[Guy]

Opened the dash up today, and peeked in with a dental mirror. Turns out I was being too gentle. The switches were " hanging up" on the edge of the dash. Worked my way in and gained access. Plenty of wire lead length was provided by Newell. Not for the faint of heart, but it is doable. On a positive note, found several connections that needed attention. Planning on troubleshooting the gen set hour meter that is not functioning. I have a pyrometer that is not working. Is this a device that falls in the too much information category, or do I really need to know the temperature of the exhaust?

[Fulltiming]

Newell has rarely put in pyrometers during the past several decades. Other manufacturers, such as Prevost and Blue Bird typically did install them. While they are certainly not required, they can provide valuable information, specifically in two circumstances. 1) Climbing hills and 2) shutting down the engine. In climbing hills, the pyrometer will be your first indication that the engine is generating too much heat and you should back off the throttle. After running on the freeway and pulling into a rest stop or truck stop, the pyrometer will be the best way to determine when the engine has cooled enough to shut it down without damaging the turbo. Newer metallurgy has reduced some of the shut down issues and more sophisticated computer engine monitoring and control system have reduced the potential to overheat an engine under full throttle but pyrometers are still a good way to monitor engine operation.

[77newell]

The mechanically governed engines benefit more from a pyrometer than do computer controlled engines. With a two-stroke Detroit Diesel engine the critical thing is to keep it wound up when under significant load. If you are running above 1800 RPM I doubt you can damage the engine due to high exhaust temperature. However, you do need to monitor coolant temperature since the heads are prone to cracking if they overheat. I never let coolant get over 210 degrees before downshifting and if it's headed upwards rapidly I shift early. It is a cheap price to pay to protect the heads. Depending on the health of the radiator this may or may not ever be needed. My previous 77 coach with a 350hp engine never needed downshifting other than to the engine speed up. The 93 coach with a 500hp engine and what appears to be the same size radiator has required downshifting due to rising temperatures a few times.

[Guy]

Jon, that brings up another question. What is the "red line" on rpms for these engines?

[Fulltiming]

Typically the 6V92's and 8V92's redline about 2100 rpm. The Newell manual for late 1980's early 1990's recommended keeping them below 2200 rpms.

[77newell]

Both V92 engines I've had were governed right around 2100 indicated. The gauge could be off a bit so I don't know what the exact limit was.

That is what the engine will do under power. Going down a hill it is possible to overrun the governed setting and I've been told by various knowledgeable mechanics to keep it below 2200-2300. I plan on 2100 max down hills and then if I get distracted it's unlikely to exceed 2200-2300. I read somewhere of someone going to 2500 while coasting. I don't plan on allowing that. The thing I don't know is how the Jake Brake would change the engine health if rev'ed beyond 2200. What I do know is that the Jake Brake has little impact at lower rpm's on the 2-strokes, but when it's working it sounds COOL!