Geoff Weeks

Ok it sounds like I at least have a handle on the basics. One question that other have brought up: Does this same thing happen to non lined or dry lined blocks? Is the casting attacked by the same phenomenon? I realize we would be unlikely to see the results unless a boriscope is used inside the block. Or does the fact that it is cast as one mean that the walls don't resonate the same way a wet liner would? If I had to guess I would say no, Wetliners are sealed at the bottom by rubber seals so can vibrate, where as parent bore and dry lined blocks are cast as one. However I am just guessing.

Makes me wonder, how many drivers outside of vocational uses have ever driven a truck OTR with spring ride? Good spring is better than bad air!

Not yet, the 5th is off the frame, and I am going to paint where I blasted the rust off with a scaler, then re assemble and sell. To be fair it is going to need some work, and I don't know how many would be willing to put in the work.

The beauty of air ride is you can add lift axles and have the equalize simply, something that can't easily be done with spring suspensions. Company I worked for had ARD's on their heavy haul trucks. Can't say it did better or worse than the IHC (HAS) I had on mine. I had a Neway lift axle and it would equalize after a fashion with the IHC when loaded.

Look at the Maxilite and count the bushings, 4 per axle, then look at the 8 bag and count the pivot points and bushings.

Yeah the ARD is a totally different beast, nothing crosses between those and the ARDAB. I actually bought a nice lightly used walking beam cut off to replace the ARDAB with. Never got around to doing the swap, and it will now be up to the next owner what they want to put under it.

I just see a million wear points when compared to the Maxilite (HAS). There is a reason Camelback and Hendrickson walking beam have such a long track life. Hendrickson was designed in the 30's IIRC. The HAS design has been around since at least the 70's. Both are proven and parts are easily obtained. I am the unfortunate owner of a Neway ARDAB suspension, and if I knew then what I know now, would not have bought the truck. New isn't always better, simple is always better than complex, fewer bushings/wearable joints is better than more. On the other hand, are these new trucks still going to be on the road 15 years on? There may be more to worry about then finding obsolete suspension parts.

No, I mentioned a torque multiplier, which is a different item, one reads the torque passing through it and the other increase the output relative to the input (more movement on the input gives smaller movement but higher torque on the output) You could use both, the multiplier to be able to reach higher torque in a small area and the meter to accurately tell you when you have reached the desired torque. One is a "transmission" in a lower gear and the other directly reads the torque applied.

If yours is a Sheppard, I've done it a few times, and whipped my butt each time, I did get them in, however. Being on a cabover and working under the cab and in front of the wheel was no fun.

HAS (Maxilite) is a good suspension, been around in many form and names for decades. One thing I noticed was that it can't be used with air-disk brakes which may be why the change. Most of the damping on a tandem is transfer of load between axles, Camelback, walking beam do this very well. KW's* bag was terrible at it and rode rough. I hope Mack has done better job with their 8 Bag. I had HAS under hypoid and amboid axles and didn't find it had bad vibration problem. As long as you set the pinion angles correctly at running ride height, the slight variation when the suspension is doing its job didn't vibrate objectionably. Correction: I miss read, it says HAS can't be used with "all" disk brake packages, so I guess it can with some?

Who knew we had an expert lurking among us! Please correct me if I have gone a stray in my understanding!

The ~45 psi is straight from the Cummins Big Cam manual. it is measured at the lower water rail (where heater lines hook up) there is a "compucheck" fitting there to measure it. Yes, we both agree that there has to be a difference in pressure for there to be flow. I always knew block pressure was higher but until I got deep into Big Cams, I didn't know it was that high. Pressure in the upper water rail is considerably less, as there are restrictor washers between the head and upper water rail (on Big Cam 4's). It was Glenn Akers who clued me on the higher pressure. I wasn't saying it is that high all over, just in the block. The Big Cam 4's and NT88's use waterpumps that differ from the earlier Big Cams, The 4 water pump looks similar to the -3 and down but has an extra bleed hole and is turned at a fast speed (smaller pulley) then the -3's and down. Many a person has made the mistake of installing the wrong pump and having problems because of it. The upper water rail, bypass, return from the radiator as well as the "bottom fill" line from the top tank are kept at radiator cap pressure, most often 8-12 PSI. The Big Cam 4 and NT88's are a whole 'nother topic as they have essentially 2 coolant loops that are in motion at all times, and come together in the water pump. Antifreeze mixture when it changes from liquid to gas doesn't change the chemical make up. Just like R 134a is the same chemical when it is in a gas or liquid form. While writing this, KT replied, and is better suited to explaining, I would love to hear more from him. Here is the liner re-used and spec for block pressure (max pressure 50 PSI). The cavitation happens 90 degs from the crankshaft centerline, so to re-use you rotate the liner so the damage is inline with the crankshaft. Sorry about one right side up and the other upside down in the attachment, I can't seam to flip just one. Cumminsspec.pdf

If the MFG was any good, they likely would have done the "thinking" for you and provided a way to vent most if not all the air. Cat 3406 has the bypass to the 'stat come down vertical, so a small hole at the top of the higher pressure side will vent to the T stat housing. If the mfg did provide a method either internal or external, it is important not to plug what they put there.

IDK, I know a neighbor had a problem with a IHC. It was wet lined . Coolant filter and SCA's were the std answer in trucks at that time. He, like many farmers never gave it any thought until there was a problem. Never used SCA's or coolant filters.

I went looking for the causes, not solutions but you bring up good questions. I would add one more, does a dry liner engine have a similar problem as a parent bore? Do either of them have a problem at all? You don't hear much about dry lined engine leaking coolant between the dry liner and block/crankcase. I know it happens with freeze cracks. It would follow that the places in the block that hold the liner would effect the resonance of the liner. So a liner pressed in at the very top and bottom might resonate differently than one with the top press fit is lower in the block. The irony about learning is: the more you know the more questions it brings up! Mostly I hear about it in wet lined engines, but those are often the most powerful engines as well, so the cylinder pressure and piston speed may be a factor? I bet there could be a collage level course on the causes and solutions alone!