Scat rods

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Model T Ford Forum: Forum 2015: Scat rods
Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Bender Tulsa Oklahoma on Monday, April 27, 2015 - 11:07 am:

Scat has made rods for the T model that allows the use of pistons made for our engines. The problem to over come deals with the wrist pin would be full floating, no wrist pin bolt or snap rings in the piston, which is not a good thing.

It has been suggested to make a button that slips into the piston/wrist pin stopping contact of the cylinder bores. Common practice with drag racers but they are luckily to get 3 weekends before going back into their engine.

Another option, my idea, maybe not a good idea, is drill and tap a set screw with a lock nut keeping the wrist pin from moving.

Anyone use a set of these rods and what did you do to correct this. Your input is welcome.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Gruber- Spanaway, Wash. on Monday, April 27, 2015 - 11:13 am:

Aircraft engines commonly use an aluminum plug at each end of the wrist pin.
They run a couple thousand hours without being looked at.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary Tillstrom 30 miles N of Memphis TN on Monday, April 27, 2015 - 11:32 am:

Bob is correct. You can pull one down after a couple thousand hours and you won't even see the contact point in the bore. I would much rather run a full floating pin than to drill it for a set screw.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary Tillstrom 30 miles N of Memphis TN on Monday, April 27, 2015 - 11:34 am:

I meant to say that airplane pins have an aluminum plug in the end. Let me know if you want me to mail you a scrap one.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Lay,,,,,,,,,,,,,,Lancaster Ca. on Monday, April 27, 2015 - 11:37 am:

VW builders also use a plug. I think it is made of nylon but I'm not sure.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Monday, April 27, 2015 - 11:40 am:

In the sixties my 327 Chevy engine in a glass replica A was spun hundreds of times at 8000 rpm with Teflon plugs on a floating pin. The engine blew up after selling the car while being dino tested. I don't know what happened.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, April 27, 2015 - 11:41 am:

Maybe teflon plugs would work too?
Easy to make in a lathe:
teflon plugs
(picture from the net)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Monday, April 27, 2015 - 12:19 pm:

I would trust Teflon as the melting point is high

I think the melting point of nylon is too low to trust

Another option is machine grooves for circlips like the pistons used with A rods


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso - Milton,WA on Monday, April 27, 2015 - 12:51 pm:

I believe Les' option for machining grooves for circlips to achieve a floating pin would be the most sound but clearly not as inexpensive as Teflon buttons.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Monday, April 27, 2015 - 01:06 pm:

My Model N uses aluminum buttons in the ends of the wrist pins. So far, no problems but not a lot of miles either.

(BTW, The NRS cars didn't normally use the buttons. The wrist pins were clamped by the rods, like in a Model T)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Monday, April 27, 2015 - 01:06 pm:

If you can do it yourself its cheap enough
Yes you will need to make a fixture so you can spin it in the lathe, but after that it is cheap (and a potential to charge others to "fix " theirs


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Bender Tulsa Oklahoma on Monday, April 27, 2015 - 01:33 pm:

Thanks for the feed back. I can make the plugs myself. Cutting a groove for a snap ring is not something I would do as that is above my pay grade. LOL.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Penserini on Monday, April 27, 2015 - 02:00 pm:

This Scat flyer shows Teflon buttons are included with the rods.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Monday, April 27, 2015 - 02:01 pm:

Mike
A expanding arbor to grab the piston on one side
A small cutter in a boring bar.
"Dial in" your digital readout so you cut the groove in the same place and same depth every time
Spend some time on this for the first groove, then repeat 7 more times!! Probably a mornings work Most of that making the fixture. I would "test it" on a old junk piston (old cast iron with bronze bushing)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Bender Tulsa Oklahoma on Monday, April 27, 2015 - 05:38 pm:

Mike thanks for the ad. I have three sets for a couple of years and were first production run as I return them to have the correct size bushings installed. They were given .750" dia on the wrist pin. Think I will contact them and see if they can ship me three sets.

Les you are correct it can be done.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Monday, April 27, 2015 - 08:37 pm:

High performance production MOPAR engines used a lock ring in grooves machined in the pin bore in the piston.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Sullivan on Wednesday, April 29, 2015 - 02:00 am:

Old Caterpillars used aluminum plugs, lasted forever


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Wednesday, April 29, 2015 - 11:55 am:

The Maytag 72 motor I had used the buttons also. I think they were steel but same idea.


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