49 B Problems

[polaschd]

I have been rebuilding a 49 B, Engine was stuck but I was able to unstick with minimal effort. I did noot take the cylinder off and check the pisotns and rings, I did however have the head check by a local shop and they cleaned and confirmed it was okay. After putting it back together and resetting the valves to the .020 as indicated I was getting 30 pressure on left cylinder and 0 on right. I did a blowback test and on the left could hear air escaping through cylinder and on right all the air escaped through the exhaust both times i had the respective cylinder at TDC. Any advice to include do I need to take the cylinder off.

Dean

 

[Greenday]

If the engine was stuck you also run a very good chance of having some stuck rings.

 

[polaschd]

true but why would the cylinder that showed 30 psi when testing the compression blow the air back through the cylinder and the one with 0 psi push all the air through the exhaust?

 

[Mike M]

Did they even grind the valves ? did they lap them ? If they did all of the above maybe there is assembly grease on them it will make them not seat. Tap the end of the valves makeing them bouce off the seats a few times and retry.( Use a dead blow soft hammer )

Guy brought me a cyl head that his local machine shop just reworked. He suspected something was wrong and it was. I took it apart and the intake valve seats were not ground on ! I suspect they did not have a large enough stone.

 

[polaschd]

Yes they did grind and lap this guy is quite familiar with 2 cylinder heads. My confusion is the compression readings and the when I push compressed air in the right side 0 psi at tdc all air escapes from exhaust on left side 30 psi i am gettting minimal escape through the exhaust but can hear escaping back through cylinder

 

[jd b puller]

(quoted from post at 11:01:10 09/19/10) Yes they did grind and lap this guy is quite familiar with 2 cylinder heads. My confusion is the compression readings and the when I push compressed air in the right side 0 psi at tdc all air escapes from exhaust on left side 30 psi i am gettting minimal escape through the exhaust but can hear escaping back through cylinder

1. I always cringe every time someone takes a stuck motor and frees it up and gets it to run. Creates these urban myths that it's ok to do that. Sets another 20 people up for failure, as well as the poor sucker that ends up buying it.
2. When you set your valves, are you sure you did it at TDC on the Compression stroke?
3. When you did your blowback (leakdown) test, did you have the piston at TDC on the compression stroke?
4. You could also take the pushrods off and check your leakdown, then it wouldn't matter what stroke you are on.

 

[polaschd]

Yes, they were at TDC> I understand it was a mistake not to take down further I got It! I am seeking advice on how to do it right no plans on selling this is a family tractor. Again why during the pressure test am I getting air push through exhaust on right and on left the push(hiss) goes back through cylinder assuming rings are stuck but that doesn't help me understand the pressure readings i got.

 

[alabamafrog]

Do you have the valve cover off so that you can see and feel the rocker arms to make sure the exhaust valve is not being held open?
TDC on the exhaust stroke is different than TDC on the compression stroke and the mark on the flywheel is only for the left cylinder.
If air is going out the exhaust then the exhaust valve is open or something is wrong.

 

[Radiator Bolt Man]

Having a cylinder at TDC don't get it done unless you are at COMBUSTION TDC - this for setting of the tappets - also, set tappets to 0.022 at room temperature, not 0.020.

As for taking the shortcuts you have - not at all a good idea. 'Seems to me that with a family tractor, you would want it to have more TLC than you've given it. But miracles do still happen - and we all wish one for you on this job. (PatB)

 

[Kurt_JDB]

Suggest you do what JD B Puller suggested. Remove your valve cover and loosen the nuts holding the rocker arm assembly down. This will allow all the valves to close. Now try the leak down test. Be aware the engine will want to rotate as you fill the cylinder with air. Let it rotate, just be careful.

Kurt

 

[jd b puller]

You need to be at TDC on the compression stroke. If you weren't on the compression stroke, then that would explain the valve being partially open. If you SET the valves on the exhaust stroke, that would affect it as well.

This link will probably explain it better than I can.
explanation

 

[Rusty wheel]

Sounds like more than one problem to me. Blow by sounds like the rings aren't seated for some reason. Pushing compression past the valve suggests the valve isn't closing. Are the valves timed right? Just a thought. rw

 

[jd parts guy]

u did use a new head gasket?

 

[jd parts guy]

u did use a new head gasket?

 

[Mike M]

There are always varing degrees of "stuck" Why would one NOT want to try to free it up and get it running BEFORE you go sinking alot of money in it ? If you get it going you can then try out the tranny and all the other things to see what works and what doesn't. You can always pull it apart apart after you get it going and much easier to do so too.
Now if I ever had to pull the cyl. head to unstick one I'd surly pop out the pistons as you are right there. I have unstuck many with good results and little time and money spent on them.

 

[jd b puller]

Mike, that's just my opinion. If you're keeping it it's one thing, how would you like to buy a "running" tractor from someone who just got it unstuck and threw some paint on it? Not saying this guy is doing that.

 

[RandyB(MI)]

Do what JD Puller says in his #4 sentence. If the results are different than you now get then you are NOT performing the leak down test correctly (ie you are using the wrong tdc)