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MG MGB Technical - Composite Tappets?

On page 71 of the premire edition of Classic Motorsports there's an advertisement for tappets made from composite materials. The ad claims that they "drastically reduce camshaft lobe wear in all applications." It's also claimed that "these lifters are the lightest and toughest made." Anybody out there have any direct knowledge of these items?
Steve S.

Steve,
I Know the guy that placed the add personally, he lives about 3 miles down the road. He is working with the manufaturure of this new material to make lifters for "our" applications. This material looks impressive! The information I have is that these so hard that they are reuseable and there is no longer a need to bed in the cam. In fact they don't even need to spin in orded for the lifters to live a long and healthy life. This opens a whole new can of worms because you can cut a radius on the end of the lifter and locate it in it's bore, then use a cam profile only possible before with roller lifters. They are lighter than the stock units and a whole lot lighter than a roller tappet. The chilled iron lifters avalible through most wholesalers are junk. I tore donw a properly bedded in engine after only 500 miles to change a few things and some of the lifters were junk. Let me know if you need more information.
Jim
Jim

Jim-
I agree that many of the tappets for our engines are junk. If you get a complete set that meets spec, that's exceptional. You have to check virtually every one for its Rockwell hardness or you risk trashing your lovely new camshaft. By all means, tell me more! Can you get this guy on the BBS to answer questions?
Steve S.

Steve,
I will try to give him a call, he has been very busy as you can imagine. If you want to e-mail me off line I can fax you a copy of an artical out of Popular HotRodding magazine that would give you a bit more info. As you can imagine these things aren't cheep. They have a hardness close to synthetic diamond and the finish is very smooth. I saw a lifter that was used for an entire race season and it looked brand new there was no indication that it had ever been in an engine. Does this mean we may soon see used lifters on e-bay??? What's next?
Jim
Jim

Jim,
I too would be interested in more information on this. If you can send something my way as well.
Frank
Frank

Here is a reference for MGB lifters. Hope it works. Clifton
http://66.218.71.225/search/cache?p=Composite+lifters&y=y&e=146227&f=0%3a2766678%3a2718086%3a145160%3a146227&vst=0&vs=www.schubeckracing.com&url=JlU7DKEoq6sJ:www.schubeckracing.com/apps_flatsolid.html
Clifton Gordon

The composite tappets look interesting. $50 a lifter sounds hi, but is cheaper than pulling the engine to replace cam etc. The next failure point will be the brass bushing in the rocker arms. I've often wondered why no one has put roller lifters in an MG. It doesn't seem like it would be that hard to overbore the lifter
bore and install a chevy lifter.
Barry
Barry Parkinson

I wonder what these composite tappets are composed of. I looked at the site Clifton referenced but didn't see the answer. Schubeck offers two sizes - is one the same as the pre-18V and the other the same as the 18V (I don't have the dimensions committed to memory or in print in front of me)? They don't seem to sell pushrods to accompany the lifters; they say one uses standard pushrods and the other uses shorter ones.
Marvin Deupree

Marvin, I noticed some of the V8 lifters are solid composite and some are steel sleeve with composite inserts. I assume the long MGB liftes are for the early engines and the short for later engines. Their codes are a little hard to understand but I think for the shorter lifters they are saying the push rod must be 1.3" shorter than stock. That would mean custom making push rods or trying to find the correc length rods from some other application.

Barry mentioned Chevy lifters. The MGB lifter is .812" diameter and I think Chevy lifters are ,825" so it wouldn't require a lot of metal removal to make them fit. As I remember a mechanical Chevy has a hole in the side for oil feed up through the push rod. So the Chevy lifter would require a shorter than stock push rod. MGB push rods are very long so finding something the correct length may nbot be difficult.

My experience with MGB lifters has all been bad. Why should you have to get over the counter lifters for a stock engine hardness tested? It doesn't seem to be a new problem. My 68 GT had the old long lifters in it with what appeared to be the original cam and about half the lifters were pitted on the cam surface. My 74 roadster had a Crane cam with a date sometime in the 80's in it and about half the lifters were pitted.
I rebuilt the 74 and ran it a few hundred miles and replaced the head with a Mike Brown head. I figured I should check the lifters and found three of them pitted. Before someone asks, I did use liberal amounts of assembly lube on the lifters and cam, the oil pump was primed before engine started and the engine was run around 2200 to 2500 rpm for 30 minutes to bed in the cam. I don't dare look at the lifters in my 68, I think I know what I'll find. Sure Chevy lifters will sometimes wear, but at extended miles and when thier hydraulic lifters stick due to infrequent oil changes.

Regards, Clifton
Clifton Gordon

Custom pushrods aren't a problem. Crane will crank out a custom set for you, no sweat. With super-light tappets and chrome-moly pushrods you should be able to wind the engine until the rocker bushings cry for mersy and still have no fear of a valve kissing a piston.
Steve S.

Valve floating (sometimes called clash or bounce) is more often caused by the valve inertia and spring harmonics, rather than the weight (inertia) of the lifter/push rod side. The biggest advantage to aftermarket push rods is not so much weight, as it is stiffness. The increased resonant frequency helps to keep the push rods from adding to pre-existing harmonic problems.

I'm not saying the lighter weight components are not advantageous, they are, I'm just saying that people should not assume they have an infallible valvetrain once they buy them. They are not the only components in the system and should only be treated as a part of the whole.

The lifters are made from a sintered material, which is imported from Germany. It is re-sintered here in the states by an aerospace contractor. This process is done in an inert pressure vessel. They are then finish ground to shape and size. That is largely why they are so expensive. There are some top SCCA racers using these and we are considering there use for the future.

Sean
Sean Brown

This thread was discussed between 07/06/2003 and 13/06/2003

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