Looking for suggestions
 

Hello all,
As I'm still really new to this type of thing, I'm after some advice. I guess the biggest part that I'm not sure of is where to start (if that makes any sense).

I've recently(ish) purchased a 1961 step-side with a 305D under the hood. My hope is to get it to where it's a reliable daily driver. But, it's also the kind of thing where I'm quite happy improving it over an extended period of time.

I'm less interested in worrying about things like paint etc.... That stuff is certainly on the list, but the goal is to have a respectable truck that gets some use, rather than a show-pony. I'm certainly not interested in trying to turn it into something that it isn't (no hotting it up or anything like that).

So, for all you folks that have done this a million times, where would you start? That's probably a really silly sounding question. But, at the moment when I look in the garage all I can think about is the thousands of parts that go into a vehicle and I start to get a bit overwhelmed with where to begin.

At the end of this post is a list of what's already been done. I'm open to any and all suggestions really.... Particularly since I'm at the point where I want to do as much of the work on my own as possible.

Anyway, any tips or advice is much appreciated.

General electrical clean-up (removed all of the dodgy wiring. It’s bare bones now)
All belts and hoses
Standard service stuff (fluids, oils changed etc….)
Standard tuning (service distributer, new plugs etc…)
Temp sender
Greased chassis points
New alternator
Exhaust repair
Brake linings and hoses front/rear
Wheel cylinders front/rear
Drums machined
Hub bearings repacked (replaced the rear)
New uni joint
Front shocks
New tires (fun fact, the spare was an old split-rim style. That’s gone)
New headlights and side mirrors
New petrol sending unit

Re: Looking for suggestions
 

Where to begin? You have begun mate. Big time!
Basically:
1. Safety...brakes, steering, suspension, tires, seat belts, lights
2. Some reliability...motor, starter, ignition, wiring, battery, fuel system
3. Try to be sure all gauges read accurately and monitor them
4. Rust, eventually
5. Don't worry, be happy

Stay out of the outback for now

You've done quite a bit. Check out the stuff in 1. and 2., Drive it and you will find the weak spots you missed. Carry a cell phone and a bunch of money.
Nice truck, nice to meet you.

Re: Looking for suggestions
 

I forgot, I've also put in a new battery.

In terms of reliability, if I was to start on the motor, what are the types of things you'd be looking for?

Nice to e-meet you as well. I'm still getting used to the idea of communicating through forums and whatnot. So, if I put my foot in it, please try to give me the benefit of the doubt for awhile LOL.

Re: Looking for suggestions
 

Does it start pretty quickly. Does it idle nicely. No smoke from tail pipe, breather, or anywhere else. Does it run good during the load of driving. WATCH heat and oil pressure gauges./lights

If you have not check and this is an unstarted/unknown motor, you need to take off valve covers and observe oil circulation or do an old/unstarted/been sitting a long time, start-up procedure. It sounds like you have not started it yet? That would open a whole new set of responsibilities. Gotta go watch the World Series.

Re: Looking for suggestions
 

It's starts nice and I've driven it about a dozen times. It was idling a little rough the other night. But, I think that was more my fault than anything else (it's recently been leaned out and I didn't give it any choke on starting).

In fact, I've uploaded a short video of how it sounds starting and running. Sorry in advance for the size of the file (it's around 300mb).

https://1drv.ms/v/s!AjwPdb4c9NJus3o3lgBeTLTkLiGL

I'm jealous! First time for the Cubs since the turn of the 20th century and I'm stuck at work on the other side of the globe.

Re: Looking for suggestions
 

First thing before I did anything , would be adjust the valves, and do compression test ,none of the rest is going to matter if you do not have a solid engine to start with, also oil pressure is great indicator of wear on lower end.

Re: Looking for suggestions
 

And now for my dumb question, when it comes to the compression test, what's the correlation between the psi reading and the 7.75 to 1 that's on the 6066gmcguy's engine data page?
What does the 7.75 to 1 actually mean? I'm not getting much luck from the Google.

Re: Looking for suggestions
 

The compression PSI to look for is 125 PSI with a MAX 20 PSI difference in all cylinders. Basically if you have a cylinder with 100 PSI and the rest or 120-125 PSI then you've got something going on with the cylinder. On mine the they were between 117 and 125 so I haven't worried about it.

You pretty much have everything you need covered. Long as it is mechanically sound and electrically safe you'll be fine.

Re: Looking for suggestions
 

Is less than 125 ok? The only reason I ask is that the specs 6066gmcguy page say that it's 7.75 to 1. When I run that through a formula I found online (which might be wrong?) I'm getting 114.

https://www.reference.com/science/co...aedc74e6b59d7#

Thanks for the help!

Re: Looking for suggestions
 

7.75.1 is 125 PSI. A max of 20 PSI less is ok. But like said...if only one or a couple cylinders has that big of a drop you have something else going on. If they are all less than 125 and even...then that just means the motor has miles on it.

Re: Looking for suggestions
 

No dramas. Thanks for the advice. I'm going to try to buy a test kit today or tomorrow, then I'll see how I go.

If I understand the process correctly, it's just a matter of disconnecting the battery, unhooking the leads to the sparkplugs, removing the sparkplugs, reconnecting the battery and then going through each cylinder with the gauge while someone turns the engine over a few times with the throttle down all the way? I've found some tutorials online. But, like lots of things on the internet there are some contradictions.

Sorry for all the questions. My issue is that I understand a lot of the basic theories, but I have almost 0 practical hands on experience. My father was a mechanic (one of those magical types that just seemed to know everything about cars), and he spent a great deal of time talking to me about a lot of this stuff when I was growing up, but there's obviously a vast difference between thinking you know how to do something and actually having the experience of doing it.

Re: Looking for suggestions
 

If you find you have low compression on a cylinder, squirt a little oil in the cylinder, if the compression goes up the you know it is rings, cylinder wear, if it does not go up the it is a valve problem.much easier fix.

Re: Looking for suggestions
 

All you have to do is pull the plug wire off the coil and you can leave the rest. Pull one plug at a time and do the test. You don't HAVE to be at WOT as with mine I was pulling 120 PSI without the wot. lol I'd do it with and without for the heck of it. Nice thing is you don't need someone to use the key switch either. You can take a screw driver and touch the power lead of the starter solenoid to the Purple wire terminal on the right side of the solenoid that will kick your starter on so you can do it all in the bay.

Re: Looking for suggestions
 

Is the fact that I've got an electric fuel pump that kicks on straightaway going to be an issue?

Trying to think about it logically, if the idea is to test the amount of pressure generated in each cylinder, then I would think that I need to leave the pump alone. Otherwise, there won't be any petrol in the cylinder, which I'm assuming would cause a false low reading?

But, if I leave the pump alone, I would think I risk frying the points and flooding the engine?

Not sure if I'm over thinking this (wouldn't be surprising if I am, it's what I do).

Re: Looking for suggestions
 

As far as safety is concern I would disconnect the electrical wire to the electric pump. If you did have a spark and there is fuel vapor around it could light off.

As far as other servicing I recommend changing the rear axle and transmission oil.

Did you get a front end alignment? If you do one be sure it is performed as per the instruction in the GMC manual. Most shop will place it on the alignment rack and adjust away, big mistake. These truck you need to measure the frame angle and the ride height to get the camber correct. On my truck someone had aligned it like a car with too much camber. With manual steering it was everything I had to turn the wheel while going around the corner. Once I corrected it the steering was still hard but I able to turn the wheel without King Kong helping me. On my truck the spec says -0° 15' to 0° 45' with a 2" ride height. I don't remember what my frame angle was but the manual will tell you how to calculate it in.

Re: Looking for suggestions
 

You are testing cylinder compression (basically rings, valves and head gasket sealing), so the fuel pump should not enter into the discussion.
Disconnecting the electric fuel pump will not hurt anything, but is a bit of extra effort.
The fuel pump only refills the carburetor float bowl. If all is working as it should. the only fuel being taken from the float bowl will be as a result of the air being pulled into the engine as a result of the piston and valve action ( the engine is basically a large air pump, to which you add fuel and a spark.....hopefully at the correct volume and time).
By having the throttle wide open, it reduces the vacuum in the manifold and carb, and will draw somewhat less fuel into the manifold and cylinders while cranking. That should not make any significant difference in your compression readings. In general, having the wide open throttle might make readings a bit higher, because there will be less restriction in the air passage. In practice, it is not particularly important, because most of the time you are looking more at relative readings between cylinders; and different compression gauges and procedures will give slightly different results also.

Try to run each cylinder through the same number of compression strokes to be consistent. Usually five of six compression cycles is plenty in a decent motor. Some guys do more, looking for the absolute highest reading. Personally I like to see what happens by the time a motor has gone through three or four compression cycles. Hopefully by four, you will be very close to the maximum pressure. If it is still climbing significantly by the end of four cycles, I would suspect weak rings; but there are a lot of other variables involved.
If you suspect weak rings, the common test is to add a teaspoon of motor oil and retry the test. That helps to temporarily seal the rings an will usually result in higher readings. If the readings go up a lot, then there is likely a ring problem, but just very minor increase could be attributed to the added oil taking up a bit of the combustion chamber volume.
It is all relative, so don't hang your hat on any specific numbers. If it starts OK, and runs relatively smoothly, does not burn a lot of oil, and seems reliable; you should be good to go with it for quite a while.
There will likely be other things to take up your spare time and provide more 'education' on big American iron.

Rod J
Issaquah, WA

Re: Looking for suggestions
 

I think you are playing with it too much. You are going to poke your eye out, cause leaks or get paranoid. Drive it.

Re: Looking for suggestions
 

LOL point taken. I do have a tendency to go overboard. Thanks!

Re: Looking for suggestions
 

Nothing wrong with being cautious. I've almost been stranded for just Driving. lol If you use the screw driver method I mentioned you won't have to disconnect the electric pump, unless it get's its power from the cranking side of the solenoid which I doubt. If you need a picture of what I am talking about I will post one. :ok:

Re: Looking for suggestions
 

I'm too clumsy and scatterbrained to not be cautious. If you've ever met someone that could brake an anvil with a rubber hammer, that's me.

A picture would be awesome. At least then I'll know what I'm looking at is similar to what I've got.

Re: Looking for suggestions
 

Compression ratio is reference to the volume of the cylinder with piston at bottom of the stroke as compared to the volume of the cylinder with piston at the top of the stroke. This is part of the physical design of the engine. At ideal, brand new condition, and probably at mean sea level, this would also result in the imperical data TJ and other refer to which includes a compressed pressure within the cylinder of 125 psi. With age, valves, valve stem seals, and piston ring seals begin to leak. So depending on the life your engine has lead, this maximum cylinder pressure will be lower.

As stated, as long as the pressure reading between all cylinders is within a reasonable margin and none are below 100 psi, you will probably have a serviceable engine with many years left in it.

You do not mention if the engine is equipped with a "new" dry-style air cleaner, or the original "oil bath" air cleaner. Be sure to use the newer more common replaceable air filter. The original oil bath is great for nostalgia, but can shorten engine life.

Re: Looking for suggestions
 

I'm glad you addressed the air filter issue, WD. I've addressed it before too, but it's been several years ago now. I like how you said the oil bath is great for "nostalgia" but can shorten engine life because that is definitely true. You just can't beat a paper element for efficiency -- they catch over 99% of contaminants vs. about 95% for a properly maintained oil bath unit. And much lower than 95% if not well maintained. And they're messy to maintain compared to a paper element which you merely throw away. There are lots of sites on the internet that compare the two types. Here's one of them:

https://www.hastingsmfg.com/ServiceT...ke_filters.htm

So if you want to get the most miles possible out of your V6, get rid of the oil bath air filter and treat your engine to a new paper element air filter.

Re: Looking for suggestions
 

http://uploads.tapatalk-cdn.com/2016...7f56a2a00d.jpg

I figured as much time as I've spent blathering on about it that it wouldn't hurt to upload a picture of where the magic happens lol.

Re: Looking for suggestions
 

The engine bay looks very clean indeed. The blue is popular in California and does look good. I'm thinking of a more smokey blue for mine.

Re: Looking for suggestions
 

Blue is how it came.... But, someday I'm going to go for June Bug Green I reckon.

Have you ever seen Longmire? Something close to the colour of Henry's truck.

Sent from my E6653 using Tapatalk

Re: Looking for suggestions
 

Bit late on the picture but here you go. If you take touch the center lead to the lead on the right with the purple wire it will kick the starter on. Be aware you'll get some sparkage, but that's normal so don't be worried, once you get a good connection crank the motor until you get to the peak compression on the gauge. Do that with all 6 and be sure to record your findings. :ok:

Re: Looking for suggestions
 

Thanks for the info. I'll see how I go.