overheating and no coolant flow

[elwood blues]

I just finished up a lot of work on my CJ. New, bigger lobes, COMP cam and valve springs, had the head pressure checked and magnafluxed, new timing chain and gears, new alternator, water pump, radiator & thermostat. I also installed a bigger Barry Grant 350 cfm street demon carb.

I got everything back together a couple of weeks ago, and finally finished up all of the little things I noticed a couple weeks ago. A small oil leak by where the oil pan meets the timing cover, an exhaust leak, etc.

So, I jump in and start down the road to the local 7 eleven. I only get about half way there when I can smell hot. Hot coolant to be specific. I stop and open the hood and notice that the top radiator hose has zero pressure in it, almost seems like there is zero flow. I also noticed that the temp gauge reads nothing. So, I took it very slow with very low RPMs back home, get in the garage, get the hood open (engine still idling) there still seams to be no pressure in the top hose. Also, there is no pressure on the system and I can open the radiator cap with no problem, the coolant doesn't seem to be flowing, but it sure is hot, steaming hot, not boiling though.

The temp gauge worked before I did all this. There are only a couple of things I can think of, wrong water pump that's spinning the wrong direction, but for a '78 I don't think that's possible, the difference is noticable between an '80 and new water pump compaired to a '79 and older AMC 258 i6 / 4.2l /AMC 232 i6 water pump.

The thermostat could be installed backwards, but I don't know if that would cause what I'm seeing.

Any advice you guys can offer before I start tearing things back apart is appreciated

 

[mtnwhlr]

The thermostat being installed backwards was the first thing I thought. And I always drill a small hole in mine when I change them it helps get rid of any air that is trapped.

 

[elwood blues]

The thermostat being installed backwards was the first thing I thought. And I always drill a small hole in mine when I change them it helps get rid of any air that is trapped.

That was also one of the first things I though of. I've never heard of drilling a hole in a thermostat, care to share a little more detail? Size of hole, where to drill, etc.

Thanks,
Elwood

 

[mtnwhlr]

Just like a 1/16 hole in the outer flange. I had a old timer tell me about it.

 

[Old Dog]

some of the high performance thermostats come with a hole drilled in them.
I had the same thing happen to me once, there was air traped in the engine somehow and the thermostat would not open. Now I allways make sure it's FULL of water before I start it.
Thre's also the possably that the new water pump isn't working for some reason.

 

[IOPort51]

Let it get hot idling with the cap off and see if you are circulating. I have found the AMC 258 i6 / 4.2l to be very easy to get an air bubble in.

I have heard that pulling the temp sender in the back corner of the head will help "burp" it as well.

 

[elwood blues]

I cracked open the water neck to double check that the thermostat was in there the correct direction (it was). I also figured out why the temp gauge didn't work, I forgot to connect the wire . I'm guessing that did the trick though, I let it come up to temp at idle, watched the thermostat open because the temp gauge went back down, took it for a ride, got it up to 50mph, the temp stayed down where it should. Thanks for the replies guys.

 

[mtnwhlr]

Glad to hear you got it working

 

[cass]

so how does it run with the new improvments?

 

[elwood blues]

so how does it run with the new improvments?

Sorry cass, I didn't catch your reply until today. It seems to run well, but I'm still trying to iron out a small valve train noise. :dunno: I'm worried that it's incorrect valve preload with the bigger cam. I'm still working that out.

 

[coldair]

What cam did you go with?

 

[elwood blues]

What cam did you go with?

Xtreme 4x4 X4250H

COMP Cams: Xtreme 4x4™, X4250H<BR>Excellent Torque, Throttle Response, Great Stock Replacement

 

[coldair]

How does it run? I know that was asked already. I looked at that cam before I ordered mine.

 

[elwood blues]

It ran very well once I got it tuned in, the valve noise that I'm getting is really bothering me though, and I don't really understand how valve preload and pushrod length and shimming rocker arms work. A colleague at work explained how to check it, but I don't have some of the tools to do it yet.

I think I'm going to call Comp Came tomorrow to see if their tech support guys can help.

 

[coldair]

If your getting noise your pushrods are to short.

 

[mtnwhlr]

If your getting noise your pushrods are to short.

Only if he replaced them if he reused the old ones it would have to be something else. elwood did you use new ones?

 

[coldair]

A cam can change the preload even if he used the same pushrods

 

[73CJ]

I put the Comp Cam for FI in mine Measured preload on each pushrod. I had many different lengths to choose from as well. I ended up grinding the bottom of the rocker pivot right under the rocker arm. Been running quite and strong for 1300 miles so far.

I hate lifter noise. .

 

[elwood blues]

Only if he replaced them if he reused the old ones it would have to be something else. elwood did you use new ones?

Brand new OEM spec.

I put the Comp Cam for FI in mine Measured preload on each pushrod. I had many different lengths to choose from as well. I ended up grinding the bottom of the rocker pivot right under the rocker arm. Been running quite and strong for 1300 miles so far.

I hate lifter noise. .

I also seriously can't stand the ticking noise either.


So, who would like to explain how to check preload and how to tell if I need shims or different length pusrods? Please

 

[coldair]

Do you have a dial indicator? Or do you have a scribe?