who ever heard of a blocked exhaust ???

[The Great Pretender]

will it start without exhaust i thought you needed back pressure or is that petrol engine or am i talking out of my blocked pipe. it can be hard work being a bongo owner but ultimately worthwile .....,,,....

An exhaust valve requires 'back pressure' as in a return pressure pulse to stop fuel passing into the exhaust in a petrol engine during valve overlap ( when both valves are open), it is probably the same in a di diesel.
Have you just opened the joints when trying the exhaust?

[dandywarhol]

Silencers can "block". The wadding can collapse and fall over the outlet pipe in the box. I've replaced a few. It's diagnosed by the lack of a force/beat from the tailpipe.

[bongomaan]

gbt,the AA niceman opened a split in the back box but still no presure coming out (on tickover),he said it should blow his hand away and didnt,anyway gone now and just waiting on flexi~joint.

[The Great Pretender]

Silencers can "block". The wadding can collapse and fall over the outlet pipe in the box. I've replaced a few. It's diagnosed by the lack of a force/beat from the tailpipe.

Are you talking about a diesel idi engine, do they have wadding?

[scanner]

will it start without exhaust i thought you needed back pressure or is that petrol engine or am i talking out of my blocked pipe. it can be hard work being a bongo owner but ultimately worthwile .....,,,....

An exhaust valve requires 'back pressure' as in a return pressure pulse to stop fuel passing into the exhaust in a petrol engine during valve overlap ( when both valves are open), it is probably the same in a di diesel.
Have you just opened the joints when trying the exhaust?

SFAIK turbodiesels don't need back pressure and run better without any.

[dandywarhol]

Any non-straight through silencers I've chopped up, petrol or diesel, have had wadding around the perforated baffle tubes. I've a Bongo rear box at the workshop - I'll give it the chop next week.

[bongomaan]

i was going to operate on both parts but i only have the equipment in work and the size of the original b/box im not putting that in my backpack! (cycling at the moment) and talking of b/boxes how bloody big huge massive is it,ive seen smaller exhausts on the spaceshuttle !!!!

[scanner]

i was going to operate on both parts but i only have the equipment in work and the size of the original b/box im not putting that in my backpack! (cycling at the moment) and talking of b/boxes how bloody big huge massive is it,ive seen smaller exhausts on the spaceshuttle !!!!

And it achieves exactly zilch I ran mine for a week without it, (just a short length of pipe pushed into the broken end of the pipe and tied up to the rear hanger with a luggage bungee,) while waiting for a new one and it was not noticeably louder. Somebody else on here has replaced their back box with a length of flexi and I think it has passed at least one MOT OK.

Yep Bongo back boxes are one of the most troublesome and useless things ever invented, mine will not be replaced again except by a length of straight through pipe.