dibarlaw

1925 Buick Master Timing gear change

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I have been avoiding installing the "Best" of 2 timing gears I have for the car. The original tore off about 10 teeth 2 years ago. I thought a rod went as there was a thumping sound before it quit. After I towed it back home I was able to start it again and there was the thump again. I shut it down and it would not start again. After I finished having the engine rebuilt on my 1925 Standard and getting it  running I decided to tackle the Master again.

 That is when we discovered no spark and no movement of the water pump shaft and fan. Timing gear time.....

 My indecision is because of the somewhat confusing Shop Manual information illustration. 

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The crank gear has a spot as noted in the illustration but it also has a scored line about 120 degrees from that spot. One of my spare gears has more of a scored spot at the root of the tooth and a line scored 180 degrees from it but on the crest tooth.

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The best gear has a well defined spot with a score 180 degrees from it on the root of the tooth.

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All the spots/scored lines etc. match to the illustrations keyway locations.

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I bored out the bad gear hub a bit to be able to try and do a dry run on fitting to see if the crank gear and cam gear matches the illustration. Notice the double spot 180 degrees (as is noted on the illustration) from the single spot mated with crank gear. I set the gear to the double spot and as per the illustration to verify the keyway location, then turned the crank 2 revolutions to make sure the single spot matched. Also notice the scored line on the cam and the scored line on the cam gear.  These lines are 11 teeth from the spot and will mate. Where the gear teeth were missing were 1-2 teeth from the double spot so I was able to turn the crank clockwise while the cam gear turned counter clockwise to effect a match.

 So my question is that the single spot cam to the single spot on the crank should get me timed correctly? I realize that the water pump gear is irrelevant as I will set the final timing at the distributer head. 

 With the gear set in either position the # 1 piston is near the top of it's stroke.

 There has been some posting over the years about these engines being timed 180 degrees off is what worried me.

 

 

 

 

 

Edited by dibarlaw (see edit history)
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Larry,

      This is the photo of my timing marks on my 1925 Buick Standard.   NOTE : #1 and #6 Piston at TDC and the flywheel on the 1-6 Mark in the timing hole. 

1) Start with the Crank shaft on TDC.  You should find that the mark on the crankshaft gear is the line about 3 teeth from the center meshed teeth.  The dot on one of the teeth is only to confuse.

2) My cam shaft gear had 1 dot on it.  That was installed so that when the gears rotated 3 teeth, they were fully meshed.  

 

So the dots are not meshed when they are at the closest point - Like you would expect for TDC.

I know Kevin Roner ran into this issue as well and did a posting on it.  

 

Also see this link.   https://forums.aaca.org/topic/317779-engine-timing-1925-buick/?tab=comments#comment-1803120

 

Hugh

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Edited by Hubert_25-25 (see edit history)
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Hugh:

 Thanks for the reference. I remember the thread at the time but I was not doing this at the time.

 The General Motors Export Company's "Motor Car Operation and Care" book is better at many things than out Reference books or Shop manuals.

 I got one with my car when I bought it. It had sat on the shelf and I should have consulted that first. This illustration in the Shop Manual would be much more helpful. In the meantime the new gear is now in! Today I can button things up and lower the front of the engine to the frame again.

 Thanks for the input.

 

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Edited by dibarlaw (see edit history)
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Larry,

This is just my thought here you must understand.  I would think that if you were real careful not to move the camshaft at all when you pulled the gear, the keyway slot in the replacement gear should keep everything in time.  Of course a person would want to have the marks on the two gears lined up.  I am getting anxious to go see my torn down engine and how the front end on this engine is after 104 years.

 

Terry Wiegand

South Hutchinson, Kansas

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Terry:

 Again, the reason I had to change the gear was because 9 teeth had stripped off.

DSCF7666.thumb.JPG.a3187042ed1d121cf1f8ba45dbc73558.JPG

So when I tried to start the car the crankshaft.... well …."round and round you go and where it stops nobody knows"!

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Larry, 

    What is the relative condition of the other "good" teeth on that bad gear.  Were they getting thin? .  The gear set in the background of your photo looks to have pretty healthy teeth still and not much wearing on the sides of the teeth making them narrow.   My spare timing gear is a little "thinner" in the teeth than the one I installed.  I wonder if in the long run if I would really install it.  

 

Hugh

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Donb,

 

The fact that the teeth crapped out was because of the gear being made of fiber.  For the life of me I simply cannot understand why anyone would put something like this in an engine knowing full well that it has a very short life span.  One thing is certain and that is that these engines did not come from Flint like this.  Larry, I understand now what is going on.  The mark on the cam gear was sheared off and you have temporarily lost the valve timing on the engine.  With the mark on the replacement gear, the mark on the crankshaft gear, and the keyslot in the camshaft gear hub, you should be able to re-establish the timing on the engine.  Sometimes those pictures are worth more than that proverbial 1000 words.

 

Terry Wiegand

South Hutchinson, Kansas

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Terry,  I thought they did come from the factory with the fibre gears.  My understanding was the fibre gear ran quieter than a metal gear. 

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Rod, 

    You are correct.  I understand that another option is bronze for noise reduction.  More expensive though.    Hugh

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I have parted out three of the 1916/1917 6-Cylinder engines and all three of them had steel (metal) camshaft gears from the factory in them.  I am going to make my next comment about the open valve train engines (ending with the 1918 models).  This is nothing but a load of horse hockey about the engine running quieter with these fiber timing gears in them.  Hugh, these fiber gears were NOT standard from the factory and I have the illustrated parts catalogs to back that up.  These were after market parts that were made available at a cheaper price than factory Buick replacement parts and that was a sales gimmick to get people to buy them in saying that the engine would run quieter.  The facts just do not support that claim.  I would challenge anyone to listen to any 6-Cylinder Buick engine running at a slow idle with the hood up and be able to determine if the engine had a fiber timing gear in it.  It just cannot be done.  If I had a choice of running a metal or fiber timing gear in my '16 engine that is being rebuilt, the metal gears is what is going to be used.  I am actually a lazy sort of person.  I do not want to go through the process of opening this engine up again to replace a composite timing gear that is going to crap out just as sure as the sun comes up every morning.  I apologize if I have come across as stubborn about this issue.  Others can do as they wish and I have no problem with that.  I'm going to spend good money on this rebuild and we're going to do it right the first time.  We plan on driving the wheels off this car once it is put back together and the facts about a plastic, composite, or whatever, timing gear do not add up to longevity.

 

Terry Wiegand

South Hutchinson, Kansas 

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Terry, 

    Buick made the change some time, and at least by 1925, the timing gears were fiber.  I believe the originals were made by Textolite and they are molded with Buick in the mold.  There are some Celeron gears and I assume they are the replacements, but they are engraved with the Buick part number so those I do not know if they were aftermarket or factory.  I have yet to see anything but a fiber gear in a 1925 Buick.  If they were steel, we would not see all these fiber gears.  Maybe it was just cost.  I only heard it was a noise issue as well but can't vouch for it.   The Mustang 2 used a nylon gear on a steel hub.  The nylon looked like the material that is used on a timing chain rubbing block.  After some time, all this plastic ended up in the oil pan, just like fiber.  The replacement in the late 70's was aluminum, so aluminum could be a workable alternative.  

 

Hugh

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Edited by Hubert_25-25 (see edit history)
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Terry,  I think I got this gear from you.  Probably as Hugh said,  an aftermarket gear. It sounds like Buick  used a steel timing gear in 1916 and then changed to the fibre gear later.

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Edited by Rod Wise (see edit history)

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Rod,

Yes you did get that gear from me.  There was two very good reasons that you ended up with it.  One, it did not have the correct I.D. in the hub and the correct number of teeth for the 1916 40 series engines and second, I would not put it in my engine even if it had been mechanically correct.  My Dad picked that gear up from the old Maupin Auto Salvage here in Hutchinson shortly after he got the car in the early 1960's.  Hugh, I do not want to argue with anyone about who is right and who is wrong about these gears.  What I do know and can say is that the illustrated parts catalogs that I have from 1915 up through 1923 show and list the timing gears as being metal.  That gear that Rod got from me was clearly wrongly identified.  I have absolutely no problem with anyone wanting to use one of these gears if that is all that they have.  But folks need to know and understand that these parts are NOT as durable and long lasting as parts that were manufactured by the Buick Motor Company and made from metal.  I do have illustrated parts catalogs going up to 1930, however, I have not set down with them and tried to discern what camshaft gears were used going forward from 1924 and up.  Maybe I should do that sometime.  My main interest is Buick's caged-valve engines which ended in 1923.  In the interest of keeping one of these engines running, if the fiber gear will work, by all means, go for it.

 

Terry Wiegand

South Hutchinson, Kansas

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22 hours ago, Hubert_25-25 said:

Larry, 

    What is the relative condition of the other "good" teeth on that bad gear.  Were they getting thin? .  The gear set in the background of your photo looks to have pretty healthy teeth still and not much wearing on the sides of the teeth making them narrow.   My spare timing gear is a little "thinner" in the teeth than the one I installed.  I wonder if in the long run if I would really install it.  

 

Hugh

Hugh: As you can see from the photo.

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Comparing the gear at the right (BEST). to the gear teeth at the left which is somewhat thinner. This one on the left is nearly as thin as the one that failed. 

975703533_DSCF7736(1024x768).thumb.jpg.1006becf466e1dc603ba0b12ac911fa3.jpg  This is the one that I bought from Fred Rawling at the Oklahoma meet as this was the best he had. Now it will be my spare. I had the other better one in the spare parts from the people I bought the car from. Fred had a cheaper one that the teeth were worn down to almost a V style profile.

Edited by dibarlaw
spelling (see edit history)

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Posted (edited)

Today I helped my mother and grandfather, in a tear down and rebuild operation on a 1933 McLaughlin Buick. As we removed the front gear cover we found that the old Textolite camshaft gear was missing half of most of the gears. Mind you, this vehicle had been sitting in a barn from '68 till just recently. I would like to know if it would be worth it to source another Textolite gear as mother has the resources to copy and recreate the gear using steel. I would love to know how long a new one would last if we used Textolite again.

  Thanks,

  Kurt.

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Edited by Kurtis Hunter (see edit history)

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My 17 has steel gears. I don't know when they changed but 25 and up had fiber gears from the factory.  To check your timing. get the 1 and 6 pistons on TDC and find which has the exhaust just closing and the intake just about to open.  If that is happening and the marks are aligned be happy.   Another thing that can happen with the fiber gears is that they come loose on the hub and slip.  They were quiet but they were sometimes trouble. 

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Oldtech,

I want to point out something in your posting that I believe you need to reconsider.  You stated that the exhaust valve is just closing and the intake just about to open.  To correctly set the timing on the engine the piston needs to be on Top Dead Center (#1 cylinder) and the intake valve has just closed.  This would put the cylinder in the power stroke with the ignition ready to fire.  Not trying to be a wise-guy here.  Just do not want anyone to read this and get the wrong idea about what happens.

 

Terry Wiegand

South Hutchinson, Kansas

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Kurtis

  Finding a QUALITY gear is hard these days.   There are some modern reproductions out there that are fibre, but of a lessor quality.   The most common reason in modern times for the gear failing is the owner not checking the water pump to make sure it is not seized before turning the engine over.   That is followed by people overtightening the packing nut on the water pump and putting an excessive load on the gear.

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Posted (edited)
15 hours ago, Terry Wiegand said:

Oldtech,

I want to point out something in your posting that I believe you need to reconsider.  You stated that the exhaust valve is just closing and the intake just about to open.  To correctly set the timing on the engine the piston needs to be on Top Dead Center (#1 cylinder) and the intake valve has just closed.  This would put the cylinder in the power stroke with the ignition ready to fire.  Not trying to be a wise-guy here.  Just do not want anyone to read this and get the wrong idea about what happens.

 

Terry Wiegand

South Hutchinson, Kansas

Well I didn't explain it real well but  if number 1 is on firing position, number 6 is just at that sweet point where the exhaust is closing and the intake starting to open. The intake closes at Bottom dead center - usually a little after.

As a way of checking that you cam timing is correct if you can put either 1 or 6 at firing position, rock the crank back and forth with your fingers on the 2 valves of the one not on firing position. you can tell if it's basically right. Probably not within a tooth but that's what the marks are for.

Edited by Oldtech (see edit history)

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