327 overheating at idle

[Joseph P.]

Re: 327 overheating at idle

Thank you all for the good check list of items to check and things to do. Joe

[Joseph P.]

Re: 327 overheating at idle

I'm thinking the same thing. The distributor will not turn any further. It is hitting the intake manifold. I am going to move the distributor tomorrow. Is there anything I need to do to mark my spot. Do I need to have the crank at a certain location. Are there any special things to do before I take it out and move the dist. or can it be done out any other presetting? Joe

[Duke W.]

Re: 327 overheating at idle

Set the crank at 8-10 deg. BTDC #1 compression stroke.

Remove the dist. and be sure the dimple in the gear is pointing the same direction as the rotor tip. If not, pull the pin and rotate it to the proper orientation.

Install dist with the rotor about 45 deg. to the right of engine centerline. As the gears engage the rotor will move CCW. If it won't drop in all the way, rotate the oil pump drive slot as required to allow it to drop in.

Rotate the dist. until the points just begin to open. The window should be approx. normal to engine centerline and the VAC should be about halfway between the interference points.

Install cap, start engine, check initial timing. If you did it right it should be between 8 and 10. Adjust initial timing as required.

Duke

[Gerard F.]

Re: 327 overheating at idle

Joe,

Take a look at this thread:
https://www.forums.ncrs.org/showthre...imple&uid=3931

The first picture (to the left) is the position of the distributor @6*BTDC with the dimple reversed from the position of the rotor, on my 67 327/300.

The second picture (to the right) is with the dimple lined up with the rotor tip. Note the position of the No 1 plugwire taped in yellow and position of the vacuum can.

The 67 has a 30* advance distributor, and the initial spec is 6*btdc. Yours is probably different.

Having the dimpled reversed is a difference of 14 degrees. Being one tooth off is 28 degrees.

Hope this helps.

[Duke W.]

Re: 327 overheating at idle

Also make sure your wires are indexed correctly IAW the photo, which is per the 1963 Corvette Shop Manual.

Duke

[Joseph P.]

Re: 327 overheating at idle

Thank you guys for the help. When I reconnect the vac the idle goes up. About a year ago I had a "mechanic" tune the car. He did not change the points, plugs or condensor. At that time he moved the dist. one or two teeth because the dist. was hitting the intake manifold and he could not get the timing to 8 degrees. After moving the dist. he could set it at 8 degrees. However I came to realize 2 spark plugs had no spark. Could that have been the problem and maybe he didn't have to move the dist. after all? What is the correct dwell reading providing I can get the timing to 8 degrees? Joe

[Dick W.]

Re: 327 overheating at idle

Thank you guys for the help. When I reconnect the vac the idle goes up. About a year ago I had a "mechanic" tune the car. He did not change the points, plugs or condensor. At that time he moved the dist. one or two teeth because the dist. was hitting the intake manifold and he could not get the timing to 8 degrees. After moving the dist. he could set it at 8 degrees. However I came to realize 2 spark plugs had no spark. Could that have been the problem and maybe he didn't have to move the dist. after all? What is the correct dwell reading providing I can get the timing to 8 degrees? Joe

Dwell is 28 to 32 degrees

[Joseph P.]

Re: 327 overheating at idle

Thank you for the help. Joe

[Gerard F.]

Re: 327 overheating at idle

Thank you guys for the help. When I reconnect the vac the idle goes up. About a year ago I had a "mechanic" tune the car. He did not change the points, plugs or condensor. At that time he moved the dist. one or two teeth because the dist. was hitting the intake manifold and he could not get the timing to 8 degrees. After moving the dist. he could set it at 8 degrees. However I came to realize 2 spark plugs had no spark. Could that have been the problem and maybe he didn't have to move the dist. after all? What is the correct dwell reading providing I can get the timing to 8 degrees? Joe

Joe,

I wouldn't be that worried about the dwell, as Dick says it is 28 to 32 and it is easily set. I'd be more worried about what distributor you have, and what your "mechanic" did to it to get to 8 degrees. Even moving it one tooth out of spec will reguire that you re-index your plug wires.

First, I think you need to check what distributor you, have be it a 24, 30, or 40 degree centrifugal advance. Then set your initial timing for a maximum of 36 degrees with initial plus full centrifugal. Also check whether the dimple is reversed to the rotor. For a 24 or 30 centrifugal advance distributor line up the dimple with the rotor contact, for a 40 you are probably better off with a reversed dimple.

Then I would get a good mechanic to go through the service manual procedure for installing the distributor with "engine disturbed" just to be sure it wasn't screwed up to begin with.

Index the plug wires per the service manual. Change the points and condensor, set your dwell. If you are getting a miss or fouling on one or two plugs, check your plug wires.

Duke will probably chime in on this one.

[Duke W.]

Re: 327 overheating at idle

When in doubt follow the shop manual instructions, which I previously summarized.

Index the crankshaft as I explained.

Pull the distributor and verify that the drive gear is properly indexed.

Verify that the wires are properly indexed.

Reinstall the dist. as I explained.

Your "mechanic" is a frigging HACK and a MORON!!! He probably hasn't read a manual in 30 years, and if I had the authority under the California Bureau of Automotive Repair, I would shut him down. This kind of work is absolutely inexcusable for someone who is charging the public for their service.

Duke

[Joseph P.]

Re: 327 overheating at idle

Thank you all for the invaluable help and the time you shared to help me. I agree that the "mechanic" probably fouled everything up. I am going to try and straighten it out myself. If I get in trouble I will take it to Dave Walters. I believe he can fix it in minutes. He is a great mechanic and a real gentleman. But I want to try to do it myself first. Trial by fire. Thanks again to all for your assistance, I really appreciate it. Joe

[Joseph P.]

Re: 327 overheating at idle

I had the car running pretty well and was going down to Dave Walters shop for a new vac. advance. He listened to my car and took it for a ride and immediately new it was running retarded. He move the dist. over one tooth and reset the timing and bingo it is running 100% better. He recommended rebuilding the carb. and it will run like new. Thanks to all of you I was able to get it to that point. I was going to put a new vac advance and then move the dist but Dave beat me to it. Thank God! He is an incredible vette expert and we're lucky to have him in Miami. Once again thanks to all of you and the great web sites and pics. Joe

[Duke W.]

Re: 327 overheating at idle

You don't have to be a "guru" Corvette mechanic or rocket scientist to install a Corvette distributor, but it's amazing how many guys who have been playing with Chevy engines almost as long if not longer than I have don't know how to install a distributor in a Corvette engine.

The fact of the matter is that a high school kid can do it if he follows the service manual instructions, which is what I was when I first encountered this problem 45 years ago, but there's a catch!

Since the service manual SAYS NOTHING ABOUT PROPER INDEXING OF THE DRIVE GEAR DIMPLE, I had to figure that out for myself without any help. Once I counted teeth and found that the drive gear has 13 teeth, which is not evenly divisible by two according to the arithemetic I learned in the fourth or fifth grade - VOILA - indexing of the drive gear dimple makes a difference.

Did the mechanic check for proper indexing of the drive gear dimple? Wire indexing in the distributor cap?

What is the initial timing set at and where is the VAC located relative to the manifold and wire holder interference points?

Duke