Should this camshaft be replaced?

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Model T Ford Forum: Forum 2015: Should this camshaft be replaced?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Tuesday, August 25, 2015 - 06:25 pm:

After checking the lift on this camshaft, I get values ranging from .237" to .245".

The MTFCA engine book says the difference in lift between cams should not exceed .005". This camshaft is showing a .008" difference.





For a car not intended to go on long tours, would this camshaft give decent results?

Could it/should it be reground?

The engine seemed to run pretty well before the teardown. I haven't driven a lot of other T's so I don't have a lot to judge its performance against.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Tuesday, August 25, 2015 - 08:06 pm:

It is borderline. But (in my highly questionable opinion) would probably work okay for quite some time.
Yes it should be properly reground. Most good engine/machine shops should be able to do it.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Moorehead on Tuesday, August 25, 2015 - 08:53 pm:

Assuming it has not been reground before, send it to Chaffins and it will make the car run very well, assuming the rest of the engine is OK.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould, Folsom, CA on Tuesday, August 25, 2015 - 08:56 pm:

.008" variation wouldn't trouble me.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Walker, NW AR on Tuesday, August 25, 2015 - 09:36 pm:

Me either. And since some of the lobes are at .245, they're hardly worn at all. For an engine with which I would be doing a lot of touring for many thousands of miles, I'd use a better cam. But for an occasional-use car, that cam will work for many years.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erik Barrett in Auburn Ca. on Tuesday, August 25, 2015 - 10:02 pm:

I have taken apart many engines that were running well and found cams far worse off than this one. It's not in great shape, but it will run fine.


Top of pagePrevious messageNext messageBottom of page Link to this message  By bob middleton on Tuesday, August 25, 2015 - 10:36 pm:

Agreed I have ran worse and they run great just little more effort fitting valves


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Tuesday, August 25, 2015 - 11:51 pm:

If you have the engine apart I would have it reground or replaced. A good cam will make quite a difference in engine performance. With a worn cam you can set the valves by the KR Wilson piston timing method. This will give the best performance but usually with noisy valves.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Wednesday, August 26, 2015 - 01:47 am:

I'll take it to the machine shop for grinding to .250

Thanks all for your input.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Wednesday, August 26, 2015 - 10:22 am:

The average cam re-grinding shop might not give you anything better than what you already have...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Wednesday, August 26, 2015 - 11:54 am:

I started work on this car because of a cracked transmission drum (low) and it has turned into a ground up restoration which the car needed anyway. It ran and drove OK before so I have been surprised to find that so many parts have had to be replaced or repaired and I've gotten to the point where I assume that everything is worn out. Maybe the camshaft is one of the parts that isn't ready for the scrap heap? :-)

Adam, I haven't talked with the machine shop yet. Are you saying that the cam grinding is a specialized process and that if it is not done exactly correctly then the grinding may not bring any marked benefits?

My thinking was along the lines that the lowest cam lift value would go from .237 to .250 and that would be a marked improvement.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Justin in South Africa on Wednesday, August 26, 2015 - 12:06 pm:

Hi Eric,

Check out this link, and the others... very good info.

http://www.tildentechnologies.com/Cams/CamHistory.html

Might help your cam grinder get it right etc.

Also,please check your two babbit bearings and rear bushing for clearance.

Your measurements on your cam lobes remind me a lot of mine! My bearings and bush were also out. Chaffins sorted me out... Made an amazing difference,

Hope this helps,
Justin

South Africa,


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Wednesday, August 26, 2015 - 12:24 pm:

I replaced the cam bearings many years ago but the car hasn't done much driving since then.

The end play is .016 (maximum permitted is .004) so I thought the machine shop might be able to take up the play somehow. If the wear is in the camshaft a new front cam bearing won't do me any good since it may not be any longer than than the one I have now.

Justin, thanks for the extensive cam information. That should be handy to decide if I grind or not!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Justin in South Africa on Wednesday, August 26, 2015 - 12:53 pm:

No worries Eric

Just fyi. If you do grind the ,238" back to ,250" your end play issue will get worse because you will need to grind the heel of the cam smaller to get the lift right. The cam tends to walk forward and would stop against the heel of the first cam lobe but now that will be almost all ground away. So it will walk further and you'll get a knock as the lobe hits the notch on the cam bearing. Hope that makes sense.

The simple answer then is to get a camshaft thrust kit. See chaffins catalog. It would be possible to make your own up in Spain., but there probably is no replacement for the original.

If you need help, let me know.

Cheers
Justin


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