Working on a buddies backhoe and having some issues regarding head gasket not sealing properly. We did have the head serviced and block had to be machined and liners pressed in. We've had the block and head both checked by two different machine shops and all is straight and square. We've replaced all head bolts and head gasket a few times to be sure it wasn't a mis-torqueing issue. Machine runs and drives great but after a few hours of use the head gasket is shot, everytime the head gasket is blowing on the same 3 of the 4 cylinders. All parts used were Maxiforce. One machine shop believes that the issue is a detonation issue whish is causing the head gasket to blow. One of his buddies said something about fuel rail shims or something for adjustment but I can't find any spec on it or anything. Hoping one of you gurus can point me in the right direction. We have checked piston protrusion to be sure piston wasn't making contact with gasket and there is no direct contact to head or gasket as well. Motor is a Yanmar S4D106-1FH. Please reach out with any questions or tips. Happy Thanksgiving everybody.
Were those genuine or aftermarket parts used on that engine. Do you have a shop manual that gives a piston distance or clearance spec.? Your block was decked, so was there any change to head gasket thickness because of it.? Have never worked on that model. If the head was shaved also maybe something is wrong with injector depth. Not there just saying some possibilities. Simon C
Having a Komatsu shop manual on hand will make this process easier. You can get it from online sellers or eBay.