TomZ

I finally got the beast running this morning (work and all the heat has made working on her less than a top priority), but now I'm overheating on the muffs.

A quick recap...

Melted #1 intake valve. Replaced all Manley valves with Ferrea valves. Checked out the heads, all seats, etc were OK. Rebuilt the heads. Replaced graphite head gaskets with Fel-Pro Marine performance gaskets (took off a tenth of a point or two of compression in the process. These gaskets have the additional cooling holes that both my heads and block have between the center cylinders which in turn should promote even cooling). Replaced the Q-Jet with a Holley 4010 750 (starts and idles nicely plus seems to have a snappier throttle response). Epoxy-coated all external areas and water passages on my intake. Bolted everything back together. Changed the oil and filter. Fired her up, set timing at 12* initial, seems to be running quite nicely though I'll probably need to adjust the valves while she's running.

Noticed while fooling around with adjusting the throttle cable that the temperature started to climb. It didn't get up there real quickly but for the short time that I had her going (maybe fifteen to twenty minutes) she got up to at least 200-210* (gauge reades 240 max with 160 in the middle, needle was half way). The risers were also hot. I had water coming from the exhaust though initially it took a couple of minutes to see it. The drive water pump is working as I'm getting water from the tell-tales (though I'll check it at the thermostat housing tomorrow when I mes with it again).

Anyone else had problems like this especially with a small block?

Thanks!

jr

Did you put your theromstat housing back together the right way? I put my t stat on the manifold once, and put it all back together (oops long winter). I had the same problem. I put it all where it belonged and no more issues.

TomZ

I didn't take apart the actual thermostat housing, I just removed the whole thing as one unit. My housing is not a typical Merc part and I have one inlet and three outlets (one going to the circulating pump and the other two going to the manifolds). I think it came off of a Marine Power or Crusader setup (the paint underneath was turquoise). There is no thermostat inside that I know of.

Thanks!

Bo Knows

I'd take a real close look at the head gaskets. If it didn't over heat before investigate the the things that have changed.Possibly not enough water pressure thru the muffs or a water pump impeller starting to go bad ?

Bo

Vinny P

TomZ,

You said "There is no thermostat inside that I know of. " Does this mean that you did all this work and didn't pull the thermostat housing apart to replace or even check the thermostat??? If so, that's were I would look first.

TomZ

What I meant was that it's a very simple housing with the actual thermostat mounted in the manifold. The housing has a divider in it that allows water to bypass when the thermostat is closed. I have never needed to open it up to look inside as it's always moved water appropriately. Myabe I'll have to look at it anyway.

I think the problem might lie in a blockage somewhere or that the water wasn't turned on high enough. I'll mess with it again tomorrow morning.

MACDAD260

What rpm are you running on the hose? I rebuilt a 305 small block a few years ago and when running on the hose at about 1700 rpms to break in the cam it overheated after about 10 minutes. I ended up tearing the whole top end of the engine off thinking something was wrong with gaskets or ?. I could not find anything out of place. I put it all back together and tried again. I found that the engine just needed more water at that rpm than what my hose could deliver. It was OK at idle up to about 1200 rpm.

If it does not overheat at idle then I would put it in the water and try it before taking anything apart.

TomZ

Hey... I just got this bucket off bolts put back together! No way in hell I'm taking it apart again!

I did run her up in the RPM range a bit to get the timing set for above 3700 RPM operation... but only long enough to bounce a light down at my balancer. Probably still too much for the water going into it. I was also starting out with a dry block so maybe I didn't give it enough time to get some good water in the block and the hose pressure was low.

olysan

Hey Tom,

This is way off your topic, but I'm curious what you meant by "Epoxy-coated all external areas and water passages on my intake".

TomZ

I got a hold of some epoxy paint and coated all of the exposed aluminum areas with it to keep corrosion down. I acid-dipped the intake to clean it good (I used an acid/oil that's used for cleaning AC evaporators and coils, safe on aluminum) and then I coated everything. The epoxy paint will last for quite a while. This was a tip that I got from Edelbrock a couple of years ago since they don't make a manifold with brass inserts for the Vortec small block.