Jubilee blowing air back through intake

jmunday · May 5, 2018

Hello.
Wanted to pick the brains of the experts. Jubilee has been running great until today. It was running fine and then it just shut down and started to blow oil and air from the air cleaner back out of the air intake. I have heard a new knock the last couple times I've used it and didn't think to much of it. What do you think came loose? Broke valve? Anybody have any advice on where to start? Top end I assume but not sure what I'm looking for first.

David G · May 5, 2018

Do a compression test.

Shetland Sheepdog · May 5, 2018

Sounds like you lugged it down to almost stalling, then pushed the clutch in, and it started running backwards.
Try re-starting it, and see if its okay.

showcrop · May 5, 2018

Most likely cause is cam shaft timing is off. It is very unusual. It happened to me once when installing those awful rear main side seals, and I took it apart three times before I was satisfied with it. Some how in the process I got the camshaft back wrong. It can happen if the cam drive gear comes of the shaft, which could be related to the noise that you heard.

jmunday · May 5, 2018

(quoted from post at 18:08:23 05/05/18)
Most likely cause is cam shaft timing is off. It is very unusual. It happened to me once when installing those awful rear main side seals, and I took it apart three times before I was satisfied with it. Some how in the process I got the camshaft back wrong. It can happen if the cam drive gear comes of the shaft, which could be related to the noise that you heard.

Thanks for the replies. It wasn't lugging down when it did this and it won't crank back up. Camshaft drive gear sounds interesting. Any way to check the camshaft drive gear without completely tearing into the thing? Thanks again.

riveroadrat · May 5, 2018

My used-to-be-uncle called me one day and told me our tractor was blowing oil out the precleaner when he tried to crank the 172 diesel. I had never heard of or seen that. I took the precleaner off and it was full of dried dust. The oil bath was so dirty it would pull vacuum when trying to suck air in. when you let off the starter air would rush in and blow what oil was left in the bottom cup out the top. I thought he actually had more brains than that, but he has since then showed that he pretty much is at a loss for brains. He thought he could take 4 tractors plus from my fathers estate and actually get away with it. He will be on his way to jail shortly. He didnt know that elderly abuse laws are actually written for people who are mostly kin to you.

showcrop · May 6, 2018

(quoted from post at 18:25:06 05/05/18)

(quoted from post at 18:08:23 05/05/18)
Most likely cause is cam shaft timing is off. It is very unusual. It happened to me once when installing those awful rear main side seals, and I took it apart three times before I was satisfied with it. Some how in the process I got the camshaft back wrong. It can happen if the cam drive gear comes of the shaft, which could be related to the noise that you heard.

Click to expand...

Thanks for the replies. It wasn't lugging down when it did this and it won't crank back up. Camshaft drive gear sounds interesting. Any way to check the camshaft drive gear without completely tearing into the thing? Thanks again.

Check your air cleaner first, but to check the cam gear, you remove the front cover. Of course you will have to remove the sheet metal, radiator and water pump to get to it.

Texasmark1 · May 6, 2018

Yeah. Whip out your repair manual and check the valve tappet setting instructions after a head removal. You are instructed to set the
crankshaft in a certain position and that makes valves x and y closed and you bla bla.

If you follow the instructions and get to the point where it's time to slide the gauge and the rocker arms aren't in the position stated in the
manual, you have a cam timing issue.

Eman85 · May 6, 2018

Remove air cleaner and if it won't start put your hand over the air inlet and crank the motor. If it blows air back instead of sucking do a compression test.

Texasmark1 · May 7, 2018

This would pick up a stuck intake valve, valve not sealing, mal-adjusted intake tappet, timing out of time...cam vs crankshaft, to name a
few.

jmunday · May 7, 2018

(quoted from post at 06:43:51 05/07/18) This would pick up a stuck intake valve, valve not sealing, mal-adjusted intake tappet, timing out of time...cam vs crankshaft, to name a
few.

Thanks for the replies. I tore into it yesterday and removed the tin and fuel tank so that I could get the valve cover off. When I turn the engine over the valves don't move so ill block it up and disassemble the front end. I'll keep you posted on what I find. Thank you for your help.

Keith Williams · May 7, 2018

Expect to find the Cam gear and the Crank gear broken.
If so the distributor would not be turning also the Hydraulic pump.
HTH
Keith

jmunday · May 17, 2018

(quoted from post at 07:28:31 05/07/18) Expect to find the Cam gear and the Crank gear broken.
If so the distributor would not be turning also the Hydraulic pump.
HTH
Keith[/quot

Thank you all for the help. I finally had time to completely tear into the front end and you are right the timing gear is missing teeth.

TinCan · May 17, 2018

Now check for bent valves. Had to be one open when you were cranking on it. Most likely the one that was letting all the air out while cranking.

Pat

Jubilee blowing air back through intake

jmunday

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jmunday

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