I posted this in the touring forums also because they tend to really run a lot of miles
I have been reading "Donny Petersen's Unauthorized Technical Guide to Harley Davidson 1936-Present the twin Cam" In the second book of this series he really puts a lot of emphasis on possible wear or "ovaling" of the rear outboard cam bearing. This is in fact a "Parent Material Bearing" which he feels is an area that TC96 owners should be watching. My question is, have any of you 2007 or later TC96 owners, who consider themselves to have high milage on their engines, had any difficulties with the cam support plate? Also report what type of Oil you are using. Just curious.

 

36k miles, no cam plate wear issues, Amsoil 20-50.

The only problem I had with the cam support plate was getting the bolts holding the tensioners off!

 

I have a customer with 25,000 on a bagger no probs. The bike runs Mobil OneSyn. 15/50

But I agree with Donny. You should be aware of that. Have your bike shop you go to or your self check it out. Take it apart if you have conserns and see for your self.

I hope this helps,

 

I have not read the book so was wondering what he says is the reason for this ovaling problem and why only the rear?I believe they have been using this type of bearing in the auto industry for some time now and they hold up well.

 

Upgrading cams at 26,000 miles, and absolutely no wear whatsoever on the rear cam bore. Very slight wear mark on the front cam bore from 6:00 to 12:00 area.

Slight wear on the front tensioner shoe, nothing on the rear.

Mobil 1 V-Twin 20w-50.

 

Running stock motor except exhaust/intake, and a PC III. I have about 20K miles on my Super Glide and have been using Shell Rotella oil regularly. I haven't had any issues with the motor or spots of concern for wear up to most recent oil change.

 

Moment Arm Torsional Forces. I am really only on the 50th page of the book. The reason that I asked about real world problems is that even though I am not deep into this book yet he has already mentioned this numerous times and has a whole section of the second chapter devoted to this "theory" as he calls it. It is readily apparent that he does not trust the "Parent material bearings."
I was just wondering if anyone had really had any problems.

I almost forgot, It is the rear cam bearing that caused all of the problems with the 1999-2000 early twin cams. Proportedly from the same condition. It seems that the original Ball bearing design could not stand the very same forces that he is concerned about. However the front bearing being driven only by the chain from the rear cam is not subjected to the same forces.

 

There have been changes that make a comparasion difficult at best.
Also what happens when the user goes to a high lift cam and 50% heavier valve springs. Not uncommon.

 

That is primarily his focus is. This second volume in the series is "Performancing the Twin Cam" However, he does not restrict his concern for just higher performance motors. Donny feels we all need to keep a weather eye out for undue wear.

 

Well folks, just so ya know, the auto manufacturers have been using "parent metal" bearings on their overhead camshaft engines for many years. With NO problems. As long as there is a constant oil supply to the cam journal, there will not be a failure. That is one reason the newer HD's have a higher volume oil pump, and idle faster, than before. I've got 65K miles on my '03 with a big bore kit and cams and I have 35K miles on my '07. Absolutely no problems with either bike. There is a lot of difference between a theory and practical application. I run HD dino oil in the '03 and HD Syn3 in the '07.