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By Gordie T - 17 Years Ago
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I'm just getting to know my 292 in my 1958 Fairlane. When setting the valves I noticed the exhaust valve on #4 was hardly rising at all. My push rod turns and looks ok..could my tappet be bad or have I lost a cam?
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By Hoosier Hurricane - 17 Years Ago
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If it was a worn tappet, once you set the clearance the valve would again lift normally. You have a worn out cam lobe, but the lifter is also damaged. Replacing the cam and lifters is the proper fix. John in Selma, IN
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By Gordie T - 17 Years Ago
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Thanks J Should I do all the tappets and push rods and cam at the same time? Or just wait for more to go wrong and do the whole engine, rockers, springs gaskets...when I have no get upand go Gt
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By HT32BSX115 - 17 Years Ago
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Howdy,
I had a similar problem with my OMC 460 King Cobra Stern Drive.
I noticed that it wouldn't make full power and discovered that I had several flat lobes on the cam.
There just isn't anything you can do short of replacing the cam and lifters. It's very possible that the cam was never broken in properly or the engine is just plain worn out.
There's some argument for using an oil that high levels of ZDDP which is a good anti-wear additive for reducing camshaft wear.
In anycase you need to replace the cam and lifters.
Regards,
Rick
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By mctim64 - 17 Years Ago
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Sounds to me like you have a cam going flat, cam and all lifters should be replaced. If your engine is getting a little tired it may be the time to go through the whole thing but that is up to you. When you do change the cam Definitely put a "Zink" addative in the break-in oil, the latest automotive oils don't have the lubricating properties for old flat tappet cams. Comp., Crane, and others make the addative and they are readily available at most speed shops and whearhouses like Summit and PAW. Just wanted to add that, atleast the last I heard, diesel oils such as Delo and Rotella still have the zink in them. Tim
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By Ted - 17 Years Ago
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Use of a dial indicator on the pushrod end and checking the lobe lift is the definitive method for determining the lobe wear. But if you can physically observe that the pushrod is not rising is high as the others, then camshaft lobe wear is at the top of the list. When either the lobe has enough wear to either destroy the rake on the lobe or the lifter has worn enough to lose the crown on the lifter face, then the pushrod will not normally turn or spin when the engine is running.
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By Gordie T - 17 Years Ago
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Thanks for the good ideas. Is there a way to repace the lifters in my 292 from the top? If I used a long magnet would they come out the pushrod hole if I moved the rocker arm to the side? Gt
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By oldcarmark - 17 Years Ago
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Gordie:Unfortuneatly they will only come out the bottom.There is a mushroom end that rides on camshaft and will not come out the top.One of the few design problems with the y-block.
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By PF Arcand - 17 Years Ago
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Which of course brings up the question of changing the cam & lifters in chassis. Considering the mushroom lifter situation, & other probable obstructions, I've never tried to do it, or know anyone who has done it in chassis. Can we assume that it's a real challenge to do?
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By Hoosier Hurricane - 17 Years Ago
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Paul: Yes, you do know someone who has changed lifters in chassis--me. At the time my brother in law worked at a Ford dealer and borrowed the tools to do the job. Very tedious, took me longer than if I'd pulled the engine and turned it upside down. And in the process, I knocked the rear cam plug almost out, and it came out while test driving the new cam. Had to pull the trans, bell, and flywheel to replace it. That's the only time I've done it that way! John
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By Gordie T - 17 Years Ago
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Thanks for the heads up on the mushroom lifters. We were going to try to do it in chasis, ...rad out, water pump off etc...I guess I'll keep driving it the way it is. I don't go over 90 that often anyway...steering is too loosy goosy... G
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By mctim64 - 17 Years Ago
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You can still do this in-frame, you have to have the pan off and get a set (16) of old wooden style clothespins. With everything apart like you said, pull the lifters up and clip a pin on each one. When they are all up pull the cam out. Then let the lifters down one at a time and replace them wit a new one, holding it in place with the clothespin. Then after coating the new cam with cam-lube slip it in, releese the lifters, and reassemble. If you are not familiar with the Y-block be sure you read how to time it, YOU DO NOT JUST LINE THE DOTS UP. Good luck! Tim
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