wrist pin clip issues

pmrphil · 03-17-2014, 08:32 PM

I've seen before when an engine is detonated hard enough it will bow the pins and push hard on the spirolox - overrev will do it also.

richie 2 · 03-19-2014, 07:08 AM

spark plugs would show signs of detonation?

toolmakeron · 03-21-2014, 01:02 AM

I haven't seen the plugs, but I was told that it's hard to see signs of detonation from alcohol engines. I don't know this, only going from what I was told. The driver / tuner would see this , I think he would know about this. I keep suspecting , on the chip in the water box. Thanks for the input guys.

Adger Smith · 03-31-2014, 02:11 AM

His alky tune up or his on & off throttle foot could be flooding the engine at some time in the run and never show up on the plugs. I'm still saying you have the combination of an abusive driver and a slightly off Alky tune up. I don't mean off at WOT. I mean off in the "Fuel Curve" when the foot is on and off the throttle.

Marine One · 04-30-2017, 02:12 PM

Have you torn it down yet to inspect for damage?

Is the damage worse on one bank vs the other? Any specific cylinders consistently worse than the others?

On the non failed clips, do they or the piston grooves show any unusual signs of wear, like four corner wear vs even wear, etc?

cjperformance · 05-02-2017, 06:39 PM

Hi all, 1st post here !
With this wrist pin damage issue, what are the rod pin bushings looking like?
Bush brand/material?
Coated pins?
AND pin/rod clearance?
I have seen where the pin clearance is too small and the pin nips in the rod, then any side movement of the piston is forcing on the pin clip and damages the clip and/or piston.

Todd Gross · 05-04-2017, 10:33 AM

I had one customers' engine that I tore down for a freshen up only to find multiple spiro loc failures. To the point of serious cylinder wall and piston damage. After digging for info I found out the previous assembler purchased his spiro locs in bulk from McMaster Carr. Needless to say the quality control ( heat treat ) may not be up to the quality of that of a Performance Piston company. I installed JE locks and 2 seasons later on freshen up, no more failures on a 700" .
I am not suggesting that that toolmakeron's engine has McMaster stuff in it, just sharing an experience*

03-17-2014, 08:32 PM	#1
pmrphil Member Join Date: Aug 2010 Location: CT Posts: 460 Likes: 1,815 Liked 348 Times in 152 Posts	Re: wrist pin clip issues I've seen before when an engine is detonated hard enough it will bow the pins and push hard on the spirolox - overrev will do it also. __________________ Phil Molski PMR Performance S/C 1623

03-19-2014, 07:08 AM	#2
richie 2 Senior Member Join Date: Feb 2009 Posts: 971 Likes: 426 Liked 205 Times in 93 Posts	Re: wrist pin clip issues spark plugs would show signs of detonation?

03-21-2014, 01:02 AM	#3
toolmakeron Junior Member Join Date: Oct 2013 Posts: 15 Likes: 0 Liked 0 Times in 0 Posts	Re: wrist pin clip issues I haven't seen the plugs, but I was told that it's hard to see signs of detonation from alcohol engines. I don't know this, only going from what I was told. The driver / tuner would see this , I think he would know about this. I keep suspecting , on the chip in the water box. Thanks for the input guys.

03-31-2014, 02:11 AM	#4
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: wrist pin clip issues His alky tune up or his on & off throttle foot could be flooding the engine at some time in the run and never show up on the plugs. I'm still saying you have the combination of an abusive driver and a slightly off Alky tune up. I don't mean off at WOT. I mean off in the "Fuel Curve" when the foot is on and off the throttle. __________________ Adger Smith (Former SS)

04-30-2017, 02:12 PM	#5
Marine One Junior Member Join Date: Mar 2010 Location: Indiana Posts: 69 Likes: 2 Liked 0 Times in 0 Posts	Re: wrist pin clip issues Have you torn it down yet to inspect for damage? Is the damage worse on one bank vs the other? Any specific cylinders consistently worse than the others? On the non failed clips, do they or the piston grooves show any unusual signs of wear, like four corner wear vs even wear, etc? __________________ Chad Sheets \| STK 319 \| 10.69 \| 1.39

05-02-2017, 06:39 PM	#6
cjperformance Junior Member Join Date: May 2017 Posts: 1 Likes: 0 Liked 0 Times in 0 Posts	Re: wrist pin clip issues Hi all, 1st post here ! With this wrist pin damage issue, what are the rod pin bushings looking like? Bush brand/material? Coated pins? AND pin/rod clearance? I have seen where the pin clearance is too small and the pin nips in the rod, then any side movement of the piston is forcing on the pin clip and damages the clip and/or piston.

05-04-2017, 10:33 AM	#7
Todd Gross Member Join Date: Mar 2016 Location: Crete, IL Posts: 167 Likes: 260 Liked 54 Times in 24 Posts	Re: wrist pin clip issues I had one customers' engine that I tore down for a freshen up only to find multiple spiro loc failures. To the point of serious cylinder wall and piston damage. After digging for info I found out the previous assembler purchased his spiro locs in bulk from McMaster Carr. Needless to say the quality control ( heat treat ) may not be up to the quality of that of a Performance Piston company. I installed JE locks and 2 seasons later on freshen up, no more failures on a 700" . I am not suggesting that that toolmakeron's engine has McMaster stuff in it, just sharing an experience* __________________ Todd Gross 3323 FS/E,F

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