Piston replacement procedures?

Jagerbombs · May 31, 2018

New to the forum, but not new to the powerstroke world. Been working for ford for 10 plus years, hopefully my findings over the years helps. Now I’ve done this awhile and always have seen in ever shop environment I’ve been in, say you have piston damage, injector tip, glow plug valve whatever it always gets a short block and head, black box or whatever. I see guys posting about single piston placement every now and then. I know the dealers I’ve been apart of never even think this an option, but they will have no problem throwin cams in. I’ve never done it but I’d like to offer that as an option, anyone have a few quick tips, tricks, or anything to look out for as long as the cyl walls pass, measurements and or machine work? Any info is appreciated

Keith Browning · May 31, 2018

Welcome to the DTS!

With regard to piston replacement due to damage I have done this several times over the years.Yes it can only be done with no cylinder wall damage as you stated, but you also need to consider the age and condition of the engine. On the ones I repaired they were all due to a failed injector in one instance and the others were instances where foreign objects got in during repairs... like a small bolt or nut. when the engine is lucky the object gets embedded into the piston and stays there or ends up stating in the valve or somehow passes. Replace everything related to the cylinder: piston, rod, rings, cylinder head or there is no damage to the head replace the valves and check the sealing while the head is on the bench. Marking compound is useful for that and of course there nothing wrong with have a machine shop do it and check the head while they have it.

Bruce Amacker · May 31, 2018

Keith, I agree with everything you said. Do you do anything to the wall like running a ballhone through it? I might do that to break the glaze quickly.

Slightly off topic, I just tore down an old air VW cooled engine where the rings weren't seating. This engine sat for years (decades?) inside a garage, I freshened up the exterior (tune-up, carb) and ran it on the run stand. Somewhere about the 6 hour mark it started pumping oil badly through one or more cylinders. Compression had dropped 30psi from my initial readings. Upon teardown this engine looks like NEW inside- .016 ring gap (meets new specs), jugs look like new with the factory German hone marks, zero bore wear, .000" out of round, everything looks like new. Internal/external items on the engine all show extremely low mileage, I'm guessing 10k-30k max. The chrome rings wouldn't seat for some reason. I've heard of this before with chrome but never experienced it. It'll go back together after a ball hone with cast rings, which are more forgiving on bores. Does anyone know if Ford uses chrome rings? I'm assuming they do.

Keith Browning · June 1, 2018

10 hours ago, Bruce Amacker said:

Keith, I agree with everything you said. Do you do anything to the wall like running a ballhone through it? I might do that to break the glaze quickly.

I don't even know where my ball hones are any more. I think they are in the back of my garage at home. To answer your question obviously I don't run a hone down the cylinder after that statement but oddly enough the cylinder walls on engines I have had apart still had good cross hatch marks. Once the ridge is cleaned up and the piston removed I will remove the oil and wipe the cylinder with red scotch brite following the cross hatch to break the glaze. I suppose that a hone would be best and would aid in breaking in and seating the new piston and rings.

Oddly enough all of the engines I have made such a repair to have been 6.0L