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Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
8/31/20 9:18 a.m.

I will also chime in.

I would never ever ever ever ever ever ever trade a Qjet for anything unless you wanted to go EFI.  The Quadrajet is hands down, bar none, the most accurately metering carburetor on the planet.  Ever.  Better than a predator, Carter, Holley, SU, Weber, any of them.  It is actually even better than the TBI that replaced it.  In fact, many TBI folks have swapped their TBI out for a Qjet and picked up power, torque, and MPG.

The man who was partly responsible for the Qjet is a fishing buddy of mine.  He is also partly responsible for the TBI but he's so embarrassed by that he doesn't tell anyone he had anything to do with it.  The Qjet was able to pass EPA standards with flying colors up through 1989, and could have been continued for several more years.  The push for the EFI was mostly because "everyone else is doing it."  

20 years ago, I would have considered myself a Qjet expert.  I have modified them extensively.  Sadly, that was 20 years ago and I haven't touched one in over a decade.  I can try to walk you through some simple stuff if you want to rebuild it.  They seem complex, but they really aren't.

As far as trans is concerned, the S6-650 is a sweet piece.  The granddaddy for the medium truck sector is the NV5600, but they tend to bring big bucks, and were primarily used in Dodge, so not an easy bolt-in swap.  If you want to go automatic, you're limited a bit.  The TH475 will take lots of abuse, but the ratios aren't something you'll be happy with.  4L80E will take the torque, but still not very good ratios, and tons of electronics to deal with.  I suppose some of the newer Allisons could be adapted, but again... electronics.

RichardSIA
RichardSIA Reader
8/31/20 11:21 a.m.

Had not realized I never stated the engine, SBC 350, "Good-wrench" replacement low compression version. Think it may have been 8.5-1. at best.

During the rebuild I am upping compression to 9-1, I live at 4,400' and am confident this will be fine. Upgraded to newer design 72cc chamber heads, Summit Racing brand made by Dart. Also upgraded the intake to Performer Q-Jet, new cam, and headers. 

Since I do actually use Granny Gear on occasion I made a point of finding an early NV4500. I need to finish pulling the SM465 so that I may measure how much to shorten my forward drive-shaft.

My hope is that I may get around 16 MPG instead of 8-10 MPG. No doubt readers will be skeptical of this but I've had that before with a very similar engine in a nearly identical truck, without overdrive. Of course that was at sea level so best possible efficiency. 14 MPG will satisfy me at this altitude.

buzzboy
buzzboy Dork
8/31/20 2:26 p.m.

The national average miles driven is 13476. If you go from 9mpg to 10mpg, at today's national average gas price of $2.23 for regular, that would be a $334.50 savings annually. That's damn good.

RichardSIA
RichardSIA Reader
8/31/20 2:55 p.m.

If I do not get at least a 4 MPG increase I will be very disappointed. This has not been a cheap upgrade. Engine had to be rebuilt but I could have "saved" a little over $2K if I had just left the transmission alone.

I've spent more improving this truck that I originally paid for it. May as well do what I really want since it's my last large truck. Would not want anything newer even if it were free, no electronics gremlins here!

RichardSIA
RichardSIA Reader
9/16/20 11:06 p.m.

Whew! I managed to avoid the "Mission Creep" becoming a whole new mission today.

Barely. I've had a couple of '57 Chevy trucks, last of the good looking trucks. Today I was told where to find a couple of '57 cabs for probably fairly cheap. I've seen them adapted to 80's chassis before so know it can be done. MUST RESIST the temptation, heck, I just bought new fender and bumper for the '81 body. 

 

RichardSIA
RichardSIA HalfDork
10/5/20 8:52 p.m.

Meh, not happy today. Supposed to finally get my block back from the machine shop. Owner went in over the weekend in an effort to catch up. Block is done but my rods are way out of spec at the small end. This is the "Mr. Good-Wrench" replacement engine that I found to have all the ring gaps lined up in six of eight cylinders. "Hecho en Mehico".

Ordered new rods from summit to speed this along. For assembly, I cannot do any worse!

EOR

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
10/5/20 11:04 p.m.

If it were a running engine i'd say you should play the lottery, since ring gaps move when running. Heck, i wonder if lining them all up makes for easier priming/cranking on initial startup before they gradually do whatever they wanna do anyway. smiley

RichardSIA
RichardSIA HalfDork
10/5/20 11:10 p.m.

I had VERY bad cylinder leakage past the rings, over 60%. Might have been more than rings being aligned but I've never seen such before.

RichardSIA
RichardSIA HalfDork
10/16/20 9:19 p.m.

Well, E30-whatever!

First set of "Just buy these inexpensive rods from Summit to get this done" rods turned out to be a waste of time as they CANNOT be assembled according to the directions*. Now returned, and a week of my time wasted. Replaced with Eagle rods for $40.00 more. Now waiting on the machine shop, again. no

I bought this truck a few years ago so I would never have to impose on friends ever again to move my cars. Guess what, very anxious to get my Europa home before the snows start, so may indeed be imposing again. sad

*Never heard of rods that claim the small end is expanded by submersion in almost boiling (180˚) water. And clearly states DO NOT use a standard rod heater.

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
10/19/20 2:49 p.m.

I throw the wristpins in the freezer too. Is that also against the rules? My first job was in an automotive machine shop when i was 15. The rod heater was an old gas stove!  Having said that, i understand pretty much any rod could be hurt by improper heating. They probably just said boiling water since it's basically impossible to heat something past 212* that way, which puts a hard limit on how much you're heating the thing. Heating it to 212 any other way would probably do the exact same thing. 

RichardSIA
RichardSIA HalfDork
10/19/20 3:15 p.m.

Yep, pins in the freezer over the weekend, still no joy. Doubt dry-ice would have been significantly better.

Eagle and done, I get my pistons today and may finally begin to assemble the engine.

Now just need a good nights sleep and no interruptions to get it done. Still have to sort the trans upgrade out too.

RichardSIA
RichardSIA HalfDork
12/20/20 10:58 p.m.

Had to quit the &#@%$! "Day Job" in order to have time and energy for the truck and other builds.

Next tee shirt says, "I'm not a mechanic, I'm a RETIRED!".

Engine together and running at last! Being a bit paranoid after spending more than enough to just buy a newer (Ewww!) truck I put the engine on my old Allen S.E.A. with Oscilloscope option.

I have one O 'Scope trace that annoys me. Moved wires and plugs around, no change. Cap, coil, and HEI module are new. Warm compression is 160-165 for every cylinder. Without seeing this trace I would be blissfully certain the engine was fine. It runs fine, idles smooth, accelerates quick, pulls more RPM than I will ever use in this truck.

But now I know there is an issue and will not be satisfied until it is resolved. Any expert O 'Scope readers here?

Went through my copy of "The Scope Book" without satisfaction. Wondering if I might have a slight intake leak as leaner equals shorter spark duration from what I see in the book.

I am going to readjust the valves now that the cam is run-in but do not expect that to change my result. I will also run the scan again and if no improvement I will apply my old Color-Tune tool. Weak mixture is Yellow, correct would be Bunsen Blue. I will compare the irritant to the well behaved for an answer, I hope!

ShawnG
ShawnG UltimaDork
12/21/20 12:40 a.m.

NV4500, they're great. We're putting one in a '69 Suburban.

Keep the Q-jet. Stop thinking of it like a Holley, it's really an SU in a different package.

Cliff Ruggles literally wrote the book on tuning Q-jets, you can find everything you need on his website. Or give him a call and tell him what you're putting it on and he can set you up with the jets, needles and springs you need.

 

RichardSIA
RichardSIA HalfDork
12/30/20 1:58 a.m.

New plugs and higher quality wires got rid of the shorted traces.

Now just need to get the engine and trans back into my truck.

Then I will custom fit new ignition wires and be able to measure the driveshaft to have it shortened.

Really looking forward to having flat-bed back in operation, decent power, and maybe even improved mileage.

RichardSIA
RichardSIA HalfDork
2/12/21 8:27 p.m.

Engine and NV4500 are "In" the truck but not all bolted up. The claim that "Once you have the trans bolted to the engine the rest is a bolt up swap" is not true. Apparently somewhat more true for 4x4 but not at all for 2WD.

So I will be making a new trans cross-member, or modifying the original a lot. Basic issue is that the NV4500 mount is about four inches further back, and the area just in front of the mount is a large square casting.

Nope, cannot just set the original mount further back unless I want to remove the cab first to do it. Original mount bolted to the upper frame rail. I'm thinking the new one is going to have to bolt to the lower rail.

Pics once I get there.

03Panther
03Panther SuperDork
2/12/21 8:55 p.m.
ShawnG said:

NV4500, they're great. We're putting one in a '69 Suburban.

Keep the Q-jet. Stop thinking of it like a Holley, it's really an SU in a different package.

Cliff Ruggles literally wrote the book on tuning Q-jets, you can find everything you need on his website. Or give him a call and tell him what you're putting it on and he can set you up with the jets, needles and springs you need.

 

I don't know SU's well enough to compare, But the" Keep the Q-jet. Stop thinking of it like a Holley" part is as true as anything I've ever heard! Q-jets are one of the most "maligned due to not understanding" devices out there!

RichardSIA
RichardSIA HalfDork
2/12/21 9:13 p.m.

Too bad they do not tune as easily as an S.U.

I have a buddy who insist that Q-Jets are easy. OK, once the engine is fully in he can show me how. I've been frustrated enough to almost go buy a Holly Sniper EFI, and that is true blasphemy for me.

03Panther
03Panther SuperDork
2/12/21 9:18 p.m.

Easy is not really the best way to describe a Q-jet... I don't know them well enough to tune one in right, and I can, on a Holly  or AFB; or most motorcycles (I'm a fan of the S&S E) But I know when they are right, they are my favorite street carb on a V8, at least.

RichardSIA
RichardSIA HalfDork
3/1/21 9:55 p.m.

The NV4500 conversion is almost done. It has not been nearly so easy as on-line sources claim.

Maybe the 4x4 version is simpler but this has been a "Bear" to do. Bell housing was simple, just buy it from AA. Clutch TO bearing they supplied was too short but I found a longer version. Driveshaft is ready to be picked up and now 5" shorter.

Cross-member, THAT is the real pain. It has to move back several inches and will not reuse a full set of existing mounting holes. I moved it far enough back to reuse two existing holes. This meant I had to add at least one rearmost hole in the top rail of the frame. Frame is a C channel, so unless the cab is off access is very poor. Drilling a hole from the bottom is not fun. Finally got to borrow an air powered right-angle drill which allowed me to finish at last.

If I had realized that modifying and relocating the original mount was going to be this hard I would have just made a new one from scratch. Of course to do that I need to fix the welder first. angry

In the morning I will modify the support pieces that bolt from the lower frame rail to the cross-member. I have to relocate some holes but that is easier than drilling new holes in the lower rail.

Minor effort to make up a patch panel for the transmission cover as the shift tower is now further back.

Glad I only have to do this once!

RichardSIA
RichardSIA HalfDork
3/4/21 9:32 p.m.

Looks like I measured the driveshaft correctly, it is in at last. smiley

Now down to the simple stuff like assembling the front sheet-metal, dash, and rebuilding the rear brakes.

Got the registration renewed, so might even make my trip to collect a couple of project cars next week.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
3/5/21 7:36 a.m.

Pics!

RichardSIA
RichardSIA HalfDork
3/5/21 2:19 p.m.

Once bolted in there is not much to see, looks a lot like stock.

Cross-member was cut away when I still thought it would work directly under the trans. To do that I would have had to make an entire new set of mounting holes which would have made the upper frame rail Swiss Cheese.

NV4500 into 81 C30

NV4500 to C30 -2

NV4500 to C30-3

NV4500 into C30-4

NV4500 to C30-5

NV4500 to C30 inside.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
3/5/21 3:06 p.m.

Looking good!

RichardSIA
RichardSIA HalfDork
3/5/21 7:19 p.m.

One last PITA, finding the wiring plug that transmits the signal for the electronic speedometer.

I never would have thought this would be a hard part to find. The expensive electronic to mechanical conversion kit I bought does not include it. The companies website does not list it, every search only turns up sellers for the Dodge version drive gears.

I may have to just go with my old GPS for speed next week since it seems companies do not worry about the little critical details that make their products actually WORK anymore.

RichardSIA
RichardSIA HalfDork
3/15/21 1:22 a.m.

Finally moved under its own power today. smiley

Definitely easier shifting than the old SM465 but I will have to get used to the new ratios. Not road ready yet so no real experience with the OD fifth. I did get to try all the gears and they work fine, so I won the private party web search purchase lottery. 

Still have some dash work to do, waiting on the speedometer pulse generator plug I had to order from GM. I will be adding an aftermarket tach to know what RPM I am turning.

And of course I'm still not happy with the Q-Jet, seems to run rich and the idle adjustments have no effect. Not that great for driving either with it's stumble.

I will be doing a fly and U-Haul drive on Tuesday to collect some cars I bought, I just cannot put the trip off any longer in order to finish this truck. 

I will get back to it once I return.

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