Valve clearance.

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Model T Ford Forum: Forum 2005: Valve clearance.
Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Jeffrey Cole on Tuesday, December 18, 2007 - 02:31 pm:

I got my engine running better but it aint fireing on number 4.I found the exhaust valve has no clearance as in not closeing.What should the clearance be?The others I checked were a tight .020. I know this is probably available by searching but I kinda needed to know so when I get back from lunch I can get started.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Seth Harbuck on Tuesday, December 18, 2007 - 02:38 pm:

Mack,

I like 0.010-0.012" on the intakes and 0.014-0.016" on the exhausts. Nice and quiet that way!

Seth


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim ( Gen3AntiqueAuto ) on Tuesday, December 18, 2007 - 02:47 pm:

An open valve won't disable your ignition system. Check for spark through the #4 plug, you may have two problems. Set your valve lash somewhere around 0.012 like Seth said, or 0.020 to make it match the others - it won't hurt it. Make sure you know what your doing before you start. Does this engine have adjustable lifters in it?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Jeffrey Cole on Tuesday, December 18, 2007 - 04:39 pm:

Well I meant not hitting on number 4 I reckon is what I tryed to say.I checked coil,plug,wires.it had spark to the cylinder,But it didnt Hit.I also gave it a few drops of oil to increase compression and see if it burned it,as in putting out blue smoke.That didnt happen,it didnt change the engines running.
but I got the head off,and I dont like what I saw in number 4.i found some rather corse,for a engine cylinder, vertical marks in the cylinder that I am sure werent there before.I reckon I will be enjoying the advantages of a 4 dip pan.:#(.Number 2 has some similar marks but not as noticeable.The marks go around the cylinder about 2 inchs,and at 1 spot can be felt by finger nail barely in number 4.number 2's cant be felt,only seen.
It may be a ring not doing right but I aint happy.
Also found where a crack had been welded and it is letting little drops of water out.I can see the crack inside the front water jacket so I will clean it with a dremel tool and will put some jb weld on the inside of the crack and use stop leak.Should stop it or at least slow it down to a barely noticeable crawl.Someone did a a super job of welding and grinding.I didnt even know it was there till I saw the pin holes in the weld letting out little drops of water..
The more I learn about this engine,the less satisfyed I am.

I can say this,my 26 engine runs good,I aint doing a thing but clean it up and make sure the bearings are set.I aint tearing it down.
But the next engine I work on that is going to be refered to as Rebuilt,I will be looking over the work,makeing sure things are to suit me.I bought this engine,at a good price yes,but I bought it being told it was good to go.Who rebuilds a flat head and doesnt set the valves?Duh.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Tuesday, December 18, 2007 - 06:51 pm:

You know, Mack, its just plain good practice to check everything on an engine, even one coming back from the rebuilder. On different engines I brought home from the rebuilder I have had to straighten rods, lap mains and rod bearings, power hone the cylinders as the clearances were too tight and replace a front cam bearing that had .012" clearance. Anymore I do most of my own work, you just can't hardly trust other people anymore. Of course there are exceptions.
My latest disappointment was bringing RE housings home from a guy who "straightened" the tubes only to find out afterward they were farther out than before. That's when I made my own jig.
Its really a pet peeve of mine. I reckon about half the things I give to others I get back with unsatisfactory results, like a pan that was professionally straightened that was so far out afterward you could see it with the naked eye. I could go on and on. The only solution I know is to do as much of your own work as you can and always check the work of others. Welcome to the club.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Jeffrey Cole on Tuesday, December 18, 2007 - 08:26 pm:

Well there will be another thread named can of worms.But here is what I found on the exhaust valve.

The keepers were sticking .035 below the end of the valve.Once I removed the valve spring and so forth the valve had a easy .015 clearance.I aint got technical yet and looks like there wont need to be for a while.
I have also determined these valves are oversized by about .005 But they sure look bigger than stock.They have a pin hole and 2 sets of slots for the keepers but they aint no way they would go in the top set of grooves.I am thinking just grind the keepers to a point they wont hang below the valve stem and be happy.I would have to drill out the orignal type "ring" that goes under the valve spring to use them and a pin on these newer valves.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Jeffrey Cole on Tuesday, December 18, 2007 - 08:27 pm:

WEll I didnt finish,hit the wrong button.Anyhow,it is obvious the keepers were hitting the valve tappet and that was holding the valve open causeing the miss.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Tuesday, December 18, 2007 - 08:37 pm:

That engine must have modern 350 Chev valves huh? Something to be said for ol' Henry's design with the hardened mushroom shaped valve stems and pins for keepers I guess.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Tuesday, December 18, 2007 - 08:39 pm:

Oops; no mushrooms shaped valve stems; I was thinking of something else.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Tuesday, December 18, 2007 - 08:49 pm:

Harold was thinking of a Model A with mushroomed valve stems.

Mack,
It sounds as though you have either a broken ring or something metalic caught between the piston and the cylinder wall. You have what is called a "scored cylinder" It could also be caused by a wrist pin if the bolt came loose at the top of the rod, or if the front and back play is so great that the pin hits the cylinder. Check it out to be sure the cause has been eliminated so it won't get worse. It could even have been left from some previous problem which has been fixed. This will probably cause little problems other than burning a little oil.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Jeffrey Cole on Tuesday, December 18, 2007 - 09:01 pm:

Thanks Norm.Check my can o worms thread.Sorry I posted twice.Something about my computer aint talking to others well tonight.Would shortning the keepers be ok to fix this?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Billy Key on Tuesday, December 18, 2007 - 11:41 pm:

Mack,
Years ago I built a T engine using eight 56 Mercury exhaust valves. (They are longer and larger than the 350's) Due to decking the block and even though I used adjustable tappets, I had to grind off the valve stems and the keepers. Of course after grinding, the keepers were flush with the bottom of the stem. It worked fine, ran great and lasted a long time.

Billy Key


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