Cam sprocket flip

TooManyToys · Nov 13, 2018

At my old facility I had a press and flipped bearings in knuckles occasionally, now retired, no press. And I've never had to press off/on a cam sprocket in my life.

The little garage by my wife's business has done bearings in knuckles for me, but not that interested in flipping a sprocket on an expensive cam. A friends local machine shop who has built 6.0s is in the process of moving and can't for a few weeks. So I need to find a place that I'm not familiar with, or go out and buy a press. I might need a press only once in 5-7 years with not a lot of storage for one.

So let me ask the question for those who have done this, how problematic is this? I've read everything from a 20t press to a hot plate and it slips on/off. It's a Colt cam and I've talked to Geoff who has no hard instructions.

Zeb · Nov 13, 2018

It’s not hard to do, but takes a pretty sizable press.
I can’t give a press rating because the press I use is a BIG shop built press. It does make a pretty good bang when the cam starts to move out of the gear. Even though I have done over a dozen of them, I still jump when it bangs, and turns loose!
It’s not necessary to heat the gear up to put it back on.
First one I ever did, I put the cam in the freezer for several days, pressed the gear off the stock cam and hung it in front of a Ready Heater until I had to use gloves to handle the gear, and still had to press it on. Since then I just press it off, clean it up, and press it on the new cam.

TooManyToys · Nov 13, 2018

Thanks, I may be buying a HF 20 ton....

Close to me was a race engine shop who built up motors for people around our small local circle track. Website is still up but the building is empty. A few miles away is a PS diesel repair shop, walked in, walked out. XDP 4 miles away is hesitant to recommend anyone.

This is nuts.

Are you able to just press through the retaining plate with standard press plates?

Zeb · Nov 13, 2018

I have a couple of 3/4” thick plates that I lay across the press bed and let the cam hang between them. Slide them up almost touching the retainer. Once it bangs, and is loose, I get ahold of the cam and push it the rest of the way out.

TooManyToys · Nov 13, 2018

So you push against the gear, not the plate ....

I was going to be hyper about retaining plate engagement.

Sorry for the questions, there's nothing out there on doing this gear change other than a previous mention on this site.

Zeb · Nov 13, 2018

Correct, I push against the gear. The retainer is way too weak to withstand the pressure to take the gear off.
When I press the gear on, I drop the press bed all the way down, stack the plates on top of each other, and set the cam on them. Set the retainer on (really sucks if you forget to), set the gear on, and press it on until it hits the shoulder on the cam.
I have a piece of heavy wall tubing that the ID is just a little larger than the OD of the cam snout that I set on the gear to press against because the snout sticks thru the gear just a little. Also it puts the load on the gear right in the center, not out at the edges.
The worst part is lining the slot on the gear up with the locating pin on the cam. That always makes me a little nervous, but the gear presses on slowly enough you can watch it and make sure everything is kosher.

TooManyToys · Nov 13, 2018

Thank you for the explanation. I was starting to look at making this more complicated, making a plate that would fit within the recess between the 8 exhaust lobe and journal so the compressive force wouldn’t go through the cam. I picked a shaft collar that will clear the cam nose during the install so good there. Yep, the indexing was already a concern.

And a collar that just fits over the journal to press the plate by the gear ID that I won’t need.

Thanks again.