1969 GTX....The T stands for tetanus

[threewood]

So annoying! Why can't these companies get their $hit together.

New parts should work like new, not need work to actually work. And the pump is so simple, 4 vanes, a rotor, button, gasket and cover. No reason for a part to ever leave the factory like that. Stamped Made in the USA too

 

[oldbee]

LOL look in the "recents". I just don't remember this crap happening 40 yrs ago.

 

[JimKueneman]

Can you elaborate on the switching regulator? How to put one together? It does get louder with higher rpms and quieter at idle.

But....it holds fuel pressure right at 5.5lbs throught the rpm range and at wot. Rock solid! It actually seems to idle better and run better now which is the important part so mission accomplished.

And now that that issue is fixed the car decides to overheat...again. It creeps up and up until it is on the upper limit of the stock gauge. No change on the highway and I had the heater running. I was planning on flushing the system again so I will pull it apart and check the t stat and see if i can back flush crud out of the radiator. It never ends.

[Nerd Alert]
I got one of these from my LT rep for free and made a few simple changes to allow it to be adjustable output. (added a pot and changed a resistor value)
http://cds.linear.com/docs/en/demo-board-manual/dc720A.pdf

Ah, fuel delivery and running hot...... where have I heard that song before?

And no it apparently never does end.

 

[threewood]

Sorry to hear that....I feel for ya..

No worries, it is back together and working correctly. I called Holleys customer service and got a recording saying they were closed and then got cutoff. No way to leave a message which is probably a good thing because I was livid. Just one more speed bump, there will be more.

 

[threewood]

[Nerd Alert]
I got one of these from my LT rep for free and made a few simple changes to allow it to be adjustable output. (added a pot and changed a resistor value)
http://cds.linear.com/docs/en/demo-board-manual/dc720A.pdf

Ah, fuel delivery and running hot...... where have I heard that song before?

And no it apparently never does end.

That might as well be hieroglyphics lol. Would a 3 prong regulator work? Say 14v in, 8v out and ground? Something like this mounted to a heat sink...

Any non adjustable fixed regulator? I like the idea a lot.

 

[JimKueneman]

That might as well be hieroglyphics lol. Would a 3 prong regulator work? Say 14v in, 8v out and ground? Something like this mounted to a heat sink...
View attachment 508090

Any non adjustable fixed regulator? I like the idea a lot.

That works but I am running my stock 34A alternator so getting 10% of the capacity back with the switcher was advantages to me. Look for something on digikey. Vicor bricks are good but very pricy.

 

[Billccm]

Vicor bricks are good but very pricy.

Agree. The Vicor bricks are bulletproof. These are used in mining vehicles and they pass SAE Load Dump up to 140V, Surge to +/-500V, Isolation of 700V typical, and Transients up to +/-1KV. Even has excellent short circuit protection and auto recovery. Efficiency seems >80% across the input range. I know these well, but expect to pay $200 for such a luxury.

 

[threewood]

Radiator cooling tubes are all gunked up so it needs to come out. I needed to flush the system again anyway but I am pretty sure that is the cause of my overheating.

 

[threewood]

Success! !!!
I pulled the radiator and let it soak with CLR/water and it didn't seem to do much. There was a layer coated inside the radiator tank. This will sound strange, but out of sheer wonder I loaded up urethane reducer and let it sit for a while.....it flippin worked! Sheets of brown scum came out. Even more with agitation inside the tank. This is one of 3 loads of crud...

So I rinsed it out with water, reinstalled everything and inserted a screen in the top hose to keep more crud from entering the radiator. On my test route (10 miles, same as previous time) the temp kept creeping up and up. By yhe time I pulled into my garage she was kissing the upper limit. F$!#!

So I went out back, did some yard work and contemplated driving the car over a ravine. My next step was was removsl of the t stat. As I got the upper hose off the screen was blocked with crud.

Which could be the cause so I removed it and took her out again.

Same route and the temp held. I even stopped for some celebratory beer

Funny thing happened while testing....a cammed out 2005ish Mustang kept running up on my ***. Now I was busy trying not to overheat so he passes when the road goes 4 lane. I hear him downshift and lay the spurs to it so I nail it and reel him in pretty quick. He tries again and he is again in peril of having my car rammed up his a$$. We catch a light, I'm going left to the highway and he is going straight. I pull up and he will barely look my way. I flip him a thumbs up, he does the same as he is looking at the 440 callouts and I part ways burning rubber. It was a good night. Man this beer tastes good!

 

[threewood]

And the GTX with her older but hotter sister....

 

[Dennis H]

N ever
E ver
W orked

 

[Glenwood]

Awesome! That beer must have tasted sweet. Much better than watching her going over the cliff!

 

[threewood]

Moving on to pinion angle. Here is what I measured. Engine is 4° tail down, driveshaft is 0° and the rear end is 4° nose up.

Which equals 0 and is good. But I want to set it up so under acceleration it equals 0. How many degrees would a set of s.s. springs on an 8 3/4 rear wind up?

 

[JimKueneman]

Here we go, if you would have just put a slant 6 in there you would have been done!

 

[440+6]

Moving on to pinion angle. Here is what I measured. Engine is 4° tail down, driveshaft is 0° and the rear end is 4° nose up.
View attachment 511297
Which equals 0 and is good. But I want to set it up so under acceleration it equals 0. How many degrees would a set of s.s. springs on an 8 3/4 rear wind up?

The rear pinion should be down 4 degrees or more at rest, when accelerating the pinion will move up 4 degrees and zero out, with slicks on a track it might come up 6 or 7 degrees on a stock suspension.

 

[threewood]

Here we go, if you would have just put a slant 6 in there you would have been done!

Nope, at some point I would have swapped in a big block anyway. This way just cuts out the middleman.

 

[threewood]

Awesome! That beer must have tasted sweet. Much better than watching her going over the cliff!

I like your new avitar picture.

 

[threewood]

The rear pinion should be down 4 degrees or more at rest, when accelerating the pinion will move up 4 degrees and zero out, with slicks on a track it might come up 6 or 7 degrees on a stock suspension.

Thanks. That was kind of the direction I was leaning. I have a set ordered. I was a little concerned because there are scrap marks on the driveshaft end where it was contacting the rear pinion yoke on acceleration so this should stop it from happening.

 

[threewood]

Been driving it without issue. Temp doesn't budge off the middle and no stumble. Runs fantastic besides the noisy fuel pump but I can desl with that as long as it runs. I did get my shims which I will put on tomorrow.

And here is a shot of where I mounted the fuel pump relay.

 

[69 GTX]

Great news that your enjoying your car!