Hot Rods AD_NAPCO's 39 GMC Rocket 324 Build

Go with the top pic; fig 11-22. The lower pic is misleading to me...because the apparent lack of one washer at the front of the cluster...from what I see

The top pic matches the parts number book illus, and seems right to my memory...

Two tiny needle retainers, one at each end, but then each are backed up by a "retainer washer",,,then a bronze at either end.


I did read what you said you took off the rear of the cluster...if you can't sort this out with the company, put up a pic of what you had in there at both ends.

I know I ended up with some clusters from who knows where...and something prevented me from using them. I know there was a gear tooth angle difference, but don't recall if the recesses for washers was different too..
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I will set up a picture showing how mine came apart. For now, though, here are a couple of pictures of the inside of my case. I wonder if this rear thrust surface looks like it's just worn to you, or if it's actually been milled deeper than standard? Two steel washers and two bronze washers is a lot of extra room at the end of the cluster/countershaft to have to account for just in wear. Don't you think? I realize these pics may not tell enough of a story.

In the meantime I called NW trans and gave them measurements of my original thrust washers. They are checking things out and should be calling me back soon.

 

Looks all chewed up to me, as 5 minutes ago, I looked at two cases for you... One is a 37 case that never had the Olds gears, the other is a stock Olds selector case.

I was studying the front thrust surface on both. Yours looks like something spun, or who knows why, or better yet, HOW could they get in there with cutters to contersink??

Anyways, I did not look to see if I had a bore micrometer to go between 7 to 8"....and even if I did, you won't likely have one.. So, I measured through the cluster shaft bore with a folding ruler. Not accurate I figured, but looking at yours now, let's compare rough measures..

Mine are 7-11/16; kinda on the outside of the 11/16 line.

check yours and get back

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Starting to get a bit discouraged with this trans. Feeling like I got a sour deal to a degree. My cluster is 7-7/16" pretty much exactly. So that explains the need for all the extra washers. What it doesn't explain, at least initially, is where this cluster came from. The reverse idler fits exactly as it should. I will say this. When it was all assembled, everything seemed to move smoothly... I didn't feel any rough spots or dragging. That said, I have to assume things would be different under load. Also, just to clarify, the above pics were both of the rear thrust surface. The front thrust surface does not look nearly that bad. It has some slight grooving but nothing like the rear.

 

Let's do some measures;
-measure the thickness of the front thrust wall, from the front of case to the machined thrust surface. My 37 case here looks mint, and I have .525 . This must be a preset dimension to get the cluster aligned with the input gear on any given production trans case. I used both a vernier caliper through the main bearing bore, and also a conventional 1" micrometer.

-the rear thrust can't be measured that way as it is a rough casting on the rear outside. So, for a close measure, use a folding ruler to go from the front trans gasket face, through the cluster bore, back to the rear thrust face: I get 8-1/4" exactly.

Find out how close the front thrust thickness is first; Then if that is good, now the rear thrust face can be "flycut" or "faced" on a milling machine.

You'd need a ballpark figure of how much material "from original" to what needs to be cut back. Let's say it needs a minimum of .200 to do a perfect reface.

Don't cut it yet, as you need to find a proper machined washer(s) that will be added to get back to stock specs(so that stock cluster and orig thrust washers will drop in with correct lash). So, if the only washer you can find is say .250, or two at .125, you'd face the case to that .250 spec.


As far as getting a bad trans, there is the old saying about the guy with no shoes complaining, then sees a guy with no legs. I bought two oldtime converted 37s from a hamber in New Jersey. He had the transmissions "gone though" by a "oldtime, go-to trans guy" before selling them. One was mint. The other had the wrong shift tower spring, and the heartbreaker was that when they drilled/tapped the one new hole for the Olds tail, they somehow cracked the case from the new hole, all the way into the rear main bearing bore...It's junk to me, as I would not sell a trans like that, even though it should work OK, and can't leak, as the crack is inside. I can't fault the seller, as it could not be seen, and don't know if the trans guy told him it was cracked.

EDIT: what I mean about the "no legs" comment is that your case is definately fixable and my cracked case not repairable. As far as wondering if a 37 Lasalle trans would have been a better choice; most of those one year tansmissions have been beat to death by racers, and most really need a new syncro and a new first/reverse sliding gear...which are impossible to find now.
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I understand where you're coming from. I just feel like I paid this guy for a trans that he supposedly built, and was a advertised as a 'bolt in' ready to run deal. I'm not one to bitch for no good reason...

Strike 1) supplied cross member is clearly not for a stick bell.
Strike 2) no shift rail relief in the bell.
Strike 3) cracked tail housing

Not sure if this current madness qualifies as a strike or not yet, but I paid $1500 plus the freight from Michigan to California for the trans... Now I'm at around $400 in additional parts and labor to get to this point before possibly fly cutting the case.

Believe me... I get it. It's part of the hobby. Part of the game. I guess I'm just disappointed that it's not as advertised when it wasn't supposedly a second hand deal, and I feel like I paid him a fair price for what was advertised. Too many ugly surprises thus far to feel like that's still the case.

Now, that said, I'm going to stick this out and do my damndest to make it all work. I by no means am giving up, and I'm sure that once the sting of the extra dollars is gone it'll all be worth it.

I again want to reiterate how much I appreciate the help that I'm getting from you guys! Without you all, I'd be up a creek with out paddle! So thanks again. I can't say that enough.

I'm going to go get those measurements for you now.

 

Front thrust wall thickness checks to .535"
Front gasket face to rear thrust surface is 8-7/16" best I can tell. I didn't have a folding ruler handy so I took a thin dowel, bottomed it out on the thrust surface going through the front cluster bore and marked it with a razor blade at the gasket face and then measured the dowel from end to blade mark.

 

Seems like it might end up at .250 additional shim, after they mill the surface perfectly flat. You'd need to source some heavy machined washer(s) with correct ID/OD to make that up.

The machinist will then stack your cluster including the new stock washers and thrust washers,measure that stack,including the repair washer(s)... then he'd have a number to machine to, with an agreed-on thrust clearance spec.

I did add/edit my last post on the "no legs" as you posted at the same time. Anyways, I was also wondering if your trans mounts are for standard trans; I think someone said they were different? IDK, but could that be why the crossmember angle is wrong? Too late now, though.
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Ok... Well, I just got off the phone with Northwest Trans. They figure someone must have been asleep at the wheel when they put my parts order together. They are sending new thrust washers at no charge but it's UPS ground so I'll be waiting a few days. I'll have to talk with the guy that's doing my top cover repair and see if he knows of a machinist he'd trust to handle this job.

As far as the trans mounts, I double checked what I ordered from Fusick and the pictures/part number and description from their site. I definitely got the stick bell mounts. I am confident that he sent me an incorrect crossmember.

In any case... I'll wait for the new thrust washers to show up and then go from there.

 

Been away on other things all day yesterday. Catching up now. Will go check my 37 Buick case just for reference and add it to this thread.....
As for all the issues Josh......that is hot rodding......often 2 steps forward and then 3 backwards when dealing with this old stuff regardless of the representation made by many. Got the same deal with a Lasalle right now. Must have been a drag tranny at one time and the rear thrust area is really worn.

 

On inspection of the 37 case it appears to have little or no significant wear in the thrust areas. The rear thrust shows none! and the front has a shine to it.....go figure. The front thrust area thickness on this one is .532 and using a push rod with machinist dye for marking the face of the tranny edge I come up with 8 7/32 darn close to what Frank has. Should give you a good base line for figuring, I hope.

 

Thanks, Walt.... I know it's part of the deal. I have a much easier time forgiving these types of things when it's a part that has changed hands and the history is unknown. This, to me, is a bit different because I bought the setup from the guy that claimed to have built it and ran it, the complete assembly supposedly coming from a functioning vehicle. We now know that can't possibly be 100% true because the bell was never modified, and the cross doesn't fit a stick bell. So all things considered, yeah, parts snafu's are just 'part of hotrodding' and I 100% accept that. I don't agree that dishonest sellers should be an acceptable part of the hobby. I don't think I can chalk this up to a senior moment on the seller's part as he seemed to be very sharp when I spoke with him on the phone. Encyclopedic, in fact, when it came to interchange.
That said... I'm moving onward and upward. Like I said before, I'm gonna do my damndest to make this thing work, get it running, driving, stopping, and then drive the snot out of it!

To that end... I had five of these extremely rare RPO 18" high clearance wheels show up at the Greyhound station today. These were optional at least from 39-46 on Chevy and GMC pickups. They are the standard 6 lug truck wheel pattern. This is only the second set of these I've ever seen, and the other one was in a picture. I dug out the nicest original GMC cap I had and did a quick 'dress up' shot. I think these are gonna be sweet!

 

Josh, rims are unique. Never seen a set of those before. What size tire will you use on those? As to my comments about hot rodding...........I do agree with you regarding the shady characters out there selling this stuff. No matter how careful one is it is very easy to be taken advantage of these days.

 

Yeah I like'em! I like the more commonly seen 15" artilleries as well (which is what I have on the truck now) but these are different and just have a cool truck look to them. I have only seen one other set on a similar (1940) GMC but that truck was in Virginia, and just pictures. As far as size goes... I'm not sure. I think the range of available options for 18" x 4" rims is going to be pretty limited.

 

I've been searching here for hardened cluster washers to get to .250, to no avail..

I seem to have misplaced a box of transmission small parts, all were NOS GM. I thought I had quite a few small GM envelopes with individual bronze and steel shims, and I know I had a dozen TOB clips in that box and I can't find those either...senoir moments.

I did check some stock Olds cluster steel washers, and they are under .100, so I doubt stacking two will be enough. There is more than enough casted mass at the back of the cluster to mill it to take three washers...or two steel with a thinner bronze one.

If you were forced to machine a mild steel spacer instead, you'd want to pin it with a blind hardened dowel pin. The pinned spacer will guarantee that the case will never wear again. "Blind dowel" meaning the pin cannot wear on the adjoining washer.

What I'd do to get a blind hole that is "easy to index"; Let's say the mild steel spacer is .250 thick. Now put the spacer on the drill press to make a 1/8" hole right through one side. Now put the cluster steel shaft in from the rear of the trans a bit, to align the spacer to the case bore hole. There should be enough room to get a small hand drill into the case, then drill 1/8" through that spacer hole into the case.

Now take the spacer out and drill one side of the spacer to a "stepped hole" using the drill to match the diameter of your hardened dowel; like 3/16 or 1/4". "Step" meaning you won't drill completely through the 1/8" pilot hole. Then use the same drill in the case to fit the dowel to the correct depth. The stepped hole in the spacer will keep the dowel from wearing on the cluster washer.

I see you mentioned the 324 engine in the Olds thread; what is the status on it? Is it ready to go?

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Thanks for that detailed description... I'll be taking the case with me to the shop where my top cover is being repaired once he calls to let me know that part is done. I'll see if he has a machinist that can fly cut the thrust surfaces. I'll ask about hardened washers too. Do you think a machined mile steel washer that has been case hardened would work or would that be too little heat treat to trust?

On the 324... I assembled it nearly 3 years ago now and I don't trust my memory of where I was exactly. My first step with that will be to pull the timing cover and check to make sure that the 'slinger' was installed. I can't picture it and Tony and Walt both said I need to make sure that's there. I don't think it's pictured in the exploded views of the motor I posted last week.
My next concern is that after getting all the rods and mains torqued to specs, it's just always felt tight to me when turning it over. I'm not sure how much resistance I should expect and I'm worried I didn't get it right.
I still need to rebuild my distributor as well. I was going to send it to Tony a few months ago to get recurved. I never actually got a quote from him on doing the job but it didn't matter as my 'play money' evaporated unexpectedly. I've been liquidating extra parts lately to keep the money flowing recently so that hasn't been as much of an issue.
After that... I went around and around degreeing the cam and I'm just not sure I did it right. I'm hoping I did, and there's a simple process to check myself.

Now, I'm sure there's a major order of operations issue with the above set of concerns and when the time comes I'll be asking which things I should be worrying about in which order. One bummer of it is that the motor is all sealed up with gaskets and permatex, etc. So I'm gonna eat it on a new gasket set.

Before I dig back into the motor though I need to beef up my rotating engine stand. Unfortunately all I have is a cheapo HF stand and that thing just scares me when I put a heavy motor on it. I'm always on the lookout for older USA made stands (preferably with a gear driven head) on craigslist but they seem to be made of unobtanium.

I also need to build a test stand based on some pictures and a diagrams Walt sent me a while back.

 

I just put a J2 motor on some weird rolling engine stand I found at the scrapyard years ago. When I had my 324 on it, it felt so shaky moving across the floor. On the J2, I made two strut bars that bolt to the lower front cover threaded holes for a stock front mount. NO, the motor cannot rotate now, but it is rock solid on the four casters when moving it. I just wanted the J2 off the floor for cleaning, dropping pan, etc..and not feeling like it would tip over when I move it.

Ok, back to the trans..I had a lightbulb flashback .. If you use a stock "rear" steel cluster washer from a Selector, it already HAS a freaking dowel attached to it! All you need to do to the remachined rear thrust surface to accept the doweled washer, is a notch cut in the case. I am pretty sure a Selector case rear notch is just a rough casted slot...so you can make a shallow divot with die grinder bit or Dremel or even a drill bit. This will permanetly protect that new surface.

Then, going by: one doweled used steel Olds thrust washer, and one undoweled steel thrust washer, and one NOS Selector rear brass washer...stacked together, we are at exactly: .250" wowee.

So, you will end up using these three additional washers at the REAR, as their OD is sized for the smaller rear surface. I hope your front case surface is not needing much? Because if you cut there to, we'd need to get a thin shim with proper thickness, and also for that larger OD...because the cluster gear needs to stay aligned with the upper shaft gears. You don't want to move the cluster forward or back, compared to original..a little is OK though..

The tricky part of working with GM washers(instead of a custom made thickness steel spacer washer) is that the case can't be over cut by say .010 or whatever, as we are stuck with doing corrections with THICK washers. So the machinist needs to know that, not just clean the faces and let YOU worry about the clearances later.

How bad is the front surface? Let's try to plan this out with what is available for washers, before you get it cut. I will look some more here in the meantime.
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Pic of what I have found so far with measurements of thicknesses.

The Selector case here, has a notch at both thrust faces, but I cannot find a stock steel Selector front washer; all I show here is the brass one for the front. Middle row top one >>EDIT: There never was a steel one at the front; I looked it up..

Maybe Walt has a Selector apart right now to show us what the larger front steel washer looks like, as far as a tang or dowel protruding? I sort of recall a washer with a dent pressed into it? Maybe Fedco thread has a pic..>>EDIT: see above, there is no steel washer there from new. Is it a bad idea to let the brass one spin? IDK

I also show on the left, unknown brass washers that might work in a pinch, if the rear face needs a bit more washer. Too small for the front surface.

Also in the middle row, a front and rear view of two unknown tang type washers which are half steel/half brass sandwich. I think the OD is a bit too small to trust on the front thrust.

 

Well the pre-dowelled selector washer is certainly interesting. I agree that this needs to be planned out thoroughly before proceeding to hastily.
Earlier you mentioned milling the end of the cluster gear and that got me thinking about the fact that there is already a recess in the end of mine. Not sure if that is normal or not but you can see it in the picture below. The recess is .064 deep. My two steel washers, which were both at the rear, like the picture I posted earlier showing how the cluster came out, are .092" thick.



The front surface shows wear, but it's just enough to catch a fingernail, maybe a .001"-.002". in the two grooves that appear the most prominent. So it will probably clean up without much disturbance to the overall endplay, right?



I think that the rear surface has already been cut by someone in the past.

 

Maybe that case does not need a face cut... Let me go measure OD of stock NOS rear thrust washers. That would be slick if you can fix it with shims. Front face looks usable.

The old rear face pic last week was deceiving, it looked like the rear surface was chewed up at an angle. Is that inset rear surface at the case, good and flat?

i will look at some cluster gear rear faces too
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Ah well that's good! Maybe my photography was the biggest problem.
Running a fingernail over the rear surface, it actually seems better than the front surface. No prominent ridges. I wonder if maybe running a small stone over it might be a good thing as it does feel a bit rough. I may be able to rob one from an old brake cylinder hone if I can find one in the shop. The other thing is I wonder if I should knock some of the nasty edges off around where the inset was cut.

The inset seems good and flat at the rear. When I set the steel washer in there without the shaft in place, I can't force any rocking so I don't think there's any curve to the cut. I wish I'd have thought to measure the end play before I tore it all out of the case.

 

No, I think pics taken in whatever lighting distorts or makes things look different...just like the pic of the back end of your cluster gear.. I still can't tell what the recess really looks like in person, nor if the chips on the teeth are excessive or just an illusion..

Ok, three pics of two cluster gears. The one on the left: that has no needles in it, but does have the SECOND washer (which is 1.345 OD) installed, which makes the back end of the gear to be a flat surface for the "thrust washers". Is that what you have?

Looking at the cluster on the right; That has the first washer, which is the smallest OD of: 1.120. It fits into the main bore hole, and keeps the needles from hitting the washer shown at the left gear.
I used all three pics in case it makes things less deceptive at different angles of view?




Now the pic of the two clusters from the side. I wanted to show the difference in the way the "wide" gear at the very back of the cluster for first/reverse, is all one gear on one, but it is split with a groove on the other. One of these is unknown year or whatever, as the teeth angles differ when you try to mesh a 1/r sliding gear on them. Now, I should have check teeth angles on second gear, to find out why..maybe..that Roadsirs trans has been said to be a different sound than what I recall. IDK.

The problem I have here, is many loose pieces came from a few old Olds hoards, and one guy that is still alive, told me which transmissions the local yard used to save for him, and his racing buddies...Buicks, Pont, Olds, etc, but never gave me the years. Maybe one of these clusters are the "40-48 Buick internals"that was mentioned in Hot Rod magazine tech article from 1956.


Here are OD of rear big thrust washers:
1.785 is brass and steel is 1.790

I tried to get the decimals typed out and proof read, but this damn font is very hard for me. Well, Truman Capote probably would like it, but lets stop there. Josh, if one measure is way off, I maybe made a error
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Well... Hmmm... Of the two gears you show, mine more closely resembles the one on the right with the split gear, at least on the end. Mine, however, has had a 'cross' milled across the end, and maybe for oiling, as it has had the inset cut in so that the thick steel washer to ride in there. Remember, my cluster came out like this... At least I think it did. I can't see how I could have lost a retainer washer at the rear end.





Looking at the rear of Walt's split gear cluster, I see he has the recess for the retainer washer to fit. The larger of the two small washers. I think my gear had that at one time but was modified.





It must have been part of their original scheme to make up for the short cluster gear? I guess there's not really a good answer until I get the new thrust washers here and try to get it all installed in there and measure for end play to see what if anything I'm missing. It almost seems like they are using the second large steel washer as a replacment for the meat they cut out of the end of the gear and then the extra bronze washer, plus a tiny bit of extra from where the steel washer sticks up above the end of the gear makes up the difference in overall stack length. I don't like that the little needle retainer is not backed up by a proper washer but unless I can have a recess cut in the hard steel washer (not likely) I can't see being able to change that.

 

Well the replacement bronze thrust washers showed up this morning. Hoping to get out there tonight maybe and see if I can the reverse idler and cluster installed so I can check end play on what's here. Any thoughts on what I posted above?

 

Work on the cluster first IMO.

And maybe get some more opinions on the rear stack of brass and steel washers? If it were me, I would put the smallest OD washer, then one steel, then a brass, then the second steel, and finally the second brass against the case. I suppose it was run a long time with two brass ones together, so maybe it won't matter..Flip a coin

I can't see a way to use the medium OD steel washer, now that the cluster is cut in. I'd leave it out.

Post what you end up with for endplay.
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So don't install the reverse idler at all yet? Just see how the cluster fits first? I don't think it's possible to install the reverse idler after the cluster, is it?

 

I don't think that the R I can be installed after the cluster is in but it might be easier to work on the cluster with it out to get the end play figured out which at this time has to be the most important issue. Once you get that all done you will just have to pull it apart to get the RI in, IMO

Have not had any garage time in the last few weeks as I am painting the house, then have family coming for a week visit from out your way, then a quick trip to Canada for some R&R. Gesh, no wonder I never get anything done....

 

Ok, so I just went out to attempt to load this cluster gear into the case and I ran into the same issue three times in a row which is that once I get the cluster loaded with rollers, spacer tube, and heater hose loading blank, I go to slip the cluster shaft in to push the hose out and it binds about an inch in. What's happening is that the rollers are slipping past the roller spacer tube causing it all go to off center.
Makes me question whether the tube is correct or not.

So, with that, my spacer tube dimensions are 1.03" OD x 4.964" long. Do you guys have any spacer tubes to at least compare OD? I realize my spacer tube may be shorter because my cluster is shorter.

 

I've got a bunch, who knows what they all came from...selector, 37 LaS, Cad, 50 Olds

I'll get back soon...tonite

something sounds odd though...Have you loaded the needles and spacer, then tried to use the hose and solid shaft on the bench? rather that trying to put it inside the case. Just to see what is going on. Or maybe you know already
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