Valves

BX Tech talk
NZRob
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Valves

Post by NZRob » Sat Sep 09, 2006 2:21 am

Hi,
I've just inherited an 89 BX19TRI from a friend going overseas - it has high k's (270000!) but seems to be in good condition except for a lot of valve chatter, a leaky manifold-exhaust seal, and running a bit rich. There is no oil being burned and very little moisture coming out of the exhaust. While I'll fix the seal i'm not keen on taking off the head and getting it reconditioned. What's the worst that could happen if I just leave it be? Also there's a bit of hissing from the rear suspension and the compresser goes on every few minutes - is this normal?

Cheers,
Rob

NZRob
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Post by NZRob » Sat Sep 09, 2006 3:02 am

I just checked the air filter - very blocked - took it out, much less grey smoke now - still heaps of valve chatter.

jeremy
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Post by jeremy » Sat Sep 09, 2006 7:51 am

I wonder - valve gear noise could just be the valves need re-shimming - which would simply entail removing the rocker cover, measuring the clearances between valve and tappet, removing camshaft and adjusting the shimming between tappet and valve and re-assembly.

May be camshaft wear - in which case when you remove the rocker cover you will see the thing has a surface like concrete on or near its tips - wear is usually quite apparent and does not involve subtle measuring techniques.

Make sure it really is cam/valve related - it probably is but could be auxilliary like alternator.

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Mike E (uk)
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Post by Mike E (uk) » Sat Sep 09, 2006 8:45 pm

Worn bearings in the hydraulic pump might be mistaken for valve clatter.

I had one that rattled well when idling, but the rattle stopped when ever the pump was pumping.

Mike

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DLM
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Post by DLM » Sun Sep 10, 2006 12:33 am

Hissing from the rear suspension? A few more details are needed here to advise, please: the rear suspension should make no noise in action.

As for the "compressor", if it's literally kicking in every few minutes then you're laughing: a few seconds is the norm on a neglected BX but it sounds as if this one has a recent accumulator sphere, and the hydraulics are generally in good order. Is this an aircon model? The condenser sit low-down on the timing-chain end of the engine, and kicks in with an audible "click".

The accumulator sphere is screwed onto, and acts as the reference pressure for what is better-known in Citroen circles as the Pressure Regulator - probably the "compressor" of which you wrote, which normally sits low-down in front of the engine centrally.

Cam-off to check the valve clearances is a lot less stressful than head-off, though you may find the cost of shims required a bit expensive for what they are.
Relying on two wheels and musclepower since the last BX (or any car) had to go.

NZRob
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Post by NZRob » Sun Sep 10, 2006 3:24 am

The hiss is coming from somewhere around the right rear suspension and is definately the sound of air escaping it could be the exhaust though - I've got to get it up on a hoist to have a better look. I've also discovered that I can push the whole back of the car down through its travel using only my bodyweight (while it is running) is this normal? The rockercover may have to wait until I get all of the smaller stuff out of the way. Thanks for the advice about the pressure regulator DLM - it is the condensor coming on and it certainly "clicks" (no aircon): it's happening about every minute and a half. There's a note on one of the spheres saying they were all services about 20000 km ago.

In the meantime I'm trying to adjust the clutch. There's a lot of adjustment left on the rod but it's almost impossible to get to (I've managed to serate my wrists on the radiator) Is there an easy way to get to the locknut on the pushrod or do I just need to grin and bear it - I'm just about ready to take the radiator out. Even my mini wasn't this hard to work around.

Thanks,
Rob

tom
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Post by tom » Sun Sep 10, 2006 11:15 am

Work from underneath. Access is so good that the parts are even visible!