Got a 292 y-block bored .060 over, clay smith cam .485 valve lift, 240 duration @ .050. '57 posted heads, pressurized rockers, with 11-1 compression. Heads were completely redone and checked for cracks and everything before putting them on the engine when it was built.

My problem is I'm pushing coolant when I'm turning the rpms up high. I'll be going down the freeway in 3rd gear at 3,000-3,500rpms and get on it to pass traffic at about 4,000 rpms it'll push coolant. And it's not always consistent. I put roughly 80 miles on it over the weekend pulling a trailer and it never did it. Been doing it ever since I've fired up the engine for the first time and have about 6,500 miles on it. I've tried restrictor washers, different pressure caps, and I've made sure they actually seal good. I have a moroso 14-18 pressure cap on it now. Box says it's a 16lb cap. Put thermostats in it. Vacuum sealed the system hoping to get air pockets out. Would an air pocket do that? And it doesn't run hot. I have a 160 thermostat in it now and it stays 180-185 degrees all the time, in traffic, going down the freeway, etc.

I've pressurized the system checking the head gaskets, never lost pressure. Don't have coolant in the cylinders after sitting over night. No coolant in the oil or oil in coolant. Made sure the headgaskets weren't installed backwards. The corner of the gasket is sticking out of the heads up front towards the intake like they should be. Anyone have any suggestions? Thanks in advance!

How much coolant are you losing? Is it out the cap or the overflow? If it only loses a little bit it should be alright. The Y-block I a low pressure system and should have a 6-8 :b rating. If it only happens when you fill the radiator and make your first high rpm run does it continue to lose water. If not and its not losing too much or overheating then its seeking its sweet spot. On a lot of older vehicles with open circulation systems if you fill them to the top they will puke out some. As long as the plates are covered and you can see water over them it should be fine. Hope this is your worry and the advice helps.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Well it's spit out enough to fill my overflow bottle and overflow out of the bottle. I know losing a little bit is okay and it's suppose to do it that but it's not a little bit. Cause I did start to think I was overfilling it. I stopped refilling it then it just got to the point where it'd just spit out coolant then I'd be low on coolant and it'd start to run hot.

But I also must say my filling point is lower than the radiator. The system my dad and I designed is different. It has a separate filling reservoir. I don't fill up the top tank on the radiator. So I'm thinking I'm getting a little steam bubble up too and it pushes out the coolant when I turn up the RPMS. So I think I'm planning on putting some kind of bleeder or plug on the top tank to be able to let air out.

Does that seem like it could be it?

Here's how the system is designed so you get a better idea of what it looks like. Think I just have some more engineering to do.





Thank you for the suggestion!!

That first one looks all weird haha

Sorry, but that system is designed to leak. Speedway used to sell (maybe still does) T-bucket radiator and shells designed similar to that, without the tank yours has. The bottom of the fill tube was right at the bottom of the expansion tank. It would leak a little every time the engine got warm. I fixed it by putting the filler at the top of the radiator, accessible through a hole in the top of the shell. Like they were designed.

The cap needs to be above the highest point of the system, with a little room for expansion. Wherever it is located.

The coolant in your system is under pressure out the cap because it sure appears to be about level with the upper level of the coolant in the radiator. It's just doing the only thing it can do. Liquids don't compress. The pressurized pocket above the cap is pushing the liquid out.

Probably nothing wrong with anything else

Right, that's what I'm thinking it is. So you think a steam pocket is causing it to push out coolant then? All of this was custom fabricated by my dad and I, just weren't thinking about that when we made it! Haha oh well, not that big of a deal to put a filler on the top tank

Usually the top of remote expansion tanks are a little higher than the top of the radiator, so that the level of the liquid in the tank is equal to the level of the liquid in the radiator. So that the pressure builds in the upper part of the expansion tank, underneath the cap. Just like it would if the expansion tank was at the top of the radiator like they used to be. There has to be room somewhere for expansion of the coolant. It is no tiny amount. Your tank is mostly just part of the coolant system. Looks like little to no room for expansion once the normal level of the coolant fills most of the tank.

Cool thought, but it doesn’t seem to be working. How about something like this, it would just require some hose work. If it solves the problem you could work out a solution you liked better.

https://www.jegs.com/i/JEGS/555/53098/10002/-1?CAWELAID=1710676818&CAGPSPN=pla&CAAGID=39714413703&CATCI=pla-457013475083&CATARGETID=230006180040357466&cadevice=t&jegspromo=nonbrand&gclid=EAIaIQobChMIxd-B7d7K3AIVBcpkCh2BCwtQEAQYESABEgJGlPD_BwE



miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

"But I also must say my filling point is lower than the radiator. The system my dad and I designed is different. It has a separate filling reservoir. I don't fill up the top tank on the radiator. So I'm thinking I'm getting a little steam bubble up too and it pushes out the coolant when I turn up the RPMS. So I think I'm planning on putting some kind of bleeder or plug on the top tank to be able to let air out."

Do you have a coolant overflow/recovery tank in the system in addition to the expansion tank shown?

It would be a shame to have to remove that expansion tank (the inline filler mentioned is the quickest out without having to modify the grille shell).

____________________________

My unasked for opinion is the simplest all around best looking system is the one the car came with. Any other system only adds more unnecessary clutter and results in a system that doesn't work as well as prior to the modification. I have a mostly original (sheet metal wise) Y-block powered 32 5w, see the radiator and all every day. I see nothing objectionable about the original form. Still using an original radiator by the way.  

The glass T-bucket I had was a Total Performance unit from before the sale to Speedway. Apparently they had the same idea of cleaning up the top of the shell also. Didn't work there either. The way I fixed it, with the cap I used, the top of cap was barely above the top of the shell. Actually was cleaner looking than before because there was no filler neck sticking out the back of the expansion tank. And I was able to have probably about 1 1/2 quarts more coolant in the system. 

The original type system was better on every count in my book.