Lifter Problem

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Steve Simmons
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Lifter Problem

Post by Steve Simmons » Fri Sep 27, 2013 11:37 am

TC8975 had a complete engine rebuild recently (about 5k ago). When it was fired up, the tappets appeared to be rotating normally. Upon inspection yesterday I realized that is no longer the case. A couple of them are pitted and a few others show signs of no rotation at all. The cam and lifters were re-ground at the time of rebuild (against my better judgement) on the advice of my machinist. He assured me the hardening on the lifters would be thick enough. The cam was ground with an angle on the lobes, and the lifters domed.

Now the question on what to do. I'm wary of driving it the way it is, even for my short (500 mile) trip next weekend. In the interest of getting the car on the road in time for the trip, and assuming the cam looks ok, would you replace the lifters and hope for the best?

Opinions welcome.

Here is a photo of the lifters (click image to enlarge) and one of the only place on the cam (side of #7) where I saw any problems. The spot on the cam is slightly rough.
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XPAG Lifters
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1949 TC8975 / XPAG 9609
1948 TC6011 / XPEG1182 (XPAG6472)
http://www.mgnuts.com

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stephen stierman
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Re: Lifter Problem

Post by stephen stierman » Fri Sep 27, 2013 6:08 pm

Sorry to say given the condition of those lifters, I would replace them all along with the cam. I would be suspect of the grinding job that caused this.

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Steve Simmons
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Re: Lifter Problem

Post by Steve Simmons » Fri Sep 27, 2013 6:31 pm

I suspect the problem was grinding through the chill hardening. The machinist was confident that it would be thick enough, I wasn't so sure. I foolishly differed to his expertise. The grinding work was done by a very reputable shop in Southern California. I'm sure they were just doing what they were told.

Until I saw the cam, I was considering putting it all together with fresh oil and driving on my trip next weekend. Now I'm not so sure that's a good idea.
1949 TC8975 / XPAG 9609
1948 TC6011 / XPEG1182 (XPAG6472)
http://www.mgnuts.com

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olson_gene
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Re: Lifter Problem

Post by olson_gene » Fri Sep 27, 2013 7:34 pm

Until I saw the cam, I was considering putting it all together with fresh oil and driving on my trip next weekend. Now I'm not so sure that's a good idea.[/quote]

I would think if you put it together (good lifter on the worn cam bit) it would go 500 miles. Not likely to be a catastrophic failure, just get more wear, and If you are going to replace them anyway, might as well get some more wear.
on the other hand, I happen to have a set of lifters and a stock cam sitting in my garage.
Gene Olson
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Steve Simmons
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Re: Lifter Problem

Post by Steve Simmons » Fri Sep 27, 2013 8:01 pm

I'm more worried about the particles circulating through a new engine, but maybe that's overly cautious.

Want to come put a cam and lifters in while I work this week? ;)
1949 TC8975 / XPAG 9609
1948 TC6011 / XPEG1182 (XPAG6472)
http://www.mgnuts.com

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stephen stierman
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Re: Lifter Problem

Post by stephen stierman » Sat Sep 28, 2013 4:48 am

[quote="Steve Simmons"]I'm more worried about the particles circulating through a new engine, but maybe that's overly cautious.

That would be my fear and I would not risk it, even with a good filtration system.

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