Is it an Engine Brake?

[spitsnrovers]

I have a '91 KB with a diesel engine, which is registered as a 1600 - but I know the engine has been changed by someone. It is supposedly a 4BJ - or something motor.

This engine has what is called an engine brake or "freno de motor" here in Costa rica. It is a butterfly flap in the exhaust pipe, just below the exhaust manifold before it is connected to the down pipe. It is operated by vacuum and a solenoid. A switch on the dash enables the system, while other switches on the throttle pedal and clutch pedal 'disable' it when the pedals are pressed slightly.

I'm sure it does not have the correct gasket between the engine brake and the manifold. I've replaced it twice with a home made flat gasket out of a sheet of steel mesh between two layers of asbestos (type) material.

Does anyone know anything about this system? And what type of gasket it should have?

Sure works great on the many hills of Costa Rica!

[MrBIGHORN]

Can you please take some photo's of the engine so we can help you further.

[geeves]

If its the 4jb1 engine which is most likely the exhaust brake is not an original part of the engine. It may be a modification of the cold start device. We need a few photos to know what it is

[spitsnrovers]

Thanks guys. I will work on the photos, but it is pretty crowded in there!

Not knowing how a cold start device works, I wonder... How would blocking the exhaust (as this device does with the butterfly valve) help starting in cold weather? I looked on the internet and found similar devices - different than a Jake brake - which prevents the engine from taking in any more air by blocking the exhaust, thus acting as an engine brake.

Make sense?

[spitsnrovers]

Trying to find out how to post a photo, but see no info. Any Clues please?

[pig75]

viewtopic.php?f=4&t=80
or viewtopic.php?f=4&t=30

[costaricanzuu]

I'm pretty sure yours is an engine brake I dont know why but a lot of 4JB1 came to CR with that device if you want just send me the picture I will post it!

[costaricanzuu]

sorry for double post

[spitsnrovers]

Here is a closeup of the engine brake. The canister is the vacuum chamber, covered by a heat shield. The butterfly valve is in a casting just below the exhaust manifold. Costaricaisuzu seems to be the only one who knows about this thing.
Any one else?

[geeves]

That is different to anything we have here.
The cold start device is much smaller and only part blocks the exhaust. This holds the hot exhaust gas in the engine longer so more heat remains in the engine. It only works at very low temperatures that would rarely happen anywhere in Costa Rica and probably nowhere you could drive to

[turnturn]

Try working out what triggers the vacuum supply to your "vacuum chamber".
If it goes to an electrical solenoid type thing then follow the wiring and see what activates it.

The cold start device (QWS - quick warm up system) normally also works a valve/butterfly on the intake system (also uses vacuum to activate). Does your vehicle have this valve (sort of looks like a small throttle body)?
To work these two valves (exhaust and intake) there is usually a couple of solenoids grouped together somewhere with a bunch of rubber vacuum lines.

[spitsnrovers]

I think I found the source of the vacuum! There is a unit built onto the rear of the alternator with a hose connected to a TEE. One leg of the TEE is open to the air, but I feel no vacuum on it. Maybe plugged on purpose somewhere inside. I don't know where it was intended to go.

The other leg of the TEE goes to the reservoir - which seems logical.

The electricity to operate the solenoid comes from the ignition switch, via a dash switch, a throttle pedal switch and a clutch pedal switch (all in series).

I finally got a gasket into it! When the original (whatever it was) disappeared into the exhaust pipe shortly after buying the truck, I tried to find a replacement. Didn't seem easy here is Costa Rica. I put in two home made ones, made out of a supposedly asbestos/metal sheet. Each one burnt out in 2 weeks.

Now I find I needed to ask for a "turbo packing"! 2 1/2" dia, 1/4" thick and it fits perfectly. Lets just hope it lasts.

[wbski007]

You know what fellas it could be a exaust brake, being hooked up to the fuel pedal and clutch pedal, its hooked to the clutch pedal so when you push the clutch in it shuts off so it woun't kill the engine and to the fuel pedal so when you let off on the pedal the exaust brake comes on and the brake it self is electric over vacuum operated, pretty cool, wish I had one

[geeves]

Whats described is defiantly an engine brake. It must be aftermarket as nothing like this ever appeared on any of our wagons. Well help where we can but on these things we are running blind

[wbski007]

Are there any names or part#'s on we could look up on the net?, boy would I like to have one for when I'm pulling my trailer

[spitsnrovers]

Thanks for the positive replies, guys. I didn't see any names on it when I had it apart, but then wasn't looking at that time. Will try to check again - without taking it off AGAIN. I've replaced the gasket 3 times - requires removing 2 bolts for the exhaust downpipe, 10 bolts and nuts for the manifold, then 4 more for the brake housing!

You are right, this thing is fantastic! In the hills around here in CR, I rarely touch the brakes so they should last a long time. Just as long as the diff/driveshaft/clutch, etc don't give out first.

The butterfly valve doesn't quite close completely so the engine won't die during idle with the brake on (ie foot off gas and clutch pedals), but it sure slows it down.

I get 10 - 12 Litres/100km (sorry guys you'll have to work that out into Imp and US gals and miles), which I think is pretty good. I'm not sure if the engine brake contributes to this figure.

[wbski007]

If you can't find a name or part# on it, then can I at least have your address and where you park your KB at night, LOL

[spitsnrovers]

Hey wbski007, the laugh's on you - there are no addresses in Costa Rica! Seriously, no house numbers and no posted street names in our town. Everybody just knows how to get to where they want to get to. Or asks somebody who does know.

[wbski007]

You gotta be kidding me, how the hell am I going to get my exhaust brake now?? Guess I'm going cancel my airline tickets, LOL that brake is really cool, if you ever find out who made it, let me know,OK? Take care now, Wayne

[geeves]

A while ago I saw an add for an aftermarket exhaust brake for diesel 4x4s No idea where it was but it might be worth a google