Re: Restoring Rusty
 

Yes I concur, I am not a big fan of where the sending unit sits now.

I plan on getting a forward facing water outlet so that I can install the sending unit on the driver side and clear the upper radiator hose. Not a fan of putting any more holes in that intake. ha ha

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Why not put the water temp sending unit in the head? I noticed that the temp sending unit on my 80 4.1 was 3/8 npt.

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I dig the new look.

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I love home spun upgrades like that.

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Not as simple as you think.

The 3/8" NPT tang senders have a different resistance range than the 1/2" NPT Nail Head senders.
You could swap in a matching 1979/1980 or later temp gauge along with the 3/8" NPT tang sender.

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Looks like there's enough clearance right now.

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Exactly

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not really, that pic is deceiving

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New Clue: truck will not idle below 750 RPM, even with the idle speed screw all the way out, timing set at 12* BTDC

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OK, back to basics

went out and bought a Vacuum gauge at NAPA for $25 bucks this should help set the idle mixture screw on the Holley 4160 carb

so following a Super Chevy article (love that magazine) we set the idle to 850 RPMs that should give us a stable vacuum reading

Re: Restoring Rusty
 

That sucks.

(gufaw, gufaw, gufaw, hyuck, hyuck, hyuck)

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so we hook the timing light up and the vacuum gauge to a non ported manifold vacuum off the base of the 4160 carb and the needle won't sit still, it jumps spastically between 15 and 20 PSI, see video

we bottom out the idle mixture screws one on each side of this carb (it only has two) and then turn them out 1.5 turns as per Holley's instructions

than we play with them screwing them all the way in slowly then backing them out to about 2.5 turns, and that pesky needle keeps dancing and won't stabalize

https://www.youtube.com/watch?v=ry9ShldWpUg

Re: Restoring Rusty
 

so at this point I am thinking vacuum leak, so I disconnect anything that may be sucking vacuum, brake booster, PVC, etc. and plug those ports up with some spare hoses and bolts in them to clog them up, still no change, needle keeps dancing

so I remove the carb and notice I got a 1/4" spacer but it ain't sandwiched between base gaskets, (not sure if it must be, but something tells me it ought to should) so I shoot over to the parts house and buy 3 different types of gaskets (two of each)

a 54

a 55

and a 57

hey, who knew? right?

Re: Restoring Rusty
 

Now Silver-hair was by this time very tired, and he went downstairs to the garage, and there he found three Holley carb gaskets. He tried the largest one, which belonged to the Big Bear, and found it too big; then he tried the middle-sized gasket, which belonged to the Middle-sized Bear, and he found it too small; then he tried the smallest one, which belonged to the Little Bear, and found it just right, so he laid it down upon the intake manifold, and put the carboretor on it

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and to add in salt to injury, check out how high my feeler gauge goes up to, ha ha, .035 man GM Gods sure have a sense of humor - had to resort to the goofy wire style one I swore I would never find a need for, lol

Re: Restoring Rusty
 

WOW! I'm sure glad you didn't step in it!!

If you haven't figured this out yet, I'm reading the entire thread from start to finish. I love it.

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I would run through the valve adjustment again, it is acting like they are a tad too tight.

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Spark plug gap on a HEI Chevy should be .045 as .030 was for a points system. Yes using the wrong gap will make a vehicle run like absolute crap. When I put plugs in my truck they were gapped for .030 and I could not get it to run properly no matter what.

Also doing vac gauge measurements I am pretty sure it should be on manifold vacuum not ported vacuum as should your distributors vacuum advance to get optimal performance.

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I was just curious why the engine would overheat with the heater lines plugged,my big block is capped and it runs fine.Is your style engine have a different water gallery set up that would cause that?

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I been looking at your photos... y'all gonna have to change that truck's name.

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ha ha, I said that, hmmm, thank you so much and enjoy the read

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Hi Jake, I agree about the valves needing an adjustment, not sure if they is too tight, as I am not that good at diagnosing them, but I will definitely check them today and report back

I do hear a tick and to me it sounds like one may be loose sounds like it is a comin' from the passenger side, here's the absolutely crazy thing though, it sounded exactly precisely the same before I did the top end swap/job, in other words the old heads aka the old valve train was generating the exact same tick (lets just keep that in mind as if it may turn out to be something else, something silly, like a bolt sticking out and tapping a firewall or something crazy like that)

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interesting, we are going to try all on .040 as per the GM Performance Spec sheet, but may bump it up to .045 as you recommend if needed

it is

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my best guess is that something is wrong, we have not truly found the source of the problem yet, I agree that it should run without the heater core, and without the bypass hose from the intake to the water pump

let me get passed this vacuum issue and then I may try a different water pump, and maybe a more than single core radiator after that, maybe go aluminium

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ha ha, not just yet, we still have to tackle the kick panels inside the cab and pull the dash completely out to see what lurks behind it (Winter Project?)

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I used to run .060 gap with a Jacobs Mileage Master multi spark setup on my 1985 5.0L C10. She ran nice and smooth. That or an MSD6AL is about the only aftermarket coil system I would use because it doesn't bork the stock ignition module. The mileage gains were not enough to make the price worthwhile.

Run the gaps as wide as you can get away with it lights the fuel better. .045 is a good number for stock HEI with a new Delco coil and Ignition module.

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Dentist appt. !! Don't take it out on poor Rusty, he has to be worried now.

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Can't you combine the .035 and .010 to get to your .045? That's the way I was shown by my dad when I was learning engine stuff.

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thought about it, but they have some heavy lube on them so that probably will add thickness to it, so I just used that wire wheel one, I may pick up a proper feeler gauge set today, I like decent measuring implements when I can afford them

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Ha, ha, Rusty is about to meet the 3 lbs sledge if he don't shape up real quick!!!

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What vacuum can are you running? That can make the engine throb like that, although that is usually on the low end of vacuum, not the high end where you are.

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hi Rich, what can are you talking about? if the one on the dizzy than I am not using that during the test, its like setting initial timing, no vacuum advance

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No, it's not like initial timing. You need to tune the carb with the vacuum advance hooked up. There's your problem. You are running a way-too-late spark.

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1) Initial timing = vacuum advanced unplugged

2) Mechanical Advance = How much your distributor pulls with weights and springs

3) Total Timing = Initial + Mechanical @ 2500-3000 rpm

4) Carb tuning is 1-3 setup PLUS vacuum advance

Vacuum advance is there to help with idle and cruise and can help with MPG

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Koogle Mooglie, lemme re test than, and get back atcha all

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decided to do a compression test before doing a valve adjustment, it's always good to have a baseline

man I was so bummed to find out that my trusty ol' compression gauge was not working, it read 0 for the first 4 cylinders

so rented one from AutoZone for $40 bucks (which they refund you if and when you return the tool) before Pontiac Mike told me to check the Shrader valve on my old hose, and sure as sheet the cheapo tiny valve is bad, so that tells me my gauge may be good after all

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man my cylinder pressure looks great, #1 and #2 were initially low but retested great

I always like to test twice once 1 through 8 and later on after re warming up the vehicle 8 through 1