logo
12 Port News - Features
12 Port History
Casting Numbers
Online Store
Tech Tips
Become a Member
Previous Thread
Next Thread
Print Thread
Rate Thread
#100765 04/22/23 03:37 PM
Joined: Jul 2012
Posts: 131
Likes: 1
B
Contributor
OP Offline
Contributor
B
Joined: Jul 2012
Posts: 131
Likes: 1
Hey guys, what should I set my timing on my Chevy 250 motor? I believe it should be on 4. Just can't remember. And at idle, should it be 700 rpm?

Joined: Jul 2000
Posts: 4,585
Likes: 19
1000 Post Club
**
Online Content
1000 Post Club
**
Joined: Jul 2000
Posts: 4,585
Likes: 19
Anywhere between 4 & 10 btdc depending on the year. ( Stock ) after market cam can Vary


Larry/Twisted6
[oooooo] smile
Adding CFM adds boost smile
shocked God doesn't like ugly.
Joined: Jul 2012
Posts: 131
Likes: 1
B
Contributor
OP Offline
Contributor
B
Joined: Jul 2012
Posts: 131
Likes: 1
Mine it's a stock 72.

Joined: Jul 2000
Posts: 4,585
Likes: 19
1000 Post Club
**
Online Content
1000 Post Club
**
Joined: Jul 2000
Posts: 4,585
Likes: 19
Start with 4 degrees And that is if this a stock cam.

Last edited by Twisted6; 04/24/23 09:07 PM.

Larry/Twisted6
[oooooo] smile
Adding CFM adds boost smile
shocked God doesn't like ugly.
Joined: Jul 2012
Posts: 131
Likes: 1
B
Contributor
OP Offline
Contributor
B
Joined: Jul 2012
Posts: 131
Likes: 1
Twisted6, I was able ti time the motor, in fact she's running goog. However, she's overheating. The reason why I bought this new motor was because the previous one was overheating as well and after replacing everything, including having the head and radiator checked, it still overheated. So the new motor is doing it now. I just don't understand, it has me pretty upset. New motor, hoses, water pump, thermostat, radiator checked by a shop, so what can it be?
My only thought is that the radiator has to be bad. I also replaced the after market temp gauge that isn't electrical.
Please advise. My next step is probably to buy a new radiator. I have also removed my tranny cooler from the front of the radiator thinking it was blocking air flow and nothing.

Joined: Jul 2000
Posts: 4,585
Likes: 19
1000 Post Club
**
Online Content
1000 Post Club
**
Joined: Jul 2000
Posts: 4,585
Likes: 19
Check the thermostat. Put it in boiling water if you have a thermometer use it to check water temp with stat opening temp or just simply heat the water until you see the stat open. to be sure it is working. But you very well may have a rad flow issue. Just because a radiator pressure checks well doesn't always mean it flows well. It may flow but some of the cores could still be blocked.


Larry/Twisted6
[oooooo] smile
Adding CFM adds boost smile
shocked God doesn't like ugly.
Joined: Jul 2012
Posts: 131
Likes: 1
B
Contributor
OP Offline
Contributor
B
Joined: Jul 2012
Posts: 131
Likes: 1
I did check it last night and the thermostat opened just fine. I ran the engine again this morning and I even put a house fan in front of it and still overheated just sitting there.

Joined: Apr 2004
Posts: 3,556
Likes: 35
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Apr 2004
Posts: 3,556
Likes: 35
For the overheating issue, I would look at the timing.
Is the dist vacuum line hooked to live vac or to ported?
Can you test to be sure the vac can is advancing with vac?
Retarded timing can overheat a engine quickly.
Do you have a timing light? Advance type light (adjustable)?


Inliner Member 1716
65 Chevelle Wagon and 41 Hudson Pickup
Information and parts www.12bolt.com

Joined: Jul 2000
Posts: 4,585
Likes: 19
1000 Post Club
**
Online Content
1000 Post Club
**
Joined: Jul 2000
Posts: 4,585
Likes: 19
I didn't think about it being a timing issue because you said it was running fine, But yes I would agree to check your timing. But if it started and run at 4degrees I would not think that it's retarded Try bumping it up a few more degrees. If you're still having the same issue at Idel, I still would look more deeply at the Radiator.


Larry/Twisted6
[oooooo] smile
Adding CFM adds boost smile
shocked God doesn't like ugly.
Joined: Aug 2003
Posts: 353
C
Contributor
Offline
Contributor
C
Joined: Aug 2003
Posts: 353
FWIW
My 64 Chevelle 283 has a stick shift carb rather than one for an automatic.
The vacuum port on the stick carb is ported but full vacuum on the auto carb.
So me running with no vacuum at idle was enough to make the engine overheat for no apparent reason.
I replumbed the vacuum to the distributor so it was full vacuum at idle and no more overheating.

Disclaimers:
I don't know what years Chevy spec'd different carbs for stick shift engines and automatics, but I think early 60's, and later on emissions probably influenced how this was done.
No, I can't say for sure why no vacuum to distributor works on stick shift cars. I'm guessing the Powerglide is enough of a load on engine at idle to make a difference.
Lotsa people tell me the PG is a load ; )


Pete
64 Chevelle
61 C30 Panel truck
Joined: Jul 2012
Posts: 131
Likes: 1
B
Contributor
OP Offline
Contributor
B
Joined: Jul 2012
Posts: 131
Likes: 1
Thank you for all the suggestions. I will definitely look into all of this.
Another thing that came to mind is the fact that I have just water in the radiator. I have removed my hoses on and off and flushed my radiator a couple of times, that I did not want to waste antifreeze.
Could this be my issue?

Joined: Jul 2012
Posts: 131
Likes: 1
B
Contributor
OP Offline
Contributor
B
Joined: Jul 2012
Posts: 131
Likes: 1
So I just bought one of those fancy radiator funnel kits to ensure I had no air or bubbles in the system. I ran it with antifreeze this time and still overheated. It ran for about 20 minutes. It got between 215 and 220.


Moderated by  stock49, Twisted6, will6er 

Link Copied to Clipboard
Who's Online Now
1 members (Twisted6), 112 guests, and 46 robots.
Key: Admin, Global Mod, Mod
Newest Members
uncle dave, trustedmedications20, Jsmay101, Paul Mahony, KeithB
6,784 Registered Users
Sponsored Advertisement
Sponsored Advertisement
This Space is Available
Powered by UBB.threads™ PHP Forum Software 7.7.5