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MG MGB Technical - Piper 270 Camshaft

Hi.

I've got a standard 1800 engine, the only different thing is the K&N filters and disposal of the old filter boxes.
Reading thru the archives I found out that the best camshaft for my situation would be a Piper 270.

In this case:
1. would it be necessary to cut-out the pistons because of the greater lift?

2. I've read that when installing a new cam one should install new lifters. I've order new cam followers is it the same thing? What about tappets? Just different names for the same thing?

Thanks in advance.

Valter.
Valter

Valter,
1. No piston cutting is needed. You do need to set the cam timing. This is best done with a degree wheel. For details on cam degreeing see Chris Betson's web site;
http://www.octarine-services.fsnet.co.uk/alex1950.htm

2. Cam followers, tappets and lifters are different names for the same part. Yes, they do need to be replaced when a new cam is installed, old cam followers will ruin a new cam.

Good luck, Clifton
Clifton Gordon

Valter-
1) You should not need to alter the crowns of the pistons in order to use a Piper 270 camshaft. However, if you have an engine whose engine numbers start with 18V, you should have your machinist check to be sure that the counterbores for the exhaust valves that are machined into the deck of the block will provide adequate clearance. These deeper counterbores will need to be cut with a 1 17/32" (1.53125") diameter end mill to have a 1/16" (.0625") radius at their edges and be recessed at a minimum to provide a 1/16" (.0625") clearance when the valve is at full lift. The depth of the recesses in the deck of the block should not exceed .200" below the original height of the deck, otherwise the combustion flame will be directed onto the top ring of the OE style pistons, resulting in severe ring damage and ring land breakage on the pistons. The edges of the combustion chamber, piston bores, and the valve seat recesses must be carefully deburred and smoothed to preclude the possibility of "hot spots" developing and thus prevent preignition from consequently occurring.
2) Just to confirm what Clifton said, yes, the words cam followers, lifters, and tappets all mean the same thing.
Steve S.

Thanks a lot.

Just checked and the engine is a '73 18V. So I must check clearances but I should be fine without any rework, right?

Cheers, Valter.

Valter

Valter-
As long as you are using pistons with the standard crown height you should be fine.
Steve S.

This thread was discussed on 06/01/2004

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