300CE WBX Repair
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300CE WBX Repair
Well the engine has now been removed from the bus at long last ready for a gander at the possible reasons as to why she has been over pressurising. Removal was pretty painless, however, I am going to require a new exhaust as there were a couple of noticeable cracks once removed (to be fair it's a mild steel one which has been on there for about 9 years so it hasn't done too bad). Will be going the stainless route and put up a post in the wanted section shortly.
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Unfortunately, I have completely mislaid my brand new compression tester so was not able to test the compression numbers prior to removal (I know I need a slap Paul!). I've posted up a couple of pictures of the ports on either side of the head - you can see slight discolouration on the first port on the right hand side compared to the other 3. This could possibly be leakage?
Left Side:
Untitled by Justin C, on Flickr
Right Side:
Untitled by Justin C, on Flickr
Present from Brickwerks (Gasket Set):
Untitled by Justin C, on Flickr
Engine is now at my mates garage ready for strip down in the coming weeks so watch this space.
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Unfortunately, I have completely mislaid my brand new compression tester so was not able to test the compression numbers prior to removal (I know I need a slap Paul!). I've posted up a couple of pictures of the ports on either side of the head - you can see slight discolouration on the first port on the right hand side compared to the other 3. This could possibly be leakage?
Left Side:
Untitled by Justin C, on Flickr
Right Side:
Untitled by Justin C, on Flickr
Present from Brickwerks (Gasket Set):
Untitled by Justin C, on Flickr
Engine is now at my mates garage ready for strip down in the coming weeks so watch this space.
'86 DG, Weber Carb
- itchyfeet
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Re: 300CE WBX Repair
fingers crossed on the studs, heating the nuts helps and I recommend it even if it does bugger the plating its better than a snapped stud.
you want to be careful not to heat the valve springs, you can use a shield.
you want to be careful not to heat the valve springs, you can use a shield.
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Re: 300CE WBX Repair
Cheers Paul, will deffo heat them up prior to removal and fingers crossed they’ll be ok. What do you reckon on that slight discolouring?
'86 DG, Weber Carb
- itchyfeet
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Re: 300CE WBX Repair
300CE wrote: What do you reckon on that slight discolouring?
to me looks like just one is clean
steam cleaned?, had the same when I had a cracked head
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Re: 300CE WBX Repair
Hmm, not looking good then - Are they usually toast if the head has a crack or are they repairable?
'86 DG, Weber Carb
- itchyfeet
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Re: 300CE WBX Repair
A cracked head is toast but don't assume its cracked, if you have a compression seal leak, when you stop the engine sometimes the valves will be open and steam will get into the inlet, an indication perhaps that this is the one with the leak?
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Re: 300CE WBX Repair
Aah, I see, cheers Paul - so in essence, it’s the clean one may be the leaky one! Will update with some pics once the heads are off for further info!
'86 DG, Weber Carb
- itchyfeet
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Re: 300CE WBX Repair
This was a leaky compression seal, this is what you may find, you can see the discoloration at the top of the barrel sealing surface and the damage to the bore surface caused by water entering.
https://flic.kr/p/VVju6q" onclick="window.open(this.href);return false;
https://flic.kr/p/VVju6q" onclick="window.open(this.href);return false;
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Re: 300CE WBX Repair
That does look a bit of a state - in the event it is like that, is it worth just replacing that one barrel/piston?
'86 DG, Weber Carb
- itchyfeet
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Re: 300CE WBX Repair
lets wait and see
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Re: 300CE WBX Repair
OK - started to take off and strip down the heads today. No drama's getting them off:
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Seem to have located the source of the problem - the o ring seals on two of the barrels (one on each side) were not sealing properly due to poor condition and probably down to there being no anti freeze being used previously at some point in it's life:
Barrel 1
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Barrel 2
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
All internals looked fine, with no heavy scoring or lips.
For now, cleaned up the heads and re-lapped the valves:
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
So, at the moment its looks as though i need two barrels and all will then be honed at my mates workplace. Piston's will also be removed as i'm going to replace the rings whilst everything's off.
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Seem to have located the source of the problem - the o ring seals on two of the barrels (one on each side) were not sealing properly due to poor condition and probably down to there being no anti freeze being used previously at some point in it's life:
Barrel 1
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Barrel 2
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
All internals looked fine, with no heavy scoring or lips.
For now, cleaned up the heads and re-lapped the valves:
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
Untitled by Justin C, on Flickr
So, at the moment its looks as though i need two barrels and all will then be honed at my mates workplace. Piston's will also be removed as i'm going to replace the rings whilst everything's off.
'86 DG, Weber Carb
- itchyfeet
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Re: 300CE WBX Repair
The bad sealing you have shown is not compression seals but when the green o rings fail it allows coolant to get to the compression seals and degrade them.
worth inspecting the barrel top sealing surface and the head sealing surface in detail
also worth lapping the barrels into the heads with fine grinding paste.
worth inspecting the barrel top sealing surface and the head sealing surface in detail
also worth lapping the barrels into the heads with fine grinding paste.
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Re: 300CE WBX Repair
itchyfeet wrote:The bad sealing you have shown is not compression seals but when the green o rings fail it allows coolant to get to the compression seals and degrade them.
worth inspecting the barrel top sealing surface and the head sealing surface in detail
also worth lapping the barrels into the heads with fine grinding paste.
Cheers Paul - do you think that the o ring failure could have been the cause of the problem? The more I think about it, the more I reckon it’s worth going for a set of new barrels and so I’ve gone for it and purchased some
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- itchyfeet
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Re: 300CE WBX Repair
Personally I'd change rings too for the brickwerks KS ones, I know it's more money but piece of mind
https://www.brickwerks.co.uk/piston-rin ... dh-cu.html" onclick="window.open(this.href);return false;
https://www.brickwerks.co.uk/piston-rin ... dh-cu.html" onclick="window.open(this.href);return false;
- itchyfeet
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Re: 300CE WBX Repair
your cooling system was pressurising right?
You don't get a compression leak from the failed O rings, it comes from a failed compression seal ( the metal rings)
the cooling system works at 1 bar the engine makes 9-12bar so if the metal rings have failed even a good oring won't hold 9-12 bar
the o rings are just there to keep coolant away from the compression seal.
that scratch on the right hand cylinder may well be what caused the failure.
You don't get a compression leak from the failed O rings, it comes from a failed compression seal ( the metal rings)
the cooling system works at 1 bar the engine makes 9-12bar so if the metal rings have failed even a good oring won't hold 9-12 bar
the o rings are just there to keep coolant away from the compression seal.
that scratch on the right hand cylinder may well be what caused the failure.