Did I just destroy my engine?

Ryker · December 03, 2018, 08:01:30 PM

My exhaust tip got hit a few times so I had a new one made. I put it on this evening, then started the bus to move it. It idled for about 10 seconds then made a bad clacking sound and quit. I knew that the only thing I did was install the exhaust tip so I went back and turned the fan blade and saw that it was hitting the exhaust clamp bolt so could not turn. I adjusted the clamp and made sure the blade was spinning then started the bus again. It ran for a couple seconds, I heard the sound again so quickly turned it off. This time it ran smoothly for another 10 seconds after I had turned it off. It has never done the before. Now if I try to start it, it just turns over and I can still hear that clacking sound after it turns over a couple times. Detroit 8V71 and Allison trans.

Geoff · December 04, 2018, 04:56:52 AM

Perhaps the blower lost a bearing and the fuel pump is no longer turning.

Ryker · December 04, 2018, 11:56:38 AM

Update. I started the bus this morning and it did the same thing, so I am thinking blocking the fan is not the problem, it was just coincidental. This morning I started it and it fired up immediately, ran for about 10 seconds, loud clatter and died. Any ideas?

luvrbus · December 04, 2018, 01:05:48 PM

Check things on the rear of the engine ,like the alternator,power steering pump,to me it sounds like transmission problems with the V730 just runs long enough for the V730 to pickup fluid.if it wasn't for the clacking I would say your Jakes are on

Ryker · December 09, 2018, 03:14:26 PM

The problem ended up being the Jake Brake. I left the switch on last time I parked it, so I flipped it off and it started and idled fine. Now I have to figure out what is wrong with my Jake Brake. I was driving and as it slows down it starts to kill the engine, so for now I am not using the Jake Brakes.

I have another issue though, and that is the forward and reverse toggle switch. It is being very hesitant to go into gear. I checked the transmission fluid and the level is correct. The switch does have a delay and the buzzer will sound if I try to switch over too quickly but now it just won't go into gear. I have to sit there and switch it several times to get it working. Maybe a bad switch?

richard5933 · December 09, 2018, 03:36:24 PM

Quote from: Ryker on December 09, 2018, 03:14:26 PM
...Maybe a bad switch?

Have you checked the connections on the switch? The ground connection especially. Had a problem like this on our 4106 and the problem was a loose ground connection.

Geoff · December 09, 2018, 04:53:06 PM

So the loud clatter was having your Jake's on??? My God, are you one of the ones who think they don't need a Jake buffer switch?

Also, are you running straight 40wt.? If you were, the Jake's wouldn't work until the oil warmed up.

luvrbus · December 09, 2018, 06:00:13 PM

When a Jake dosen't disengage with the power off you either have a solenoid sticking open or the o-rings under the solenoids have blown, sounds like it won't be long before they start engaging with no power ? did Kevin rebuild the Jakes when he sold them to you

Ryker · December 09, 2018, 06:15:21 PM

Quote from: Geoff on December 09, 2018, 04:53:06 PM
So the loud clatter was having your Jake's on??? My God, are you one of the ones who think they don't need a Jake buffer switch?

Yes, the Jake was he clatter. I have no idea whether or not I have a buffer switch. I was emailing Ted from Coach Maintenance in Williams, CA and he asked if I have a micro switch as well, so sounds like maybe I do not.

Also, are you running straight 40wt.? If you were, the Jake's wouldn't work until the oil warmed up.

Yes, I am running straight 40wt.

Ryker · December 09, 2018, 06:16:02 PM

Quote from: luvrbus on December 09, 2018, 06:00:13 PM
When a Jake dosen't disengage with the power off you either have a solenoid sticking open or the o-rings under the solenoids have blown, sounds like it won't be long before they start engaging with no power ? did Kevin rebuild the Jakes when he sold them to you

When I bought this bus it already had Jakes. I've never done anything to them.

Ryker · December 09, 2018, 06:28:06 PM

Quote from: Geoff on December 09, 2018, 04:53:06 PM
So the loud clatter was having your Jake's on??? My God, are you one of the ones who think they don't need a Jake buffer switch?

Also, are you running straight 40wt.? If you were, the Jake's wouldn't work until the oil warmed up.

Where would I look for this buffer switch? Where is the solenoid? I will look for them tomorrow but could use some direction. Sounds important.

luvrbus · December 09, 2018, 06:52:21 PM

Quote from: Ryker on December 09, 2018, 06:28:06 PM
Where would I look for this buffer switch? Where is the solenoid? I will look for them tomorrow but could use some direction. Sounds important.

You need to take it somewhere, if not download the Jake Manual and spend time to study it fooling around with a buffer switch can cost you a engine if you don't watch it,the buffer switch has cost people engines here before

Ryker · December 10, 2018, 08:43:52 AM

Quote from: luvrbus on December 09, 2018, 06:52:21 PM

You need to take it somewhere, if not download the Jake Manual and spend time to study it fooling around with a buffer switch can cost you a engine if you don't watch it,the buffer switch has cost people engines here before

I have the manual and am studying it. What do I need to look out for? For now I am just going to leave the Jakes off. I certainly do not want to lose an engine! What would you consider "fooling around" with the switch? I know that fooling around can cost me a marriage but how can it cost me an engine?

buswarrior · December 10, 2018, 09:07:52 AM

Think of it this way:

The Jakes interfere with the normal sequence of events in the valve train and injector.

interfere at the wrong time, due to wrong adjustments, or failed components, and instead of a dance between moving parts, there gets to be a collision.

Sometimes, paying a professional is well worth it?

Happy coaching!
Buswarrior

bevans6 · December 10, 2018, 10:17:48 AM

The buffer switch is mounted on the governor, it senses when the governor is in "no-fuel" mode and turns on the jake brake system. The governor is in "no-fuel" only when the engine is running and throttle is off, and the engine is decelerating. When it decelerates to idle speed, the governor goes to idle fuel settings and the jake brake is turned off. The reason it's dangerous to fool with if you don't know what you are doing is the buffer is tied directly to the idle speed control, and helps control the smoothness of the idle speed. It's really easy to adjust it wrong and have the idle speed get out of control, engine runs away and goes boom. So you need to learn about how that part of the governor works and how to adjust it before you start working on it - it's a read AND understand the manual before you even get near the bus deal. The solenoids being referenced are inside the engine, under the valve covers, and are inside the jake brake heads over the valves. They are electric switches that control the flow of engine oil into the jake heads, the high pressure oil is what actually activates the mechanics of the jake heads to open the exhaust valve at the right time. Those electric solenoids are what the buffer switch controls. The reason your engine ran for a few seconds and then died is the jake heads need oil pressure to work. Even with the switch on, they don't do anything without sufficient oil pressure, and the top of the valves is about the last place in the engine that gets pressure on a cold start.