also designed to run on 1 inch diameter lifters.
Much easier to find.
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Old 04-11-2019, 10:57 AM   #18
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Default Re: Valve Clearance

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Last edited by Benson; 04-11-2019 at 11:43 AM.
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Old 04-11-2019, 02:55 PM   #19
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Default Re: Valve Clearance

Outside on minor improvements,Ford identified and held off doing major improvements to the A engine during A production.These were held to the introduction of the B:
1.bigger crankshaft,ultimately counter balanced
2.pressurized main bearing lubrication
3.Re designed camshaft
4.fuel pump
5.mechanical advance distributor
6.side mount fuel bowl,redesigned carburetor
7. larger runner intake manifold
8. Higher compression head
9. redesigned water pump

Plus other improvements on design,its amazing how much they moved forward with the engine..Some were not so good,block casting was suspect in the upper valve area and the compression increase was minor..some were real good,like pressurized lubrication, redesigned camshaft,the distributor and carb.All in all,alot of B improvements can be bolted on to an A engine..one,the mechanical advance distributor,will provide improved engine performance and eliminate the major cause of center main bearing failure,detonation (ping,or spark knock)...
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