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teksid guide pin upgrade issue

2K views 5 replies 4 participants last post by  Bullitt5566 
#1 ·
I ordered a set of 8mm guide pins from cobra engineering and rtusnake was nice enough to loan me the fixture to do the job.

The install went off without a hitch, and the fixture was super nice and made the job simple.

When I went to slide my guide over the new 8mm pins, 1 side slide over no problem, but the other side I couldnt get that guide or the other guide to slide over it (as a test). Both guides would slide over the 1 pin perfectly, but neither would on the other.

So I went ahead and measured the good pin with my caliper and it showed 8.0mm on the dot from the tip/chamfer to the base of the hex/nut. But on the other one, it measured 8.26mm at the tip/start of the pin and tapered down to 8.0mm on the dot right after the chamfer. I couldn't see any damage on the tip, and just assumed it was oversize when made.

So my question is, I tried to sand down just the top of the pin where it was oversize, but after a while I just gave up and reamed the hole in the guide until it fit over the pin. This won't be an issue with the guide as far as integrity is concerned will it? Obviously I didn't remove much material from the hole, but wanted to double check before I proceeded.
 
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#3 ·
I would have contacted Cobra Engineering first as I’m sure he would have sent you a replacement pin. I would be concerned now that there is going to be a small amount of slop since you reamed the the rail to fit over the end. Didn’t you say the base of the pin checked out at 8.0 mm? I don’t think the material removed will be an issue but the added slop now once you get past the end that was slightly out of spec possibly could be.

Ken
 
#4 ·
+1 on what Ken suggested. I am a bit confused as to why you would not have asked the manufacturer of the part about the anomaly before modifying parts or posting on a site like MF. The person best positioned to either explain the why behind the issue or correct the issue is the manufacturer. It would behoove you to start there.

As a side note, the arm you have reamed the hole on will not work as intended by Ford in that condition with an 8mm pin. You have essentially two paths before you; 1) upgrade to Cobra Engineering 9mm pins and ream the guides to fit properly or 2) ask James for a replacement 8mm pin and buy a new guide.


Ed
 
#5 ·
Yes I contacted them and let them know. I didn't ask for a replacement, but of course being a dummy i made the modification prior to contacting them, my mistake. By sanding the high spot, I got it down to 8.06mm before I decided to ream the last likely .02 to .03mm out of the guide. After it was said and done, it didn't feel anymore sloppy than the unreamed guide and pin. I didn't measure the id of the bore in the guide for the pin, but these were brand new ford motorsport guides and even on the stock pins they were never a tight tolerance fit to begin with. Don't get me wrong, they weren't sloppy like a loose bearing for example, but they are definitely not .0005" clearance tight either.
 
#6 ·
I did this upgrade on my TEKSID block after one of the pins broke. I didn't have any problems with the the fixture or the replacement pins, but I think I needed to use the 2V guide to fit the larger pin. I would get a replacement pin that is the same diameter. By making the hole in the guide fit, you still didn't fix the problem. The guide may not pivot on the pin squarely and may put all of the pressure on the area where the pin is wider. Truthfully the pins are cheap insurance against timing chain failure and I can't see why you wouldn't replace a suspect part.
 
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