Need advice on adding air shutdown to m35a2

[Katavic918]

I want to install a shutdown valve on the metal u-pipe right before the turbo. My only concern is the rubber hose that connects the pipe to the turbo. In the case of a runaway would the suction generated be enough to basically suck that rubber hose into the turbo and continue running away? Any advice or opinions are appreciated.

 

[HanksDeuce]

Here's what I did. Not the original multifuel engine though.

http://hanksdeuce.com/air_shutoff_valve.htm

 

[gimpyrobb]

I seriously doubt it could pull the rubber hose off.

A (large)1/4 turn ball valve, or a butterfly valve should work for the intake side. Have you thought about an exhaust brake? You could use it everyday in addition to emergencies.

 

[Katavic918]

Here's what I did. Not the original multifuel engine though.

http://hanksdeuce.com/air_shutoff_valve.htm

I saw this anwhile ago which is why I have a blast gate. The only thing I don't like is that it's not sealed. Not that it makes much difference but I'm ocd about that kind of thing. Good idea with the spring. Thanks.

 

[Katavic918]

I seriously doubt it could pull the rubber hose off.

A (large)1/4 turn ball valve, or a butterfly valve should work for the intake side. Have you thought about an exhaust brake? You could use it everyday in addition to emergencies.

No I haven't. Do you mean a Jake brake? That would be pretty cool.

 

[pitpawten]

Here's what I did. Not the original multifuel engine though.

http://hanksdeuce.com/air_shutoff_valve.htm

Thought I came up with this idea myself Brilliant minds and all that I guess

Have you thought about an exhaust brake? You could use it everyday in addition to emergencies.

I have one on my F350 and while it does a good job of helping brake, I do not feel confident at all that it would be very effective in a runaway situation (leastwise not near a effective or quick as a positive air shutoff on the intake)

 

[gimpyrobb]

No I haven't. Do you mean a Jake brake? That would be pretty cool.

NOT a jake brake.

Look up exhaust brakes, pretty interesting(and helpful. Most don't close all the way, but you could modify it for that. I doubt it would be much more work than an intake block off and you'd have the bonus of using it while driving.

 

[Jeepsinker]

You think the headgaskets will handle engine braking?

 

[rustystud]

You think the headgaskets will handle engine braking?

Good question !

 

[Katavic918]

I was wondering the same thing. Also rods and pistons.

 

[Katavic918]

I retract that. It probably wouldn't exceed the pressures reached on a combustion stroke.

 

[gimpyrobb]

Cranetruck put an exhaust brake on his truck and liked the results. I've been wanting to do it to mine for a while now. It took me almost 2yrs to put the air assist steering kit on after I got it.

I have yet to get an exhaust brake to install, so it will probably be 2020 before I get one installed...

 

[Jeepsinker]

Any particular exhaust brake you were considering using? I've never looked into them before.

 

[98G]

I've got an exhaust brake on the Redtruck and like it a lot....

 

[m16ty]

An exhaust brake is unlikely to put more stress on the engine than it would be under power.

Even a full fledged engine brake (Jake brake) doesn't put any undue stress on the engine. They never made one for a multifuel anyway.

 

[gimpyrobb]

No, just one I can get cheap. They all work in a similar fashion. I'll get one eventually, just not in a big hurry.

 

[rustystud]

An exhaust brake is unlikely to put more stress on the engine than it would be under power.

Even a full fledged engine brake (Jake brake) doesn't put any undue stress on the engine. They never made one for a multifuel anyway.

The reason a Jake doesn't put undo stress on the engine is because the exhaust valves are hydraulically opened just before "Top Dead Center" and the fuel is shut-off on electronically controlled engines. That's why you get that "PHFFFFT" sound when their on. If you just use a butterfly valve to totally close off the exhaust you might end up with some undesired effects since the injectors are still firing just at a idle setting. That pressure needs to go somewhere.

 

[m16ty]

A Jake brake doesn't shut the fuel off, it just goes to a idle setting. A Jake brake isn't connected to the fuel injection system in any way on any of the engines I've seen (Cat, Cummins, and Mack's Dynatard), other than the brake cut off switch on the accelerator rod. The reason for the brake cut off switch is to cut the brake off when you accelerate past idle.

None of the exhaust brakes I've seen cut the exhaust completely off. I still doubt a exhaust brake would produce more cylinder pressures than fuel fuel at load. I'll admit I haven't researched it though.

 

[pitpawten]

You typically adjust your exhaust brake (how much the butterfly valve closes) to keep it at a certain amount of backpressure.

Recommendations I have seen are to keep it below 30psi backpressure and hence the need for a gauge when you use one.

I would still much rather use a blast type gate in the intake to instantaneously stop a runaway rather than an exhaust brake. The nature of a butterfly valve is weak at WOT and even if you could get an almost 100% seal on the exhaust side (would never want to use it adjusted like that for actual braking) it would not be near a quick as 100% mechanical O2 starvation.

Two different tools for two different problems IMO.

 

[rustystud]

View attachment Scan0096.pdfView attachment Scan0097.pdf

A Jake brake doesn't shut the fuel off, it just goes to a idle setting. A Jake brake isn't connected to the fuel injection system in any way on any of the engines I've seen (Cat, Cummins, and Mack's Dynatard), other than the brake cut off switch on the accelerator rod. The reason for the brake cut off switch is to cut the brake off when you accelerate past idle.

None of the exhaust brakes I've seen cut the exhaust completely off. I still doubt a exhaust brake would produce more cylinder pressures than fuel fuel at load. I'll admit I haven't researched it though.

I should have prefaced that with "all modern electronic controlled injection" . You must be able to open the exhaust valves to prevent any problems like I said earlier. The compressed air must go somewhere. Also you must deal with the Turbo pressure.