Adding telltale to ’72 V4

[amuller]

In many quarters this seems to be a highly recommended mod. Advice seems to be to drill an opening into the top of the water jacket on the Stb. bank. I’m OK with doing this but would like to know as much as possible about just where to drill. With Photobucket apparently having shut down access to images I’m not finding any pics. Can anybody advise?

Thanks.

[amuller]

"V-4 blocks
The V-4 configuration presents some interesting issues for locating the indicator outlet. Typically the V-4s run hot on the starboard side. That’s because of a tendency to develop air pockets high up on cylinder #1. By adding the indicator outlet to the top of the water jacket above cylinder #1 you provide an opportunity to "burp" any air out of the system and fix this issue. On many of the ’73-’77 V-4 blocks there’s a cast-in round boss just perfect for locating the indicator outlet. If you don’t happen to have that boss, you can go in through the top, just behind the coil brackets also."

[fleetwin]

Well, the telltales on the V4s are usually tapped into the exhaust manifold…But, I don’t know if there is enough meat there on an older model, and I sure don’t want you to pull that cover off…
I hear what you are saying about the starboard bank, perhaps placing a small tap up there would make sure air is bled out. But, again, I just don’t know where there is enough meat to make some decent threads up there. Use a small diameter thread elbow/tap to get the best bite. You will want to use the little plastic restrictor found on the newer engines in the pan as well. Allowing to much water to escape is kind of like bypassing the thermostat and might leave that side running cold at idle. I would be very careful choosing a metal tap/elbow, dissimilar metals could cause the aluminum around it to erode/corrode…Better off using the cheesy plastic elbow found on newer models, sealing the threads with something strong…

[amuller]

There is actually a 1/8" pipe plug on the side of #1 cylinder where the boss shows in some pics. It doesn’t want to come out but I expect it can be persuaded. It’s not at the top of the water jacket though, so not so valuable as an air bleed. Agree on using the cheesy plastic vs dissimilar metals. The cheesy little outlet fitting that goes in the pan costs around $10. Probably should use an upward pointing discharge like a jetski…..

Thanks.

[fleetwin]

OK, I do remember that flat boss on the block, maybe for some of the choke plumbing on the original V4s…Be careful when directing the indicator flow, you don’t want the spray getting sucked inside the engine…

[frankr]

I don’t have my pictures with me, but yes there should be a plug or blanked hole that is a leftover from bygone days when it was used for the hot water choke. Use that, and restrict the flow down to pee stream.

[amuller]

Mostly done. An unpleasant little job drilling out the plug–hard steel. I probably buggered up 6 bits. Going to make an outlet from a 1/4" nylon bolt and two nuts. Anybody know what the bore size should be for appropriate peeing?

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