Would the thicker wall stainless effect the flow through the
rail enough to worry about?
In my opinion, no. I had a 1/2" stainless steel flat washer
installed in my RH upper radiator hose to encourage more flow through
the B bank, worked fine. Lutz disagrees, though, and advocates going
with a LARGER pipe than OEM to maximize flow.
Will the difference in
expansion/contraction of the dissimilar metals effect the
sealing integrity?
If you’re talking about installing the SS pipe in the same manner as
the original, using the top hat seals, no. Those seals work very
well, at least until they dry out and crumble. The biggest threat to
them sealing is using a steel tube that rusts, since the rust will
break the seal. Thank you Jaguar for providing the worst possible
material in this application.
Why are so many people using copper instead of aluminum
tubing? Pressure rating? Appearance? Fragility?
The copper is handy because it’s readily available in the correct
size, no machining necessary. Just use a tubing cutter to cut a
piece to length. If you wanna do a top-notch job, cut rings off a
sweat fitting and solder them in place around the copper tubing to
prevent it from sliding too far into the rubber seal.
I also thought it looked kinda neat, but aluminum would look nice,
too. The only thing that doesn’t look good in that application is
rusty steel. Thanks again to Jaguar…
The Stage 1 Lutz mod seems alarmingly small in the first
port. 1/8 inch looks pretty small. I am sure any size
restrictor will promote flow to the rear manifold. Would
3/16 or 1/4 be an option? What have others fond to be optimal?
IMHO, the Lutz mod renders the first port pretty much a bleed port,
something to let air bubbles out of that corner when filling. The
flow through that port might be enough to prevent the coolant from
stagnating, but it’s likely not enough to keep the front cylinders
cool. The idea is clearly to drive essentially all of the flow past
all of the cylinders.
Going with a larger port might work for the same reasons that not
doing the Lutz mod at all might work. The thing is, though, that I
personally suspect that the OEM setup was thoroughly tested at Jaguar
and found to work fine at full power, but we owners discovered that
it doesn’t work well at idle where flow is weak enough that all of it
can pass through that first port and none gets to the rear of the
engine. If that’s the case, then the Lutz mod to the first port
would need to be pretty small indeed, because your objective is to
restrict flow here at idle where flow is weak all around.
Those who have performed the Lutz mod as specified haven’t reported
any downsides that I am aware of. Of course, most of them probably
wouldn’t know if their 1A and 1B cylinders were running hotter than
the rest. There are a few members here, though, who have purchased
IR thermometers, though, and use them to look for hot spots, and I
don’t think they’ve discovered anything alarming resulting from the
Lutz mod.
The Lutz press-fit concerns me a bit, too. However, I don’t
like the gasket sandwich restrictor idea because I think it
would make the front manifold gasket too thick, resulting in
the front rail being higher than the rear, which may effect
the alignment of the water rail, compromising the rail seal.
Nonono – the way I would do the gasket sandwich idea would be to
do it at all ports, front and rear. The restrictors at the back
just aren’t restrictive, they’re full size passages.
– Kirbert
// please trim quoted text to context onlyOn 20 Nov 2011 at 8:07, Billbo wrote: