Technical Hemi crossover for blower application (From idea to production)

I can see in that picture that the fitting coming out of the top of the water pump does not look vertical but seems to be leaning rearward slightly. I am going to measure my friends two engines tomorrow and see for sure.

 

Except the port you used on the water pump is where my heater hose will go.

 

If you're putting in a heater core, you'd use those same 2 ports with a longer hose.

 

No it's not, look closer.
There is a heater hose port that is in use, as well as the bypass hose.

 

This would be the correct way to run the heater hoses. If you look closely you will see the hot side comes out of the head between the intake ports and the cold side returns to the water pump inlet. The bypass is hooked up correctly as it would be on a stock hemi water pump.

The problem arises when you install a blower then there is not a proper place to pull water from. A couple options are to have a tee with one side going to the heater and the other to the top of the water pump for the bypass. If you don't get enough heat out of that you might have to put a restrictor in the bypass to slow the flow. Another option would be to pull water from the back of the head for the heater.

 

I just got done measuring my friends 392 and the measurement from the block to the center of the water pump nipple is 3" and that puts it forward of the crossover. The best option is to make it like the original PAW unit and sett the bypass up like the picture that HemiDeuce posted. For a heater on the blower engine one could use the back of the left head by installing the adapter that HH sells for their crossover and installing a 90 degree hose fitting in it. Or just make one out of 3/8" plate and tap it for pipe thread.

 

I see that the 331 head's have no provision for the crossover so how did the factory deal with that?

 

Went over that in detail other thread. Wet intake manifold with integrated thermostat housing. From the factory Most were 2bbls. Some 2x1 some 2x2 One year only 1954 4bbl. After market Edmunds had 2x4 small runner for 51-53 and large runner 1954
There's more but they are wet manifolds.



Some heads got drilled and tapped for pipe thread. That's risky because the casting is thin but it was done plenty

 

Another friend of mine has some 331 long bell housing that I just looked at and see the difference. He also brought up a problem that HH told him about the cast aluminum crossover. The aluminum and cast iron have different expansion rates and they supposedly would develop a crack after a while. I am wondering if that is why PAW doesn't make it anymore and you can't find any?

 

Good point,
why does HH still make their version of an aluminum crossover ?
And why did HH put the outlet out the front? - it's in the way there.

 

They made a lot of them and some people insist on the cast one. Probably the reason it is on the front is ease of machining. Maybe the way to do it is to make two nice castings with a short connector hose.

 

That could work out quite well.

There's a cameo appearance of the crossover here .
You can't see much but it's not a bad way to spend a couple mins

 

I did a search for PAW that led me back here to the HAMB. So it looks like they went out of business around 2010. I did find an eBay store connected with them selling engine bearings for Hemi's. I emailed the seller about the crossover and asked if they still have the pattern. I also asked them that if they did have the pattern would they be willing to cast some or sell the pattern to me so I can have them cast. We shall see what this nets us.

 

Are you planning on making the casting pattern yourself??? and do you know the shrink values of a aluminum casting this size??

 

Yes, and yes. I will make the pattern and do a test run before I make a production run.

 

They responded to my email. PAW still has all the patterns and tooling but are undecided about whether they will cast more parts or sell all of it to someone who will. There are some interested parties.

 

Given how much interest there is in JUST the Hemi stuff, why are they sitting on it?

 

Not sure, because they closed in 2010 and now it's 2017. All they have for sale on eBay is some engine bearings.

 

I can get fill-time access to one of the low-resolution (350-micron, 0.35mm) scanners at work, with nobody making a fuss. For a cast part that will require machining to finish it, this should be fine.

I think that I am just going to start scanning and publishing everything that I can get my hands on.

 

That's some good intel.

If they are lacking Operating capital they can't do much with anything with tooling they have. The offeres to buy are probably low in their opinion or they would have sold.

Big speculation here in assuming the above is true, then What they need is a partner to get parts back into the market. Perhaps a group of enthusiasts ?

 

I don't own a hemi so can't give personal experience, but I think this might be the best solution. Tolerance stacking after head and deck surfacing, and the expansion issue are a great reason to do the two separate sides with a rubber hose connecting the two. It would appear perfectly traditional.

 

Here's how I measured on my 392.
Long bolts into head at lower water crossover mount
Straight edge across on top of bolts (need to subtract 1/2 bolt diameter )
Measured down to top of BBC water pump mounted to block with HH BBC adapters.
That dimension is 0.970 less 3/16 for 1/2 the bolt diameter

Center line lower crossover bolt hole to top of water pump Is 0.7825

 

I get why a one-piece crossover is more desirable, but I wonder if casting it in two pieces may not solve several problems. If you make the center section as a round cross-section, then would it be possible to machine it for a metal sleeve to connect the two? Seal the sleeve with O-rings, you can leave a small gap between the two for expansion, and maybe even make one design for both the high and low deck motors. Simply shorten the end pieces for the low deck. You'd still have the 'one piece' look without the issues.

Just thinking out loud here....

 

These pics aren't for a blower application necessarily, just food for thought.
However there are plenty of head that could become usabl.
Here's a part that TR waters used to make to get water from the front of truck heads. You can tell the truck heads by no water outlet, the accessory mounting face and the big lug
This Required the head to be drilled and milled then the pipe thread adapter bolted on with O ring seal.


That above part allows enough tapered threads to be safe VS just tapping the thin casting like this. There isn't really enough meat there for tapered pipe threads.


Here's how Bass got water out of a 331


Here's some crazy stuff Chrysler did

 

Thanks, that helps. I also measured the distance out from the block to the center of the outlet on the Chevy water pump and that is 3". That puts the outlet just ahead of the crossover so the one picture that has that as the bypass connection there is right. The more I think about it the two piece design looks like the way to go. If someone wanted to use 354 head's on a 392 they could just use a longer connector hose. I can make the bolt standoff the same height as stock so that if someone needs to install an accessory drive it will interchange.

 

Just to clarify, the crossover remains the same for either engine until you start swapping heads across the tall and low deck blocks. Like the famed 1955 331 Tripple nickel heads onto a 392 block, Then it won't fit. Btw the nick name "triple Nickel" comes from having three 5s in the casting number. For situations like that the 2 castings with a hose would be needed.

Conceptually, two bolt on units joined with a hose is the idea behind what's currently available. It would be great to make the idea visually presentable, traditionally flavored, and the hose outlet vertical.

 

The 'low' deck (55-58) 331-354 and the 'high' deck (392) do not have different thermostat manifolds.
When MaMopar cast the 392 heads she kept the same port location, relative to the block.
354 and 392 water pump assemblies are 100% interchangeable as a package.

.

 

Hey, I'm not a Hemi guy, just throwing out an idea... LOL

 

That's what I was thinking a nice cast two piece unit would work for most everything and would be easier to make a pattern for because the shrinkage would not be an issue.

 

Good!
Just Thinking out loud
Take a look at the parts TRWaters made.
Take that concept and and use it to add a mounting boss to heads without water outlets that would accept your water crossover and T Stat housing.

Anyone running a 1951 thru 1954 331 with an intake manifold other than the crappy factory or expensive rarity could potentially be in the market base.