The Stovebolt Site Forums The Shop Area Engine Shop Loose 235 distributor - any ideas?

After running flawlessly for about a year-and-a-half, I took my '40 to a Curse-in (Portland) and barely made it home. With a little investigation I noticed my distributor rotates freely, even with clamp fully tightened. Any ideas on what to look for would be welcomed wholeheartedly.

When I figure out what went wrong I have to adjust the timing (of which there are many previous instruction posts.) Given than I'm a visual learner, anyone have any good pictures posted of where to look for the triangle on the flywheel (front face?), where is the line to match it up with? (dust cover?), etc.?

I plan to dive-in this weekend to figure it out.

Thanks!

Doug

If the bolt has come out of the fine adjustment plate on the bottom, it can be rotated about 15 degrees.

The vacuum advance moves the distributor so some movement is normal. How much is yours moving?

With Truckernix comment about the missing bolt (thanks) I looked around for other fasteners and there is a collar with a horizontal screw around the right side of the distributor. That was loose also and when tightened, the distributor rotates only as far as the vacuum advance will permit - this seems correct.

I took a picture of it here:
(https://plus.google.com/photos/1139...7801054018&oid=113956755236860259179)

Now that I know how to tighten it down, I will adjust the timing. Q: Would you recommend I use the timing light from a top view (under the hood) or do I have to go underneath the front bumper and see it from below?

thanks

You should be able to see the hole and marks from above.That'll make adjustment alot easier.
Make sure your octane setting is at "0", then loosen that nut/screw you just tightened to adjust you're timing.
You may want to advance it a hair or 2 above the pointer and then road test to make sure it doesn't ping on exceleration. If it does retard it a hair & test again.
btw, nice truck.

I belive below the pointer gives you advance. That shows that it fires before or in advance of the pointer position.

I am feeling a bit thick-headed because I've heard a lot about "setting the octane level to zero" but for the life of me cannot find anything around my distributor that has an adjustment with any graduations (numbers) on it. Even the "http://chevy.oldcarmanualproject.com/chevyowner/52tom31.htm" has an entry about octane adjustment but in the old b&w halftone print, I still can not see that specific parts are being referred to. Has my octane adjustment gauge fallen off? Is it too gunky to see? Did I ever have one? .... I'm not sure because I'm not quite sure what to look for. Can any of you kind people take a look at my distributor and let me know if I am missing something?

https://plus.google.com/photos/1139...2597156306&oid=113956755236860259179

Thanks for any help you can provide :-)

Doug

It is the flat plate with a bolt through it between the dipstick and the distributor. There should be graduations marked on the aft end of it. There is a line on the engine block under it for reference.

Doug,

The Octane Selector is part of the distributor collar-clamp that bolts to the block. The octane selector is shown in your photo.

http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0619.htm

...click...

To the left is an A
To the right is an R

Thanks Cletis, Tclederman, and DADS50 for clearing that up! I am going to go home and set the timing!

It is mostly to adjust how much advance is in the timing...
The higher the octane fuel used the more the timing could be advanced.

John

do you know where to check the timing? Do you know about the BB in the flywheel, and the pointer in the bellhousing? I only ask because you were wondering if you should check from under the front bumper. That shouldn't even be a question. The octane selector can be anywhere as long as it is tight. Unless the gas in your area tends to vary widely in octane levels ( I have never used it in 30 years) The screw you found loose is what is used to set the timing. Some people say to set the timing with a vacuum gauge, I have always used the prescribed "ball and pointer" method, but last week I decided to give the vacuum method a try, I found absolutely no difference in performance.

Usually the timing was set with a slight ping on an uphill pull.

John