Inliners International Forums General Discussion Engines Can someone explain the by-pass hose on a 292?

I was looking at some aftermarket power steering brackets, and it said that they must be used with the later water pump with the smaller by-pass hose. Of course, I have the earlier, larger by-pass water pump. So, what's the purpose in general for the by-pass, and does bigger or smaller make any difference?

Bypass hose allows water to circulate inside the engine while the thermostat is closed so you don't get hot spots or steam pockets during warm up.

I suspect that the smaller hose flows enough, or they wouldn't have used it.

That makes sense, I guess. Was it just not a problem on the 250/230's? Maybe I should put one on my 250-it runs hotter than heck:)

Bypass hoses can also aid in maintaining operating temperature by allowing the thermostat to cycle. In BBC v-things without the bypass the engine would hold the thermostat open all the time - which doesn't give the radiator anytime to do its job . . .

Perhaps it is the same for the 292 . . . dunno . . . never had one.

the Nash-designed engine I have in my Rambler (195.6 OHV) doesn't have a bypass, and it needs one. I drilled and tapped the thermo pod to accommodate one, but from experiments and anecdotal info from others, it appears that simply drilling a hole in the margin of the thermostat allows enough flow for hot water to signal the thermostat (this particular engine's design flaw) and also to burp out air.

3/16" hole seems more than adequate here.

tom,
Doesn't your Rambler have heater hose inlet and outlet connections on either side of the 'stat? Why not use them? Or do you need a heater to be in the "off" position.

Maybe I just answered my own question. Some cars do have heater bypass circuitry.

the head on this motor is an idiotic mess. the thermostat is in a pod, ahead of #1 cylinder by inches, so warm-up heat signal isn't 'telegraphed' to it. the head temp skyrockets, and steam pockets form, until the thermo opens and the temp plunges. it's a bizarre head.

the heater is in parallel with the head (so you get heat in the winter in about 60 seconds!) but it doesn't inform the thermostat.

The engine is the venerable Nash 'Flying Scot' with a one-off cylinder head glommed on in 1958. It's the only engine other than the L-head that fits in the chassis without substantial modifications.


http://www.wps.com/AMC/195.6OHV/Head-cooling/

Tom,

My 1965, Rambler 195.5 came with a bypass hose from the
thermostat housing to the water pump... The engine was a "crate"
engine sold in 1966 to repower a Willys pickup..Anyway, even
though the engine has a bypass hose, I still drilled the thermostat (two 3/32" holes)... Today with an oustide temp of
100 degrees, I road tested the truck and watched the temp guage
very carefully....Now, the gauge goes to 1/4 and stays there.
Before the mod, the gauge went to 1/3 and gradually fell back
to 1/4.. I have a 195 thermostat... It seems like drilling
the thermostat, "softened" the warmup... I'm hoping this will
extend my head gasket life.

Melon