Head torque specifications

[Shane Wade-HT]

I have a ym 1700. Just put a new head on it, and torqued it down to manual specs. which was 130.

After installing the head and everything back together. We proceded to start the tractor. I sprayed some fuel in the intake several times and tried to crank. I noticed that the head was already leaking right under both injectors. Any ideas anyone? Has anyone ever seen a distorted block? I am at a loss. I really hope the block surface is not uneven.

Also, does the ym 1700 have a compression relief?

 

[Norm-HT]

" the head was already leaking right under both injectors."

If you are talking about a leaking head gasket, YM1700 head torque is 130psi. You may have ruined your head gasket. Otherwise did you replace the injector gaskets. You just replaced the head. Does it have compression release?

 

[Shane Wade-HT]

I bought the tractor knowing it had a cracked head. Bought new loaded head, all new gaskets, water pump kit, rings, rod bearings. Went back with everything, and tried to crank the tractor. Starter would barely turn the engine over. Hence asking if it has a compression release. I can not find it if it has one. While trying to crank the tractor I notice diesel fuel squirting out from under the injectors in between the head and gasket. The manual I have calls for 147 torque pounds on the head bolts.

I apologize. The manual does call for 130. They were torqued to 130.

 

[Aaron-HT]

All Yanmars have a compression release. Just follow the linkage from the valve cover back to the dash if you cant find the lever. Did you torque the center head bolts first & then move outward? Are you sure your torque wrench is calibrated correctly? Are you sure that the sleeves were seated all the way down? Was the block clean & free of any deep scratches?

 

[Norm-HT]

. . .also be sure and torque the head in increments of 1/3, 1/3, and 1/3 to prevent distorting the gasket. If the engine is too tight, that could be a whole 'nuther can of worms. My first overhaul, a '50 Merc flathead wouldn't turn over by the starter. Had to pull-start with another car, but it was fine after a while.

 

[Shane Wade-HT]

I did everything the way ya'll have described. I tore the engine back down today and removed the gasket. The gasket is fine and has no bad places. Sit the head back on the block and and you can see where the block is dipping slightly in a few spots. I also checked the head and it is good and level as it should be. I have purchased some good, fine crosscut files, going to level it up tomorrow and try again.

The man that owned this tractor never did any up keep to it. The oil looked as if it had never been changed. The engine had been overheated more than once. Despite all of this abuse the engine, crank, cylinder sleeves, mains, and rod bearings all looked good, I did replace the rod bearings while the pistons were out. Cylinders were not egg shaped, but did have an excessive amount of glazing on them.

Anyway, I hope this works. As I have always loved these little yannies.