Date: Wed Mar 05 10:08 EST 1997
From: "Brinkmann, Gerry" <brinkg@uf4124p01.BHeightsNJ.ncr.com>
Subject: Rebuild with Hot Cam and Roller Rockers?
Date: Tue, 4 Mar 1997 13:28:18 -0800
From: David Hall <dhall@vcd.hp.com>
>>As far as the rebuild goes - I am debating the advantages /
dis-advantages of
>putting a hot street cam in it, as well as roller rockers. I've read
through
>Peter Burgess book - Power Tuning a MGB Engine. He seems more concerned
with
>balancing the engine and porting the head than the hot cam.
I just finished an engine rebuild on a 3-main MGB engine. I used the
Burgess book as the basis for the rebuild. I tend to agree about the
rollers rockers - it seems to be a lot of money for what seems to be an
small increment in power increase. I think that there are a lot of other
things that can be done to a MGB engine to increase power/torque before
investing in roller rockers.
For reference - I had every moving component in the engine balanced. the
crank, flywheel, pressure plate, con-rods, pistons etc etc. I built
basically a stage 2 engine using a Piper BP270 camshaft with the vernier
timing gear. I installed bronze valve guides, 3-angle valve job and
ported the intake and exhaust ports (there is a lot of metal that needs
to be removed from the intake side). The only original components in the
engine are the block, head, crank and con-rods, everything else was
replaced with new components. The flywheel had 5lbs taken of as well.
So what does it feel like ?
I have only driven the car for 1 week since the rebuild and have only
taken it to 4500 rpm. The engine is very smooth, no vibration at all,
none of the usual mechanical complaints when revved hard. The engine
seems to have loads of torque, from 2000 rpm I can bury the throttle and
I get a nice steady rate of acceleration. I think the engine is probably
still fairly tight (the starter has a hard job turning the motor over),
so I expect to release more torque once the engine has loosened up a bit.
If you are building a street engine, I would be wary about using a
hot/wild camshaft. I would stay on the conservation side. I built a
Midget engine with a wild cam, and it was not much fun for daily driving
- however on the open road above 3500 rpm, the engine really came alive.
gerry
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