Valve Cover
 

I think I may have a valve sticking on one of my T engines. Can I take the valve cover off and run the engine with it off to watch the valves or will that cause a problem?


Thank you,


Jeff

Re: Valve Cover
 

Might get a little oil splatter, but not much else. It is splash feed.

Re: Valve Cover
 

Y-not just perform a compression test on each cylinder, you will know right quick the offending cylinder then plan your work.

Re: Valve Cover
 

It only seems to be missing every now and then. I have been chasing plugs, wires, distributor, cap, rotor button, etc. and I took a friend for a ride and he said it was a valve sticking. I thought that maybe I could run it and see if it would do it while watching it and then come up with a plan like squirting something on it like PB Blaster. Any reason I shouldn't do that?



Thanks for the help everyone, it is greatly appreciated.

Re: Valve Cover
 

I ran with no valve cover for a while so you should be fine.
While it'd be cool to set up a slow-motion camera to catch the misfire & compare valve lift with a frame of normal fire, it'd be huge amount of work for nothing.
I can't really see a problem with squirting them with a light oil.

Have you tried putting a small amount of oil in the fuel? Works for me.

Re: Valve Cover
 

A few tablespoons of MMO marvel mystery oil could help matters, you might just have a weak or failing valve spring causing problems.

When you say distributor, I always think moisture inside or a small crack in the cap that is hard to find giving you fits:eek:

Let us know how you make out there Jeff.

Re: Valve Cover
 

It wouldn't hurt to remove the covers and have a thorough look. check the springs and note the clearances and clean any gunk. I like using MMO in the gas 4 oz. to 10 gallons. It keeps the valves from sticking.

Re: Valve Cover
 

The first 30 or 40 thousand Model Ts made did not have any valve covers, and they run just fine. Model Ts had exposed valves until sometime in 1911-as did most other cars.

Your plan should work if the problem is indeed a sticking valve.

Re: Valve Cover
 

Yes you can run it without the valve cover. Not much comes out, remember that the early
T's had no valve covers. I ran one once that had a sticky valve, I squirted it with carb
cleaner to unstick it with it running then lubed it with Marvel mystery oil.

Re: Valve Cover
 

Seafoam works wonders on sticky valves. Straight on the valve stem

Re: Valve Cover
 

Thank you all for the replies. I put new plugs in and a new distributor cap and rotor button and it still misses every once in a while. I took the valve cover off and tried to use my phone with a slow motion video and that didn't catch the problem, but it is cool to watch. I finally got frustrated and took an oil can and just squirted 30 weight oil on each valve stem and as much as I wanted to think it was better, my son said it is no different. I am at a loss. With dad's passing, I am running out of mentors to call because they are all passing away. My next thought is to pull the head off and see if I can pour some Rislone down each valve from the top, or even take each one out and clean them and the guides and see if that helps. I called a local guy with a T that I met and it turns out, he hires his work out and couldn't help. I have a few other folks I can call that worked with my father and see if they can help me because they used to remachine cranks, cams and engine blocks years ago. If I take the head off, I might give it a valve job and see if that would help. I live with the oil leaks because it is a model T, but I don't like it not running properly. I have almost all of my other toys running like swiss watches, and this thing deserves to be the same way.

Re: Valve Cover
 

A Model T will not run like a Swiss watch, it's a Model T! :) Have you done a compression check? When is it missing; idle or running speed? Mine has a miss at idle, that's just the way it is and runs fine at speed. Have you tried enriching the mixture? You may be running too lean.

Re: Valve Cover
 

You may have arcing in the coil box that is intermittent look for black burn spots inside the box from moisture if that,s the problem replace with a plastic coil box i had a miss and could not find ran it in the dark garage did not see any thing so i took coil box out and bench tested it and had arcing in the box, black lines. Clean all electoral connections with muriatic acid and dip in water with backing soda and then in plane water and dab of silicone lube

Re: Valve Cover
 

It has an aftermarket distributor and I replaced the cap and rotor button last week.

Re: Valve Cover
 

The miss is all over the place. It can be at an idle or when I'm trying to cruise above 32mph. It has an aftermarket intake with a Tillotson model x carburetor and I just bought a rebuild kit for it and will install it soon. I run with the knob on the dash closed.

Re: Valve Cover
 

With the mixture knob closed, you are running too lean. Open it up 1/2 turn and see if it runs better.

Re: Valve Cover
 

With out knowing what modifications have been made to engine?
What intake/exhaust are you running?
Have you checked for vacuum leaks?
If you are running the Model A manifolds and compression is too low, maybe the engine is having a hard time pulling fuel in at lower RPMs. I ran an early aluminum intake (Ford) for a while, the engine even with good compression (in the 50 LBs range) was not happy at lower RPMs with the extra volume that the intake had. Switched back to iron type and it was much better.

Going back to what I suggested before; check your compression and adding to that, vacuum leak check and maybe bleed down test. If the manifold has a port might also do vacuum gauge test.

https://www.fordbarn.com/forum/showthread.php?t=278006

Re: Valve Cover
 

That seemed to make it worse. I'm at a loss. I may pull the head and replace the springs. There isn't a lot of time on this engine so I may lap the valves if I see rust on the seats from when it was in storage.

Re: Valve Cover
 

DO NOT... I repeat DO NOT pull the head!!! There's no reason on earth to do that and it will give you absolutely no answers + cost time and $. First off running with the needle valve closed indicates another problem to me. Actually I didn't think it was even possible to start/run that way. Truthfully I'm not very familiar with the carb you have so that might not be right. Secondly if a valve was hanging up it's very likely you'd hear something. An intake valve would pop back thru the carb and an exhaust would pop thru the tail pipe Not hearing either one? It's very likely not a valve. I'm more with the ign. people right now. Perhaps a worn distributor bushing is the problem. It would cause missing at various times by messing with the point setting. Good Luck and get help if you need it.

Re: Valve Cover
 

I think you just helped me with your comment on the tail pipe pop. I will listen to some of my videos and see if it pops.