ZZ4 in a '60

[Jim Houston]

Question: Just place a ZZ4 into my '60.... Problem: within 5 minutes of the engine running, it cooks itself to 240 degrees... Any ideas...

I've heard many comments, like air pockets, pump needs priming, etc... I've drilled little holes on the temonstat. for it to burp....I'm trying to figure it out...

I can't find out if the ZZ4 needs a reverse flow water pump or can it use a standard '60 pump....

Any comments would be great!

[Kenneth G.]

Re: ZZ4 in a '60

Jim,

I would suggest posting in the Corvette Forum message board (www.corvetteforum.com). I t seems a few people over there have ZZ4 motors installed in various year Vettes and maybe could help you out or have some advice.

Kenny

[Kenneth G.]

Re: ZZ4 in a '60

look under "63-82 C3 message borads"

[Tom B.]

Re: ZZ4 in a '60

Jim,

What sort of a cooling system do you have set up? Is your thermostat opening? TBarr #24014

[Jim Houston]

Re: ZZ4 in a '60

I'm running a Be-Cool rad. w/ 180 deg. temstat... Using stock '60 fan w/o a fan clutch...

Yes, the stat is opening after testing Sunday!....

I'm wondering if the new temp. sending unit is working now! I know they operate on resistance, I wondering if the resistance is incorrect... It is a brand new one from Ecklers.... Maybe it's bad!

[John H.]

Re: ZZ4 in a '60

If you've got a part number for the water pump on the ZZ4, maybe Joe can verify whether or not it's a reverse rotation pump, designed for use with a serpentine belt system. John

[Tom B.]

Re: ZZ4 in a '60

Jim,

Your temp sending unit function is always a possibility. May want to check if the wire is laying / touching anything hot, like a manifold. One way to tell is if you're getting any boil over at the cap.

Also, just some other basics, coolant mix at least 50/50, correct / full amount of coolant in system, fan placement 1/2 in and 1/2 out of the shroud (you do have a shroud in place?), alternator belt tension is correct (not too loose or too tight), correct radiator pressure cap is working, hoses aren't leaking or collapsed. Other thought is that your hood is closed so that your drawing air through the radiator instead of just blowing it around. TBarr #24014

[Jim Houston]

Re: ZZ4 in a '60

I'm using a standard water pump off the '60...

But the water pump that comes with a ZZ4 is #12496652....

[Jim Houston]

Re: ZZ4 in a '60

WRT: Temp Sending Unit.. The wire that connected to the sending unit is laying across the maniford... But will that really make a difference... Isn't the sending unit sending only resistance across the line? Would the heat really cause a problem?... Because the original line laid across the valve cover, held in place by two metal straps....

BTW: I do have the wire in the correct heat shield.

WRT: mixture and fan, etc.... Bacially that all original setup.... Except for the Be-Cool Rad. I'm running!

[Tom B.]

Re: ZZ4 in a '60

Jim,

If the wire has a cover/insulation (not just the plastic) then, you're correct, it shouldn't make that much difference. This hasn't happened to me in a while, but I once disconnected my wire from the temp sending unit and the plastic tip melted onto the exhaust manifold. The next time I ran my engine, getting it up to temp, the melted tip and wire measured the surface temp of my exhaust manifold and eventually pegged out the gauge. TBarr #24014

[Joe L.]

Re: ZZ4 in a '60

Jim----

Your ZZ-4 engine does NOT require a reverse flow water pump, unless you are using a reverse direction serpentine belt system. Also, in case you were at all wondering, the ZZ-4 does not use reverse cooling similar to the Gen II 92-96 LT-1 and LT-4 engines; the ZZ-4 is a "Gen I" design with conventional cooling. You can use a standard 1960 water pump on this engine; however, I wouldn't. I'd use an aluminum Weiand or Edelbrock unit of the short-leg style, as all 55-82 Corvettes were equipped with short leg style water pumps. Make sure whatever water pump that you use that you get one with a 5/8" PILOT shaft, so you can use your 1960 pulley system. The ZZ-4 crate engine comes with a cast-iron, long leg water pump, GM PART #12529305, which is unsuitable for use in a Corvette.

There are, of course, many factors which could effect your cooling, many of which have been discussed. However, one that hasn't is the radiator. If your car has an original-style 1960 brass radiator, I don't believe that radiator will have sufficient cooling capacity for your 350 engine. The heat rejection of a 350 cid engine will likely overpower cooling designed for 283. On the other hand, if you have an original 270 or 290 hp car with aluminum radiator, that radiator MAY have sufficient cooling for your ZZ-4.

[Jim Houston]

Re: ZZ4 in a '60

Joe, thanks for the info.... I think I will replace the Water Pump with an alu. one... But first, I'm going to try to see if it's the temp gauge or sending unit that mess up. It's a Brand-New sending unit... So I'm going to get another one and try that... Then if that doesn't cure the problem, then I will get an aftermarket temp gauge and plug it in... To see the reading...

Then if that doesn't work, I'm selling the car... Just kidding!

WRT: Rad. I'm using a Be-Cool Rad...

I'll keep you guys informed! Wish me luck!

[Edward M.]

Re: ZZ4 in a '60

Are you using the stock (original) gauge? Are you using the original temperature sending unit. I seem to recall some discussion about the resistance valve of early vs. later model temperature sending units.

If possible, I would try using the sending unit that came with the car originally. If that is not possible, measure the resistance level of the sending unit you are using. I don't recall the specs at this time, but I'm sure we can figure it out.

[Don Groppe]

Re: ZZ4 in a '60

Jim, Look in the archives for a test that was done on old and new temp. sending units. The test shows a curve on a chart for measuring the ohms of resistance. I found that the new temp sending unit would show hotter and when I measured the ohms there was a difference. Does your radiator boil over or is it just the gauge showing the high temp. thats bothering you? I found that the new sending unit would read higher. It doesn't take must of a difference in the ohms reading to make a difference. Good luck!

[Jim Houston]

Re: ZZ4 in a '60

I have been digging in the archives.... Still looking... Did find a lot on this subject... But haven't found the right set of threads yet!

thanks!...