83 Suburban build - Big truck for a big family!

Beerdy

Observer
On Saturday I brought home a 1983 Suburban K20, which I got for a song and a dance. It’s not perfect, but I think it can end up being the perfect vehicle for my family and I.

I’ve been searching for an older Suburban for a while, and I had a few things on my wish list.

1) Manual locks and windows (I can’t stand power window failures)
2) Barn doors
3) 350 engine
4) Manual Transmission
5) Front and rear bench seats

This new vehicle checks all of those boxes, which I honestly never expected to do at a reasonable cost. With that said, there are a few issues with the vehicle that need to be addressed. But first, a little background.

My family and I live in North Carolina. We have four kids that are eight and under, so we really needed a bigger vehicle. We love to go hiking/camping/backpacking, so having a vehicle that matches our hobbies will be a great addition.

I personally do not have much of a mechanical background. I’ve done my own oil changes in my truck, have replaced my brakes, replaced a radiator in my old jeep, but that’s about it. As part of my research into vehicles, I learned that the Chevy 350 was one of the simplest (and cheapest) engines to work on, and this works perfectly into my experience level. Couple that with the fact that, outside of the power steering, there are no “power” components to this truck, and it’s a perfect match. My plan is to dive into the engine, using this as a way to learn about how it works, and more importantly, how to fix it. This is where the internet, and possibly a helping hand or two will come in.

The Suburban started its life as a State Park vehicle in Idaho. The previous owners friend bought it from them, and he sold it to the previous owner when he moved out here to North Carolina. At some point during its life, the truck got a rather crude paint job, which will eventually be fixed.

truck.jpg


The inside of the truck hasn’t seen a vacuum, much less a carpet cleaner, in a very long time. The front bench has a seat cover that I’m afraid to see what’s underneath, and the rear bench is folded down on the driver’s side, I assume to keep the back of the driver’s seat upright. The dash is cracked, but I expect that from a 30 year old truck.

front interior.jpg

The rest of the interior is full of spare parts, including a small brush guard. It does not have a third row, and this was on the wife’s wish list. Perhaps I’ll add a jump seat in the back, although I do love the extra space it gives us.

rear interior.jpg

There is one spot of rust that has gone through the floorboards. Body work was one of my biggest fears in a truck. I have little mechanical experience, but I have ZERO body work experience. However I am a realist, and I know that I would have to deal with some rust unless I really wanted to break open the piggy bank. Aside from this spot, there is only minor surface rust.

rust.jpg

Another thing that I’m not really sure about is the transmission. I didn’t realize it right away, but this truck has a granny gear. I have no experience with a vehicle with a low gear like this, so it will take some time getting used to it. What I thought was a 4 speed manual is essentially a 3 speed manual. I’m unsure how this will do for us when we eventually move out west. Anyone have any thoughts on this?

shifter.jpg

The engine starts up fine and seems to run pretty well. I drove this from Fort Mill South Carolina to Huntersville North Carolina with no issue. There is no tach and the speedometer doesn’t work. Being a three speed and not sure how it is geared, I was unsure of how hard I was pushing the engine on the highway.

engine front.jpg

It does come with dual batteries already setup, which is nice as I eventually wanted to go that route anyway. Plus this engine bay has TONS of space.
engine right.jpgengine left.jpg


That’s not to say it is without problems.

engine top.jpg
The previous owner did tell me of an oil leak, so I’ll need to find it and fix it. That is my first real dive into the engine. Here’s the stain on the driveway after about 24 hours.

oil stain.jpg

As for my plan of attack, I think I have come up with a realistic, smart, and responsible order to do things. The best part of building an expedition vehicle is adding on all of the “fun stuff” like suspension, sleeping arrangements, cook space, etc. As much as I’d like to dive right into that stuff, I need to get the truck running for daily use first. Fixing the oil leak is the first concern.

Second, the engine backfires when the RPM’s return to idle. It’s quite loud and scared the dog and child that accompanied me on bringing the truck home, not to mention any surrounding vehicles. The previous owner said that this was due to it needing a new exhaust. I don’t know enough to say whether this is true or not, so I’ll need to do some research on that.

The odometer does not work, so I have no idea how many miles are on the actual engine. With that said, I am trying to figure out the best course of action. My options are A) replace all of the gaskets/filters/fluids/spark plugs, B) Engine rebuild kit, C) replace engine.

I could probably do A by myself, but it obviously is not the most thorough. B and C could only be done with assistance, but I would learn the most about the engine and how to repair it, and theoretically would be the best option for giving me a reliable engine. I’m just not sure if it’s necessary or not. Thoughts?
 
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Martinjmpr

Wiffleball Batter
Well, that sounds like quite the project. Those old square bodies were known for rust, particularly around the fenders.
.
As for the transmission, you're correct, think of it not as a 4 speed but as a 3 speed with a "granny low." My first 3 trucks actually had this arrangement, you start in 2nd gear and shift it like a 3 speed. This was very common in trucks all the way through the early 1980's when they finally started getting more modern 4 and 5 speed transmissions.
 

Beerdy

Observer
Well, that sounds like quite the project. Those old square bodies were known for rust, particularly around the fenders.
.
As for the transmission, you're correct, think of it not as a 4 speed but as a 3 speed with a "granny low." My first 3 trucks actually had this arrangement, you start in 2nd gear and shift it like a 3 speed. This was very common in trucks all the way through the early 1980's when they finally started getting more modern 4 and 5 speed transmissions.
Is it more geared (rimshot) toward technical 4 wheeling? Any use for it as an expo vehicle compared to a standard 4 speed?
 

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Martinjmpr

Wiffleball Batter
Is it more geared (rimshot) toward technical 4 wheeling? Any use for it as an expo vehicle compared to a standard 4 speed?
.
"Granny low" was actually very common in old trucks. Think of it not so much as a 4 speed transmission but a 3 speed with a "poor man's low range." Even 2wd pickups of that era had granny low gears.
.
Yes, very useful for off roading, especially climbing or descending a steep hill.
 

rayra

Expedition Leader
Well that's all very familiar, right down to the interior colors. Just as well it doesn't have AC, it likely would not be working condition anyway. You'll want to get familiar with a company / website named LMC Truck. They have a lot of useful parts for you, and IIRC they have patch panels for things like that hole in your floor.

As for the engine, it's well worth a first pass with a gasket replacement kit. It ought to solve your leak trouble but also it will give you a far better insight into the true state of the engine.

The Speedo is an easy fix, it's typically either the cable or the small nylon gear that drives it, which you can access on the side of the trans behind a cover plate where the speedo cable enters the trans.

Best advice I can give is to change all the fluids and just go ahead and change the water pump, they're so inexpensive it's worth doing it right off, along with a full coolant system re-work. And what the heck is that thing plumbed into the heater core hose, mounted to the passenger wheel tub?

Also, due to the nested nature of all the stuff bolted on the front of the engine, it might be worth the trouble to plan other related work while you have things apart. Up to and including a timing chain replacement, as a target of opportunity. Depends what your mid-term engine plans are.

Your backfires aren't likely to be caused by the exhaust system but can damage the exhaust system. If you've got the original carb on there the culprit is almost certainly the infamous Q-Jet bowl leak. Another symptom of that is a wandering erratic idle. But with a engin that old and in shabby visual condition, you'll likely find many issues with engine vacuum, cracked plastic vacuum lines, intake, carb and EGR gasket leaks. All of which can lead to a backfire condition. In short it's all a very good excuse for a full engine re-fresh. Which is again quite affordable in the whole SBC world. It can be as inexpensive or costly as you care to make it. If you have the means it's also a prime opportunity to start with new motor or replacement / new short block.

I've had my '85 C-10 since '86. Got ~350k mi out of the original motor before I inadvertently smoked it. I've done rebuilds and replacements, plus all the trevails of keeping an old GM truck on the road. If you've got any specific questions on your Sub, feel free to PM me whenever.
 
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Beerdy

Observer
Thanks for the reply Rayra. You've given me a lot to look in to. Also thanks for the LMC Truck link. I've just ordered their catalog!

So far what I want to do it...

All fluids
Oil Filter
Fuel Filter/pump
Air filter
Spark plugs/wires
Distributor
PS Pump
Water Pump
Radiator and hoses
Thermostat
Engine Gaskets
Clutch
Timing Chain
All belts

This is really without going over the engine. I'm sure there will be other things that pop up while I'm in there. Any parts that I replace that are still in working order will be used as emergency replacements while out on trails.
 

rayra

Expedition Leader
Another common issue on such an old motor will be the engine valve stem seals. They get cooked hard over time, crack or fail and oil just streams into your compustion chambers, resulting in plug fouling and high hydrocarbon numbers in emissions tests. Cheap parts, but a troublesome bore to change out as it involves dismantling the rocker assemblies and you'd best know how to properly adjust your rocker / valve fit in sequence and properly, or it can lead to much worse trouble if you get it wrong. Not to scare you away from it, just saying do some research or find an old hand at it for assistance. Physically, technically, it's easy work.

Get a compression gauge and run a full test on all cylinders (after warming up the engine). Numbers OUGHT to be about 175, but could be as low as 150. What really matters is how much variance you have. All low is typically work rings / hi mileage. Having a 20-30psi variance between random cylinders is typically valvetrain issues (generally speaking). Low on an adjacent pair can be a head gasket issue. It isn't directly determinative on diagnosing things, but it gets you in the ballpark.

Drop your oil pan for a gasket change (and the oil pump change), but use that for an opportunity to inspect your pistons, their skirts, cylinder walls, connecting rod play or wear, look for other signs of severe bottom end wear. This should be the primary decider on what you need to do about your engine. If the lower end is good you could do okay with a set of rebuilt heads and full gasket changes. And you'll almost certainly need to change your rear main seal anyway. Look for oil streaking on the forward face of your flywheel.

Really depends how much money and how much you want to get into things. A small block chevy rebuild over the winter is a fine traditional project. And a great learning opportunity.

 

letgonow

New member
The trans is a 4 spd, with a very low 1st gear - you'll be best to start out most of the time in 2nd gear.

Before replacing engine gaskets you may want to check the amount of engine blowby, to determine if gasket replacement is advisable.

Distributor will likely benefit from disassembly, cleaning & lubrication of advance mechanism.

And, check trans/front diff/transfer case/rear diff for appropriate fluid level. Funny, level like kayak is the same spelled forward or reverse?

Oh yeah - the grease fittings too, steering/suspension/driveshaft - treat to a shot of grease.

And pull up all the floor mats, unbolt & remove the seats to get a better idea of corroded areas to address.
 

justcuz

Explorer
Leak looks like the front of engine. Timing cover seal at the vibration dampener is very common. Also fuel pump at passenger side front of engine will leak if not tight and there is a bolt hole at the fuel pump rod in the block that can leak oil if it's missing.
 

rayra

Expedition Leader
...and when you go to put the manual fuel pump back in, first coat the push / transfer rod with heavy grease before inserting it in its hole, so it will stay up while you get the fuel pump lever inserted in the correct position. Learned that one the hard way ;)


Too, your harmonic balancer rubber insert is likely shot. A new balancer doesn't cost a lot. And the old one's shaft is likely heavily worn at the seal anyway, so even if you just changed the seal it will likely still leak. IIRC there's even a repair part that is essentially a really thin metal sleeve for the balancer shaft, to give you a fresh surface at the seal line. If the rubber is oozing out of your balancer or visibly cracked, ****can it.
 

justcuz

Explorer
It's called a speedy sleeve. Many seals come with them now. Try to find a double lip timing cover seal like national or other name brand.
 
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toastyjosh

Adventurer
Nice Rig!!!
You sound like your on the right track!
As far as your options, I would replace your oil pan gasket, inspect the bottom end. Do a light tune up, plugs wires, filters and just drive it.
If your start burning a lot of oil or the engine smokes then start looking for other options.
if you do need to replace the engine a crate motor like this is one of the easy options.
http://www.jegs.com/i/Chevrolet-Performance/809/10067353/10002/-1
 

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