Help identifying an engine cog wheel on 1993 Mazda Bongo

[Neilos]

Hi, I left my vans oil leak to be fixed by a local mechanic whilst away on holiday. On return the man tells me he cannot remove a cog wheel connected to the cam belt.
Can anyone with engine knowledge please look at photographs I have uploaded to flick to help me identify the part that needs to be removed (my mechanic is Polish and cannot explain what he needs). I am thinking he needs some sort of extractor. I have researched and contacted many places local to Coventry to no avail. My van is a Mazda Bongo 1993 (not like later vans of the same name but more like an E2000).
Any helpful advice would be welcome.
http://www.flickr.com/photos/30177620@N ... 721553335/

[francophile1947]

Not sure anyone will be able to help This forum is for Bongo Friendees which have a different engine to yours (the 2.5TD WL-T engine).

[rita]

Hi Neilos,

Does this Cog have threaded holes,if so they could be used with jacking screws.

Ps Is this a Diesel Engine??

[Neilos]

The centre is threaded -the mechanic has sourced a large bolt like extractor for the job but it is the wrong sized thread. There are also 6 smaller threaded hole around the edge. It looks like he has used a smaller extractor with these and in doing so broke off some off the outer edge casting. I wish I had just lived with the oil leak now.

[dave_aber]

That smaller toothed cog is the crankshaft cam drive cog. On most engines, these are pretty easy to remove, once the big bolt is removed from the middle. The keyway may be damaged, which would make it a pig to remove.

You might get away with fabricating an circular extractor plate which has 6 holes aligned with the outer ones on the cog, and a larger bolt in the middle (but smaller than the one which was removed from the end of the crank). Looks like it could be a pig of a job....

Edit : Just a thought - Is the raised collar sticking out of the middle, with the notch in it, a locking ring which has to be unscrewed? I doubt that it is - more likely the notch is the end of the key in the keyway.

[Neilos]

Thanks Dave, now at least I know what to ask for. The Polish mechanic is trying to get a bolt to fit the centre so I assume he is trying to make some sort of home made extractor. I dont think the ring does come off but I will check it out. Do you know if the seal that needs changing be behind this cog or inside the centre?

[dave_aber]

The centre is the end of the crankshaft. Don't screw anything into that thread or risk damaging it or you will be looking for a new engine.

The extractor you will need is a heavy steel disk, with 6 plain holes which match the 6 threaded holes in the cog. In the middle, you will need a hole approx. the same size as the threaded hole in the end of the crankshaft. You will then need to weld a large nut on the outside of this plate. The nut should be a smaller thread size than the thread in the end of the crankshaft. With this plate screwed onto the cog using 6 small bolts, screw a long bolt into the nut you have welded in the middle. This should pass through the centre of the crankshaft threaded section without touching the threads. Once it reaches the bottom of the hole in the crankshaft, it will push the plate (and the cog with it) off the end of the crank.

Behind the cog will be the crankshaft nose end oil seal, which looks like what is leaking. This will take some 'persuading' to get it out. Sometimes the only way is to screw in a couple of screws (not deep enough to touch anything behind!) and pull it out. The new one needs to be pressed in carefully using a large socket or a similar section of pipe. You can make a special tool for this by cutting off a section of pipe the same diameter as the seal. Assemble the seal, pipe section, large washer and the original big bottom bolt, and draw the seal in with it.

refitting the cog - make sure that the keyway isn't damaged, and use the bottom bolt to draw the cog onto the end of the crank. It shouldn't need a huge amount of force to get it to go on. If it's reluctant to go on, find out why before you strip the thread in the crank.....

Good Luck!

[Neilos]

Thanks Dave, that all makes sense. I would ask the man to just put it all back together as it is but I think he has damamged the key slot and back of the cog. I don't hold much hope for my van beeing back on the road.
thanks for taking the time to write.
Neil

[Alison01326]

A long, long, longshot here, but I wonder if anyone on this forum bought the items referred in this thread http://www.igmaynard.co.uk/bongo/forum/ ... 3&p=393490

If they did they are staying very quiet about it because they might be able to produce a new cog for you if yours is damaged.

Not much help, but someone somewhere must be breaking one or have bits of one. Seems like Ford Spectron could be a good thing to be googling, but you probably already know that.

[Neilos]

Yes interesting Alison, the Bongo in the listing looks like mine alright. I think Jap Auto Spares in Coventry will sort me out with a new cog - the problem at the moment is getting the old one off. My old fella has suggested getting some heat on it and a tap with a lump hammer, he is dropping by in the morning to give the Polish man a hand. I'm missing my old van that everyone else laughs at already despite the fact that I hate the hard to get to and awkward mechanics of it.