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+--- Thread: Liner protrusion (/showthread.php?tid=2786)
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Liner protrusion - Joesixpack - 02-21-2018
So we've got an ISX in the shop here and the liner's are sitting right between 9 and 9.5 thou proud.
No visible fretting at all where the liners seat and no head gasket issues.
Wouldn't have thought twice about throwing new liner's in it as is except for coming across some guidance on here suggesting cutting the seats and raising them up with shims to 15 thou.
So just how prevalent are head gasket problems if the liner's were sitting at 9-10 thou?
I think new liner's are coming with shims now, can a guy order the shims + 5 thou?
RE: Liner protrusion - Unilevers - 02-21-2018
if you dont cut it it wont last, im warning you now.
shims do not come in 5 thou that i know of
RE: Liner protrusion - Nilao - 02-22-2018
You can’t visibly see 2 thousandth of fretting. There is a reason the proper way to measure it is to put a liner in without the o-ring and compress it with a liner seating tool. Then measure it with a dial indicator. If it’s fretted it will show up.
RE: Liner protrusion - Signature620 - 02-22-2018
If the liners are coming out, machine the counterbores.
RE: Liner protrusion - tree98 - 02-22-2018
What causes liner fretting anyway? Is 15 thou the magic number?
RE: Liner protrusion - Signature620 - 02-23-2018
Liner movement and vibration (generally from the power stroke)
RE: Liner protrusion - Hammerhead - 02-23-2018
(02-22-2018 )tree98 Wrote: What causes liner fretting anyway? Is 15 thou the magic number?
(02-23-2018 )Signature620 Wrote: Liner movement and vibration (generally from the power stroke)
Increasing the liner protrusion to 0.015" increases the clamping force. When the head gets installed and torqued down, the head gasket crushes to final thickness to make the oil and coolant seals along with the combustion rings that contain the cylinder pressure. The increased vibration cycles, especially in 2250 and later engines with pulse injection making several bangs* during combustion increases liner vibrations. By raising the liner height the head gasket doesn't quite crush as much in the oil and coolant passages area, but still enough that the sealing isn't affected, however the liners get pushed down into the liner shelf with much more force.
The ISX is a mid-stop liner, meaning the liner is prevented from being pushed out the bottom of the block mid way down the liner as opposed to the older Cat and S60's that the liner stop was right at the top. The theory behind a mid-stop is that you are supporting the liner in two places (mid-stop and head) instead of one so it should be more stable. In the 570 & 870 with CDI combustion technology and lower static compression there wasn't enough pressure and vibration cycles to show that the OEM spec of 0.009-0.010" didn't have the necessary rigidity to stand up to the increased pressures and vibration cycles.
Using the old verbage of Suck, Squeeze, Bang, Blow to describe a four stroke engine...to describe pulse injection technology it's now Suck, Squeeze, Bang, Bang, Bang, Bang, Blow
RE: Liner protrusion - Joesixpack - 02-23-2018
(02-22-2018 )Nilao Wrote: You can’t visibly see 2 thousandth of fretting. There is a reason the proper way to measure it is to put a liner in without the o-ring and compress it with a liner seating tool. Then measure it with a dial indicator. If it’s fretted it will show up.
Well yeah, the 9 thou is in the block compressed. There's ALSO no visual indication that there is any fretting in the fine tooling groves on the ledge anywhere.
Its going back together as is. Couldn't find a cutting tool locally and Monaco is out of stock.
Guess I'll find out if it lasts.
The head on the other hand had cracks from the injector holes to the valves in every hole except #1. So there's a new head going on. So if I do see some pressuring I'll know where it's from! LOL
RE: Liner protrusion - Wiseman - 02-23-2018
(02-21-2018 )Unilevers Wrote: if you dont cut it it wont last, im warning you now.
shims do not come in 5 thou that i know of
Joesixpack ,
Everyone here tried to warn you in the best possible way !!!