As usual, the search engine on this site doesn't work for me = it hangs up. Another Model T website's search engine does work, but nothing useful came up. Also, photos found through a "Google" search contradict each other. So, once again I turn to this site's experience for help with a simple question.
Q: A friend's early engine I am working on apparently has a reground camshaft, as there were the usual three thrust washers on the camshaft nut's snout: one thick brass washer and two thin steel ones. Unfortunately, after I removed the front timing gear cover and tipped the engine, the oil-covered washers fell onto the floor before I could note their orientation. (The way this poor engine had been assembled, I wouldn't trust their orientation anyway!) The engine is now going back together and I need to determine the order of the washers. Some photos from vendors and on-line snapshots show them in a sandwich orientation with the brass washer in the middle. Others show a drawing with the brass washer against the special camshaft timing gear nut. This kit has the brass washer with grooves in it, not the kind with a "step" that locks against the nu's square shoulder. No dealer's instructions or drawings specify the order of washer installation, only that approximately a .005" endplay should be achieved.
I don't have the parts here to examine them. If there are grooves on only one side of the brass washer, which way do they go? If there are grooves on both sides, ignore this question.
I can see arguments for all combinations of orientation, but I'd prefer to install the washers the best way.
By the way, there's nothing in the MTFCA engine manual to help with this question.
The front camshaft bushing is the thrust washer.
Larry, on 09-24 camshafts, the front camshaft bushing won't work as an axial thrust when the cam shaft is reground.
Marshall, the logical order is the hard steel washers to each side and the softer bronze washer sandwiched in between. That's how I made mine, though I made a delrin plastic washer instead of bronze.
Just check so the hole in the middle is big enough to go over the large radius on the timing gear nut in all the washers - someone may have used odd sizes so that only one of the steel washers works towards the nut?
The rough surface on the inside of the timing gear cover calls for something hardened towards there, not a soft washer that'll be chewed up.
(Message edited by Roger K on April 13, 2017)
First, there is no such thing as the "usual three thrust washers". Those are fixes to accommodate the fact that the cam has been ground down such that it no longer contacts the intended thrust surface on the front cam bearing, (that Larry refers to).
Putting those 3 washers back, sandwich the bronze washer between the two steel ones. The bronze will wear better against the hard steel washers than against the cast iron front cover or the timing gear face.
Larry knows that. He assumes everybody uses new-old-stock parts and has no advice for anyone who does not.
'Sorry. By "usual", I was referring to the three washers that come in the camshaft thrust kit sold by the vendors. I realize that there is more than one way to skin a cat, meaning some guys could make their own thrust washers or equivalent. The washers in this engine match those shown in the vendors' kits, which I would guess most guys buy rather than make themselves.
Thanks to all for the replies. The consensus is to make a brass washer sandwich!
Sorry if it sounded as if I were chastising you for your wording. I didn't mean it that way.
I'm a little confused on this topic. How about a few pictures of the area that shows what you all are talking about? I can see where the front camshaft bushing keeps the cam from going back. As far as the cam moving forward, the front bushing seems to restrict that movement too (as I remember). Doesn't the front lobe of the cam restrict it from going forward? Are you guys talking about installing washers just behind the timing gear cover? In front of the special nut that holds the timing gear on?
I am with you Verne, never have seen any washers with the cam bearings I have bought from our vendors and cannot visualize a space for them to fit. Pics and diagrams would help for inquiring minds.
There is no Front Camshaft Bushing. There is a Front Camshaft Bearing. This bearing has a notch in the rear for clearance for the front lifter. When a camshaft is reground the heel of the front lobe is ground down to restore lift. This allows the toe of the front cam bearing to move forward when the front lobe lines up with the notch in the rear of the front bearing. This was the source of many knocks in the engine until we designed the thrust washer packs to prevent this knock. We made new cam nuts without a radius so the front steel washer could ride against the front of the nut. The second steel washer goes against the inside of the timing cove with the Bronze washer in between the two steel washers. The thickness of the bronze washer is adjusted for a small amount of clearance. This prevents the front cam lobe from entering the notch in the rear of the front cam bearing and causing a knock when it tries to exit the notch. Hope this helps. Glen
It sure does Glen, thank you!
Thank you, Glen. Perhaps your explanation is included with the stack pack when new, but this engine came to us in the car already assembled. I was aware that a re-ground camshaft needed such thrust washers, but was not sure exactly why until I read your excellent explanation. How about including that on a small piece of paper with your stack pack? Or do you do that? Sometimes understanding the "why" is as important as the "how".
I have encountered enough T's that have excessive camshaft end play, and some of the suppliers have recognized the need for a method to stop the knock/rattling sound this causes. Hence the availability of the washer kit I believe you are inquiring about. You have received sufficient information about how Henry managed it (which I suspect has been of no usefulness)!!
I believe it has been suggested that you install the steel washers at each end of the washer pack and put the bronze washer in between. I concur. I feel that a total end play of.005-.010 would be a reasonable target. So stack the washers as suggested and install the front cover and measure the end play of the cam. Oh and remember to centre the front cover about the camshaft (buy, borrow, or make a centering tool)
I hope this is the information you were after!!!
Yes, the comments were helpful and my questions were answered. I do have the timing gear cover centering tool and will use it to seat the front seal.
Thanks again to all who participated in this discussion!
I still do not understand where those washers go, is it on the cam before the bearing, between the gear and the bearing....... A diagram would be helpful. Eliminating strange knocks is a good thing!
Chaffin's kit includes the cam gear retaining nut, made to accept the washers which go on that nut and gauge clearance between the inside face of the gear cover and the cam nut.
I think the info is in the currant catalogs but in case, the thrust washers go between the gear and cover.