Timing Question??

[ABX131]

I have been told by a few people to check my engine's timing as part of my overheating issue. My engine is an all stock 350 from a 73 chevy blazer. The ignition and distributor are also stock. The pully set up on it blocks the harmonic balancer with the power steering pump and when I crawl underneath, there is no timing tab. I purchased an aftermarket one and pulled the PS pump to install. Am I correct in assuming you set the timing with the PS pump removed? What is the correct timing setting? I have heard various setttings somewhere around 8 deg BTDC?? Does that sound right? Is there anything I am missing here?

[ABX131]

Have also read that it may be different for a manual tranny vs an automatic...I have a th350...now I am hearing it should be closer to 12 deg BTDC..any input here would be great.

[jayoldschool]

My 71 350/350 combo uses 8 deg BTDC.

[akaupp]

I've never set timing at idle, I was taught to set it at full advance. I usually have someone hold their foot on the throttle at around 2500-3000 and give it between 32 and 36 degrees.

[TBONE1964]

First of all, you do not have to pull the PS pump to check the timing. It is a little difficult to see but it is visable with everything in place.

It will depend on many things as to what the base timing is on your engine. 8 degrees should be ok.

I would try advancing it two degrees at a time until it runs the best without spark knock and/or hard starting. If the engine has any amount of miles on it, the timing chain may be stretched a little and that will give you a false reading, especially at high rpm or full advance timing.

Keep in mind that all the adjustments on an engine will vary depending on how many miles it has and how it lived it's life to this point. 8 degrees of base timing was good when the engine was new, may not be good with 150,000 miles. See where I am going here?

Good luck and keep us posted.

[ABX131]

I am doing some radiator work and had it pulled out which made for a lot of space to work...Had to pull the PS pump just to put the timing tag I purchased on. I have a 63', two of my neighbors each have a 72' and a 75' so we have 3 generations of Chevys and it gives me great references to refer to. The 75 has the same set up I do and you can't see the tab to time it. We have the PS pump brackets that come off the head. The 72 has air conditioning so the alt has been moved to the driver side head and the PS pump is pushed down to the lower part of the motor and engine mount. This gives a clear view of the timing tab making timing very easy. Anyway I think it would just be easier to time with the PS pump off but just needed clairification on what to set it to. Thank you all for your help.

[TBONE1964]

I would start with 10 degress and see how it runs that way. Like I said, there are many factors that will change this +/- from the factory setting. Do you have access to the 73 Blazer the engine was removed from? The emission decal that would be placed on the left inner wheel well or the core support is the only way you would know what it was set at. That would depend on if the truck had california emmisions, if it had A/C, manual or automatic transmission, gear ratio, etc. You are going to have to play the trial and error game and see what works best. start with 8 and go up 2 degrees at a time until you get it running the best.

Mr Chevrolet would not and never has designed an engine that had to have parts removed to set the timing. I know it is hard to see and you need to be at just the right angle to see it but like I said, you should not have to remove the P/S pump to check timing.