How did you handle installing larger intake valves? And other boring questions...

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Model T Ford Forum: Classifieds: How did you handle installing larger intake valves? And other boring questions...
Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary London, Camarillo, CA on Monday, February 19, 2018 - 05:32 pm:

I'm working on a new engine to use with the Dubats crankshaft I bought a couple of weeks ago. I've found a good candidate block; it has a hole cut into the water-jacket when the manifold mating surface was machined, and I can see where it was welded for a repair previously. Fortunately I know a great welder in our area, and he's going to cut it out to thicker medal and braze it to fill, then the machine shop can just clean it up. The block is a '14 so it's worth the effort.

Right now it has standard head size stainless valves, with hard seats in the exhaust. I have a Neway cutter set and am thinking of using that to enlarge the intake seats, which are not hardened seats. The valves and seats are in great shape, right now lapping them is all I need to do, the current valves use modern spring seat keepers and the stems are .030 over. If I buy the larger valves from the vendors are the Neway cutters able to enlarge the seats? I think so, my experience with them is they cut the cast iron easily, but I'd love to hear from someone that has used them for this.

The cylinders are beautiful, not tapered, nice and round, no scuffing, but they measure 3.800..... .050 over. It's definitely not from wear. Anybody familiar with pistons this size in a modern rebuild? I'm stumped on it.... I know I can have it bored .010 over, and right now that's the plan, but I'd really like to know if there was some 'old school' reason for the odd size.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Spencer Vibert - Granby ,CT on Monday, February 19, 2018 - 05:39 pm:

Gary my 1960's era gaslight catalog offered 50 os pistons and I believe you could have gotten 45 os cast iron pistons back in the day if it were mine I would punch it to 60 as for the larger intakes I would lap them and be done with it you are not going to gain much with larger intakes


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Monday, February 19, 2018 - 08:00 pm:

Try googling mtfca; over sized valves
Fordson tractor valves come to mind, having been suggest in the past. Which ever valves you use, make sure they clear the gasket and don't hit the combustion chamber. On a posting in the past was suggest to make sure there is clearance around the valve for the mixture to flow, not shielded by the area around it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Woods, Richmond, Texas on Monday, February 19, 2018 - 08:27 pm:

If you check the Model T speed books, such a Model T in Speed and Sport, you'l see that back in the day, they used Fordson valves and /or some year Dodge valves.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Pharis on Monday, February 19, 2018 - 10:51 pm:

If you have adjustable lifters... you are half way done with the chebby valve conversion. And if you open the Manley valve catalog... you'll find you can get chebby exhaust valves in a length that will drop right in, and you can get head diameters in almost any size you want (I went with 1.720" in my speedster). You say your block is already cut for +.030 valve stems... I'll bet those valves are chebby in there already.

Only problem with O/S valves... You may have to cut the cylinder head and gasket to clear the valves if you go too big.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary London, Camarillo, CA on Monday, February 19, 2018 - 11:38 pm:

I just realized I posted this in the classifieds... sorry about that.

My main question with the valve installation is with the Neway cutters; as anyone used them to enlarge seats when installing larger valves in standard cast iron seats? If so did you run into any problems? If I go that route I'd buy the valves the vendors provide that work with the standard head gasket.


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