Tight wrist pins
06-15-2011, 07:46 PM
#21
Registered
Tango,
What type of pistons are they ? I have found lately that there is quite a variation in pin sizes from manufacturer to maufacturer and a lot of them are coming in a lot tighter in the piston than I like to see for sure. I like to see at least .0007" - .001" on performance engines. I guess they are press fit from your description. What I do is similar to what gtrdone said. When I install the pistons using the rod heater, I wait about ten minutes to let them cool off a little and then I squirt some assembly lube on the pin and it wicks in like soldering a pipe. I have never had an issue doing it this way.
I bet once your guy removes the pistons from the rods he will find some hot spots on the pins.
Personally I think that a lot of unexplained rod bearing failures are from pins geting tight and not allowing the rods to pivot freely.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
What type of pistons are they ? I have found lately that there is quite a variation in pin sizes from manufacturer to maufacturer and a lot of them are coming in a lot tighter in the piston than I like to see for sure. I like to see at least .0007" - .001" on performance engines. I guess they are press fit from your description. What I do is similar to what gtrdone said. When I install the pistons using the rod heater, I wait about ten minutes to let them cool off a little and then I squirt some assembly lube on the pin and it wicks in like soldering a pipe. I have never had an issue doing it this way.
I bet once your guy removes the pistons from the rods he will find some hot spots on the pins.
Personally I think that a lot of unexplained rod bearing failures are from pins geting tight and not allowing the rods to pivot freely.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
06-15-2011, 08:18 PM
#22
Geronimo36
Gold Member
I assume you're not re-using the rings?
Take your rings and pull them apart. They should crack in half pretty easily. If then bend and don't break the cylinders saw a ton of heat.
Take your rings and pull them apart. They should crack in half pretty easily. If then bend and don't break the cylinders saw a ton of heat.
06-16-2011, 08:59 AM
#23
Registered
Thread Starter
Thanks again for all of the great input. As far as detonation, it is an efi motor with a knock sensor that is supposed to send a signal back through the MEFI-3 to make adjustments.
I am no engine builder, but are guilty of researching things to death. seems to me that the initial clearances/lubrication of the wrist pins may have been the culprit.
With any luck, we will be putting itback in on Saturday and getting it out onto a local lake. leaving with it on Sunday for lake of the Ozarks for the Midestboatparty.com Support our Troops Poker Run.
I am no engine builder, but are guilty of researching things to death. seems to me that the initial clearances/lubrication of the wrist pins may have been the culprit.
With any luck, we will be putting itback in on Saturday and getting it out onto a local lake. leaving with it on Sunday for lake of the Ozarks for the Midestboatparty.com Support our Troops Poker Run.
06-25-2011, 08:58 PM
#24
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Join Date: Oct 2009
Location: Madison, Wisconsin
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I'm No builder But......
I just went through the same issue. Unfortunatly, I lost the whole unit, block and all. My EX- Marina rebuilt due to a cam lobe, and when they installed the new build, the oil line was pinched a bit and destroyed the new cam, mains, crank, and a couple of rod bearings. Oh yea, and the tainted oil did kill the pins also. Do yourself a favor and take a real close look at the piston skirts for any signs that metal be driven into them.
Best of luck and I feel your pain. Mine pain was 9K worth of learning the lesson that when you want somthing done right,,,Do it yourself!
Best of luck and I feel your pain. Mine pain was 9K worth of learning the lesson that when you want somthing done right,,,Do it yourself!
