COMPRESSION TEST FAILURE

joshwhitehead · Post by **joshwhitehead** » Mon Feb 11, 2008 11:09 am

My mechanic has just told me he's tried several compression tests on our P reg bongo, 59,000 miles from Elite Campers, and it's failed every time. The glow plugs have recently been changed and we've had a new alternator fitted. He's saying there's a possibility it's the piston rings but in all likliehood we'll need a new engine. Can this really be true? Has anyone ever heard of this and if so is there anything else it can be? Basically it's not got enough compression to start, we have to use a squirt of easystart up the inlet to get it going.

Any advice gratefully received, Josh, London.

francophile1947 · Post by **francophile1947** » Mon Feb 11, 2008 1:12 pm

Welcome to the madhouse - not a good start!
I would have thought a new engine is pretty drastic. You can test for worn pistons rings by putting a squirt of oil in each cylinder - this will raise the compression briefly. Another possibility is burnt exhaust valves. Replacing/reseating the valves is a lot easier, but still requires the cylinder head to come off.
How long have you had the Bongo? It may just be that it's stood for a long time and the piston rings are sticking in their grooves. You can get stuff (can't remember what it's called) to free the rings - might be worth trying as a cheap opening idea.
Good luck.

The Great Pretender · Post by **The Great Pretender** » Mon Feb 11, 2008 9:59 pm

francophile1947 wrote:Welcome to the madhouse - not a good start!
I would have thought a new engine is pretty drastic. You can test for worn pistons rings by putting a squirt of oil in each cylinder - this will raise the compression briefly. Another possibility is burnt exhaust valves. Replacing/reseating the valves is a lot easier, but still requires the cylinder head to come off.
How long have you had the Bongo? It may just be that it's stood for a long time and the piston rings are sticking in their grooves. You can get stuff (can't remember what it's called) to free the rings - might be worth trying as a cheap opening idea.
Good luck.

Remember reading somewhere that coke works dont know if it is true though.

dandywarhol · Post by **dandywarhol** » Tue Feb 12, 2008 12:12 am

The Great Pretender wrote:
francophile1947 wrote:Welcome to the madhouse - not a good start!
I would have thought a new engine is pretty drastic. You can test for worn pistons rings by putting a squirt of oil in each cylinder - this will raise the compression briefly. Another possibility is burnt exhaust valves. Replacing/reseating the valves is a lot easier, but still requires the cylinder head to come off.
How long have you had the Bongo? It may just be that it's stood for a long time and the piston rings are sticking in their grooves. You can get stuff (can't remember what it's called) to free the rings - might be worth trying as a cheap opening idea.
Good luck.
Remember reading somewhere that coke works dont know if it is true though.

In the engine GP, or up yer nose??

Any figures for the compression test ?

The Great Pretender · Post by **The Great Pretender** » Tue Feb 12, 2008 12:24 am

Well Dandy I wouldnt drink it lol, have you seen what it does to copper?

Cillit bang eat your heart out.