got some pics from a while back that some of you might be interested in
engine hung a valve because a lifter that'd been tacking along for the last 50k miles finally got eaten, nothing to do with the coke buildup
the coke extends out from the injector nozzle holes in a cone shape, real interesting
it is easy to notice when it is building up because you'll have bad white smoke at idle, when you beat on the engine very severely it does knock loose most of the time on its own but sometimes you've gotta pull the injectors and crank it with them out in order to break it loose and eject it
I'd imagine it gets this bad about every thousand miles or less from that white smoke metric alone.
Fairly soon I'm gonna try some thermal barrier ceramic coating on the piston and head to see if it'd be enough to keep the combustion chamber temperatures high enough to keep it from sticking.
Got the engine apart again and it is about the same, 40k miles later (broke a piston ring, probably from using ether to start it because the high-viscosity fuel burns so poorly) no pics yet, just gotta get around to transferring them from the camera to the computer one of these days/months/years... Anyways, this time the exhaust valve heads got this white ash buildup on them that's pretty thick. I'm betting that is from the metallic antiwear additives or some such. It scrapes off real easy but I did notice some gentle imprints in the coke on the piston tops from the valve heads so that is certainly a concern worthy of... concern. Nothing like timing belt marks, just outlines in the buildup.
anyways, pictures:
engine hung a valve because a lifter that'd been tacking along for the last 50k miles finally got eaten, nothing to do with the coke buildup
the coke extends out from the injector nozzle holes in a cone shape, real interesting
it is easy to notice when it is building up because you'll have bad white smoke at idle, when you beat on the engine very severely it does knock loose most of the time on its own but sometimes you've gotta pull the injectors and crank it with them out in order to break it loose and eject it
I'd imagine it gets this bad about every thousand miles or less from that white smoke metric alone.
Fairly soon I'm gonna try some thermal barrier ceramic coating on the piston and head to see if it'd be enough to keep the combustion chamber temperatures high enough to keep it from sticking.
Got the engine apart again and it is about the same, 40k miles later (broke a piston ring, probably from using ether to start it because the high-viscosity fuel burns so poorly) no pics yet, just gotta get around to transferring them from the camera to the computer one of these days/months/years... Anyways, this time the exhaust valve heads got this white ash buildup on them that's pretty thick. I'm betting that is from the metallic antiwear additives or some such. It scrapes off real easy but I did notice some gentle imprints in the coke on the piston tops from the valve heads so that is certainly a concern worthy of... concern. Nothing like timing belt marks, just outlines in the buildup.
anyways, pictures:
