HEMI Tech: Oil systems- filters, pumps, pans

Which is an absolute no-no with the new, off the shelf, Melling (and Hot Heads) pumps BECAUSE the bolts used are torque-to-yield bolts. i.e. use them ONCE. If you pull them out, REPLACE them. Hot Heads, it would appear, re-uses them. And DON'T re-torque them, either as that'll stretch them even further.

As for the mention of non radiused steps in the Hot Heads pumps, that issue was corrected a few years back. The shafts, however, were NOT hardened - at least not as of last year when I bought the one that fell apart in under 1800 miles. Had half a dozen "spectators" standing in front of the garage door when I finally got the oil pan off and lo and behold, there was the missing pump bolt in the oil/antifreeze mix on the bottom of the pan.

BTW 331 and 354 have the same bottom end, just a different bore size.

 

No. If you use one of their pumps, it's a converted M-72.
They remove the hex drive shaft and replace it with a shaft that is similar in design to the stock hemi oil pump. This entails disassembling the new Melling pump for modifications.

The older Melling pumps didn't use torque-to yield bolts but all of the current Melling pumps do. Torque-to-yield bolts should NOT be re-used. My original HH pump had grade 8 bolts on the cover but the shaft wore out in less than 37,000 miles. The new pump, (the one the cover fell off of) had torque-to-yield bolts as does the current M-72 I have in there now (the one I bought to work with the longer shaft from Kent Redd). The new pump put in my Volare wagon a few years back had torque-to-yield bolts as does the one I put in my Gran Fury.

Because the M-72 is for an A block, the shaft is in the wrong location SO they (HH) also manufacture an adapter that shifts the pump over to align the shaft with the hemi intermediate shaft. This, as you might guess, drops the pump down as well.

SO, the new shaft the make is also longer than the original hemi shaft.

Aside from redrilling your rear main to accept the M-50 pump, you're left with the HH setup until the new extended hex drive shafts can be developed. (A process currently under way)

If you have an older (pre-2012) M-72 from Hot Heads, it's got a soft drive shaft and you'd probably want to drop your oil pan and see if the drive shaft looks like the one in the picture.

If you have the new style with his hardened chrome moly shaft, check the cover bolts. If they're torque-to-yield bolts, pull the bolts out and replace them with new ones before you button things up.(see picture of the wandering tirque-to-yield bolt)

 

If I had to do it over again, I'd probably just re-drill the main bearing cap for the M-50.

However, since there are so many HH oil pumps out there, I've lined up a machinist to work out a shaft like the late Kent Redd's so that the pumps can be converted back to stock M-72 over-the-counter units that'll bolt up to the HH adapter and use the pick-up tube.

i.e. we're engineering a HH repair solution.



One interesting point to consider. If HH has been denying, for all these years, that their pumps have issues, why have they suddenly started offering pumps with "specially hadrened" shafts?

Either they KNOW they have issues or they're too blind to recognize they have issues. I doubt they know much more about the products they're re-selling than any other parts-counter sales person.

 

The M50 should be a direct fit on a 354 cap (double check the bolt holes as Tom says). No adapters, no additional costs, no worries...

.

 

Leo's book shows 2 pumps that were used 51-6, & 2 other ones used for 57-8.

 

The actual pumps may be different, I think this was discussed some pages back, but there is, AFAIK, only two (2) designs for the foot as Tom also mentioned. And, of course, the pickup tube assembly is still another story.

.

 

To be very honest, I dont know how hard I will continue to pursue the hex shaft project.... unless the M50 pump disappears in the future. Besides the sb pump, the pump mount plate needs to be made to cover both main caps. Then the pump drive shaft length has to be addressed.(at least four different lengths.)

 

The hex shaft's advantages are (1) that it can be used to retrofit (remove) the modified Hot Heads M-72 without having to remove the rear main cap from a running engine and (2) the pump is a current application readilly available in auto parts stores.

If you're building a fresh engine, it's an easy task to plug and drill the rear main cap.

However.......

If you're upgrading the pump in an already-assembled engine with some miles on it, you have to not only modify the rear main cap but you also have to deal with replacing the seal and bearing (although the bearing could be optional, the seal is a given if you don't want leaks). Dropping in a new hex shaft eliminates all of that hassle.

Pull out the stock intermediate shaft and drop in the new hex shaf. Buy a new, unaltered, M-72 from your local parts store and install it on the HH adapter, and you're done. ....and you have a readilly available, over the counter, oil pump that you can find anywhere in the country on a moment's notice because the application fits a currently operational engine (the A block).

 

Actually an LA, even though many now call it an A, even Ma Mopar. Can cause confusion where there are A & LA engines. One of the hemis built for one of the Engine Challenges used a standard volume LA pump w/o any problems even though it may have less flow then the OEM hemi pumps. Just tossing that in!

 

You will still need at 3 different length shafts if you also want to cover the use of an A-LA distributor...

.

 

Good point. I wasn't even considering the late distributor issue as I don't have any use for electroic distributors. I use the stock Prestolite distributor to trigger an Accel 300+ box. The vacuum advance mechanism works much better than the eccentric unit in the sngle point and/or electronic unit distributors.

 

How do identify the torque to yield bolts? and where is a good source for replacements?

I'm familiar with how they work as I was a Gm dealership tech and we never re-used them but it was simple. I tell parts guy get me the bolts when requesting parts and there you go. I have no idea if they are available aftermarket.

 

just ordered the m50 from summit, hopefully cap and shaft and all will work out I'm using an MSD "ready to run" dizzy, but I have not been able to sleep at night worrying about the HH unit sitting on the bench.

 

look at the head of the bolt in the picture. That's a torque-to-yield bolt

 

I just love that picture.

You can see the ground though that big hole in the oil pan!

 

Put an LA pump on my 354, used the hex shaft. Removed the oil pump bolts and replaced them with grade 8 Allen bolts and safety wire. Safety wired the oil pump to main cap bolts also. Made my own adapter.



Ago

 

I have a question for the experts...

I recently purchased an oil bypass plug from a private party on ebay. I noticed there is a very small hole drilled down the axis on the plug end:




Does anyone know why this is? I was under the impression these bypass plugs where solid.

Thanks in advance for your time.

 

They're supposed to be, don't use it! It'll allow unfiltered oil into the engine & allow oil to drain out of the engine when sitting. Maybe some Goober misunderstood the thing about drilling a .050 hole in the galley plug behind the Dizzy...

 

You may want to ask the seller. He might know.

 

A windage tray is very inexpensive HP, most litature out there states that one can gain 5 - 10% HP gain from the use of a windage tray.

 

How big is the hole? Then, how much oil can actually pass through such a small dia hole at 40psi? You could play with the numbers, but it won't be much. Since it would be unfiltered, it will likely plug itself in short order on anything less than a perfectly clean engine.
Gravity flow through a 030-040-050 hole ? Easy to check if you are bored, but probably not much all depending on engine variables and oil viscosity.
Perhaps the shot of oil coming through the hole is pushing the filtered oil through the sharp right turn up into the block.

Such a small hole would be easily plugged with a screw if you are worried. Not sure that it would concern me.

Edit: Since posting the above, I got a PM asking if #1 Permatex would also work to plug the hole. Seems to me that it should do the job. Most folks are familiar with #2 which is non-hardening, #1 gets rock hard. I would force it through the face and make sure that a small 'bulb' appeared on the inside. I am pretty sure that you would need to put the tube-o-goo in some very hot water to help soften it so that it would go through such a small hole.

.

 

The screw would probably work. My thought is why have any leakage?

 

Hmmmmmm....no PHOTO...... and so little verbage as to be pointless...

It is common to mount a Mopar 340/360-type scraper on the EarlyHemi. Since the Hemi main spacing is different than the LA you will need to fabricate some brackets to hold the tray to the block. The Mopar tray does require some trimming around the oil pump on the 241-260-270.

.

 

That's what I used but I got creative on the mount. I had a few extra tall nuts that fit the main studs that I welded a smaller bolt to. Loctited them onto the main studs and mounted the tray to them. And yeah, I had to trim a bit around the pump.

 

Gary (73RR): The hole is about 0.062 according to a gauge pin. I bet drilling and tapping it for a small #6 or #8 setscrew that can be #1 loctited into the dealybobber would seal it up. I think I'll just use this one as an example and pretend I'm Jacin (HemiRambler) and make my own!

Kerry: I love the way you (and others) think! That windage try looks great. Thanks for sharing that. I would like to try what you have done there myself. I can see from the pictures how the main studs do protrude enough through their nuts that you have something to grab a hold of. Very cool.

 

Looks good Kerry! Is that a Milodon piece?

I'll try to get a pic or two of a Mopar tray in place for comparison. I should have the pieces lay around the shop.

Gary

 

Yep, It's a Milodon. Thanks for the kind words. Since the main spacing is off a bit I welded the bolts a bit off center. Even if the loctite dies it might rattle but it'll never come off.

I've got a couple of the old stock flat hemi trays somewhere. I'll try and get a picture of one of those as well.

 

Here are a couple (side by side) pictures of LA windage trays.One is off a 340 the other is an evilbay find. Note the variations.

 

Definitely!!

 

was there a difference in the 241 hemi oil pump shaft lengths?
I recieved a oil pump rebuild kit from egge and the pump shaft was 1/4" short . mine is 5" long and egge's was 4.75" .
Thanks !
john