Blake: If you are using a head off of an 18V motor on an early block, and
especially if it has been surfaced a couple of times you may be having a
problem with the exhaust valves fouling on the block. Furthermore, you have
more lift on the valves now, adding to the problem. The later blocks had an
exhaust-valve sized .040 relief cut in them for this reason. Also you should
be using the short lifter-long pushrod combo from the later cars, this is
much lighter than the early arrangement. Also, be aware that the late rocker
shaft is Not the same, it has offset lube holes so make sure your lube holes
on the block and pedestal match up.
I've heard of cases with a radical enough set up that folks used the short
lifters and the short pushrods plus lengthened adjusters to get their rocker
openings right. Still the likely suspect here is that you are fouling the
block with the exhaust valves.
(question was...)
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Date: Sun, 07 May 2000 19:18:22 CDT
From: "Blake Wylie" <blake_wylie@hotmail.com>
Subject: Pushrod question..
Here's my situation:
I have a 3-main 1800 engine in my MGA
I have a performance cam in it
The head is a later model B head (the years they had the bigger exhaust
valves)
The rocker arm pedestals are the same
The pushrods are the ones from the 3-main engine (the same)
The pushrods are too long, and they are apparently binding on the top of the
pistons because the engine is basically locked-up when the rocker assembly
is bolted down.
What do I need to do? What am I missing? Where do I get shorter pushrods
if that is it?
Anyway...thanks for your help...
Blake Wylie
'61 MGA
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