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MG MGB Technical - reground camshaft

Anyone ever have any trouble with reground camshafts? Wear, short life, etc?
Bryan

yes, Bryan,

i had one regrid and trouble started with setting valve clearance soon, bent pushrods and sheered off adjusting screws soon followed.
The problem is the under dimensioned ground circle that is a result of regrinding a stock cam.
I do not know upon wear, i pulled it after a few hundred Kilometres and bought a Piper cam grid from a blank and that was worth it's price! Fitted it with a set of new followers several years ago and i am still extremely satisfied with it.
Do not waste your money upon theory, if you do not want to burn your money, buy an original grid not a regrid!

Ralph
Ralph

Bryan,

I had a reground/reprofiled early 88G303 camshaft. I installed it without taking measurements. Later on I purchased a new 88G303 camshaft and when I took the reprofiled cam out of the engine I measured the lobes and was amazed at how small they were compared to a new one. I mean small. I learned my lesson. What Ralph states above is true. Don't wast your money!

Ray
Ray 1977mgb

Bryan. Much depends on whom is doing the regrinding of the camshaft. Properly done, a reground camshaft can be quite good and save you some small amount of money. But, there are very few companies left who can do a proper regrind, which includes adding metal to the worn lobes of the cam, regrinding the surfaces back to very close to factory original dimensions, then properly heat treating the finished product. When that is done, you have a regrind that is almost identical to the factory camshaft and, in some ways, may be better. (My new County brand camshaft had a main diameter of .035" wider than factory and the ARP con rod bolt heads hit the camshaft, requiring that the bolt heads be modified to work--they would have worked with a factory camshaft.)

Unfortunately, most companies do the job as cheaply as possible, leaving you with the problems that Ralph and Ray describe. With CNC machining available, the major cost of producing a new camshaft--the labor, is reduced to the point that a properly rebuilt/reground camshaft, produced on manually operated machines, is going to cost as much as a new camshaft.

Les
Les Bengtson

To follow up on what Les said. Here is one of the good one's. Delta Camshaft in Tachoma Washington can build them up and grind them to whatever you need. They have a very good reputation with MG engines.

http://www.deltacam.com/

I had them do my TD cam and lifters. May not be as much an issue with the B, but some cams are a bit harder to get and buildup/regrind may be the easiest way to go.
Bruce-C

We have delt with cam grinders & there are some that KNOW & there are the ones that do not know, what needs to be with the british cams. Delta camc at 1-800-562-5500 are ones that know. We have had a lot of cams from them & thay do a great job every time. Moss lifters are JUNK, Delta cam regrind your O/E lifters and they are better than most supplyed today.
Glenn Towery

I had my camshaft reprofiled from stock to a fast road grind by Colt Cams in Vancouver BC. I only have 3000 miles on them, so can't comment much about wear. It was very hard to set the valve clearances (the heel of the cam was not exactly round, so I had to set the clearances at about 90 degrees on the shaft from the centre of the heel.
The car runs great, with more power than before, although I did have the whole engine rebuilt, with other mods also.
There seems to be debate over whether to regrind the tappets, or use new ones. I had mine reground on the advice of Colt cams, who said that the new tappets wear very quickly, whereas the originals are much harder and will last longer with a regrind. I have heard others say that regrinding the tappets removes the hardened surface, so that very soft metal is left behind which also wears very quickly.

It might be a couple of years before my verdict is out.
Erick Vesterback

Thanks for all your input. I had purchased a reground camshaft from a very reputable vendor locally. I pulled my oil pan to put a new gasket on and done a visual inspection while the pan was off. My lobes were showing pitting and wear with less than 10k miles on it. Fortunately, my vendor is doing an excellent job with exchanging this. It will be another reground camshaft which is being exchanged though. Sounds like depending on who does the regrinding it may or not be a good one. Since my money is spent, I may do another inspection of this one at about 10k.
Bryan

Bryan

Check out the various threads on the lack of ZDDP and the resulting rapid wear on new cams. I did a search in the archives on "oil cam ZDDP" and then the thread on "engine oil" is a good place to start.

There is LOTS of info on this in the archives and on the web.

HTH

Larry
Larry Hallanger

This thread was discussed between 14/01/2008 and 16/01/2008

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