1914 Low Compression Issues

E

Ed in Maine

Well-known member
Today I removed the two valve covers and checked the movement of the valve stems. The valve compartment looks pretty clean (no heavy sludge) and all the valves move up and down. It all looks functionally correct. When the valves are down on the seat, you can turn the push rods easily with your fingers. They are not gummed up! I didn't check the gaps but they are small, it doesn't appear that any of the valves are stuck open.

Before I start to take the head off, are there any other checks that could be made in the valve compartment? I would like to avoid any unnecessary work. The exhaust manifold is not leaking. Can I leave it in place while I am doing the valve work? Thanks for your help. Ed
 
Ed are they correctly adjusted/ do they have clearence when their supposed to be closed? Usually the only reason you can rotate a valve stem when it's closed is because it's not seated. That is it's not fully down on the valve seat. Better check this before going further. If they have no clearence you could save yourself the trouble of pulling the head by adjusting them correctly.
 
ED they make a simple tool that uses suction on intake and exhaust ports hook up to air presure and check for % of loss if any .simple and easy cadiguy
 
I may have confused you, the valve stem doesn't turn, it is the push rod under the valve stem that can be turned. That tells me the valves are on the seat and the push rod has dropped a bit further for the clearance. Cadiguy, you make an interesting suggestion. Could I put air pressure into a cylinder that is in the compression stroke (both valves closed) and look for the decay. This still wouldn't tell me what is defective, rings or valves. Ed
 
C'mon Ed... push has come to shove! Youve already spent more time than it wouldve taken to pull the manifolds, drain the sludge (!) and pop the head. If the valves have the two valve lapper drive holes, chuck 'em. Those are two piece valves with cast iron heads. Picture one breaking. Invest in a guide and a seat reamer and clean up a new seat and lap a new set of stainless valves. Go 1/32 OS on the guides.
The PO that had mine had cut new seats that were off center and the valves wouldnt seat properly. I had to take off nearly 1/32 to recenter them. Now the comp is 55-58-57-59. Do you have adjustable lifters? Invest in 1/32 OS when you rebuild the bottom this winter. For now its a matter of trimming the stem tips for the lash.
Dont forget to check the exhaust manifold for straightness... ws
 
Yer' probably right Bill. Judging from what he's posted at least it's time for the head & manifolds to take a little walk. Don't think he'll find out much more by looking at it. That zero comp. cylinder is troubling though. Hope it's a burned out valve.
 
You guys are right, I should stop thinking about it and get to work. But I have not been entirely up front with you. In the next stall in the garage I have a 31 Cabriolet that is completely stripped down with parts everywhere. The Model T wasn't supposed to pull this stunt this year. At this point it is one big distraction! I'm retired, what else do I have to do? Thanks for all your help, I will let you know what I find. Ed
 
While it would be a bandaid, why not pull the pistons hone the cylinders replace the rings grind the seats and replace the valves. This could all be done with the engine in place and would get you through the rest of the summer.
 
Your choice Ed but the Cabriolet doesn't sound like it's goin' anywhere soon. You might yet get some summer/fall driving out of the t though.
 
Before you remove the head, run another compression test. Use motor oil not wd40 to see if you can increase the compression much. That will give you the condition of the rings. Judging from your previous test it looks like you will need a valve job. Does the car burn oil? is there smoke out the exhaust? Better to narrow down what's wrong before you remove the head.
 
If you are using a regular compression tester that holds the pressure between compression cycles, given the readings you posted, adding oil at this point isn't going to change much. the head need to come off and problem addressed.
" Posts: 156

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Compression Test Completed on 1914
I had a compression tester but did not have an adapter for the Model T. I made one this morning and this is what I found:
#1 15psi
#2 20 psi
#3 26 psi
#4 0-2 psi

I did spray some WD40 in #1 and it did not make a difference. I guess I have some valve issues. I will take off the valve covers and see if I can see if any of them are not all the way down. Will it do any good to spray some lubricant on the valve stems?

I do remember complaining about the lack of power with this car. It is a touring and if I had four people in the car, climbing hills was getting difficult.

Thanks for your help. Ed"
 
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