The Stovebolt Site Forums The Shop Area Engine Shop Installing temperature probe on 1953 3600 216 ci

I need some help. The PO used a different thermostat housing from another engine, and it has a temperature capillary probe installed. Problem is, with that in place, I can't install a thermostat - it hits the probe.

I want to go back to the original housing, with no probe. I am told that the probe will mount on the left side of the engine, on top of the block, just aft of the carb.

I looked, and sure enough, there is a hex plug. I removed it, only to find that it is a bolt size (5/8 x 11) rather than an NPT size. Have not found any bushings to fit this hole. How do I get from 5/8 coarse threads to NPT sizes? Am I correct in the first place that this is where the tube goes? Seems a little strange.

Thanks.

Harry

On my '48, the probe goes into the block on the opposite side of the engine.

Tom & Harry,

I thought that the water temp probe/sender went into the top side of the head between the #0 and #10 head bolt, as Harry is most likely describing?

Harry,

Can you post a photo of the fitting on the end of your probe? Mine has a square "head" but I do not know the thread size.

Here it is. I went to the harware store and tried a nut on it. The threads are 5/8 x 11.

http://share.shutterfly.com/share/r...75b2f2841c4d4a52e&sid=8AZOGLNu0bMmOm

No, but thanks for the proper terminoloigy. I guess the bottom portion, which you show, is the :"thermostat housing." The truck did not come with a radiator (another story) so that hole is plugged and evenutually will have the heater outlet.

The PO mounted the probe in the upper housing (water outlet) - the piece that has the water outlet to the top of the radiator. I don't think that's the correct housing for the 216. In fact I know it is not, because it has 1 1/4 hose, where I think 1 1/8 is correct. I am using 1 1/4 shimmed at the top end.

SO, the thinking seems to be that it should go in the hole on top of the head, where I removed the 5/8 x 11 threaded plug. But how?

Thanks again, and I will see about posting in the engine forum.

Harry

Brain cramp. I was referring to the oil gauge. Sorry.

That is a NPT thread. The orig size is 3/8 NPT.

Denny, thanks, but please listen careful. I did not cast the block. The hole is the block is NOT "5/8-18 straight machine thread having a thread diameter of .625”" as you said. It is a 5/8 x 11 "coarse thread." Let's start from there, OK? I don't want to be an engineer. There were millions of these made, why would mine be different?

Please see the pic I posted, you can see the coarse thread.

yours might be diffrent because the thermostat housing or engine or head or temp sender were from some different application, maybe a car? what Denny is saying is you have something different than the original arrangement, so it's time to put on your engineer suit, whether you want to or not, and figure out what can be changed to make what you have work the way you want

Bill

OK, I am about ready to give up. Obviously, I have not explained this very well. This has nothing to do with the thermostat housing or anything forward of the carb. Those were interesting (I thought) symptoms of what the PO did.

The real issue is that my block is drilled 5/8 x 11 coarse thread, NOT 5/8 x 18 fine thread. Just want to be clear.

Of all the 216 and 235 engines ive built and swapped out and heads iv switched, the temp bulb goes in the top of the head,as described above.
On some, i've had to use a special adapter,not just a reducer.
The adapter has a "shoulder" about halfway down, inside for the bulb flange to seat against.
I have the part right here in front of me if someone can post a pic.,,i'll send it to you.
Marty

Marty,
Will it thread into A 5/8 x 11 coarse thread, as my pic shows?

that's clear Harry - and if the sender that's attached to your gauge doesn't fit the hole where the manual shows it usually is, I would take that to mean yours is different because the head [or engine] is not original to the truck ..... also I'd expect that the original sender wouldn't have a long enough tube to reach the stat housing - PO changed the gauge?

I doubt you'll find any adapter to go from coarse to fine thread in the same diameter hole, and I doubt the factory would have had one there .... next step?

Bill

Have you ever heard of a coarse thread mounting hole?

Hi Harry,
If you PM me your e-mail address, i'll send pics of this adapter to you, with measurements. It looks to be 5/8 x 11
Hope it helps,
Marty
EDIT:: I just read your beginning post,, the capillary tube from a stock temp gauge wont reach the thermostat housing.