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03-03-2024, 12:07 PM | #1 |
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Adjustable Lifters
I’m sure that this isn’t a new topic but I wanted to start fresh and lay out what I’m thinking. I’m working on a ‘51 F-1 and when it came time to adjust the valves I found some problems; namely, several lifters had apparently adjusted themselves but one of them, the adjustment screw was fully bottomed out and was quite tight with about .100 clearance. When I backed the adjuster out I found that it was very loose the the point that I could “wiggle it around”. There’s no question that that one will do the same thing it did before in a very short time. The motor only has maybe 3,000 miles on it since a complete rebuild but it has been sitting for 40 years since the rebuild. The cam and lifters were installed new at the time of the rebuild. And yes, I’m aware that the lifter’s are not going to adjust themselves while the engine is sitting so that means it did not take long to reach the point it is at now.
(1) My first thought was to change all the lifters and after adjusting them use the wicking type of thread locker. (2)But then it occurred to me that I don’t think you can use new lifters on a used cam? (3) Does anybody know why Johnson didn’t design their lifters to use a jam but? (4) I can remove all the lifters, clean them up real good and then, after adjusting, use the thread locker (I still don’t like that one that is so loose, I don’t think the thread locker would be enough on that one. (5) Some of the lifters have enough threads showing that a thin jam nut could be used (but some don’t), has anybody done this? (6) If jam nuts are a good way to go I could grind the end of the stems to make room for the jam nuts? (7) I also am a wee bit confused that same of the lifters appear to go farther down into the boss then others. Some can be adjusted at the lowest point but some require rolling the cam until the screw comes up so it can be adjusted and then rolled back down for a measurement? (8) I know that many think that the only long term solution is to do it Ford’s way but since I don’t weld nearly well enough to be working on valve stems. |
03-03-2024, 12:37 PM | #2 |
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Location: upstate SC
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Re: Adjustable Lifters
I had sort of tthe same problem with some old johnson adj. lifters, i ran the adjustment all the way out and "staked" the threads on the adj. part and then adjusted the lifters, that was a lot of miles ago and I have not had the problem
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03-03-2024, 04:50 PM | #3 |
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Re: Adjustable Lifters
You better get the cam out and inspect for excessive worn lobes.
You are going to need a new set of lifters no matter what and that is another set of headaches. Consider using Stock steel OEM lifters and adjusting valves like original factory. If lobes are worn excessively, the engine will have to come down to bare block cleaning and complete start from scratch. |
03-03-2024, 05:11 PM | #4 |
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Re: Adjustable Lifters
If it were mine, and if it has stock valve springs with their low tension, I'd not worry one bit about running a new or reground set of tappets on that cam. Pete's correct in suggesting stock steel tappets and adjusting them per factory method.
Yes, best plan is to have a look at the cam lobes. Otherwise it's a guess...in your favor I think, if stock cam and springs.
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"It don't take but country smarts to solve the problem" (Smokey Yunick) '41 Merc Town Sedan / 260" 8CM engine '66 Fairlane four door / "warmed up" 302 |
03-03-2024, 08:26 PM | #5 |
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Re: Adjustable Lifters
Like Pete said, I would expect some worn lobes. You could take the heads off and check valve lift with a dial indicator. Worn lobes would show lesser valve lift.
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03-07-2024, 01:02 PM | #6 |
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Re: Adjustable Lifters
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03-07-2024, 02:09 PM | #7 | |
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Re: Adjustable Lifters
Quote:
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03-07-2024, 08:01 PM | #8 |
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Re: Adjustable Lifters
.350 is fairly typical for a 3/4 cam. The 8CM Merc has .331.
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