Green Machine

[cariboumarkt]

Originally Posted by gmc684x4

Nice truck
Is the teflon you used fuel rated all fuel rated teflon i have used is yellow and non fuel rated teflon is white

Huh, never thought of that! I imagine not. I never did finish rebuilding that carb so I can't even speak to its performance. Here's where I got the idea: http://rmcavoy.freeshell.org/Q_Jet_bushings.html

[cariboumarkt]

So, on the hunt for some hubcaps. Tried the local pick-n-pull sites with no 16" hubcap love. Found a few later model 15" caps but none for me. I'd also been keeping a close eye on local classifieds and online auction sites when this came up:

Nice guy, Shawn, had bought the rolling chassis here for a 1972 project and had 4 later model caps. "Come over and take 'em" he said! $20 later and I'm in buisness!

[cariboumarkt]

Although I believe these hubcaps are the wrong vintage for the #GreenMachine I jumped at their availability and the chance to test drive any set on the new wheels. Not having these in hand, so not being sure if they would fit and function kept me from buying any online so my procrastination paid off!

The question I had (that I couldn't seem to find a concrete answer to after numerous searches on this site and others) was "will these 73+ caps fit over the front and rear hubs?" I believed that I needed a 4.5" center hole on the front caps to clear the hub, so this cheap set would allow me to cut/trim/grind/whatever to fit. But, at least on this truck, these later caps popped right on!

The're a bid dented and dinged and could use some touch up paint, but I think they really improve the look of the truck overall. The hunt continues for some hubcaps of the proper vintage, but I'm in no hurry now.

[Getter-Done]

Good things come to Good people.













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[Ol Blue K20]

Looks good, nice find

[Low Elco]

Good story, neat ol truck!

[cariboumarkt]

Not a lot of work done on the ol' #GreenMachine over the summer... too hot! It was the warmest summer on record here and we had too many other things going on to worry too much about the truck, but that's all changed now. We got a wild hair and traded my daily in on a new convertible sports car in June, so we're now down to one winter appropriate vehicle, so the nagging issues keeping this truck from being my new daily driver are now on the front burner. First up? The clutch! It's been many a moon since I changed a clutch and after a few threads here and videos online, and consulting my old age and wisdom, I decided to pay someone else to do it. So, after a week in the shop and $800 later, it's done, done right and back in the driveway. Good thing I didn't try and push this off too much longer... the pressure plate and flywheel were both burned up and showed some stress cracks.

[cariboumarkt]

So one nagging issue with the #GreenMachine was the fan and fan shroud. The stock (?) 4 blade fan was inches displaced from the shroud posing a health hazard for any mechanic as well as an inefficient method of cooling the engine. I've learned that the 4WD versions of these trucks had their engines set back a couple of inches in the engine compartment for some reason. (still hoping someone can explain THAT engineering to me someday) Our truck seems to have had a 2WD fan shroud on it for some reason. A proper shroud came up for sale on the local marketplace so I was able to remedy that situation. While I was at it I added a 6 blade fan and a fan clutch for some (hopefully) economy and noise reduction. the clutch was a Hayden Automotive 2705 Premium Fan Clutch and the fan was a Derale 17118 Heavy Duty Fan Blade Series 1000 18" Steel Clutch Fan. Thanks to the members here who also made this upgrade to their trucks and listed these part numbers on this forum for us others to copy. All the parts fit correctly and seem to function properly. I haven't done a MPG test yet but expect a modest boost from this project.

[cariboumarkt]

Hello everybody. Hoping somebody can help me with a detonation problem. I've got a 1969 Chevy K20 four-wheel drive pickup with a high mileage and basically stock 350 engine. It has an Edelbrock 1406 with an adapter, headers and an HEI distributor I got from the parts store. Not sure the brand of the HEI. I initially started trying to time the thing by reaching for a total mechanical advance of around 32 degrees, so I needed an initial advance of around 18° with the HEI adding another 14°. I figured I'd deal with the vacuum advance after I got the MA sorted out. Anyway, the thing pinged like crazy. I started backing off the initial timing a couple degrees at a time and ended up all the way back at 6° btdc with the thing still pinging. I verified the timing mark on the crank with a piston stop so I'm confident it is reading correctly. I then determined where my mechanical advance was starting and ending with this aftermarket HEI. Turns out the advance was starting to come in around 1200 RPM and was all in by 1800 RPM. I got an aftermarket spring kit and started swapping in for heavier springs to push the onset of mechanical advance off and ended up doing multiple spring changes. I did some calculations on the Mr Gasket spring kit that I got and figured out foot pounds per inch for these springs. Even the heaviest spring, the gold one in the package (which came in at 13.8 ft pounds per inch, by the way) barely made any change in the onset of advance. The stock springs in the HEI and the silver springs in the kit had my mechanical advance starting at 1100 RPM and fully in by 1600 rpm. The heaviest Gold spring in the kit started the advance at 1200 RPM and was all in by 1800 rpms. At this point I went rogue and started buying springs of different pound for per foot readings that were above the gold (13.8 pounds per foot). I got springs that were 16 and a half pounds per foot 22.8 lb per foot 36 lb per foot up to a whopping 54 lb per foot! Those 54.7 lb per foot springs gave me a mechanical advance that began at around 1800 RPM and was fully in by 2800 RPM which I felt was more appropriate. Even so, when trying to run an initial advance of around 15° btdc, at the RPM where the mechanical advance starts to come in, I get detonation! Very low RPMs under a heavy load and all other situations no detonation but right when that mechanical advance starts to come in the thing starts pinging. It's not super bad but it is there nonetheless. I've now dropped the initial advance off by a couple degrees at a time down to eight degrees initial and I still get pinging when the mechanical advance comes into the picture. FYI, plug gap set to .045. Sorry for the long post but was hoping somebody might be able to explain to me what might be happening here? This truck will likely live most of its life under 3500 RPM, just weekly trips to the dump in the hardware store but I would like to A) not destroy the engine from detonation and B) get the most mileage out of the thing that I possibly can. Does anyone have any advice on how to avoid this pinging?

[Getter-Done]

What plugs are you using?

Have you tried a (Cooler)lower heat range plug?

I like Autolite plugs in an older engine with some miles on it.

They burn oil better .IMHO

[fatbass]

I'm late to the party but I love this truck. I had a '71 K10 shortie the same color scheme and always wanted a 3/4 ton to make a pair.

Is there a chance someone did something to increase cylinder pressure/ compression ratio? Wrong head gasket, pistons, poorly machined heads, etc...
In the old days of points ignition (poorly maintained) and poor gas/air filtration, carbon buildup on pistons and head surfaces was a problem to the point of causing preignition.
I would do a baseline compression check. If wildly high or erratic readings are seen, scope your cylinders to check for carbon buildup.

[cariboumarkt]

Originally Posted by Getter-Done

What plugs are you using?

Have you tried a (Cooler)lower heat range plug?

I like Autolite plugs in an older engine with some miles on it.

They burn oil better .IMHO

Yes, they are NKG V-Power XR5, which I believe is right in the middle of the heat range scale. Which plug would you reccomend?

[cariboumarkt]

Originally Posted by fatbass

I'm late to the party but I love this truck. I had a '71 K10 shortie the same color scheme and always wanted a 3/4 ton to make a pair.

Is there a chance someone did something to increase cylinder pressure/ compression ratio? Wrong head gasket, pistons, poorly machined heads, etc...
In the old days of points ignition (poorly maintained) and poor gas/air filtration, carbon buildup on pistons and head surfaces was a problem to the point of causing preignition.
I would do a baseline compression check. If wildly high or erratic readings are seen, scope your cylinders to check for carbon buildup.

I suppose there is that chance. This was my father-in-law's truck but he did sell it off for awhile. Knowing a bit of how it was used/abused for that decade I doubt there was even an oil change done on the thing much less an engine rebuild. I have been meaning to do a simple compression test, I'll put that on the list for cooler weather.

[Getter-Done]

Originally Posted by cariboumarkt

Yes, they are NKG V-Power XR5, which I believe is right in the middle of the heat range scale. Which plug would you recommend?

Here is a good read.

Link: https://www.onallcylinders.com/2018/...ug-heat-range/

Which cylinder heads do you have?

Tapered seat plugs or the one that has the compression washer?

[cariboumarkt]

Originally Posted by Getter-Done

Here is a good read.

Link: https://www.onallcylinders.com/2018/...ug-heat-range/

Which cylinder heads do you have?

Tapered seat plugs or the one that has the compression washer?

Well, there's no washer so tapered seat I guess? Thank you for the article, very informative! I think a plug change to a step or two cooler might be a cheapish experiment. Going to try non-ethanol premium on my next fill up to see if that helps as well.

[Getter-Done]

Originally Posted by cariboumarkt

Well, there's no washer so tapered seat I guess? Thank you for the article, very informative! I think a plug change to a step or two cooler might be a cheapish experiment. Going to try non-ethanol premium on my next fill up to see if that helps as well.

I am old enough to say back in the day.

I used to go to the Local Airport and get 101 octane low lead air plane fuel when I had a race.

I would . Tell them it was for a Ultra Light.

104 Octane Booster was Great additive also.

I dont know if {104} is as Great as it was Now a Days.