Good morning. My father passed down a 1925 2dr coupe to me last year. He bought it in 1962 from a farmer in Illinois. I can drive the car, but my mechanical skills are at the novice level for the T. I know that an engine rebuild was done in the 1990s but do not know who did it, nor what was done. Lately, it has been running rough and is hard to start. When I checked the valve clearances, all were set at 0.021 except for the intake valve for cylinder 4 which was at 0.0 When I pulled the exhaust manifold, the outlet for #4 had no soot. I replaced all of the spark plugs and there is spark at #4 when I short the connector. The valve stems look like stainless steel, so should I adjust clearances closer to .012/.014? And, what is the effect of no clearance on the intake valve for cylinder 4? Thanks all.
With 0 clearance on any valve you run the risk of burning that valve. I run my T at 0.010 inch, but that is what the cam maker specifies for his cam. Since you don't know which cam in in your T, the 0.012 to 0.014 inch clearance would be better that 0.021 inch. I'm sure others will share their thoughts. Do you have adjustable lifters? If not you will not be able to close up the gap without new valves or going into the engine to install adjustable lifters.
Thanks John. I do have adjustable lifters. I guess my next step is to take off head and inspect the valve for damage.
Re-adjust the lifter for clearance and run it without pulling the head. You won't do any further damage and the valve will most likely be just fine. If not you can always pull the head and valve if you detect a problem..
I adjusted the lash to 0.012 on all of the valves (they are aluminum). I still thought it was running rough, so I decided to take off the head and take a look for the first time. Gasket was copper and in good shape. There were no stuck valves, so I suspect some kind of electrical problem. Anyway, upon inspection, I found that the steam hole near cylinder 4, in the block was totally filled. I am trying to clear the passage with picks, nails, wire, and small drill bits. What would be the effect of the blocked steam hole? Thx!
Drill all of the "steam" holes with a 1/4" drill bit.
I have cleaned out the steam vent (couldn't use 1/4 in drill bit because of firewall). Does anyone know what is the effect of a plugged steam vent?
You could get a steam pocket at the rear of the head, no water circulation. Sounds like you have the hole open some, try twisting the drill by hand or hold with vice-grips, it would just be rust and gunk build up and should be easy to clear.
Alan, in a set of hex drive bits, I have a set of 5 drill bits with hex drive. One of those and what you guys call a box wrench would help drill the steam hole out. They are only a couple of inches long, so will fit next to the firewall.
Hope this helps.
Allan from down under.