On my engine with the Holbay head, the exhaust ports on the head are
larger than stock Alpine ports. I came across a S1/S2 type tri-Y exhaust
headers that was actually the size of the Holbay head exhaust ports - the
stock S1/S2 exhaust headers are NOT larger enough. I had these
tri-y-headers Jet Coated and installed. The only problem was that the
front tube was not bent enough to allow the 55 amp Hitachi alternator
(Datsun Z) I was running. So, I found this tiny, and I mean tiny, 35 amp
Hitachi alternator (Mazda RX?) that fit perfectly. It fit in the space
and its mounting tabs lined up perfectly with the stock Alpine mount and
with the pulleys.
But, not all was perfect. As soon as I did this, I found that when I was
driving with the OD on, it would pop out once and a while - usually
earlier in the day. My assumption was that with the alternator pumping
the battery, perhaps with 35 amp limit (also presumably a peak limit not a
constant) at the limit it was fluctuating and causing issues for the relay
that keeps the solenoid on.
So, now that I'm putting this all back together, I'm thinking of going
back to the stock SV cast iron exhaust manifold that will allow me to put
the larger alternator back on. I had actually ground out the initial
openings in the cast iron exhaust manifold to match the Holbay exhaust
ports. That took out the immediate step, but it still narrows down too
far.
It could be that this OD issue I was having had nothing to do with the
alternator. I'm looking for any thoughts on whether or not that makes
sense. Or, I should put it back as it was and track down whatever other
problem is actually causing this OD issue.
Thanks for any thoughts.
Jay
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