JoeH

I'd pull valve cover. Never know what you'll see, broken rocker arm shafts, broken valve stem.... I'd also look into condition of the camshaft EUP's and H Clips, you could have broken bits there eating up the camshaft. If so, this would be a prime time to read the "old dog dead dog loggin dog" remediation thread to delete your ASET AI (guessing your truck is a granite) emissions system.

Keep us posted on what you find, helpful for us E7 owners down the line!

Dont waste your money on air compressor from Mack, it'll do the same thing. My 1979 endt676 does the same thing. We put a dryer on to try and keep the tanks clear, but it makes so much oil it was leaving stains on customers' driveways so we pulled it right back off. E7's forward actually pull the air compressor intake line off the intake manifold, so they're actually getting boost pressure off the turbo. Plumb your air compressor supply line this way and it may help with the situation. There's a whole science behind piston compression rings, they're slightly sloped so that more pressure actually helps press them against the cylinder walls harder for better sealing. Or at least an engine textbook I inherited from my deceased uncle says as much.

Before I pulled my engine, I disconnected the oil cooler and the radiator, plugged the lower radiator line and filled the engine with water to watch it for leaks. Had water coming out the oil pan drain bolt, so we pulled the motor, stripped it down and found the o rings that seal the piston sleeves were toast. Did a thorough visual inspection for cracks in the block due to overheating, then rolled the dice on a $2,000 rebuild kit. Not sure about the ETECH block, but the E7 block supposedly is half dry half wet sleeves. There's a great video on YouTube from the early 90's by Mack that shows rebuilding the E7. The sleeves have a step shoulder halfway down the sleeve that gets Mack RTV silicone, I think in addition to O rings. Think through the possible cross contamination points between the water jacket and the crank case. Cracked heads, head gasket, cracked block, sleeves corroded through, oil cooler...

We paint our 3 TDC marks with a bright yellow marker and which cylinders are on TDC with each mark. Saves a lot of headache.

I'm rebuilding a motor right now that dumped all the coolant into the engine oil. The coolant will chemically bond in with the oil and make the oil about as thick as grease, if you get enough coolant mixed in. I have several buckets of this tar that I drained out of the oil pan on the engine. If you truly have coolant in the oil then you need to deal with this ASAP. Pull the pan, pull the connecting rod caps and main caps and inspect the bearing faces. Mine had a LOT of copper base metal showing under the babbit, we caught this engine before things really went south. If you catch it quick enough you can save the crankshaft, camshaft, etc, but it's a major overhaul involving pulling every single piece of engine apart and cleaning, including oil gallery plugs and flushing the oil gallery to wash out every bit of this greasy mix. On the connecting rods, the top bearing shell takes the bulk of the wear, and on the Main bearings the bottom shell takes the bulk of the wear. We're doing piston kits, bearings, cam bushings, on this Case W14 engine. Basically replacing all the soft parts.

220 is too hot. Water boils at 212. What RPMs are you running when it gets that hot? You need to keep engine speed up to keep fan spinning and air flowing through the heads.

We aren't shy of some their tools, but most of our repairs are once in a blue moon type stuff. Hard to justify thousands of dollars for something that'll get used maybe 3 times in 10 years. Their Titanium plasma cutter has been great. Runs great on 220v, but not so well on 110v. Sorry to hijack thread; I'd consider making a bracket for my stand to hold a Mack engine by the side like Joey's is so the center of gravity is closer to the post. But I'd weigh the engine on my 1800's wagon scale before taking that risk.

I could understand a left/right mirror image on it, but there's some funny business involved in putting that AR together.... Almost like if Joe Biden bought an AR-15 kit and tried putting it together himself? 🤠

And the shell ejector window should be on the right side. I'd have to get my AR out to double check the little bump they have by the ejector well, but that should be on the right I think, and have a button on it for you to slam a partially seated cartridge forward the rest of the way into the chamber.

Lots of questions on this pick lol. Grandma has 6 fingers on her right hand, the magwell has a trigger guard, and the magwell and mag appear to be on backwards. And the pistol grip appears to be on the stock, not the lower receiver...

What are you seeing on radiator temps climbing the canyon? You can ditch the clutch for a solid fan. If you're getting any belt squeal whatsoever then tighten your belt a little, that may help with staying cool. My E7-350 would run hot and squeal a bit at slower speeds/higher RPM. Tightened the belt and it runs cooler. My '79 also lists 1125 as max on pyro, not sure we ever hit it though. The engine is ready to downshift before it gets that hot.

I quit riding 7 or 8 years ago, got married, got little kids now, but mostly I don't like other drivers. Everyone texts and drives, Grandma is just as bad as the grandkids.

Man that stand is a monster.

When you're working 14 hour days it barely leaves you the steam to take your boots off...

We just bought the harbor freight 2,000# engine stand for a Case A336BD 4 cylinder diesel engine we're rebuilding that dumped all its coolant into the oil... Caught onto its problems before any bearing spun. Had to make some longer brackets to bolt the engine on there, but it holds this engine nicely. I wouldn't put a compete Mack engine in there, but if you're the adventurous sort you might be able to get away with putting the block in there if you support the front end with an engine hoist or car jack... This engine rotates fine with a cheater pipe on the handle.

+1 on 55 mph. If you've ever ridden a motorcycle on the highway then you know this first hand. Wind resistance on your body is negligible up to 55 mph, start getting above that and your arms start getting a workout to keep you in the saddle.

My volumetric concrete trucks get about 3.5mpg annually. We have a 15 mile radius, and a typical delivery is drive 20-40 minutes to a job, sit at the job for an hour or so idling/revved around 1300 rpms, drive back to the yard to reload for next job. Or drive straight to next job from previous. 1979 R686ST with endt676 gets best around 4-4.5mpg but it's the lightest maxing at 50,000 lbs 1995 RD688S with E7-350 and 8LL gets around 3.5mpg but maxes around 73,280 lbs 2003 MR688 AI-350 with Allison HD4560 auto gets worst at sub 3, maxing close to 73,280. That auto is nice but sucks on economy. Note that our trucks are almost never empty, whatever material a customer doesn't use gets lugged on back for the next load. Frequently as much as 8,000 lbs of extra material getting carried around.

I think you need the king pin forward 6 inches or so. Wiser heads will steer you straight. If your 5th wheel is too far back you can do this... https://youtu.be/udE01fKbWCk?si=PhfTDYy6-Snp3YSc

But my 1979 r686st does probably the same hop you're talking about. Endt676 motor with a 2 stick 6 speed. 5th gear, ~45mph. Solution? Just don't drive at 45 mph. Even though it might be a very comfortable speed otherwise.

Rubber bushings probably bad on the engine mount, no big deal to replace. Could have loose bolts threading the rear engine mounts into the bell housing. Bellhousing is probably aluminum, so hopefully they aren't stripped out. How's your 5th wheel positioned? Is it dead center over the tandem or is it forward enough to put some weight on the steer axle? What weight rating springs are on your steer axle? Too light could be too weak to steady out any uneasiness in the chassis. Does it do this around 45-50mph on all roads or just on one particular road at a certain spot? I've got roads around me that certain bends make you feel like the tie rods are about to fall off. Only does it at one pair of bends, everywhere else it does fine. Had another road started making my triaxle buck for a couple hundred yards, always the same exact strip, then they came through and paved the road and the truck goes smooth as glass over it now.

Joey is right, you just weld a bead vertically along the inside of the sleeve and they pop right out when they cool.

This block uses the same oil pan gasket as the E7. I think there are incremental differences in the 673 block casting as more was demanded of it. Pistons and liners should be the same, the displacement never changed. Biggest question will be head gaskets, and replacement heads if these can't be rebuilt.

Replace the whole thing is what I've heard in the past, not sure it's worth the safety risk of fixing, but I don't have much experience with 5th wheels

Says he can apply power to the Jake and it works... What's the vmac III use for brake control? Throttle signal through the pedal and a clutch mounted switch? Maybe it's got nothing to do with pressure washing and the clutch switch is buggered or got tweaked coincidentally.