6066 (1960-1966) GMC Truck Club

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-   -   Timing and Tuning (https://6066gmcclub.com/showthread.php?t=48700)

Scoutmann March 19th, 2015 02:09 AM

Timing and Tuning
 
Hey Guys,

I have a 1964 Vintage 305 V6 in an old school Hyster H150E forklift at work. I installed a new distributor, coil, plugs and plug wires. I've set the point gap at .016 and I used a dwell meter to confirm the dwell was at 32 degrees. I cannot for the life of me find the timing mark. I am unfamiliar with these engines. I know that there are three marks on the balancer. I'm assuming 7.5 degrees advance, TDC and 7.5 Retard. I cannot find the mark on the block to time it to. Any help appreciated! :yourock: :thumbsup:

PS any literature, shop manuals, etc. on this motor is greatly appreciated! :signthankspin:

TJ's GMC March 19th, 2015 03:15 AM

Re: Timing and Tuning
 
On my 64's 305E the the block has a pointer...course my engine is a later engine as well. The pointer is a needle and its on the opposite side of the alternator. I'd take a scrub brush to the balancer if you can and see if some marks show up.

OLDTRUCKHAULER March 19th, 2015 09:25 AM

Re: Timing and Tuning
 
Good Morning

Ebay is one resource for manuals, Amazon another.
I talk to the shop mechanics at the rental and repair
shops that I haul small equipment for. You can maybe
find the oldtimers may have the books, or have the info
in their heads for that unit.

Mike OTH

1965 1502 series ramptruck
1965 Cheby short step
1964 GMC 1000 parts truck
1985 GMC hybrid 3/4t dually
1962 willys p/u on 37's
1988 INT 5t Rollback
1967 GMC/Cheby? 1/2t longbed fleet 4 sale

Scoutmann March 19th, 2015 04:58 PM

Re: Timing and Tuning
 
I have the marks on the balancer. I am having trouble locating the pointer. This project has been nothing but headaches!

bigblockv6 March 19th, 2015 08:03 PM

Re: Timing and Tuning
 
1 Attachment(s)
Here is a pic of the timing cover, if you look just a little bit to the right just above the center of the crankshaft opening there is a pointer

Scoutmann March 20th, 2015 02:09 AM

Re: Timing and Tuning
 
Thanks So much! :yourock:

Scoutmann March 20th, 2015 06:09 PM

Re: Timing and Tuning
 
The vacuum advance also does not seem to be functioning. Do any of you know what the vacuum PSI is supposed to be?

Clarke March 21st, 2015 12:43 AM

Re: Timing and Tuning
 
Quote:

Originally Posted by Scoutmann (Post 57282)
The vacuum advance also does not seem to be functioning. Do any of you know what the vacuum PSI is supposed to be?

I'm not sure mine is working either... Everytime I have disconnected the steel line between the carb and the distributor (to set the timing), I don't notice any change in RPM like I have with other vehicles. And, when I put finger over the tube end I don't feel any change in pressure or vacuum.

It seems to run pretty good, so I don't worry about it. Maybe I should though. I'm interested in what others say.

Andice March 21st, 2015 02:59 AM

Re: Timing and Tuning
 
1 Attachment(s)
My '64 GMC (has a '66 305 V6 w/ Holley carb) was professionally tuned a year and half ago and here is what the guy gave me:

Idle: 600 rpm
Base Timing: 12* @ 600 rpm
Total Timing:38* @ 2500 rpm
Idle AFR set for best idle vacuum
Dwell is 30*
No vacuum advance - do not connect
Uses 89 octane fuel, with additive

Truck runs great.

GMCDAC March 21st, 2015 03:20 AM

Re: Timing and Tuning
 
Quote:

Originally Posted by Clarke (Post 57283)
I'm not sure mine is working either... Everytime I have disconnected the steel line between the carb and the distributor (to set the timing), I don't notice any change in RPM like I have with other vehicles. And, when I put finger over the tube end I don't feel any change in pressure or vacuum.

It seems to run pretty good, so I don't worry about it. Maybe I should though. I'm interested in what others say.

Hi David, and Scoutmann, I am going to stick my neck out here and guess that the carb you are using is "ported vacuum" which means there is none at idle. "Direct vacuum' usually comes from the intake manifold or the carb base. On the rochesters and holleys I have I just use direct vacuum. Then you will notice the difference when the line is disconnected.

If you have one of those vacuum type brake bleeders the vacuum advance can be tested with that.

DAC


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