MF 135 sucking through exhaust

[Reddoggy]

Hello folks, I have a massey 135 diesel with the AD3.152 perkins 3 cylinder. It came into the shop with a blown head gasket, radiator bubbling, so Okey, let's change this head gasket.
I drove it into the shop and tore it down.
I changed the head gasket, purchased a NEW head with new valves and all that jazz, put it all back together by the book, set the valve lash by the book-.012 cold.
Go to start it and it backfires once then stalls. After some exploration I realize that the exhaust is SUCKING, not all the time, more a push-push-suck, although it is happening to both exhaust ports(with the manifold off, valve 1 and 2 on first port and valve 3 on second) indicating that its at least two if not all three valves doing this.
I have tried loosening exhaust valves, a lot, with little to no improvement. Timing seems on since I am getting no push at the intake manifold, and when I had the head off the TDC mark was perfect with number 1 being flush with the top of the block and the camshaft had all but #4 and 6 lobes facing down.
Please help tractor forum!

 

[rustred]

describe your procedure u did to adjust valves. i have run into a lot of this . valves not set correctly. first you get number one cylinder
on COMPRESSION STROKE at TDC. rock the crank back and forth and you will see its running mate number 4 cylinder rockers doing the same
thing... rocking. so with it on tdc you adjust number one cylinders's valves. then you follow the firing order, 1342 and get the next
cylinder which is 3 on compression at tdc and watch its running mate number 2 rocking. that verifies you are on compression on number 3,.. so
set the 2 valves . keep going like that which would be cyl 4 then cyl. 3. and done. also .012 is a fine gap so you need to be really precise
on your settings. and once i have them set i run over them again for a final check. and in case you dont know there is 2 pistons on tdc on
engines at each time, which is why you must be on the compression stroke for adjusting valves.

 

[Jim.ME]

(quoted from post at 12:35:05 08/23/23) describe your procedure u did to adjust valves. i have run into a lot of this . valves not set correctly. first you get number one cylinder
on COMPRESSION STROKE at TDC. rock the crank back and forth and you will see its running mate number 4 cylinder rockers doing the same
thing... rocking. so with it on tdc you adjust number one cylinders's valves. then you follow the firing order, 1342 and get the next
cylinder which is 3 on compression at tdc and watch its running mate number 2 rocking. that verifies you are on compression on number 3,.. so
set the 2 valves . keep going like that which would be cyl 4 then cyl. 3. and done. also .012 is a fine gap so you need to be really precise
on your settings. and once i have them set i run over them again for a final check. and in case you dont know there is 2 pistons on tdc on
engines at each time, which is why you must be on the compression stroke for adjusting valves.

He is going to have trouble seeing the valves on #4 rock when working on a 3 cylinder Perkins.

Reddoggy,

I suggest you go through the valve adjustment again. If the problem wasn't there before you worked on it, it is likely related to something you did. If you didn't do anything but change the head, timing wouldn't have been affected. Check that all push rods are in place. You said you went by the book. Just to confirm. 1,2,3 cylinders are front to rear and they number the valves 1,2,3,4,5,6 front to rear. You need to look at the distributor to see where the rotor is pointing when you have the TDC mark in place, the marks line up every rotation, but are only right for setting valves on the top of the compression stroke which is every other rotation and the rotor will be pointing to the #1 terminal in the distributor cap. You could have set the valve 180 degrees off from the firing point.

 

[rustred]

your right on that, didnt read the top end.

 

[Masseyharrisnut]

My eyes arent great but I believe he posted that it is a diesel. No distributor on those.

 

[Jim.ME]

(quoted from post at 20:37:04 08/23/23) My eyes arent great but I believe he posted that it is a diesel. No distributor on those.

LOL, you are right and I read it.

This post was edited by Jim.ME on 08/23/2023 at 05:51 pm.

 

[Jim.ME]

Appears it would be best find where the #1 cylinder valves (valve #1 and #2) are on the rock with the timing mark showing TDC, then turn the engine over, in the correct rotation direction, 1 full rotation (360 degrees) until the TDC marks line up again. That should put it in the proper position (top of the compression stroke) to start the valve adjustment procedure. The rockers for #1 cylinder will have a lot of clearance when at the top of the compression stroke, if the valve adjustment was done at the top end of the exhaust stroke before.

 

[Phil Tibbetts]

No distributor on a diesel as far as I know!!

 

[Jim.ME]

(quoted from post at 21:21:22 08/23/23) No distributor on a diesel as far as I know!!

Yup, I read it and spaced it, there is no distributor on a Perkins AD3.152 to look at to see if it is on the right stroke TDC for valve adjustment (any more than they have a fourth cylinder to watch valve rock on to be sure #1 is in the right place for timing or setting valves).

However, there were some diesels with distributors, such as the old IH ones, that started on gasoline and swapped over to diesel. They had an ignition system and injection system.

 

[ptfarmer]

From the Perkins 3.152 shop manual on valve adjustment.

 

[used red MN]

Hello Red welcome to YT! Once you get settled in on a
proper valve adjustment and the problem persists. I
believe it is time for a compression check. You never
know what may wrong, although that is an unusual
symptom for leaky valve, but the new valves or seats
my have problems or the valves may be sticking. The
camshaft could be out of time, but in tractors with a
gear timing it is unusual for the gears to slip and get
out off time. It is stranger if after slipping it continues
to run, usually slipping is enough to make the gear
train stop.