Builds The Clustertruck Rides Again - Refurbishing a 1975 Chevota (4 Viewers)

[RWBeringer4x4]

Naw man, its like 20ga. if that. If it is like (ours is a 75 and a little rusty) I used 20ga. to repair mine with and I think it was thicker then it was. I ended up putting a support under it just to be on the safe side.

Well that sucks given I just bought a whole panel of 16ga to practice on.

Although I guess learning to weld on 16 gauge or larger will be easier than jumping straight into 20...on the plus side, at least I can cut a 20 gauge patch with ton snips!

 

[reddingcruiser]

Use the 16ga. as a sacrificial backing the 20ga. If you are clever, and careful enough you can grind away the 16ga. backing along the weld line, leaving a clean flat surface.

 

[RWBeringer4x4]

I'm bummed I'm going to be out of town this weekend - itching to start messing with the welder (helmet came yesterday). My guess is I'll need different wire to get into the sheet metal. I think Colin left me with a spool of .030 wire in the welder, which, from my understanding, will WORK on 16/20 gauge but it's probably wiser to size down to .024...

 

[reddingcruiser]

If your welder will push .023 I would use it.

 

[gator25]

I used .023 also, hell use the 16 ga. on the back side. But what ever you do I'm sure in no time you'll get the hang of it and do fine.

 

[RWBeringer4x4]

Finally managed to get back to the truck for a few hours tonight. Summer got derailed by a never-ending bathroom renovation (still going) and a 300ft drainage ditch collecting my downspout and sump pump exits and moving the water underground to the edge of my property. Hopefully this will help dry out the basement.

BACK TO THE TRUCK -

When I left off, I'd just re-pulled the engine after measuring for driveshafts. I then dropped off my driveshafts at a friend of my father in law's at Associated Truck Parts to be modified to their new lengths. I'm a little nervous about how they turned out. They balanced fine but I suspect I'll only have about 1/2in of "collapse" before they bottom out, once installed...I have no idea how much driveshafts really stretch or compress under flex, so I'm not sure if I should panic. I'll also want to test fit them first. We will cross that bridge when we get to it...

Meanwhile, back at my garage, I separated the engine and transmission and got the engine back on the stand for disassembly. It started out pretty well.

I started by removing this strange, through-bolted and sandwiched contraption that was trying to prevent the old road draft tube hole from leaking. Lots of permatex, a welch plug, some other metal disk, and some all thread and bolts to press it all together? I have no idea...A for effort?

Next I pulled the tube connection for the mechanical auxiliary oil pressure gauge that had be installed in the old radio hole in the cab. I figured out why that oil tube never stopped leaking - large crack in the fitting:

^^^Do they sell replacements for these? Is it anything special to hold the tube in place?

Next came the water pump, timing cover, and freeze plugs:

The timing chain definitely seems to have excessive play (~1/4 - 5/16" on each side of the chain). One of those things I'll probably replace "while I'm in there."

Everything seems to still be lined up - it hadn't skipped time or anything, yet...

The pan also came off - very little sludge or collected shards of metal, which made me happy...

Note the high quality "Steel toed sandal." I know, I know... I just hiked ~25mi over the weekend and the heel blisters have negated my ability to wear shoes...

 

[RWBeringer4x4]

First time looking at a crank and bearings. I can confirm that everything appears to be there...but without further disassembly, is there any good way to inspect the bottom end of the engine? Anything to look for as a sign of something sinister to come?

This is, unfortunately, where most of the good news ends. I also pulled the block's water jacket plugs (what was left of them). They had completely dissintegrated. What is left in the hole is legitimately metal glue that I can drill through with ease...so I guess that's a silver lining - but I'll need some new plugs...

Removal of the freeze plugs on the side of the block. I put a screw/string through them for easy retrieval in case they fell into the block while I was driving them out:

3 brass plugs, and one steel plug later, I found this waiting for me:

I don't even know what that material is - some sort of nasty hardened permatex? Perhaps paint that had long ago separated from the back of the freeze plug (do people dip them in paint to create a seal??). It's brittle to the touch, almost like paint chips, and it was present behind most of the plugs.

 

[RWBeringer4x4]

Behind the gasket - RUST. In mass quantities. the bottom of the block is legitimately filled to the welch plugs with rust powder. I'm actually surprised my truck had been cooling properly. Perhaps this is "normal" of an old block - but seems way excessive to me!

Is there a good way to flush the block with the Welch plugs out, or will this need to wait until I've started reinstalling this, then hook it up to a garden hose and purge?

 

[SuperBuickGuy]

the oil sender - there's a holder and a ferrel (however you spell that)... believe it or not, most hardware stores and even Home Depot have a supply of them.

the coating is probably something someone put in to stop a leak... if it's in the block, it's in the heater... if the heater doesn't heat - that's why.

there's always rust inside - nothing to worry about.

as for checking bearings. Pull the caps, look for copper showing through the tin. Also look for scoring on any of the surfaces.

 

[RWBeringer4x4]

the oil sender - there's a holder and a ferrel (however you spell that)... believe it or not, most hardware stores and even Home Depot have a supply of them.

the coating is probably something someone put in to stop a leak... if it's in the block, it's in the heater... if the heater doesn't heat - that's why.

there's always rust inside - nothing to worry about.

as for checking bearings. Pull the caps, look for copper showing through the tin. Also look for scoring on any of the surfaces.

For pulling the bearing caps - anything to keep in mind when disassembling or can I legitimately just unbolt them one at a time and inspect?

The heater core was actually a little grungy but flowed/heated so I may have dodged this bullet. What I found strange is that the weird film behind the plugs was only on the plugs along the side of the engine...if it was a stop leak I figure I would have seen it everywhere - but strange nonetheless.

Interesting about the sender - I looked all over summit racing and could only find them in gauge kits. Didn't think to check Lowes...

 

[Cdaniel]

The sender ftg is 1/16 NPT thread x 1/8 compression tube,.....probably

Rod caps very off with gentle side to side tapping. And gently prying once a gap appears. Be very careful not to distort the edges when prying.

You can also check rod side play and crank end play right now.

 

[RWBeringer4x4]

Well - this is a pretty big setback...

I pulled the main bearings today, and wasn't too happy with what I found. This could have been the source of my low(ish) oil pressure...Main #2, in particular, was pretty rough, but all show a lot of wear.

Front Main Bearing

Main #2 - note the deep score on the upper left of the bearing.

Main 3 - smooth, but worn to the brass

Main 4: About the same as 3

I didn't bother taking off the oil pump and looking at 5, I'm pretty confident I know what I'll find.

Rod side play was good, for what it's worth - .011-.013 across the board.

You can tell someone has been in this engine before - a couple of partially stripped rod bolts...

So what's my recourse here? Is it even worth just replacing the main bearings without messing with the crank (polishing, rounding, etc.) Can I get away with just pulling the main bearings, replacing them, checking them with plastigauge and bolting them back up?

 

[RWBeringer4x4]

Even stranger -

I tried to pull 3 rod bearing caps (ones I thought I could get to without moving the crank) to inspect, and I could only get one pulled. The other two, even with some prying, would break loose but them bind on the stud to the point I couldn't get them off...No amount of wiggling/prying seemed to help...

This is the one connecting rod I've looked at so far:

Not as worn as the mains, but still worn...

 

[Cdaniel]

Well, that's the trouble with opening up an old engine that runs okay. You never like what you find.
At this point you can do as little or as much as you want.

Button it up and go until something changes.
Pull the crank and polish the journals, then just new bottom end bearings.
Ring and bearing the whole thing. (prepare for unwanted findings under the heads).
Just rebuilt it.
Crate motor or better donor time.

how much $$$$ is too much?

 

[RWBeringer4x4]

Well, that's the trouble with opening up an old engine that runs okay. You never like what you find.
At this point you can do as little or as much as you want.

Button it up and go until something changes.
Pull the crank and polish the journals, then just new bottom end bearings.
Ring and bearing the whole thing. (prepare for unwanted findings under the heads).
Just rebuilt it.
Crate motor or better donor time.

how much $$$$ is too much?

Yep - that's where I'm at. I'm going to measure the crank. If I can get away with new bearings, I'll probably rebuild the bottom end and throw it back in the truck and see what happens. If the scoring and wear on the crank is too bad, it becomes a matter of throwing (even more) good money after bad.

Really, this engine probably needs a rebuild. But a rebuild on a 283 is about the same price as a crate 350 without all the uncertainty of a rebuild.

Really was hoping I could get away cheap by running the engine I had but it was always a dice roll with this being a likely outcome. We'll see what the micrometer tells us.

 

[bikersmurf]

With the price we're paying for fuel, I'd lean towards fixing the 283. It'll get better fuel economy than a 350 if you don't need the extra hp.

If it's not cost effective to rebuild, sell it to someone who wants a 283.

My next choice would be to find a wrecked newer truck/van/SUV with a 5.3/5.7 and swap in a Vortec with EFI. It'll likely be cheaper than a crate motor, and you'll end up with EFI. If you sell off the rest of the truck you could come out ahead.

Or... 6.2/6.5 diesel.

Or while I'm spending money I don't have. Mercedes Turbo diesel

 

[SuperBuickGuy]

ya know. as long as the crank isn't scored, you can simply change the bearings and leave the upper half alone. With that said, change your oil, folks - all of the scoring comes from that. The scoring reduces the oil pressure and causes the wear to the copper on the mains. 350 Chevy motors are so cheap. Steve (sgould) bought a 350 with low miles for $500 complete, TBI to accessories to pan - he is rebuilding it, but (and he agrees) could have run the motor as-is for a long time.

LS is an interesting idea, but it costs a lot more then most think.... here's a comparison I did on the 76 Corvette I'm building.

To update the decision-making process. Cost:
I have an LS motor, which would be great for this car - it's a 6.0 from a Denali. As with all things, it cost so I'll put that cost as part of this.

LS motor
1) Motor cost 2k
2) mounts, oil pan, bracket for only alternator 1,200
3) Cam $400
4) re-ring (it does have 190k on it), $500, bolts $200
5) headers - no one makes side pipes, yet, but I'd adapt OBX pipes so $800
6) adapters for LS motor exhaust, $100
7) flywheel $300 (for LS to ST-10 trans)
8) intake (either EFI or Carb the end number is about the same) $1200
9) misc $500

net hp 450
$7200
BBC 427
1) motor cost 1200
2) mounts, oil pan, alternator bracket. All interchanges except the alternator bracket $100
3) heads, rings, bearings, bolts $1500
4) cam $800
5) OBX stainless sidepipes $800
6) adapters zero
7) flywheel, zero, same as SBC that came out but to be fair 150
8) intake, carb, distributor (200, 400, 200) $800
9) misc $500

Net hp 700
$5850

SBC
1) motor cost $10,500 - for a 427 ci SBC
yeah... not going further

The strength of the motors is kind of a thing as well. By my own experience, at this hp level, the LS and the BBC are equal, even weight is within 50 lbs of each other.

Build the motor you need - that's kind of my point of reciting this. If you need north of 750 hp, you'd be a money-spending fool to do anything but LS (and I am one of those fools because of a Buick motor that's up soon to be assembled - no condemnation, just facts). I like the hp of a big-bore, short stroke motor (it's what I think Ford got right with the 302 - too bad the motor has a zip-strip up the cam bore). That said, you would not want to drive this in traffic, I think it's hp at idle is less then 100 hp (not kidding), it doesn't make 200 hp until almost 3000 rpm.... of course, at 3500 it makes 300 hp and at 6500 it makes 700 hp. But it will be a pain to drive (and that's fine, I know what I want and I frankly love it)... also, in its defense it makes nearly 400 lb torque at 2000 but be sure, it'll be a dog at anything less then 3000 rpm.​

 

[RWBeringer4x4]

ya know. as long as the crank isn't scored, you can simply change the bearings and leave the upper half alone. With that said, change your oil, folks - all of the scoring comes from that. The scoring reduces the oil pressure and causes the wear to the copper on the mains. 350 Chevy motors are so cheap. Steve (sgould) bought a 350 with low miles for $500 complete, TBI to accessories to pan - he is rebuilding it, but (and he agrees) could have run the motor as-is for a long time.

LS is an interesting idea, but it costs a lot more then most think.... here's a comparison I did on the 76 Corvette I'm building.

To update the decision-making process. Cost:
I have an LS motor, which would be great for this car - it's a 6.0 from a Denali. As with all things, it cost so I'll put that cost as part of this.

LS motor
1) Motor cost 2k
2) mounts, oil pan, bracket for only alternator 1,200
3) Cam $400
4) re-ring (it does have 190k on it), $500, bolts $200
5) headers - no one makes side pipes, yet, but I'd adapt OBX pipes so $800
6) adapters for LS motor exhaust, $100
7) flywheel $300 (for LS to ST-10 trans)
8) intake (either EFI or Carb the end number is about the same) $1200
9) misc $500

net hp 450
$7200
BBC 427
1) motor cost 1200
2) mounts, oil pan, alternator bracket. All interchanges except the alternator bracket $100
3) heads, rings, bearings, bolts $1500
4) cam $800
5) OBX stainless sidepipes $800
6) adapters zero
7) flywheel, zero, same as SBC that came out but to be fair 150
8) intake, carb, distributor (200, 400, 200) $800
9) misc $500

Net hp 700
$5850

SBC
1) motor cost $10,500 - for a 427 ci SBC
yeah... not going further

The strength of the motors is kind of a thing as well. By my own experience, at this hp level, the LS and the BBC are equal, even weight is within 50 lbs of each other.

Build the motor you need - that's kind of my point of reciting this. If you need north of 750 hp, you'd be a money-spending fool to do anything but LS (and I am one of those fools because of a Buick motor that's up soon to be assembled - no condemnation, just facts). I like the hp of a big-bore, short stroke motor (it's what I think Ford got right with the 302 - too bad the motor has a zip-strip up the cam bore). That said, you would not want to drive this in traffic, I think it's hp at idle is less then 100 hp (not kidding), it doesn't make 200 hp until almost 3000 rpm.... of course, at 3500 it makes 300 hp and at 6500 it makes 700 hp. But it will be a pain to drive (and that's fine, I know what I want and I frankly love it)... also, in its defense it makes nearly 400 lb torque at 2000 but be sure, it'll be a dog at anything less then 3000 rpm.​

I STRONGLY suspect this motor was a fresh rebuild at some point in the not too distant past - there is evidence everywhere that it has been worked on. I suspect the issues with the bearings are a direct result of the incredibly leaky, flood-prone, and oversized Buick Wildcat quadrajet that the truck came with. I think it, or the fuel pump (which I also replaced), was getting fuel into the oil even before I bought it - which possibly washed the oil out of the bearings. Not 100% sure on that as the rings seemed to seal OK - there was a little blow-by but compression was between 140 and 160 across the board. There was ZERO coolant in the oil, no sludge, sediment, or "chunks" in the pan.

If the crank looks OK when I put a micrometer on it, and it's relatively free of scoring, I may just roll in new crank and rod bearings and pray.

Funny - I went through the engine specing process as well. Funny thing is I came out with almost that EXACT cost for an LS swap. The LS is a phenominal motor but honestly, this is a truck and will be primarily a mall cruiser/fire road crawler/camping truck (someday). For the amount it will get driven, a stock, flat tappet 350, or a rebuild on this 283 will likely outlive me, and do anything I need it to do. I like the Vortec/Roller 350 for durability, but hesitate to computerize my truck and swap to an electric fuel pump. It's by no means an insurmountable task but I love the bone-stupid mechanical simplicity (and comparative cheapness) of the setup I have now.

I think my numbers came out to something like:

- Rebuilt 283 or a Crate 350 was ~$2000 since most of my parts would transfer (although it looks like Chevy discontinued the super cheap Goodwrench Crate 350)
- Junkyard Roller/TBI, rebuilt - $4000 (having a rebuilder do the work)
- LS swap - ~$7000+

 

[pb4ugo]

You can tell someone's probably rebuilt that motor b4, The rods have been stamped with their corresponding cyldr numbers. If you look on the back side of the bearings halves it will reference the size of the crank journal. such as: std, 0.010, 0.015 and so on. If it's something other that std then someone's been there b4. Just rebuilding the bottom end of an old motor showing that much wear would be a waste of money and may not work. IMO, the engine showing that much wear, should be completely torn down and tolerances checked. With an engine that old, it maybe at its max limits on any future machining. If the crank is undersized already, I'd probably not want it turned again. If it ran good and did not knock, I'd probably throw in a new rear main seal, reassemble and seal the motor back up. Or source a good, "can hear run" low mileage complete(carb to pan w/all the accessories and brackets) used SBC 350, or get a new GM crate 350 long block with a 50k warranty. You can always button her up, and then be on the lookout for a good replacement motor for the future.

 

[RWBeringer4x4]

You can tell someone's probably rebuilt that motor b4, The rods have been stamped with their corresponding cyldr numbers. If you look on the back side of the bearings halves it will reference the size of the crank journal. such as: std, 0.010, 0.015 and so on. If it's something other that std then someone's been there b4. Just rebuilding the bottom end of an old motor showing that much wear would be a waste of money and may not work. IMO, the engine showing that much wear, should be completely torn down and tolerances checked. With an engine that old, it maybe at its max limits on any future machining. If the crank is undersized already, I'd probably not want it turned again. If it ran good and did not knock, I'd probably throw in a new rear main seal, reassemble and seal the motor back up. Or source a good, "can hear run" low mileage complete(carb to pan w/all the accessories and brackets) used SBC 350, or get a new GM crate 350 long block with a 50k warranty. You can always button her up, and then be on the lookout for a good replacement motor for the future.

I strongly suspect you are correct in this assessment, and agree that, even if I were to roll in new bearings, I'd never fully trust this engine to get me where I needed to go. A buddy of mine who builds race engines will be stopping by Wednesday to give me his assessment as to what the best path forward will be.

In reality, if the assessment on the 283 is a complete rebuild, I'll likely pawn it and get a 350 - first for the warranty, and second for the fact that it has accessory bolt holes in the head, which will help me solve some clearance issues. Of course, Chevy just discontinued their cheap crate motor, it looks like...that or prices went up almost $500 overnight.

This rebuilt motor seems interesting though - a one-piece real main seal AND provisions for a mechanical fuel pump??

First Mate Automotive Chevrolet 350 C.I.D. Remanufactured Engine Assemblies 350G8795