The 1947 - Present Chevrolet & GMC Truck Message Board Network

The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)
-   The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=4)
-   -   Restoring Rusty (https://67-72chevytrucks.com/vboard/showthread.php?t=645440)

enaberif 05-31-2016 03:13 PM

Re: Restoring Rusty
 
Quote:

Originally Posted by Gregski (Post 7610713)
Thank you for that, however let me share with you an interesting observation, one that I have validated with a number of tests. The point that I will be making is that it is not that clear cut, Base Timing + Mechanical Timing, or in other words so far I have not seen such a thing as pure Base Timing, allow me to explain

It appears that Initial Timing (what you call Base Timing) always includes some Mechanical Timining aka advance. In my case my original Mechanical Advance Curve starts at around 800 RPM, so if my idle RPM is 850 I am already relying on mechanical advance in the initial 16*. This could explain why in my original configuration 16 Initial plus 24 Mechanical = 32* instead of 40* (that's because the initial 16 already has some of the 24 mechanical in it) hope I didn't just confuse the hiebie jibies out of somebody

If you look at the curve for the new weights, (pic above in the thread) it starts even earlier at 600 RPM, so for sure at 850 RPM idle we are using the mechanical advance. Now what muddies the waters a bit is crappy aftermarket inaccurate parts. Which I blame for 10 initial plus 8 mechanical = 18 (which really shows that their curve does not start at 600 RPM, lol)

Now looking at the GM HEI distributor part number 93440806 which I will be purchasing tomorrow (aka Pay Day) it's Mechanical Advance curve don't start till 1600 RPM - so we shall see how that all adds up

The springs you use is what determines your advance at idle. You should have a few different springs from a soft to a stiff spring. The softer the spring the earlier the advance comes in and vice versa with the stiff springs.

Depending on your cam shaft you may want your advance to start early or a bit later so find out your cam profile and where the lowest point of torque is made.

hatzie 05-31-2016 04:23 PM

Re: Restoring Rusty
 
Advance can be adversely affected by one more setting that's usually ignored...
What's the end play on the distributor gear. http://www.chevytalk.org/fusionbb/showpost.php?post/1257140/Measuring HEI gear end play.
It should be 0.010" +0.004" - 0.000" but most are set up way too loose. Every 0.0128" is 1 of advance as the gear lifts so the closer you can get to 0.010" the better.

It's cheap and easy to fix...

rich weyand 05-31-2016 06:29 PM

Re: Restoring Rusty
 
To answer some earlier questions. I am running 16-17 base timing. That is, timing without the vacuum advance hooked up and with the idle slowed to about 600 rpm.

The GM HEI adds 20* mechanical advance, so I am running 36-37 degrees total timing.

The AR23 vacuum advance adds another 15* (spec is 7.5*, which is camshaft degrees), to make 51* all in.

51* is what the advance is at cruise, 2500+ rpm, with the throttle plate mostly closed (not accelerating), so the mechanical and vacuum advance are both in.

I have seen 52* given as an absolute maximum for cruise "all in" timing.

Check this: http://67-72chevytrucks.com/vboard/s...d.php?t=689321

Gregski 06-01-2016 02:25 AM

Re: Restoring Rusty
 
Quote:

Originally Posted by hatzie (Post 7610908)
Advance can be adversely affected by one more setting that's usually ignored...
What's the end play on the distributor gear. http://www.chevytalk.org/fusionbb/showpost.php?post/1257140/Measuring HEI gear end play.
It should be 0.010" +0.004" - 0.000" but most are set up way too loose. Every 0.0128" is 1 of advance as the gear lifts so the closer you can get to 0.010" the better.

It's cheap and easy to fix...

thanks I just checked mine and its at .065 and that's with one shim already in there

I also checked my old original OEM points distributor and it has about the same at .062

keep in mind a gasket will take up some of that space, I think at least half

Gregski 06-01-2016 02:35 AM

Re: Restoring Rusty
 
Quote:

Originally Posted by rich weyand (Post 7611045)
To answer some earlier questions. I am running 16-17 base timing. That is, timing without the vacuum advance hooked up and with the idle slowed to about 600 rpm.

The GM HEI adds 20* mechanical advance, so I am running 36-37 degrees total timing.

The AR23 vacuum advance adds another 15* (spec is 7.5*, which is camshaft degrees), to make 51* all in.

51* is what the advance is at cruise, 2500+ rpm, with the throttle plate mostly closed (not accelerating), so the mechanical and vacuum advance are both in.

I have seen 52* given as an absolute maximum for cruise "all in" timing.

Check this: http://67-72chevytrucks.com/vboard/s...d.php?t=689321

thanks my original setup was very similar to yours, now as I am getting more comfortable with this stuff I am just trying to tune it in a bit more precisely, can you tell me at what RPM your mechanical advance starts ie kicks in please

hatzie 06-01-2016 11:31 AM

Re: Restoring Rusty
 
Quote:

Originally Posted by Gregski (Post 7611539)
thanks I just checked mine and its at .065 and that's with one shim already in there

I also checked my old original OEM points distributor and it has about the same at .062

keep in mind a gasket will take up some of that space, I think at least half

I have no idea why GM would set them up so loose. Maybe that much wear? Yours is new tho.

There's no gasket there just shims and an odd spacer. At .062 you'll need three of the five shims in the Moroso kit... 2x .020 & 1x .010 should get you .012 clearance or even .011... 1 timing float isn't bad at all.
http://www.summitracing.com/parts/mo...FYomhgodmgEDkQ

The gasket or spacers between the intake manifold and the distributor housing will fix the distributor bottoming on the oil pump drive or block if that's an issue.

rich weyand 06-01-2016 03:26 PM

Re: Restoring Rusty
 
Quote:

Originally Posted by Gregski (Post 7611540)
thanks my original setup was very similar to yours, now as I am getting more comfortable with this stuff I am just trying to tune it in a bit more precisely, can you tell me at what RPM your mechanical advance starts ie kicks in please

Not sure. I know it was messed with a bit before I got it. I know it is 20* all in, and I also know it doesn't come in below 800 and is all in by about 2500. They had the correct (AR23) vacuum advance can on it, which is not stock, so I assumed they played with the mechanical as well and I just left it alone.

Gregski 06-02-2016 09:55 PM

Re: Restoring Rusty
 
5 Attachment(s)
picked up some MasterPro RAMCOA rubber bushings for my anti sway bar from O'Reillys. They were only $8.00 bucks a pair, and I must say I am rather impressed and excited to give them a go, they are made in the USA and seem pretty nice

not sure why one pair came in a bigger box (dated 2012) than the other pair (dated 2016), they are identical

I have not favored the eurothane bushings everyone seems to talk about in the past, in my opinion rubber bushings are designed to cushion the situation and those polyeurothane things are essentially spacers and just make things rigid, sorta defeats the purpose in my mind

I looked at the MOOG ones but for some odd reason their 1-1/16 ones only came in BLUE green truck and blue bushings, come on man! that would totally cramp my style, how was we going to go fishin' lookin' like that

Gregski 06-02-2016 10:00 PM

Re: Restoring Rusty
 
5 Attachment(s)
a little stare and compare of the old ones and the new

I can't wait to try these, I don't think I ever had an anti sway bar before, it must be good for at least 20 horse power, ha ha

Gregski 06-02-2016 10:28 PM

Re: Restoring Rusty
 
1 Attachment(s)
i gotta tell ya, I paid less ($3.61) for all the 3/8ths Grade 8 nuts and bolts on the left at Blue Collar Supply than I did for the twelve locking washers on the right at ACE Hardware

this is for the anti sway bar, I usually don't like using the gold stuff on my vehicles but since this aint going to live in the engine bay I think it beats cleaning those old bolts

by the way do any of youz know if the cad plated "gold" bolts are better than stainless in terms of rust resistance?

Gregski 06-02-2016 10:31 PM

Re: Restoring Rusty
 
2 Attachment(s)
man I am pretty proud of myself when it comes to this project

mandatory before and after shots

Gregski 06-02-2016 10:36 PM

Re: Restoring Rusty
 
4 Attachment(s)
and some close ups for those in the cheap seats

I gotta ask: Do it matter which way the open ends of the rubber bushings go/face ie towards the front? or the back of the vehicle?

enaberif 06-03-2016 12:20 AM

Re: Restoring Rusty
 
On a 2wd truck that is lowered the stiffer you can be the better the road handling is. Rubber is fine but requires replacement more often than poly.

One thing your new bushings do not have is grease nipples to keep them working and being supple.

Regarding the slit no it does not matter and just becomes preference.

rich weyand 06-03-2016 01:45 AM

Re: Restoring Rusty
 
Quote:

Originally Posted by Gregski (Post 7613366)
by the way do any of youz know if the cad plated "gold" bolts are better than stainless in terms of rust resistance?

Stainless steel is more electropositive than carbon steel. You will get bimetallic corrosion. That is to say, the stainless steel will not rust, but it will promote and accelerate rust in carbon steel to which it is attached, compared to using carbon steel to attach to carbon steel.

Grade 8 hardware has 50% more tensile strength than stainless steel hardware. Grade 5 hardware has 20% more tensile strength than stainless steel hardware. No comparison.

Stainless steel hardware sounds good at first blush, but you probably don't want to go there.

68post 06-03-2016 10:26 AM

Re: Restoring Rusty
 
Quote:

Originally Posted by rich weyand (Post 7613485)
Stainless steel is more electropositive than carbon steel. You will get bimetallic corrosion. That is to say, the stainless steel will not rust, but it will promote and accelerate rust in carbon steel to which it is attached, compared to using carbon steel to attach to carbon steel.

Grade 8 hardware has 50% more tensile strength than stainless steel hardware. Grade 5 hardware has 20% more tensile strength than stainless steel hardware. No comparison.

Stainless steel hardware sounds good at first blush, but you probably don't want to go there.

Good info Rich !

enaberif 06-03-2016 09:51 PM

Re: Restoring Rusty
 
Quote:

Originally Posted by rich weyand (Post 7613485)
Stainless steel is more electropositive than carbon steel. You will get bimetallic corrosion. That is to say, the stainless steel will not rust, but it will promote and accelerate rust in carbon steel to which it is attached, compared to using carbon steel to attach to carbon steel.

Grade 8 hardware has 50% more tensile strength than stainless steel hardware. Grade 5 hardware has 20% more tensile strength than stainless steel hardware. No comparison.

Stainless steel hardware sounds good at first blush, but you probably don't want to go there.

This is why when using stainless hardware in places that isn't stainless you should use a anti-size coating of some sort to prevent seizing or corrosion.

Gregski 06-04-2016 02:26 PM

Re: Restoring Rusty
 
4 Attachment(s)
Slippery Grip Garage was closed yesterday on the account of it being 104 F

so we opened early today at 0600 and installed the new purple(ish) 43 tooth driven speedo gear and that little baby seal

we put some white lightning grease on the shaft of that gear and around the big rubber O-ring

we also topped off the transmission with some Red Wine (ha ha)

Good News: now our odometer is only .1 off for every 6 miles we drive, good enuff fer now, IT'S A TRUCK!

Gregski 06-04-2016 08:57 PM

Re: Restoring Rusty
 
3 Attachment(s)
time for Doo Dadz, I don't know about you, but I like doing finishing touches like this, makes things look complete, makes it look like it was meant to be

we ended up using one 3/8" and one 1/2"

Gregski 06-04-2016 08:58 PM

Re: Restoring Rusty
 
4 Attachment(s)
a little WD-40 on your pinky finger and lubbed up the inside for better slideability

heater core? what heater core? now no one will even be able to tell it was ever there, ha ha

hatzie 06-05-2016 11:43 AM

Re: Restoring Rusty
 
Quote:

Originally Posted by enaberif (Post 7614268)
This is why when using stainless hardware in places that isn't stainless you should use a anti-size coating of some sort to prevent seizing or corrosion.

Galvanic corrosion "galling" between active 410, 304, & 316 Stainless and Cast Iron or Cast Steel is not slowed enough by the application of Nickel based anti-sieize compounds to be equal to steel bolts with the same coating. Be careful of your anti-seize flavor of choice. Copper based anti-sieze can cause galling in aluminum and stainless parts.

Passivated 304 & 316 stainless, either by oxidizing in an air furnace or treating the surface with an acid to cause an oxide to form, is much better at resisting galling but is also more expensive.

Gregski 06-06-2016 01:44 PM

Re: Restoring Rusty
 
Monday, drove the truck in to work today! Great feeling guys I'm sure you all can relate after pulling off a big project. Truck runs strong, windows down, wind in my face, its going to be hot driving back home this afternoon, but the morning drive was glorious.

Speedo is spot on up to 50 MPH than deviates slightly and is about 5 MPH off by the time I'm doing 75 MPH on the highway, maybe tire pressure and a different tire size can dial it in further, but for now it will do, most of my driving aint on the freeway anyways

Ordered a new rear window seal from Classic Parts (love their printed catalog, yes I'm old school and it makes for a great toilet read, ha ha, also it aint got no salt & pepper shakers nor bunch of "universal" parts, nothing but essentials, plus its all in COLOR cause it's 2016. - I'm looking at you LMC Truck) hope to install that tinted slider window next.

Gregski 06-09-2016 03:31 AM

Re: Restoring Rusty
 
2 Attachment(s)
went out and bought a Mr. Gasket inline fuel pressure guage at AutoZone, wanted to see what my current fuel pump is delivering before I replace it (on the suspision that that's where the ticking noise is coming from)

Gregski 06-09-2016 03:34 AM

Re: Restoring Rusty
 
5 Attachment(s)
since they didn't have a single piece T with two 5/16 hose ends, I had to get these fittings

Gregski 06-09-2016 03:37 AM

Re: Restoring Rusty
 
2 Attachment(s)
got it all installed and learned that an inline fuel pressure gauge with a mechanical fuel pump jumps around constantly as the car is runnin' so it aint much use, I did turn the car off and ran and took a pic before the gauge fully dropped, here it is a few PSI lower than when its running

Pic 1 - truck off, just showing you the gauge installed

Pic 2 - right after I shut it off and captured some pressure

Woodyboat 06-09-2016 07:20 AM

Re: Restoring Rusty
 
Quote:

Originally Posted by Gregski (Post 7619543)
... an inline fuel pressure gauge ... aint much use,

Yeah, it's kinda difficult to see it from the driver's seat. Is that what you're saying here? LOL


All times are GMT -4. The time now is 03:04 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com