The Truck of Doom: An Occasional Build Thread

[ArdWrknTrk]

Sounds like a plan, Stan.

When are you getting in again?

Friday afternoon/evening, depending on how far I make it on Thursday.

And...assuming I don't get called up for strike duty. My munificent employer is still negotiating with the union in the southeast, and this time around the union is being a bit more rambunctious than usual. If they go out for real, or even convince the company that they're likely to go out, I can get put on vacation lockdown, or worst case get deployed to South Carolina to play lineman.

Normally I don't even consider the possibility, but this year everything's been weird.

I hope for the best, but I don't really blame them.

I put up with WAY too much when it came to labor negotiations.

And though I was moderate, and just wanted a contract, in retrospect I would/should have told them to go #+&"*# ¥π©%? sideways... twice!

and walked, picketed, and sabotaged every thing I could lay my hands on.

[ArdWrknTrk]

I hope for the best, but I don't really blame them.

I put up with WAY too much http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/poo-23_orig.png when it came to labor negotiations.

And though I was moderate, and just wanted a contract, in retrospect I would/should have told them to go #+&"*# ¥π©%? sideways... twice!

and walked, picketed, and sabotaged every thing I could lay my hands on.

I checked my leakdown tester.

There is no indication of orifice size.

Though it may be rather small. (a 500cc four cylinder bike would have a 125cc cylinder)

A 302 (5.0l) would fit 10x that size engine, or more that the total displacement in one cylinder.

[Gary Lewis]

I checked my leakdown tester.

There is no indication of orifice size.

Though it may be rather small. (a 500cc four cylinder bike would have a 125cc cylinder)

A 302 (5.0l) would fit 10x that size engine, or more that the total displacement in one cylinder.

Ok, Jim. Thanks for checking.

I've read that the "good" ones have a very smooth orifice that doesn't induce turbulence. Supposedly some of them, probably like mine, go turbulent at high flows. However, at that point I'm not worried - if there's that much flow then there is a problem and it doesn't really matter how bad the leak is. It is bad.

[ArdWrknTrk]

Ok, Jim. Thanks for checking.

I've read that the "good" ones have a very smooth orifice that doesn't induce turbulence. Supposedly some of them, probably like mine, go turbulent at high flows. However, at that point I'm not worried - if there's that much flow then there is a problem and it doesn't really matter how bad the leak is. It is bad.

The fact that Matthew's 5 SCFM compressor can't keep up with the leak is telling enough for me.

[Gary Lewis]

The fact that Matthew's 5 SCFM compressor can't keep up with the leak is telling enough for me.

I think we need to think through how to use the results of a leak-down test.

As I'm going through this myself I've been thinking about it a lot, and the conclusion I'm coming to is that if an engine is running seemingly well then I'd leave it. But, if you have it out, like I do with Big Blue's 460, then I'd seriously consider rebuilding it.

Had I not already pulled the engine when I ran the test I probably would have at that point since I'm in the midst of a huge rebuild/transformation. But, were I not in this quest I'd probably have left it as it was getting pretty much bog standard carb'd 460 MPG. (IOW, poor.)

I say all of that to say that the leak-down test is one tool to use in decision making on an engine. If it is running well and not using an excessive quantity of oil then poor results of the test are an indication that at some point in the future a rebuild will be needed. But if it is dropping a couple of cylinders, as Big Blue was at idle, then the test may tell you how to repair it.

[Dorsai]

The fact that Matthew's 5 SCFM compressor can't keep up with the leak is telling enough for me.

That presupposes that the compressor is actually producing that volume, does it not? It also assumes I know what I’m doing, a questionable assumption at best.

I’m just having a hard time with the idea that I have ring problems on a truck that has had the oil changed religiously since day one, and only has 135K miles on it. Yes, it sat a while and something could have happened as a result, but surely there would be some other sign of problems?

[ArdWrknTrk]

I think we need to think through how to use the results of a leak-down test.

As I'm going through this myself I've been thinking about it a lot, and the conclusion I'm coming to is that if an engine is running seemingly well then I'd leave it. But, if you have it out, like I do with Big Blue's 460, then I'd seriously consider rebuilding it.

Had I not already pulled the engine when I ran the test I probably would have at that point since I'm in the midst of a huge rebuild/transformation. But, were I not in this quest I'd probably have left it as it was getting pretty much bog standard carb'd 460 MPG. (IOW, poor.)

I say all of that to say that the leak-down test is one tool to use in decision making on an engine. If it is running well and not using an excessive quantity of oil then poor results of the test are an indication that at some point in the future a rebuild will be needed. But if it is dropping a couple of cylinders, as Big Blue was at idle, then the test may tell you how to repair it.

You can see the suggested protocol at the bottom of the pink page.

EVERY engine is going to need a rebuild in its future, unless the vehicle it is in is totalled.... or we discover the flux capacitor.

Matthew has discovered that his engine may have compression, but can't hold it.

Does he have excessive blow by?

Does he have cracked rings in that one cylinder?

Is there a pit in one spot at the top of that cylinder?

Is there a hole it that one piston?

Pull out your crystal ball and peer deeply, oh wise one!

[ArdWrknTrk]

The fact that Matthew's 5 SCFM compressor can't keep up with the leak is telling enough for me.

That presupposes that the compressor is actually producing that volume, does it not? It also assumes I know what I’m doing, a questionable assumption at best.

I’m just having a hard time with the idea that I have ring problems on a truck that has had the oil changed religiously since day one, and only has 135K miles on it. Yes, it sat a while and something could have happened as a result, but surely there would be some other sign of problems?

Matthew, you know that when the inline 6 came out engines didn't last 100k, even with the best treatment (unless it was Mercedes or something)

Maybe the rings are just stuck in their grooves and you need to treat it to some Rislone and a steady diet of high detergent diesel oil.

Maybe you need to beat on it pretty much all the time to free them up.

Maybe the bores are severely worn.

Check with the borescope at Gary's while you're doing the leakdown.

[85lebaront2]

Matthew, you know that when the inline 6 came out engines didn't last 100k, even with the best treatment (unless it was Mercedes or something)

Maybe the rings are just stuck in their grooves and you need to treat it to some Rislone and a steady diet of high detergent diesel oil.

Maybe you need to beat on it pretty much all the time to free them up.

Maybe the bores are severely worn.

Check with the borescope at Gary's while you're doing the leakdown.

Now you are going way back, but even then some of the old in-line sixes lasted, particularly Nash, and Chrysler stuff. Their old flatheads would run forever. The early OHV engines were plagued with valve problems which is why Willys and Rolls-Royce both built F-heads, overhead intake, side exhaust.

[ArdWrknTrk]

Now you are going way back, but even then some of the old in-line sixes lasted, particularly Nash, and Chrysler stuff. Their old flatheads would run forever. The early OHV engines were plagued with valve problems which is why Willys and Rolls-Royce both built F-heads, overhead intake, side exhaust.

When the Mustang came out with a generator in '64 the (other) I-6 was the only engine available.

And I was in diapers.

Machined surface finishes (bores) looked like the surface of the moon compared to what we get today.

Mostly because they just needed to be cranked out and people didn't drive as much as now.

Customers didn't expect an engine to last.

The whole crosshatching to break the rings in thing was because metallurgy was far inferior and tolerances were not good.

A newly built engine was 'tight' and those bores needed to be plateaued.

I can still remember building a 441 Victor that I couldn't get to seal up, or stop seizing.

Rick held it wide open and tossed some BonAmi into the velocity stacks!

Even today the bore needs some surface roughness to give the oil somewhere to go.

But the opposite problem is true. The bores can be too smooth.

That's why we recommend break-in oils instead of full synthetics for the first 500-1,000 miles.