M-38 TWIN BELT WATER PUMP

RICKG · Post by **RICKG** » Mon Oct 18, 2010 9:13 am

THE TWIN BELT M-38 WATERPUMP CAME FROM WALCKS. THE PRICE WAS COMPARABLE TO OTHERS. THERE WAS NO CORE CHARGE SINCE
IT WAS NEW(OFF SHORE SURELY)-NOT A REBUILD. HAVENT RUN IT YET
SO I HAVE NO INFO ON LEAKAGE OR LONGEVITY.

HERES THE DEAL: THE TWIN PULLY IS POTMETAL-CAST. THE OUTER
SHAFT FLANGE IS TOO BIG FOR THE ORIGINAL FAN CENTER HOLE TO CLEAR. WILL HAVE TO REAM THE ORIGINAL FAN CENTER HOLE BY+- .060.

GOOD NEWS IS I STILL HAVE MY ORIGINAL CORE FOR REBUILD IF
THIS ONE GOES SOUTH ON ME.

idiocrates · Post by **idiocrates** » Wed Oct 20, 2010 10:47 am

The biggest problem I had with my new water pump was getting the twin grooves to line up with the alternator and crankshaft pulleys. Here's the difference that made my life difficult for a while.....I ended up ditching the pulley on the new pump and pressed the old pulley on the new pump....and then of course you have to make sure you get it on far enough...but not too far.....fun fun fun
[url=http://www.flickr.com/photos/22032 ... .jpg[/img]
P1010016 by idiocrates, on Flickr[/url]

RICKG · Post by **RICKG** » Wed Oct 20, 2010 12:40 pm

Thx, idiocrates. after reading your reply i took a closer look at my pulley-
(water pump installed, radiator installed-i thought i was done with it).
although my pulley is in fact centered correctly, the spacing between the
belts is .125" at the water pump and .25" at the crankshaft and generator.
just like the 2 pulleys you posted fotos of.
does anyone think that difference is enough to affect the belt tracking,
wear, throwoff potential? i'm wishing i'd purchased a rebuild kit and done it myself. (try to do it the easy way=do it 2 or 3 times) rick

idiocrates · Post by **idiocrates** » Wed Oct 20, 2010 12:48 pm

I don't know about the premature wearing or anything......but I put mine back to original just because as my ex used to say.......I'm like a canal without the sea in it.....at least that's what I think she said! I just couldn't stand the uneven belt spacing.

Post by **wesk** » Wed Oct 20, 2010 10:17 pm

Jim's right side pulley is correct. the crank and genny spacing should match it but the genny pulley has a solid middle section..

You 0.100 variance in tract will result in accelerated belt wear. But I don;t see a big issue if she's not a daily driver. The more important issue is bearing wear in the front of the genny and the water pump. Again not a very big issue if not a daily driver.

RICKG · Post by **RICKG** » Sun Jul 10, 2011 1:04 pm

The time came yesterday to fill the system w/coolant.
should have been a good day.. What's this?? a coolant leak
at the bypass hose fitting on the offshore POJ waterpump.
A 1/8 turn with an open end wrench should do the trick,
right?? WRONG!! the threads in the w/p body are junk.
There is no way to tighten the fitting-i'm leaking coolant
(at 10 bucks a gallon) on the barn floor and the system
is not even under pressure. I pulled the poj pump and
its going straight to the trash (after i take photos)..
Beware the offshore junk waterpumps, Mark @ RAPCO
tells me that FEDERAL MONGREL (MOGUL) has a
replacement pump made in calif (i hope of US made parts).

The threads in my orig willys w/p (in need of rebuild) are still in good shape. see below.

compare that with the junk threads on the offshore pump below

I found the overall quality of the pump to be poor, from the incorrect
belt spacing on the pulley to the poor casting. Another thing to note is
the impeller on the offshore pump penetrates the engine block housing
only 7/8 inch whereas the orig type willys pump penetrates 1-1/8".

rgmutchler · Post by **rgmutchler** » Sun Jul 10, 2011 4:43 pm

RickG
Just out of curiousity, what does Walck's have to say about the water pump. I looked on their site and there aren't any reviews. I have considered doing business at Walack's and am curious how they react to critism of their parts.
Up to know I have stuck with Mullin's, Midwest Mil,. Rapco and Willys Overland and haven't had any complaints but I have to wonder if their new water pumps are any different.

willym38 · Post by **willym38** » Sun Jul 10, 2011 7:01 pm

Alot of the bad parts suppliers websites have a place for parts reviews, go ahead and try posting a truthful bad one, it will never show up...

rgmutchler · Post by **rgmutchler** » Sun Jul 10, 2011 7:30 pm

RickG,
If you do decide to post a review on Walack's and talk to them about the pump I would be interested. It would sure help others (me at least)decide if they are worth doing business with.

Oldsalt · Post by **Oldsalt** » Mon Jul 11, 2011 7:02 am

Walcks is one of the good guys in the parts supply business. I've dealt with them several times and they've always been very stand up. When I ordered an exhaust mainifold from them, the heat riser kit that came with it had a part missing. I called them and they sent me an entire new heat riser kit, not just the missing part.

Call them. I'm sure they will make it right.

RICKG · Post by **RICKG** » Mon Jul 11, 2011 12:10 pm

I've dealt with Carl and Danny a lot in the past couple of years and
yes they always treat you right. Good Guys. I contacted them by
E-mail this am but haven't heard back yet. I'll keep you posted.

RICKG · Post by **RICKG** » Mon Jul 18, 2011 1:37 pm

I think Carl is going to blow me off on this one..
His response was " How did you strip it out?"
Here's how..
1. The fitting was a chinese/turkish 20 tpi fitting.
2. the w/p body threads are/should be 1/4-18 NPT.
3. the threads didn't penetrate the full length into
the water jacket.

My fix, carefully run my 1/4-18 NPT tap the full distance
into the pump body, wrapped a new 1/4-18 NPT galvi pipe
nipple with teflon tape the first 3/8" then coated the outermost
(closest to hose) threads w/JB WELD. It's not leaking (yet)
but i do have some seepage at the #1 (in torque sequence)
head stud-more on that later..