Ultimate push rod settings for rebuilt engine with new valves???

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Model T Ford Forum: Forum 2008: Ultimate push rod settings for rebuilt engine with new valves???
Top of pagePrevious messageNext messageBottom of page Link to this message  By Alex Brown on Sunday, January 11, 2009 - 04:33 am:

Just interested to know what different mechanics say are the ultimate push rod settings (gap)

Thanks


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce Peterson on Sunday, January 11, 2009 - 07:43 am:

With a new cam (Stipe) I have used .015" with good success.

With an old original used cam try .015" intake and .018" exhaust.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Sunday, January 11, 2009 - 09:05 am:

Royce:

New Stipe cam has excellent computer designed lobes. the 250 cam is better standard NOS Ford & the 280 gives a bit more lift of .015.

Stipe specifies seting stem/lifter gap at .010" .

Why cheat yourself & add .005 gap ??


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Putnam on Sunday, January 11, 2009 - 11:25 am:

Single piece stainless valves and lifters expand at the same rate weather they are above a Stipe cam or an original Ford cam, regrounds included. I use .010 on all engines that I rebuild. I am very careful to get the setting at .010, not .009 nor .011. As Royce saays "why cheat yourself" and sacrafice performance in the process. JP


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Sunday, January 11, 2009 - 12:13 pm:

" As Royce saays "why cheat yourself" and sacrafice performance in the process. JP "

Hope you meant to say " Bob" , Jack.



Bob Jablonski


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Sunday, January 11, 2009 - 01:46 pm:

Jack - I am not sure of this, but I have always been under the impression that on a new valve job, the valves will "pound in" one or two thousandths during the first hundred or two miles that a newly rebuilt engine is driven. Alex did say "rebuilt engine with new valves". I would think it would be prudent to re-check clearance after a hundred or so "break-in" miles. Couldn't hurt, right? I think .010" is minimal valve clearance for an exhaust valve. The only chance an exhaust valve gets to cool is when it is closed, i.e., seated against the valve seat which allows the hot valve to transfer some of that heat to the cooler engine block. The more valve clearance, the longer the valve is closed and the longer it can cool. It's important to remember that when an engine gets hot, the valve clearance deminishes somewhat, it if an exhaust valve hangs open by just one thousandth due to insufficient clearance, that will cause the valve to leak, and what it's leaking is FIRE, past a valve which because it does not seat tightly against the valve seat, the valve does not have ANY chance to radiate ANY heat into the engine block via the valve seat, and even a brand new valve will not last very long this way. (read...burned valve)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Sunday, January 11, 2009 - 01:54 pm:

Alex - I am not sure of this, but I have always been under the impression that on a new valve job, the valves will "pound in" one or two thousandths during the first hundred or two miles that a newly rebuilt engine is driven. You did say "rebuilt engine with new valves". I would think it would be prudent to re-check clearance after a hundred or so "break-in" miles. Couldn't hurt, right? I think .010" is minimal valve clearance for an exhaust valve. The only chance an exhaust valve gets to cool is when it is closed, i.e., seated against the valve seat which allows the hot valve to transfer some of that heat to the cooler engine block. The more valve clearance, the longer the valve is closed and the longer it can cool. It's important to remember that when an engine gets hot, the valve clearance deminishes somewhat, and if an exhaust valve hangs open by just one thousandth due to insufficient clearance, that will cause the valve to leak, and what it's leaking is FIRE, past a valve which because it does not seat tightly against the valve seat, the valve does not have ANY chance to radiate ANY heat into the engine block via the valve seat, and even a brand new valve will not last very long this way. (read...burned valve)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Sunday, January 11, 2009 - 01:56 pm:

Ooops,...sorry about the double post; not sure how that happened.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Henry Petrino on Sunday, January 11, 2009 - 02:09 pm:

I am very far from an expert on this topic, but I thought I'd chime in. Being a marginally skilled shade tree mechanic, I looked around a lot before doing my engine. I wanted to be carful to not mess it up.

I found a set of instructions that I can't recall in detail (it's been several years), but they did not use a gap measurement in the sense discussed above at all. Essentially, what I did was turn the crank a few degrees past where a given valve should seat, then grind the stem a little at a time until when inserted into the guide (without the spring), pressed a little and twisted, I got resistance from the seating surface.

Even though I can't recall the exact instructions, it was a very simple way to do it and the engine has been runnig great ever since, with no problems. Of course, the engine was on the workbench and both the head and the pan were off, so it was easy to get the right crank position. An engine in the car my be more difficult to do this way.

Anyone else have better, more detailed data on this method?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Putnam on Sunday, January 11, 2009 - 02:34 pm:

Opps: Bob its "Bob", not Royce. Sorry I got the names mixed. I wont blame it on a "senior" moment, just a brain short.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Sunday, January 11, 2009 - 04:28 pm:

Henry - That's a method I sure never heard of before, but it sure sounds like it could work, but not too accurately. When you think about it, it sounds like some sort of method the farmer, back in the Model T era, could use when he had no feeler guage or other measuring tools. Sure would like to read those instructions if you, or anybody else could find them!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Alex Brown on Sunday, January 11, 2009 - 05:25 pm:

Thanks so far :-)

Cam is original old one not a new one


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso on Sunday, January 11, 2009 - 05:46 pm:

Harold - it was the method of setting valves by piston travel. K R Wilson made a special off-set tool for setting valves this way. I have one in the original KRW envelope. One drawback - you have to have knowledge of the block never being decked or of valve seats being other than bone stock position to set the valves properly.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Henry Petrino on Sunday, January 11, 2009 - 05:50 pm:

I found the instructions. There are 2 articles in the "The Engine" book, " A Comprehensive Guide for the Repair and Restoration of the Model T Ford Engine", prepared and edited by the members and staff of the Model T Ford Club of America. It's the red book (8 1/2" X 11" paperback), "Repairing and Restoring the Model T Engine". I also have a blue one for electrical and a green one for the transmission. Seems like there were a couple of others, but I can't remember for sure.

Pages 29-33 have a great article written by Ted Aschman and pages 33-35 have another great article written by Bruce McCalley. If you're really interested in understanding properly timeing the valves, they're worth reading.

Harold: Interestingly, Ted says in his article "The commonly used method of timing the valves by clearence between the valve stems and the push rods on old often rebuilt engines is really "shade tree" and is rather sloppy and unmechanical". He goes on to explain why and what to do that is better.

I looked on the current MTFCA website to see if this publication is still offered and couldn't find it. It was printed in 1993 adn 1999, so there should be copies floating around.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Monday, January 12, 2009 - 12:28 pm:

I believe the original T cam was designed for a gap of 1/32". If you have a new-old-stock Ford cam, or a proper re-grind (and many available re-grinds are not "proper"), you will get your best "power curve" at 1/32" gap. However, you will get slightly quieter operation at .010" gap. The difference in power is fairly insignificant and I usually gap re-ground Ford cams at .010" unless the customer specifies otherwise. If you are installing a used cam, then timing by piston position will most times give you a much better running engine.


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