tc55da fuel knock

[farmer long]

I have a tc55da that I replaced the head gasket on, started right up but had excessive smoke from exhaust and a fuel knock when revving up, I replaced the injectors but still does it, mainly when needing some torque or at idle, runs and starts great other than that, never touched the pump and fuel filter was changed and fuel quality seems good, threw some atf and power service in, no luck. any ideas? thanks.

 

[Hay Dude]

how many hours since head gasket?

 

[farmer long]

0 it started doing it right away

 

[jaxs]

That's strange. I don't know alot about them but I believe that's a Shibaura 2.2L 4-cyl diesel that other mfgrs used as well. Only a wag mind you but's possible each mfgrs model is a varant with different pistons that require head gaskets of various thickness for desighned compression. I'm not so sure I'd pop the head to check unless i found reliable information to support it. If failed gasket involved or caused overheating the block and/or head might be cracked. Hopfully someone with more experience with the Shibaura 2.2L 4-cyl diesel weighs in with better info.

 

[Hay Dude]

Any chance of bent valves?

 

[farmer long]

the head was sent in and checked out good, the water pump had gone out last summer causing the head gasket failure, could be the block?

yes its a shibaura not sure on gasket thickness but will check into it.

Thanks everyone.

 

[K5lwq]

Did you set the valves after reinstalling the head? Just a thought.

 

[5030]

Did you measure protrusion height and order the correct thickness head gasket or did you wing it? head gaskets come in varying thickness for protrusion height adjustment. I would have at leat used a micrometer to measure the thickness of the old one and ordered accordingly. Sounds to me like your base compression ratio is too high due to a reduction in head to deck height. Kind of surprised the valves are contacting the top of the pistons (and they may be) when you pull the head again.

 

[farmer long]

set the valves, just winged the gasket, no knocking until you throttle up or under torque, starts really easy and runs good at full throttle with no smoke, sometimes will idle a fair amount of time without smoking. the little bit i used it it seemed to have good power once it got through the fuel knock. I may drain the fuel and start fresh before i tear it down again.

 

[5030]

Keep in mind that unlike a gasoline engine, the 'squish' space (pistons at TDC) is very small. Why the correct thickness head gasket (or spacer plate on some engines) is necessary. I suspect your only cure is to pull the head again and install the correct thickness head gasket and I would carefully inspect the piston tops for valve contact as well as the valve faces themselves. While not familiar with the engine, I would also carefully inspect the tips of the injectors if they protrude into the combustion chamber space. If it's a pre chamber engine, injector tip protrusion won't be an issue as the injectors are in the prechamber area.