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'51 Chieftain - On The Road


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Well Phil, on to positive side, when you get it fixed you will be more confident about going anywhere with the car. I was hesitant at first about opening up engine or transmission, ( manual ) but I am glad I did. I found some issues and fixed them. My intentions are to travel cross country with this car, and should any issues surface, I now have the knowledge to be able to repair or diagnose most issues. And with the help of this forum, if I don't know what's wrong, there's enough people connected to it, to help me(or anyone) to figure it out.             Keep us posted... Glad to hear you are in your new garage . John

 

 

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True.

 

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I now have a collection of pieces. Need more trays.

 

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Case looks good.

 

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Next up will be to split the drums open and check the clutches. Hopefully all that swarf is just from that and not the center bearing.

 

Phil

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6 hours ago, john hess said:

Well Phil, on to positive side, when you get it fixed you will be more confident about going anywhere with the car. I was hesitant at first about opening up engine or transmission, ( manual ) but I am glad I did. I found some issues and fixed them. My intentions are to travel cross country with this car, and should any issues surface, I now have the knowledge to be able to repair or diagnose most issues. And with the help of this forum, if I don't know what's wrong, there's enough people connected to it, to help me(or anyone) to figure it out.             Keep us posted... Glad to hear you are in your new garage . John

 

 

 

John

 

That's rather where I'm at with this. First automatic transmission I've had to pull apart- the manual is actually really very good at demystifying it. 

Broken down into its modular parts each function becomes less difficult to comprehend. This thing definitely had some aircraft engineers working on it though, there are some really very aviation style designs, wrapped in inch-thick cast iron...

 

Overall it's not that bad to figure out. The trouble with me will be listening for odd noises and worrying over them.

 

Phil

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20190804_161505.thumb.jpg.ff27cd306b0eb78561a3e61be55834a3.jpg

Root cause, this bearing failed, causing the other one to misalign and fail. The resulting off-center of both drums caused the fluid sleeve to come into forceful contact with the drums, melting the sleeve and fracturing the oil control ring.

 

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The inner bushing remains in good condition and as such held the primary epicyclic shaft true.

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So, the hubs of the clutches are toast and the fluid control sleeve and rings. The rest of the rotating parts are ok, the planet gears on that shaft are a bit worn but not horrible.

 

I've yet to pull the clutch packs apart to see how they are inside, hopefully they've not ingested too much swarf.

 

I'll see what FATSCO has to say on the matter, if they have the hubs and bushings individually. They do list the fluid sleeve new so that's a start.

 

Phil

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That's more like it, a la carte non-broken preloved parts.

 

Gonna pull the clutch packs out and see what shape they're in- if I can get away with just new hubs and bearings and fluid sleeve then that makes me happier.

 

Phil

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One thing I would advise about reassembly, and this is for automatic transmissions in general, not just Hydra-Matics. Cleanliness is absolutely essential. A tiny spec of dust in the wrong place can ruin a rebuild. I know that is hard to believe since you find all sorts of crap from the steels and clutches laying in the pan of working transmissions. I don't know why that is different, but it is.

 

If you are not assembling in a clean, dust free room, and have to use a garage, like I used to do, close the doors and wet down the concrete floor and anything else that might put dust or dirt up in the air. Use a clean, clean, bench. If it is not a metal bench, put down some hard faced paper, something that won't release lint. Don't do part of the assembly and the rest later. Do it all at once and get it closed up.

 

Make sure your case, including any passages, is completely free of that swarf before you start.

 

Clean parts with clean solvent, blow them with compressed air, lubricate as necessary with ATF or transmission assembly lube, and put them in immediately. Do not get them near any shop rags! A tiny piece of lint can ruin your rebuild. Lint free rags are (or used to be) made for transmission rebuilding, but they can't be had on a minute's notice, and probably aren't a  good idea anyway. Banish rags, paper towels, etc from your shop while you assemble this.

 

Spool valves in valve bodies need to be able to drop out of their bores under their own weight. Don't be fooled by springs. Most of these spool valves are pressure balanced in actual operation. It really doesn't take anything to make one stick. Be careful cleaning them, Don't try to smooth or deburr uncooperative ones. The sharp edges are absolutely essential to keep tiny dust from wedging the valve and making it stick.

 

If you have some spool valves that won't fall out of their bores, don't just try to polish them or something, because the only way back from that mistake is to find another valve body. Take a step back and plan what to do next.

 

Good luck with your rebuild!

 

Edited by Bloo (see edit history)
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I had read through this in the manual and other rebuild advice elsewhere.

I'm unfortunately having to do this in my garage. I'm at the "get the swarf out of everything" stage, which is involving cleaning things down and putting them on new metal baking trays.

 

I'm going to be ordering the spares for it soon, at which point the clean/reassemble will be through the manual in one go as you say.

I've worked with precision hydraulics before and am familiar how little it takes to completely screw up a bore...

 

Any advice is absolutely welcome though. Thank you.

 

Phil

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Spent last night taking measurements of the thrust washers and doing some calculation.

The main shaft end-float is a compound of all the thrust washers and machine faces between the main center bearing and the back of the gearbox, so 4 washers and a shim.
When the gearbox was still all in one piece I measured the lash and it is 0.019", which is just outside of the 0.004-0.018" specification.
The thrust washers are quite worn. One is all the way through the copper coating, and regardless needs replacement. They measure 0.087" and 0.088" respectively, new they are 0.090" so I just ordered 2 new standard thickness ones and a slightly thicker main shaft end-float washer to bring me back into spec.

 

--Phil

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Someone I met at Ames last year (who had a lot of road miles in flathead Pontiacs) told me "keep it below 3000  and everything will be fine".

 

Most engines generally should be able to sustain 80% of the RPM the horsepower was rated at.

 

Someone on the VCCA forum told me he could run his 1936 Eight 3250 RPM all day long, and often did on trips until it got wrecked. It was rebuilt and had aluminum pistons. Aluminum pistons put less load on the rod bearings at speed.

 

The good news is that HydraMatic cars are much less likely to spin the engine too fast, because they have a fourth gear.

 

How's that for a non-answer? :lol:

 

 

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Ha, yes. The book does not state what RPM max power is produced. 

 

Only reason is I want to set the needle on my tach. Technically it shouldn't go over redline because automatic but you never know if someone else is driving it with less sympathy than it deserves.

 

Following from what your wrote,I like to keep an engine cruising in the lower 2/3 of it's rev range if possible, but then again that comes from running small 4-cylinder engines (with design from the fifties, way to go stretching an engine design, Fiat...)

 

Phil

Edited by PhilAndrews (see edit history)
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48 minutes ago, PhilAndrews said:

Ha, yes. The book does not state what RPM max power is produced. 

 

Only reason is I want to set the needle on my tach. Technically it shouldn't go over redline because automatic but you never know if someone else is driving it with less sympathy than it deserves.

 

Following from what your wrote,I like to keep an engine cruising in the lower 2/3 of it's rev range if possible, but then again that comes from running small 4-cylinder engines (with design from the fifties, way to go stretching an engine design, Fiat...)

 

Phil

well pontiac max horsepower was read at 3600 rpms for straight eights 1949 to 1953, at 3800 rpms for 1954 straight eight, my 53 chieftain custom catalina would do 95 mph on a old tired 21 year old engine in 1974, with a 3.08 gear ratio at 90 mph the rpms were about 3400, with the highest gear ratio of 4.30 at 90 mph the rpms is 4750 according to the 49 to 54 pontiac shop manual. as a tech advisor, i have always told straight eight owners who have a tachometer to keep it no higher than 4000 rpms. 4th gear is not a overdrive gear, it's ratio is 1 to1, direct drive, no reduction.

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3750 is not an unreasonable limit.

 

I'm really wanting to keep it below 3000 anyway, that's really very fast and doesn't have much benefit in everyday driving. 

In the short distance I drove around it was happy 500-1000.

 

Other people may not appreciate that it doesn't share the same dynamic properties as more modern designs (oft with 6000-odd redlines). Just thinking of trying to preserve it a little.

 

Phil

Edited by PhilAndrews (see edit history)
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1 hour ago, PhilAndrews said:

3750 is not an unreasonable limit.

 

I'm really wanting to keep it below 3000 anyway, that's really very fast and doesn't have much benefit in everyday driving. 

In the short distance I drove around it was happy 500-1000.

 

Other people may not appreciate that it doesn't share the same dynamic properties as more modern designs (oft with 6000-odd redlines). Just thinking of trying to preserve it a little.

 

Phil

i remember my 53 cruising at 55 mph was only turning over about 2000 easy rpms

 

Edited by pontiac1953 (see edit history)
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I wasn't meaning to suggest that the HydraMatic had overdrive, just that HydraMatic cars usually came with higher final drive because they had 4 gears available, and could get away with it.

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2 hours ago, john hess said:

I guess I'm old school... No tach. I just listen and feel.. most engines will tell you if you're pushing too hard, or chugging too low... John

My point is some people can't do that. So, a gauge with a red marker "not above here" is a help. Granted yes, you can feel it but still.

 

Phil

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4 hours ago, john hess said:

I guess I'm old school... No tach. I just listen and feel.. most engines will tell you if you're pushing too hard, or chugging too low... John

i drive truck, and i don't need a tach to tell me when to shift the gear, i can tell by the sound of the engine.

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Certainly not downing the use of a tach, I was just commenting on my driving habits.. also no need for a "check engine" light in my 53. It's called 'pretrip'..… I 'check engine' every day.. truck driver thing, I guess.... 

Hope the transmission rebuild works out. Ya got quite a project there Phil..

F

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I used to drive my Hillman by ear- clutchless changes. I was taught mechanical sympathy by my father, so I hear you.

 

I just know that the car is gonna be driven by other people and not everybody has such a good grasp of the concept.

 

 

I've just booked myself a week off work, hopefully get everything buttoned up and get the car rolling again.

 

--Phil

Edited by PhilAndrews (see edit history)
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The tach/rpm subject reminded me of my motorcycles. My cruiser is 5 speed and I was used to "listening" to that engine. I then picked up a mid 80's Yamaha 4 speed. I had difficulty reading the Yamaha's engine, always thinking there should be another gear to shift. I had to use the tach to get used to it. I've since chopped it into a bare bones bobber without it's tach. I now know it's sound. The tach was helpful for me and would be for other drivers of Phil's car. If it was me, I'd have no tach because nobody is driving my car! LOL

 

Good luck with the Hydra, that stuff sounds fun but WAY over my head!

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I just stopped at AutoZone and they've changed up the transmission fluid they stock. Up until 2 weeks ago, they stocked Dexron-IIe. Now, they've rearranged everything and the oldest type oil they keep is Dexron-III compatible "universal" oil.

 

That made me think. Possibly the wrong oil had been put in, because the seals are rock hard and split like so much cheap plastic, and the only bearings that are bad are the phosphor bronze ones in the hubs. 

 

That would explain why it wore to such extremes.

 

Phil

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Cleaned out the governor. The B weight would get a little sticky in the bottom of the bore; a thorough cleaning has resolved that and now sees both weights falling freely under their own weight when the governor shaft is rotated.
That'll certainly have been a not-changing-gear issue.

Phil

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The valve block isn't so good.

The governor plugs do move a little in their range but bind up badly before coming out.

The shifter valves are so-so, 1-2 is ok despite having been full of black gunk but 2-3 and 3-4 are sticky.

I need to inspect with an eyeglass and bright light the bores and valves.

 

Phil

Edited by PhilAndrews (see edit history)
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Freed up the overpressure relief valve in the pump and reassembled it with two screws for now.

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Installed two new rings on the pump nose, where the fluid torus case sits.

 

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Then, using the old seal as a mandrel and as block of wood I knocked the new seal in place. Special tool not available so that worked nicely.

 

I like this because this is where it was leaking very badly from before. The old seal was totally unserviceable.

 

Phil

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I had not been able to remove the large plug on the front servo. With my new screwdriver, that changed.

 

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This is a good representation of the muck and metal chips I've cleaned from the hydraulics. The 4-3 valve was stuck solid, took a good 5 minutes of thumping the case against the bench, wiggling the valve and swearing to get it out.

It now slides smoothly in the bore.

 

One down, rear servo and reverse mechanism to go.

 

I think I may epoxy a strong magnet to the underside of the lower pan to magnetize through the pan and attempt to collect up any remaining metal chips, too.

 

 

Phil

Edited by PhilAndrews (see edit history)
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  • PhilAndrews changed the title to '51 Chieftain - Valve job
  • PhilAndrews changed the title to '51 Chieftain - On The Road

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