Wrist pin bolt

Topics Last Day Last Week Tree View    Getting Started Formatting Troubleshooting Program Credits    New Messages Keyword Search Contact Moderators Edit Profile Administration
Model T Ford Forum: Forum 2013: Wrist pin bolt
Top of pagePrevious messageNext messageBottom of page Link to this message  By Rick Goelz-Knoxville,TN on Friday, January 11, 2013 - 07:15 pm:

Does it matter which way the wrist pin bolt is installed? facing or away from the cam. Thanks

Rick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Daron - Brownsburg IN on Friday, January 11, 2013 - 07:40 pm:

Generally they go on the cam side. (they will run the other way)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Friday, January 11, 2013 - 11:40 pm:

One could say that it does matter, but it doesn't matter enough to really matter. The argument has to do with the angle of thrust at the time of the power stroke relative to the stresses on the rod and a few other related things. I have always been told that the wrist pin bolt goes on the cam side. However as I visualize it, that may not be the best way.
This really could turn into quite a debate. I would be curious to read what Herm has to say about it.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Saturday, January 12, 2013 - 12:32 am:

I have always turned the bolt away from the cam side, and put the bolt on the piston expansion slot side.

That would be the least thrust side. But as Wayne said, it doesn't make any difference what side, but make them all a like.

Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Saturday, January 12, 2013 - 12:38 am:

The most important thing I left out, DO NOT use any repro wrist wrist bolts, they are NOT any good. Use good Originals!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd on Saturday, January 12, 2013 - 11:46 am:

Ford called for the bolts to be on the camshaft side.
See the Ford Service Bulletin book page 42


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Saturday, January 12, 2013 - 12:56 pm:

Yes, that is right, but it was used as a point of assembly so the rod and piston got put back in the same as it was, that you didn't have it backwards for the way it had been running.

And when you replaced a rod, you wanted the replacement in the same relationship as the other used 3.

They could have just as easily made them all the same the other direction.

There was no other reason then uniformity in assembly.

If you are using the same rods, and pistons, you have to assemble the same way back, even if there is a mixture of directions, as is many times the case.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, January 12, 2013 - 01:33 pm:

Put them in the way the instructions say, later if you read the same instructions you will not have the question, which way did I put them in and was that right.
"The most important thing I left out, DO NOT use any repro wrist wrist bolts, they are NOT any good."
Why?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Saturday, January 12, 2013 - 02:42 pm:

They break, had two go in one engine, first time we used them, as customer had ordered his own parts. They were torqued the same as Fords wrist pin bolts, 30 foot pounds. They lasted 600 miles.

He was lucky to find them, when he pulled the bottom plate off, as there was no reason, but to just look and check things out.

They were not tempered right!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Saturday, January 12, 2013 - 03:47 pm:

Did the bolts break on rods that were orented correctly or just the ones you installed backwards?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Saturday, January 12, 2013 - 04:47 pm:

I am not sure what you mean backwards.

The bolts that were repro's broke!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Saturday, January 12, 2013 - 06:59 pm:

I need to reiterate the "don't use repro wrist pin-bolts". I used replacement modern grade 8 bolts on one engine. Herm, yours lasted 600 miles? Mine went about 300 miles before I developed a wrist-pin knock. I had had one before and was sure it was not a rod bearing. On a long, steep hill, I lost number one rod in the middle of an endurance run. I got the car towed to the motel, and spent a couple hours tearing the car apart and putting it back together. (The funny part about it, is that was the only time I ever took a spare rod with me, and the only time I ever lost a connecting rod bearing.)
I replaced the rod with my spare, which by chance happened to also have the stripped almost threadless wrist-pin bolt on it. It took longer to get the piston and rod apart than to tear down and reassemble the rest of the engine. Fortunately, my spare rod had a good original bolt in it. Working up through the bottom of the three dip pan, I checked the other three wrist-pin bolts. They were all tight.
Although technically disqualified because we did not quite complete the first day, the next morning, we continued on the run. I knew they were tight, but was concerned about the other three wrist pin bolts because of the one I had changed. We started off running great, and with no sound of a wrist-pin knock. Within thirty miles, I could hear it. Another wrist-pin was beginning to make some noise. It continued to get worse. At a routine stop, I looked ahead on our map. We were already technically disqualified as a DNF (Did Not Finish), so we took about five short easy miles alone to cut about forty hard hilly miles off the route. We rejoined the route with about twenty easy miles to go. Drove real easy and crossed the finish line knocking pretty good. Several people commented about my knocking rod.
I had driven the car to the start and was planning to drive it home. Instead I bummed a ride home, left the knocking car at a friends house, and returned a couple days later with my trailer.
The next weekend, I tore the engine down again. Replaced the other three wrist-pin bolts with originals after checking over the rest of the engine. No apparent damage done. The car served me well for a few years and last I heard, still sounds good.
I had used the new bolts because I was almost out of originals. These bolts were recommended to me by an engine rebuilder. As I said, they were grade 8. The final score was three of the four bolts neatly stripped threads off and became loose. One had not scraped the threads off, yet (a couple threads already broken). They were getting ready to let go. And that in less than 500 miles. I have since bought enough bad rods at swap meets just for the bolts that I will hopefully never use a modern replacement again.
Model Ts are tough! In more ways than one.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money - Braidwood, IL on Saturday, January 12, 2013 - 07:17 pm:

Counterfeit Grade 8 bolts?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Saturday, January 12, 2013 - 07:25 pm:

Doug M,
I have asked myself that question. I just know that I don't trust some modern things.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Saturday, January 12, 2013 - 10:45 pm:

Harder is not necessarily better! Harder bolts are more brittle, hence the thread failure.
I don't know, but I'll bet REAL grade 5 bolts would do the job.


Posting is currently disabled in this topic. Contact your discussion moderator for more information.
Topics Last Day Last Week Tree View    Getting Started Formatting Troubleshooting Program Credits    New Messages Keyword Search Contact Moderators Edit Profile Administration