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Engine Specific Info and Questions => IDI Engine => Topic started by: frankentoy on February 05, 2005, 09:49:46 am

Title: piston protrusion TD 1.6
Post by: frankentoy on February 05, 2005, 09:49:46 am

i checked the piston height above the block and its .022" which is .004" short of what is described in the book for the lowest of the tolerences.  this is new set of .030" over pistons will this work or am i looking at tearing this apart and decking the block? i really dont want to do that. thanks

Title: piston protrusion TD 1.6
Post by: frankentoy on February 05, 2005, 05:45:45 pm

thank you, so that .004" difference from spec isnt going to make a big difference in the compression?

Title: piston protrusion TD 1.6
Post by: jtanguay on February 06, 2005, 10:17:51 am

it isnt if you buy the right head gasket :)

Title: piston protrusion TD 1.6
Post by: frankentoy on February 06, 2005, 12:16:25 pm

what im trying to say is the lowest spec givin in the manual for the 1 hole head gasket if like .034" to .026". my reading is .022". so im below the spec they give.  ill have to go with the 1 hole gasket but ill be a few thou under what they say its for. is that going to really cause a problem?

Title: piston protrusion TD 1.6
Post by: jtanguay on February 06, 2005, 02:48:32 pm

well you can change gasket thickness to make up for it :)

Title: piston protrusion TD 1.6
Post by: srivett on February 06, 2005, 08:14:37 pm

I remember Dr. Diesel telling me about this happening to him.  He put the engine together but in the end wasn't happy about how it was running so he had the block decked.  The block ended up crooked and that really ruined things.

Steve

Title: piston protrusion TD 1.6
Post by: QuickTD on February 06, 2005, 08:52:45 pm

In the grand scheme of things .004" isn't going to make any difference. Use the 1 hole gasket and don't sweat it. Dr D's engine was considerably worse than .004" as I recall.

I would recommend against having the connecting rods "sized" when doing a rebuild. Machine shop monkeys (as Dr. D refers to them) can get carried away and shorten the rods excessively. "Sizing" is standard practice with gas engines and many shops do it as a matter of course. The goal of "sizing" is to make sure that the big end bearing hole is perfectly round and on size. The process involves removing a small amount of material from the mating surfaces of the connecting rod and the cap in order to reduce the size of the bearing hole. The rod and cap are then assembled, torqued to spec and the big end bore is honed to the proper size. The length of the rod is reduced by the amount taken off the mating surface. This is generally of no consequence in a gasser but as a few people have found out it can play hell with a diesel.

Title: piston protrusion TD 1.6
Post by: frankentoy on February 07, 2005, 08:24:31 am

thanks for all the replies. i think i got the answer i was looking for. i cant see that .004" will make a difference. whats going to happen? the compression will be lowered? and how much? i cant see it being enough to cause a problem. thanks guys