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Timing Gears (Cam & Crank)


James_Douglas
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Hi All,

 

Got the new engine in the 1949 Desoto, to replace the one that was running great except for the internal block leak...

 

Now the new engine is running like crap.

 

Everything is new in this engine.  The problem sounds like an ignition timing one.  The distributor and car are the same ones that we drove it in with and so we know that it is not that.

 

The possibilities are: 

 

1. I screwed up the static valve adjust.  It is hard to screw this up when you do it on the engine stand with the pan and head off.  You can SEE the cam lobes on the tappets.

 

2. The camshaft that Earl re-ground for me was done wrong.  I doubt it.

 

3. The "new" timing chain, cam gear, and crankshaft sprocket was put on wrong.  I doubt that as well --- I checked it like 3 times.

 

4. The "New" timing chain, cam gear, and crankshaft sprocket which I got from Chris at Andy's has an issue.  When I went to get them for eggy machine they were out and not expecting some in the near future.  Chris said that he was expecting some in.  From two different suppliers.  One making the cam gear and one making the sprocket.

 

 

I am suspecting that the set is not correctly timed even though the dots are lined up.

 

You can hear it when it runs at idle. It sounds like a crossed wire, but not that bad.  It feels like there is some mini-backfire or wave coming through the carb while it is running.

 

Anyone have any ideas?

 

What a pain in the ass!  Engine number two now with problems.

 

Having a great time.  James.

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Hi Don,

 

Apparently nobody is making sets anymore. 

 

I just checked the photo of the timing chain on the new engine.  6 teeth between the crankshaft sprocket keyway and the circle (or dot).  In the photos of my 1947 Rebuild, there is two teeth.  In the MTSC on the imperial site (http://www.imperialclub.com/Repair/Lit/Master/027/Page26-big.jpg) shows 2 teeth as well.

 

I don't know that this is the issue...but it is the leading thought right now.

 

James.

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Check the valve timing.

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This most likely isn't related to your problem,but I saw no mention of new tappets. If you can't find them new,Delta Cams on the left coast can weld them up,grind them to the correct radius,and heat treat them for you.

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Valve's were checked well prior to firing it off and it does not sound like a valve or two mal-adjusted.  The tappets are very good used. 

 

James.

I guess you can get away with that,but tappets,like every other mechanical piece,wear in to match the wear on the individual cam lobe each tappet rests on,and it is best to replace old ones with new ones when you install a new cam.

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Have you tried pulling a  spark plug wire off at a time or shorting out one plug at a time to see if it makes any difference in the running of the engine? If a plug wire is shorted or removed at idle, you should hear the engine run rougher. If there is no difference in how smooth the engine runs, that will help identify where the problem is.

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Hi,

 

Did all of the above.  The tappets came from an engine with a few thousand miles on them.  They were fine.  In fact they looked better than the modern replacements.  In any event, the tappets are mechanical and as such either work or they do not. They would not affect the timing if the valve adjustment is correct and it is.

 

I have verified by the photos that the crankshaft sprocket has a different indexing than a stock unit or an old c.2002 new replacement unit. 

 

We will spend a few days double and triple checking everything on the outside. But it is really looking like the crankshaft sprocket is 4 teeth out due to the "dot" being in the wrong place.

 

James

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post-60-0-10067600-1467474737_thumb.jpg

Edited by James_Douglas
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Hi Don, Thanks. I have checked all my shop books and photos.  All of the show 2 teeth between the keyway and the dot.

 

I am going to have to pull the radiator and front of the engine off and look I think.

 

Before I do that, I am going to pull the dizzy, pull the side covers, check the valves, and see if the "rod" I stick into #6 matches up with the valve timing as per:

http://www.imperialclub.com/Repair/Lit/Master/027/Page26.htm

 

If I do not find a smoking gun, then I will have to tear it apart. If so, then it has to be the timing gears or the cam itself. 

 

James.

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get a timing wheel, read the cam per the data sheet that should have been provided indicating the grind of the cam....it is not hard, take just a few minutes.....last cam I messed with that was not an off the shelf cam by a major company was so far out of whack it was not even funny,,,,,so yeah...been exactly where you are now...backing up is never fun...

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get a timing wheel, read the cam per the data sheet that should have been provided indicating the grind of the cam....it is not hard, take just a few minutes.....last cam I messed with that was not an off the shelf cam by a major company was so far out of whack it was not even funny,,,,,so yeah...been exactly where you are now...backing up is never fun...

I have done this in the past on my SBC's and my BB Mopar's that I used to race.  Never had to do it on a flathead six.

 

In any event, as far as I know there are no cams for the Chrysler-Desoto Flathead six's.  Only thing you can get is a re-grind.  I had Earl do mine.  The extra lift and duration is not much.  Of course the centerline of the lobes did not change.

 

*****

 

I just spent an hour going over all the work the shop did in swapping the motors for me.  Remember, I could not do it in the garage here in SF as the 1949, unlike the 1949, does not allow for the "Dog Cage" to come off.  I do not have enough overhead space to clear the sheet metal in my garage.

 

The shop that did the swap has an 80 year old owner who works every day 12 hours, his son my age, and his son as well.  They work on modern cars and every kind of old car there is.  Senior, drives a Model "A". 

 

I just puled the plugs and some were hand tight.  I then pulled the little plug on #6 and stuck in my steel rod.  I then brought the engine up to TDC.  Guess what?  The rotor is pointing to around One O'clock and not Seven O'clock as it should. 

 

I am off to the parts store for new plugs and then will try it again.  I am hoping it is as simple as that and not the cam or gears.  Wish me luck!

 

James

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I have done this in the past on my SBC's and my BB Mopar's that I used to race.  Never had to do it on a flathead six.

 

In any event, as far as I know there are no cams for the Chrysler-Desoto Flathead six's.  Only thing you can get is a re-grind.  I had Earl do mine.  The extra lift and duration is not much.  Of course the centerline of the lobes did not change.

 

*****

 

I just spent an hour going over all the work the shop did in swapping the motors for me.  Remember, I could not do it in the garage here in SF as the 1949, unlike the 1949, does not allow for the "Dog Cage" to come off.  I do not have enough overhead space to clear the sheet metal in my garage.

 

The shop that did the swap has an 80 year old owner who works every day 12 hours, his son my age, and his son as well.  They work on modern cars and every kind of old car there is.  Senior, drives a Model "A". 

 

I just puled the plugs and some were hand tight.  I then pulled the little plug on #6 and stuck in my steel rod.  I then brought the engine up to TDC.  Guess what?  The rotor is pointing to around One O'clock and not Seven O'clock as it should. 

 

I am off to the parts store for new plugs and then will try it again.  I am hoping it is as simple as that and not the cam or gears.  Wish me luck!

 

James

James. That indicates your distributor is 180 degrees out. Or number six was at the top of the compression stroke and number one was at the top of the exhaust stroke.

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James!  Don!  Am I missing something? You know that the No. 6 piston comes up twice in the four cycles.  Crank it around again, and the rotor will point to 7 o'clock.  How would you know you are 180 degrees off?

 

Which is the compression stroke?  By the old thumb on the No. 1 spark plug hole? 

 

Now, if the cam is screwed up, who knows if or when you have a compression stroke?   

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You should be able to get a pretty good idea of the valve timing by pulling the valve cover off and checking the position of the valves on #1 at TDC. If as you suspect the gear was stamped incorrectly the valve cycle won't be where it should be at TDC.

You will of course have to check this twice. ;) But it should tell you all you need to know.

 

Hth. Jeff

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Tried everything I know how to do some the outside and No Joy.

 

Interestingly, I cannot get a good seal on #1 when using my "blow hose" to check for TDC on #1.  On the reverse, I can get it on #6.

 

I jacked the car up and pulled the side covers.  I stuck my hand up there and I could spin the intake valve.  I COULD NOT spin the exhaust valve.  The engine is at #TDC I THINK.  If I blow into #6 I get free flow of air as one would expect.

 

So, either I screwed the pooch badly on the static valve adjustment or the cam-gear-crank-sprocket is screwed up.

 

I am heading back down to the cold concrete, San Francisco in the summer you know, and pull the heat shield and the inner fender lower panel so I can see directly into the valves. 

 

The thing that is a bitch is that this engine is so tight that I cannot turn it over with the fan, even with the plugs out.  Using the starter really does not work to adjust the valves.  I may have to pull the radiator and the fan so that I can use my big 3/4 torque wrench to turn the engine over to check the valves.

 

What a bitch!

 

Thanks, James.

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It seems that I faced skepticism on another thread, in saying that I could not turn the engine by fan belt even with the plugs out.  Maybe these DeSoto engines are tight. 

I posted photos of prying the flywheel through the vent opening.  

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James. I posted this information a good while back on how I static timed my Desoto engine.  Suggest you try this before you start tearing everything apart again.

 

 

Posted 28 June 2014 - 04:40 PM

 

I brought the engine to TDC and noted the rotor position I installed the distributor and positioned it very close to the same position it was in when I removed it. I made an attempt to fire the engine and it was a no go. I made attempts to fire the engine with my remote starter button and a hot wire under the hood while turning the distributor under the hood and it was all a no go. I connected my timing light while cranking the engine with the starter and found my timing was a good way off from TDC. So I brought the engine to TDC using the starter motor. I pulled the plug wire from #1 spark plug and connected it to a spare plug sitting on the head. I then (without spinning the engine) moved the powered up distributor until I was getting spark exactly at TDC correctly static timing the engine.

 

As I had been spinning the engine a lot with no fire I suspected my plugs may be fowled so I removed them and sand blasted them. While the plugs were out I also used an air gun down the plug holes to clear the cylinders of any flooding. Reinstalled the plugs, hit the starter button, and the engine fired right up. I then used my timing light to dial it in.

 

So my point being correct engine timing is a very small window. If you take the time to insure your engine is correctly static timed and all other system problems are corrected the chance of starting is greatly improved.

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Thanks Don, I am planning on doing just that.  What I am up to now is checking the valves.  It took 45 minutes for me to get the inner fender off!

 

The 1949 Desoto "smaller outside and larger inside" makes it a bitch in the space around the engine and wheel well as opposed to my 1947 Desoto.

 

I have it at what I think is TDC.  The #1 exhaust valve lifter I can hardly move with a rag.  The intake valve lifter spins fine.  The #2 Exhaust valve looks to be wide open (spring compressed) as does the #3 Intake.

 

I may find it better on my foot and back to pull the manifolds to check the valves than to try and block the car up, taking it off the wheel ramps, and pulling the tire.

 

I will check them by setting them to intake at 12 and exhaust at 14 cold.  A little loud, but better than a little tight.

 

I will then pull the oil pump and make sure it is indexed correct.  Then button it all back up and use the turn the dizzy until it arc's method on #1 .  If it does not fire correctly then...there must be something wrong with the chain and its marks.

 

James.

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James, If you are planning on doing that why did you not do it before you ripped everything apart? It matters not how the oil pump is indexed the engine if statically timed correctly will run very well no matter of the oil pump indexing. If the valves are adjusted to close completely the engine will run no matter if the clearance is correct or not. I think you are making this much more difficult than is required. You once told me to slap you alongside the head if you went over board. Consider this the required slap. :o 

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Hi Don,

 

I have not ripped everything apart yet.  I will do the valve check and then try it again.  However, the photo of the DOT and its relation to the keyway on the crank sprocket makes me wonder.  So far, everything has checked out.

 

If I check the valves and they are within spec...then I don't know what else it can be but the cam-sprocket.

 

So far three people, two pro's and yours truly have worked on it with a result of the thing just not running correct.

 

I would pull the manifolds because, as you have seen, and given my foot...it may well me a lot better on me physically if I do the valves from the top rather than the bottom.

 

I would only pull the front of the engine off as a very last resort.

 

James.

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Last one I did  (251)  1950 Windsor.....

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