My 1919 block is ready for the treatment...bore, hone, valves and insert seats.
Problem: My old shop guy tells me that in order to install the insert valve seats, they have to index off the valve guides in order to keep everything centered. Makes sense of course, but my guides are wallowed out too and he's not sure if he has a pilot that will fit the ordinary 1/64" o.s. holes if I ream them. (I can machine a guide for the reamer that fits in the cylindrical section below the existing seats..so the reaming would be straight)
I'm thinking of taking it to another shop first and having Chevy guides installed then using Chevy guides and valves.
Has anyone been down this road before and have any suggestions? Thanks!
Bore out the existing holes 1/32 o.s. and run SBC valves. This will give you a true hole to pilot off of so new seats can be installed. It will also do away with the junk pin type valve keepers.
Forgive my ignorance....but what are SBC valves?
Oh, wait.....Small Block Chevy?
Okay.....some quick checking tells me that Chevy valves are 11/32 stem diameter. So, if I ream 1/64 over stock, that results in a bore of .3281. Is that correct?
Okay......I think I just confused myself. Chevy valve stems are 11/32, which is .3437....
The 1/64 o.s. reamer results in a .3281 hole. That's too small! What did I miss?
Maybe my calculator needs new batteries.......
351 w valves work also and are a bit larger for better breathing, Scott
Found my error. The first poster plainly said 1/32 o.s. and I changed it to 1/64...my bad. Refigured and it comes out right.
1/32 o.s. it is! Thanks for your patience guys!
What's all this Chevy stuff about? Just get standard T replacement SS valves with oversize stems. Machine accordingly. If you want larger valves then get the Chevy, I suppose. Not worth the trouble. No need to install valve seat inserts...another myth. Just do it like Ford did.
Okay......last question for the day. Do you use the Chevy valve springs along with the caps and keepers? Or will the caps and keepers fit the standard model T springs?
There's some pretty good deals on new Chevy valves out there and I want to make sure I order all the right parts the first time.
SBC exhaust valves, cups & split locks and stock T springs.
Got it! Thanks for putting up with my confusion.
The reason I'm considering the Chevy valves is that I can get a set of eight 1.5" valves for thirty nine bucks, including shipping. Cups and split locks are available locally. Even having to purchase a reamer it still works out cheaper than oversize T valves and the replacements are very common.
You can use Falcon guides (bushings),then use standard Model T valves, and keep your Ford all Ford
George, there is another way. Your original vale guides can have K-liners installed to suit whatever valves you use. This will true up the guides and give you a custom fit to the chosen valves. I am surprised your machine shop did not offer this solution. Perhaps they do not have the tooling.
Hope this helps.
Allan from down under.
Seems like the last T I did used 223 Ford Valves & model a springs.
Probably used eight exhaust valves. It's been two years.
The machine shop gave me a couple hands full of keepers and retainers.
Remember you also have to use adjustable lifters for the chevy valves. I never have seen the point myself as the stainless reproductions work very well and with the original lifters will run many thousands of miles with no problems. KGB
Hard to believe you are working with a guy that doesn't have a pilot for a .343 valve stem. This is one of the most common pilots available and used in lots of engines.
Allan, I'm familiar with K-lines for overhead valve heads, but how do you get them into a flat head? I don't think the fixture used for the overhead valve arrangement would work on a flat head block.
In a Model T you do the valve guide work from below, with the camshaft removed.
I would just ream to 11/32" and use 1.66" Fordson tractor stainless valves. Seats then are an unnecessary expense so you save time, money, and have better performance with the larger diameter valves.
You should mock up afterwards to be sure the larger diameter valve does not touch anything. I found that on cylinders #1 and #4 the end valve contacted the combustion chamber on a "Z" head, although they cleared a regular high head when installed with no head gasket.
Stainless Fordson tractor valves S-242-G Valve: intake/exhaust (late- 11/32") $16.50
I have used sbc valves on many engines. The engine that I just finished building a couple of nights ago had valves that had 3/8" (.375)stems who knows what the valves were made for. So I did use the Chevy valve guide inserts in this block. The inserts are .502 in diameter. The original guides need to be bored to .500 to allow for .002 interference fit. I placed the block on the mill table and located the center of each of the 8 guides and bored to .500 making sure the bore was vertical. I then pressed the new guides in from the top, they went in very nice and the sbc valves fit very well, I ground new seats piloting off of the new guides. Made a nice repair and I would not be afraid to do it again. Here is a picture of this engine with the new valves installed.