72 C20 "Old Mustard"

[sduckworth13]

I know the feeling, I had bought a 1967 GMC from a guy and he said rebuilt the engine and he put 5000 miles on and parked it. Mysteriously kept breaking rockers arms, 4 times that I recall. Wound up being my lifter was sticking. I did learn real fast how to set valve lash, so I guess it was a pain but a learning experience too. I wound up pulling the heads off of that engine and having it all checked it. I put new valve seals in too, so it quit smoking also which was a plus. *edit* Actually might have been a bent push rod and the lifter is what made me tear it all apart

[gdavis]

Originally Posted by Mustard72

Yep, should've got at least 3 or 4 cans. 1 can ALMOST covered one coat in the center of the cab between the support rails, and I'll use another can for a second coat in there. The garage is only heated when I'm in there working, so this stuff takes a long time to dry/cure.

Well, after what seemed like years of scrubbing on the engine, I finally got the thing MOSTLY cleaned up. Looks like I'll be replacing the timing chain, though.

when I bought my 350 4 bolt. the owner said tht all is wrong with it that it ran a little warm. So i took the heads off and i am glad I did. a hole in the piston. I took ity all the way dowm and spun bearnings and bad lifters. So unless you know for sure I would rather spend some money now than in the future. it is a lot of work pulling a motor after paint and all. Just telling you what I found.

[Mustard72]

Well, I'd like to tell you guys I tore further into the engine and found everything to be OK, but that just isn't so. Two or three of the lifters were worn enough that they were slightly (very) concave on their bottoms. No galling or contaminent wear or anything like that, but the way I understand it is that the lifters should be a bit convex on the bottoms and if they get worn down to the point where they are concave, you should replace them and the camshaft. Any contradicting opinions on this?

Also found a few really chewed up pushrod tips (the rocker ends), with a little bit of associated damage in the rockers, too. So, it looks like I'm in the market for new cam, lifters, pushrods, and rockers (to go along with the timing chain, which I actually already had installed). At least a cam would be somewhat interesting to buy.

[sduckworth13]

Good job Nick, You work fast.

[sduckworth13]

I don't know much about engine wear, but I know what a broken rocker sounds like. lol

[Spoken]

I had a set of those on my 72 when I got her.
Posted via Mobile Device

[Mustard72]

Well, I got my Summit equivalent of the Melling MTC-1 cam today, along with the associated lifters, pushrods, and "splurged" on some roller tipped stamped steel rockers. That's the good news. The bad news is that the cam bearings didn't look the greatest when I pulled out the old cam, and the main bearings look pretty bad, too. At least I think they do. The babbit material appears to be worn away on the three I've looked at so far so that the bronze color is showing on the bearing surface rather than the silver babbit color. What was supposed to be a oil pan/valve cover gasket change and new paint engine cleanup is getting more and more involved. The heck of it is, the dang thing ran pretty good when I pulled it into the garage. But, it's good to find these issues now rather than next summer some time when she pops because I didn't tear it apart with my wife and daughter pulling the horse trailer around because I didnt' tear it apart. I'll keep reminding myself of that.

Falling behind on pictures. I'll try to get some posted over the next day or two.

[sduckworth13]

Looked like you had a nice 010 block, hope its rebuildable for you.

[sduckworth13]

I might have to tear my engine apart too, when I got truck the temp was around 160 steady now its running 190-210. I have a small amount of oil in the radiator too. It might have something to do with hooking the heater hose back up too though, not real sure. I have beeen running the you know what out of it though when i get a chance to drive it.

[87Jimmy4JP]

Originally Posted by sduckworth13

I might have to tear my engine apart too, when I got truck the temp was around 160 steady now its running 190-210. I have a small amount of oil in the radiator too. It might have something to do with hooking the heater hose back up too though, not real sure. I have beeen running the you know what out of it though when i get a chance to drive it.

not to jack the thread, but what are these trucks supposed to run at? What is the thermostat range?....is there any antifreeze in the oil?

JP

[Mustard72]

Mine always ran around 190, but had a 190 thermostat, too. That started sticking for a little while before I tore the truck apart, so it would get up around 230 or so for a few minutes before the thermostat would pop open after which time the temp would drop back down to the 190 range. My cam bearings in the block have some burnt oil looking deposits on them now. Not sure if that is really normal or what it is from (could be the thermostat sticking problem, too, I guess). The truck was always HARD to crank when warmed up, too, but, again, I had suspect starter connections, and numerous other conditions that could cause that. One way or another I'll fix that, too.

The head gaskets that were on the engine had tiny (about 1/8" diameter) holes to apparently restrict the amount of coolant going to the head. Is that normal? It seemed goofy to me to have large coolant passages in the head and block and then have a gasket with an 1/8" hole restricting that flow. I thought I had pictures on my phone of this, but apparently not.

[87Jimmy4JP]

Originally Posted by Mustard72

Mine always ran around 190, but had a 190 thermostat, too. That started sticking for a little while before I tore the truck apart, so it would get up around 230 or so for a few minutes before the thermostat would pop open after which time the temp would drop back down to the 190 range. My cam bearings in the block have some burnt oil looking deposits on them now. Not sure if that is really normal or what it is from (could be the thermostat sticking problem, too, I guess). The truck was always HARD to crank when warmed up, too, but, again, I had suspect starter connections, and numerous other conditions that could cause that. One way or another I'll fix that, too.

The head gaskets that were on the engine had tiny (about 1/8" diameter) holes to apparently restrict the amount of coolant going to the head. Is that normal? It seemed goofy to me to have large coolant passages in the head and block and then have a gasket with an 1/8" hole restricting that flow. I thought I had pictures on my phone of this, but apparently not.

Hey, all

I found this on another forum....it sounded fairly logical to me......

"I have written gasket makers and performance builders about this and no replies. Maybe they consider it propietatary info and think I'm some spy...

Engines are running hotter than ever before, pressure caps no longer at 7lbs but now 15lbs, higher t'stat temps, just try to find a 170 degree tstat. My guess it's an effort to raise the cylr head temp where they can get better burn in the lean environment. Looking at gaskets of 20 years ago they had water passages big enough to put you index finger through, now they are maybe 4, 1/4" holes for each cylinder which doesn't compute if you are trying to keep the engine cool.

I've been interested in that statement that water can flow too fast through a radiator for a lot of years. I don't know where it comes from and I've never seen it in print. The rules of physics do not support this for water because it's viscosity does not change with heat. I do know that turbulance is going to mix temps better in a turbulance induced oil cooler but not for water. I also know that in the case of a radiator the faster the water flows the the smaller the boundry layer exists. Switching to air for a moment we know the lamanar flow is much closer to sides of a rocket or space shuttle at high speeds, well the same exists in fluid dynamics. Now you get it out of the engine faster at a lower temp, you have reduced the boundry layer through the radiator by speeding it up.

Yes their are thing that can influence it like a water pump cavitating or a fluidic valve effect where the heater flow can stall the flow and make it inefficient but I've not see this since the early '70s.

The increase in hp demands a larger radiator for they didn't give you an overkill but you can't blame that on increasing the water flow speed. I see how much owners are wanting to make this mod or that mod to get more power but nobody says you just increased the HP 25% you will need to open up the head gasket water passages.

There is only so much heat excange for a finite amount of air which you have not increased speed flowing over the fins or increased the area if you have increased HP. Radiators have gotten smaller, engine temps hotter suppose there is a relationship... The white shirts are calculating what's the smallest radiator we can fit so it costs us the least while establishing we can run it this hot.

I've not looked at any of the trick head gaskets to see if they have enlarged water passages but it's my guess they have".

It gets a little wordy here and there, and I cant take credit for any of it...but....here ya go....


JP

[Mustard72]

Hmmmm...

[Mustard72]

Originally Posted by sduckworth13

Looked like you had a nice 010 block, hope its rebuildable for you.

What makes the 010 block nicer? I'm not familiar with what any of the numbers mean.

[sduckworth13]

I think they are high nickel blocks not a 100% I'll have to look it up again
Posted via Mobile Device

[sduckworth13]

I did a little reading on it just now, but from everything I've heard the 010 is a excellent block for high performance applications. There might be more than just the engine block number on the back that factors into if its high nickel though.
Posted via Mobile Device

[Mustard72]

The way this is looking, the block will be headed for a machine shop at some point. The local engine builder guy does lots of race car motors, too, so I'll have to ask him about it. More things to ponder.

[Mustard72]

I asked one of the maintenance guys at work about the reduced coolant passages. He thought they were to restrict the flow when the thermostat opens up to prevent a gush of colder coolant from rushing to the hot head and increasing the likelyhood of warpage. Makes sense, I suppose. I guess if you were only running in the summer and didn't run the thermostat, a larger opening wouldn't hurt, but I don't think I'll mess with them for my truck.

I've also read/heard about some of the phenomena mentioned in that bit above from JP about water/coolant flowing too fast through a radiator (or any heat exchanger, for that matter) and reduicing it's effectiveness. I think there's some merit to that.

[Mustard72]

OK, here are the recent pics. Nothing too exciting. Alll of the pistons came out without having to ream out the ridge, so I'm hoping for just a rehone. I'm thinking of having the shop inspect the cylinders and crank when I get the cam bearings replaced, as I don't really have the right tools to do that. The crank does have some ridges on some of the connecting rod bearing surfaces. Not too bad, but should probably be addressed. I'll get the expert opinion on that, too. Got out of the freeze plugs except for the two on the rear of the block. Looked to be in pretty good shape, actually, with no rust on the insides. Got two of the three oil gallery plugs out of the back of the block, but stripped out the third being a bonehead with the 1/4" square ratchet. Tried pulling the dipstick tube through the bottom of the block and thoroughly chewed that up, too. That should slide out with a little twisting force, right? Thing kicked my butt! Fortunately, I don't believe I messed anything else up, yet, on the engine disassembly, so I'm calling that pretty good.

[87Jimmy4JP]

looks like you made good progress, there on mustard!

gotta hand it to ya...Im a little scared when it comes to motor tear downs...but after reading posts on this forum I will have more confidence when it comes time for mine....

looking good...any hints on engine block colors?

JP

[Mustard72]

It's gonna all be Chevy orange when I'm done. Parts of it were orange prior to the tear down. In the pics you can see that there is quite a bit of brownish paint on it. Not sure if that's a factory primer or what. The timing cover was a bright green (???).

[Mustard72]

Well, things have definitely slowed down a bit on the Mustard project. I did manage to get the cab off it's back and it's actually sitting on the frame right now. The bad news is that it's only sitting on the frame because I need the other stall to work on the rest of the fleet, with a coolant leak in the back of the mighty Sedona and a front wheel bearing going out on the Taurus wagon. .

Oh, well. We'll get back at Mustard pretty soon. I'm thinking we're going to bore the block 0.030 over and go up in compression ratio while we're at it.

[Mustard72]

Got the coolant leak fixed on the Sedona, and the Taurus wagon will have to limp along on the noisy wheel bearing for a little while more. After having the last 6 days off, I finally got around to working on Mustard today.

Pulled the cab back off from it's temporary perch on the frame and got the right side cab corner installed and b-pillar welded to the new floor. This is the cab corner I actually had on a while back but then removed it so I could get the new floor in. It took a bit of tweaking/bending of the cab corner to get it to fit half way decent, and then it still wasn't too great, but got welded in anyways. I reinstalled the door and test fit the rocker to make sure everything looked OK before welding stuff together, though. The door works GREAT. Hopefully I can get it back into this position again, as I'm sure I'll have it off and on a few more times.

Fought with the welder quite a bit, today. I'm no great welder to begin with My gas flow gauge got bent at some point, and now the gauge doesn't work so good, so that was the first problem. I drilled in a bunch of sheet metal screws and welded those holes shut. Those welds all worked pretty well. I then tried welding along the seem between the original cab steel and the new panel. I had trouble with burning through the original cab steel as it was thinner than the new panel. Dickens of a time getting the welder dialed in right for this, for some reason. Got it to the point where it is structurally sound but pretty ugly. Fortunately most of this will be hidden by the bed when it's all said and done. I have to keep reminding myself that this is a work truck, too, and doesn't have to be perfect.

I've tried to attach some pics, but the "Manage Attachments" button keeps taking me to some goofy web search page for whatever reason.

Gonna get some prices for getting the TH350 rebuilt this week, too. It's supposed to be in good condition, but it did see over 100,000 miles in the 79 Vette it came out of. If the price isn't too bad, it'll probably see a rebuild.

[sduckworth13]

Nick, might not hurt to get you one of those copper spoons, its suppose to keep you from burning through your metal. I've got to get one tomorrow myself.
Posted via Mobile Device

[mjensen]

Originally Posted by Mustard72

I've tried to attach some pics, but the "Manage Attachments" button keeps taking me to some goofy web search page for whatever reason.

I was about to call BS...no pictures...no progress Just kidding, at least you're moving forward!