Build The Clustertruck Rides Again - Refurbishing a 1975 Chevota

[bikersmurf]

Yes a Mark III Gt6... 71 if I'm remembering right.
I bought it as a basket case with a rebuilt motor. Little rust... rebuilt the lower rockers, the bottom end, and got it running well. Had to sell it when we moved out east. It still needed an interior and a shiny paint job.

It was fun, but you made the right choice in a 40.

 

[bikersmurf]

From 50 feet it looked like this... photo from Wikipedia. I kinda miss it, but it was even less practical for a family than a 40.


Just noticed this photo has the wheel on the wrong side as well.

 

[RWBeringer4x4]

Very nice! I can't remember which model I looked at, just that it was a hodgepodge of GT6 body panels - I think it was mostly Mark III - or whichever one had the hood and door pillar louvers. An FJ40 was always my objective ever since I worked on a farm (age 14-21), and one of the other farm hands had one. That said, I'm always willing to entertain other cool vehicles. Oddly, I HATE the look of spitfires, and most all other British roadsters - but have a soft spot for the hard-top versions.

My understanding from everyone I know who has ever had a British roadster is that they're pretty much the highest maintenance car you can own. Fun to drive, but they're 3 hours of labor per hour of driving. I'm happy I settled on the 40 - so far it's about 10 hours of labor per hour of driving...

From 50 feet it looked like this...

My father-in-law calls that a "20/20" car - looks good if it's driving by 20 feet away at 20 miles an hour

 

[bikersmurf]

I've heard there as good as the mechanic who worked on them... a rebuilt motor, a new starter, a new battery, and a Landcruiser alternator made it quite a reliable vehicle. It would go very well... and besides stopping was highly overrated.

Loosing at what people are asking for them now, I'm thinking I should have found a barn to hide it in... it looks as if I could have got way more for it than I sold it for.

 

[RWBeringer4x4]

Well, started pulling bearing caps and Pistons tonight. Wanted some opinions on the findings:

1. Two cylinders have "chips" in the corner - not sure if this is something I should just replace as a precaution... Below is the worst of the two:

2. I have 3 rod caps that absolutely will not come off. They're completely loose, off the knurls, but will not slide off the bolts - it's like they bind on the threaded portion:

Tried tapping gently with a dead blow and brass drift, upward or side to side, no change. Is there anything I can do outside of driving the bolt out of the big end to get these off?

 

[SuperBuickGuy]

usually they get stuck when they get crossed up. push the cap down to the crank, then tap gently on either flange with a drift or a punch. Don't nick the crank, but it usually doesn't take much to tap it back off. The other thing to do is drive the cap back on just a bit to unbind it.... that said, a stroker kit is merely a bit of a slide of the drift away

 

[SuperBuickGuy]

and the piston is fine. it's if it's missing big chunks, it's severely out of round, or a skirt is cracked....

 

[RWBeringer4x4]

usually they get stuck when they get crossed up. push the cap down to the crank, then tap gently on either flange with a drift or a punch. Don't nick the crank, but it usually doesn't take much to tap it back off. The other thing to do is drive the cap back on just a bit to unbind it.... that said, a stroker kit is merely a bit of a slide of the drift away

Yeah that's what is odd about this - they don't seem crossed up - they're completely loose, but one side of each bearing cap simply "stops" moving up the stud. it's like there is a burr or the rod studs get further apart as you go up...

 

[SuperBuickGuy]

tap on the flanges - be sure to have something to catch the piston when it does pop loose.

 

[RWBeringer4x4]

Well, after much trying, the camshaft is out. I ended up having to do what I didn't want to do - tapping directly on the rod bolts with a deadblow and drift to push the piston down.

It's odd - there were collections of crud around 1 of the two bolts on each of the stuck rods...

All the top bearing halves seemed OK except the front one. Oddly -

1. All the bottom main bearings were fried, (except the rear) with the front main being in best condition.

2. The TOP of the bearings were fine, except for bearing #1 ie: the opposite of above.

3. The BOTTOM of the connecting rod bearings were fine, but the TOPS were all worn.

Does this indicate anything to anyone?

Cylinder bores are so/so - could definitely use a hone though there are a few places I can catch a vertical groove with a fingernail.

Cylinder 8, for some reason, has rings of what appear to be carbon buildup all down the bore - maybe from sitting?

Anyway - I'm gonna have my buddy come back hopefully and take a look before I make a final call ok this engine. Not in love with my findings so far...

 

[waiting for time]

Well, after much trying, the camshaft is out. I ended up having to do what I didn't want to do - tapping directly on the rod bolts with a deadblow and drift to push the piston down.

It's odd - there were collections of crud around 1 of the two bolts on each of the stuck rods...

View attachment 1509240

All the top bearing halves seemed OK except the front one. Oddly -

1. All the bottom main meetings were fried, (except the rear) with the front main being in best condition.

2. The TOP of the bearings were fine, except for bearing #1 ie: the opposite of above.

3. The BOTTOM of the connecting rod bearings were fine, but the TOPS were all worn.

Does this indicate anything to anyone?

View attachment 1509241

Cylinder votes are so/so - could definitely use a hone though there are a few places I can catch a vertical groove with a fingernail.

View attachment 1509242

Cylinder 8, for some reason, has rings of what appear to be carbon buildup all down the bore - maybe from sitting?

View attachment 1509243

Anyway - I'm gonna have my buddy come back hopefully and take a look before I make a final call ok this engine. Not in love with my findings so far...

It looks like the oil was deluted with fuell at some time.
Make sure the treads that got stuck are clean and the nuts run smooth before re-assembly.
If they have an extra resistance during tightening, the pre-load in the bolts will end up to low causing fatigue resulting in a destroyed engine.

 

[White Stripe]

To me it looks like it needs the cylinders bored out rather than just honed. Someone correct me if I'm wrong, but can't you get wear like that on the first bearing if the belt was too tight?

 

[RWBeringer4x4]

It looks like the oil was deluted with fuell at some time.
Make sure the treads that got stuck are clean and the nuts run smooth before re-assembly.
If they have an extra resistance during tightening, the pre-load in the bolts will end up to low causing fatigue resulting in a destroyed engine.

This has always been a possibility. The first carburetor that came with this truck, even after a rebuild, was constantly running rich, would drain overnight, and finally started flooding (even after I rebuilt it and epoxied the welch plugs). I finally just replaced it with a SMI rebuilt carb, and replaced the fuel pump at the same time as a precaution. Even still, the gas in the SMI quadrajet (which supposedly has the welch plugs epoxied) mysteriously vanishes after a day or two of sitting...

To me it looks like it needs the cylinders bored out rather than just honed. Someone correct me if I'm wrong, but can't you get wear like that on the first bearing if the belt was too tight?

I'm not sure where the line gets drawn on "bore" vs. "hone" - using calipers (I don't have the fancy tools) the cylinders seem round. I'll probably push a ring down them to check taper. There's no ridge at the top. The scratches are mostly down toward the bottom where the skirt rides. That said, there are scratches, and I'm still trying to discern what the black stuff is in cylinder 8. Seems like carbon, but doesn't want to scrub off, so it could be pitting.

 

[1Fine40]

"I'm still trying to discern what the black stuff is in cylinder 8. Seems like carbon, but doesn't want to scrub off, so it could be pitting."
I've seen that before, it is likely the result of water sitting in that bore for a while which unfortunately rusted and thus some pitting...I'd bet on a bore job fixing it up pretty again..probably wouldn't take too much...maybe .010 over, but a machine shop could certainly start there and if it needs more, they punch it out a little further..Mine ended up bored .040 over! But it came together nicely thereafter with a polished crank, new everything else..

Cheers!

 

[bikersmurf]

You're starting to venture down a slippery slope. At the end of the day you'd end up with a much nicer motor than a reman/crate motor... but likely more expensive. Doing your own wrenching it might not be terrible though.

The motor in the Gt6 had a balance Crank. It was done old school on a 4" wide grinder... some of the counterbalancing lobes had chunks ground off the size of a small fist (1/2 of mine). Boy did it run smooth... 4g was silky smooth... 6g she purred.

If you could build the 283 with a balanced Crank for the same money as a crate motor, I'd recommend it. That said, for a wheeler I've always tried to keep costs down.

Built well, a 283, should pull economy numbers that'll have people accusing you of lying. I've heard of builders that can get 27 mpg out of a 350 in a heavy car... but they're incredibly detail oriented and spare no expense.

 

[gator25]

Those black stains looks to me like you may have got some moisture in the cylinders at some point, and it sat on top of the piston. I think I would have the cylinders and crank miked and see where you stand, from what I see I'd probably bore it. By the time you get done with a hone you may be to far out. Your crank probably needs turning, if I had the money I'd balance the rotating assy. If your dead set on using that motor.

But... with had said that, I had a .030 350 that the cyls. should have been bored. I hit them a quick lick with a ball hone, took and file fitted some CAST .040 rings to get the gaps right. I ran the dog out of that thing. Still have it wrapped up down in the shed, it was still running great when I pulled it out. My son and his buddy poured cold creek water in it and cracked the block.

 

[RWBeringer4x4]

You're starting to venture down a slippery slope. At the end of the day you'd end up with a much nicer motor than a reman/crate motor... but likely more expensive. Doing your own wrenching it might not be terrible though.

The motor in the Gt6 had a balance Crank. It was done old school on a 4" wide grinder... some of the counterbalancing lobes had chunks ground off the size of a small fist (1/2 of mine). Boy did it run smooth... 4g was silky smooth... 6g she purred.

If you could build the 283 with a balanced Crank for the same money as a crate motor, I'd recommend it. That said, for a wheeler I've always tried to keep costs down.

Built well, a 283, should pull economy numbers that'll have people accusing you of lying. I've heard of builders that can get 27 mpg out of a 350 in a heavy car... but they're incredibly detail oriented and spare no expense.

Those black stains looks to me like you may have got some moisture in the cylinders at some point, and it sat on top of the piston. I think I would have the cylinders and crank miked and see where you stand, from what I see I'd probably bore it. By the time you get done with a hone you may be to far out. Your crank probably needs turning, if I had the money I'd balance the rotating assy. If your dead set on using that motor.

But... with had said that, I had a .030 350 that the cyls. should have been bored. I hit them a quick lick with a ball hone, took and file fitted some CAST .040 rings to get the gaps right. I ran the dog out of that thing. Still have it wrapped up down in the shed, it was still running great when I pulled it out. My son and his buddy poured cold creek water in it and cracked the block.

The issue is that this is a later "thin" 283 casting - as such I'm not sure how much farther I can overbore before I get too close to the water jacket. I've heard older blocks can be bored to a ridiculous extent - like .090, but the later blocks top out closer to .040. This one is already .030 over - so it's starting to push the limits of re-usability.

While fuel economy is (always) a concern - this 283 was pulling about 13-14mpg highway, 10ish city. I'm sure this would improve on a fresh rebuild, but I can't imagine the numbers being much worse on a 350. @bikersmurf - whats your experience? Plus, with the mileage this thing currently sees, it's not my ultimate determining factor for engine choice...Seems even folks running fuel injected vortec blocks, or even LS-swaps max out around 16-18mpg. I've seen a few folks claim 20.

There are a lot of advantages to going to a 350 too - specifically, accessory bolt holes in the head - which would allow me to reconfigure my pulleys, tuck the power steering pump in, and better align my engine in the bay for proper drive-line angles. Not to mention even greater ubiquity of parts, and better resistance to modern fuels (hardened valve seats in the head, for example).

I'm hoping my buddy will be able to drop by again when I get back from a trip to the mountains this weekend. I think my plan is still holding true

Plan A: if it can be honed, I'll turn the crank, put in new rings and bearings, hone it, and run it, keeping the existing cams and lifters (and maybe the cylinders, if he thinks the chipped ones are useable).

Plan B: He's got a line on a guy who can probably get me a Jasper 350 for close to their cost. Won't be cheap, but it might be my cheapest route forward if plan A doesn't pan out.

 

[bikersmurf]

Can't remember exact mpg numbers, it's been a while. Factoring in the error for oversized tires I've been getting better mpg than your 283. Probably 11-12 city and pure highway 17 mpg (Anacortes to Vancouver BC).

The best highway run, which I've never been able to make sense of the numbers was Phoenix Arizona to Vancouver British Columbia... started with a full tank of gas and $120 USD... 27 hours later I arrived with 1/2 a tank and $2 USD... I nursed it the whole way, but I still can't figure out how I made it. It was around 20 years ago, but it has never made sense. A 40 with 31" AT tires isn't capable of getting such economy.

 

[1Fine40]

Can't remember exact mpg numbers, it's been a while. Factoring in the error for oversized tires I've been getting better mpg than your 283. Probably 11-12 city and pure highway 17 mpg (Anacortes to Vancouver BC).

The best highway run, which I've never been able to make sense of the numbers was Phoenix Arizona to Vancouver British Columbia... started with a full tank of gas and $120 USD... 27 hours later I arrived with 1/2 a tank and $2 USD... I nursed it the whole way, but I still can't figure out how I made it. It was around 20 years ago, but it has never made sense. A 40 with 31" AT tires isn't capable of getting such economy.

Big tail wind and lots of downhills!!...the only possible explanation

 

[RWBeringer4x4]

Well, it's official. My buddy came over again last night and we took another long look at the block. After a bit of poking and prodding, it was his opinion, and all of your collective opinions (thanks) that with the pitting found in the cylinder walls, boring to .040 over would be about the only option. Even then, there's a good chance the pitting is well on its way to breaking through into the water jackets, so sleeving the cylinders might be necessary.

Long story short - RIP 283. 1967-2017. It was a good run. Time to go shopping for a 350.

The low hanging fruit is definitely the 4-bolt main, ~230horse/300 torque flat-tappet 350 that summit's selling for $2050 (which was $1650 six months ago ). A fresh engine delivered to my door is pretty appealing.

Obviously, a roller-block would be better but for the amount of driving this truck will likely see, a flat-tappet base 350 will probably outlive me, and it is now the most cost effective option.

The one thing I may "splurge" on is a long water pump and new pulleys and brackets to match. This solves my power steering conflict, but may, in turn, result in my needing to cut the alternator mount off my new rams horns...

All in all - I added it up last night; I've only got about $200 in parts for the 283 that I won't be able to transfer to a 350 - so in the grand scheme of things, it could have been worse. I'm hoping I can sell some of the short water pump pulleys and brackets, along with the (still good) PowerPak heads off the 283 to recoup some cost.