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Does a Schrick cam work? - Answer
Last night I decided to put the schrick cam into my new '83 CGT engine. The
engine has 250 miles on it. New block with stock crank, rods and pistons
(should have used different pistons). The head was completely rebuilt (only
the aluminum body was reused) and it was ported & polished with most of the
work done on the "short side" radius of the intake and exhaust ports and the
air flow through the valves was "cleaned up". I can discuss more about that
later... Being an '83 I am using solid lifters. The larger CIS-E throttle
body was used, as well as 4kq exhaust manifold. Exhaust is 2-1/2",
currently w/ cat, and one single borla turbo muffler (straight through
design). Also, K&N filter is in the airbox.
The head was milled to minimum height spec. This should have the same effect
as advancing the cam timing by about 2 degrees. An adjustable cam gear was
also fitted to the car. With the stock camshaft the difference between the
new engine and the old engine was night and day. Of course, so many things
were changed you'd expect that.
My first "data point" was taken with the cam gear set for 2 degrees of
retard. This should be close to stock given the head milling. Spark timing
was dialed in to stock specs (6 ATDC) per Bentley. Torque felt higher
through all RPM ranges compared to old engine. High end breathability was
magnificent and the car would accelerate very well at all RPM's. It would
pull very strong starting at 3700 to 6000 (I didn't venture higher than 6k
on such a new engine). Feel free to flame me about proper break-in
procedure... Additionally the car would idle well at 600 RPM's.
The next data point was taken with the adjustable gear set at 0 deg. This
should be about 2 degrees advance. Idle was a little rougher. Spark was
readjusted to 6 ATDC. Slight but noticably less low end torque. At 4k
RPMs, the engine really started to breathe and you could feel the HP
difference. There was a noticable difference in performance above 4k. High
RPM accel. greatly improved.
The final stock cam data point was taken at 3 degrees advance on the cam
gear (~5 deg total adv.) Spark timing again was reset to 6 ATDC per
Bentley. Idle rough below 850 and adjusted to 850, 'cause car stalled once.
Low end torque was definitely lower. Felt like towing a trailer through
2k. From 2k to 4k felt like stock. From 4k on it felt like a tiny little
turbo was kicking in; this was a very noticable difference from the last
Then I swapped in the Schrick cam. All said and done this took 70 minutes.
I left the cam gear on 3 degrees advance and had difficulty getting the car
to idle. Reset the cam gear to 2 degrees retard and it would idle at
minimum of 1100. (Ok, it would kinda idle around 850 but it wasn't a
friendly idle). Let the car idle at ~1500 for 30 minutes for the cam to
break in again. There was no discernable difference in low-end torque
between the schrick and stock cam on this setting. After 3k RPM, there was
a slight difference that appeared to grow as I approached redline.
I set the cam then to 3 degrees advance and reset spark timing to stock.
Idle was a little rough at 1100. Idled well at 1400, but left it set to
1100. Absolutely no low end power. My pushmower could beat me to the 100
meter line if I did a 2nd gear start. Under 3500 performance was
lackluster. Car would cut out if RPM dipped below 1k when stopping at stop
signs. However, at 4300, performance was phenomenal. On the highway a 4th
gear acceleration from 65 to 85 would be done instantly. Absolutely a
blast, but probably only useful for the track or auto-X.
Finally I set the cam to 0 degrees advance. This seemed to be the best
compromise between torque and HP. The car will idle at 1100. Acceleration
in any gear below 3500 RPM's feels like stock. Above that mark, you know
there is a big difference. Car pulls very strong through to 6k, and tach
needle visibly accellerates faster and faster the closer to the red you push
it. The sound out of the exhaust is definitely different too. More of a
rumble-grumble than with the stock cam.
So, is a Schrick cam worth it? Maybe. It depends on what you've done to
the car. I don't think it would work nearly as well by bolting it into a
stock engine. I'd say first you should do the simple stuff, like throttle
body, filter, no cat, and adjustable cam gear. Then move to 4kq manifold
and better exhaust. To make the manifold job easier, go ahead w/ the P&P on
the head a the same time. It's a costly way of doing it 'cause then you
need to do the head work, new manifold, and exhaust all at the same time.
Only after all this would I suggest going with the cam, since it does cost
Anyway, my $0.02. Sorry no numbers or HP/Torque curves, just seat o' the
pants observation. Feel free to argue or question anything I've said.
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