Questions about my need to me engine.

[Airshac]

Thanks for the diagram! I know there have been a lot of good suggestions here. I’m not at the boat during the weeks days so just trying to gather as much info as I can before I head back down there this coming weekend.

[roadnsky]

You always have full flow through the manifold regardless of thermostat position, even if you have no thermostat. As I offered earlier, an infrared temp gun measuring head temperatures would be an excellent diagnostic tool. Also, you can guaranty water flowing through the block if you obstruct the bypass hose, thermostat installed or not. If there's any uncertainty, the bypass hose is the one right next to the starter. Even a pair of vice grips will do in a pinch.

I'll second Neil's advice to acquire an infrared gun to be certain what the engine temps are.
From there, you can get a permanent temp gauge working and you'll know that it's working properly.
While you're verifying temps, try using the vise grips on the bypass (use a cloth to protect the hose) and observe the temp changing.

Those simple tests will give you some confidence in your engine cooling for your upcoming trip.

Finally, here is a very good read related to your current questions.

[sastanley]

Wow...A-4 in the bilge!!
Not too many boats did that.
Hughes 38 is the only one I know of!??!!

Welcome!

[Dave Neptune]

A-4 in the bilge on my E35MkII, almost completely below the water line right on the keel. Only finger clearance in some spots along the pan as she sat down in the turn of the bilge. The dinette seat was above the engine.

They sit pretty deep in a Cat 30 as well.

Dave Neptune

[TimBSmith]

What has helped me understanding cooling...and bypass valve..

Context. I considered myself a redshirt freshman last year owning my first A4 since August. Never did much mechanical, though always loved when I did. I am something like a A4 freshman this year.

The greatest help besides studying and reading threads here especially search on running with or without thermometer and all of the great debates on running colder or running hotter:

1) The Moyer publications.
2) Slow experimentation with infrared thermometer
3) Studying rebuild threads here and noting hot spot and water jacket references and Raw Water vs. Fresh Water Cooling.

My PO happened to post here under SMosher. That was one hell of a discovery.

In a way the bypass valve is simply a manual thermostat without any temperature sensitivity. It can augment your thermostats water blocking or flow function or it can be serve the block to manifold water directing function exclusively in the absence of a thermometer. The valve can provide some benefits when winterizing because you can force flow through the block and manifold, knowing that you have a well pickled engine. Good luck.

[ronstory]

Context. I considered myself a redshirt freshman last year owning my first A4 since August.

*Much* better than being a redshirted ensign. (for the Trekkies out there )

[TimBSmith]

Yes...I am still alive and my A4 is too....

Very soon to unpickle my engine and reconnect batteries that I have been conditioning all winter like a mother hen watching her eggs.

[campbdon]

Also, when working around the alternator (ie: visegrip on the bypass hose) remember to turn your battery selector to OFF. Don't ask how I know this ;-)
DonC