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Conquest Century core plugs

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David Williamson
Posts: 8
Joined: Mon Feb 15, 2016 10:41 am

Conquest Century core plugs

Post by David Williamson » Sun Apr 14, 2019 6:45 pm

Good evening all,
I've just had my Conquest Drophead radiator recored and the water pump refurbished and have all fitted back in the car. Apart from the difficulties of working with a mirror, all went smoothly! It does appear to sorted out a minor overheating problem with a nice steady temperature up and down hills!
Unfortunately I have now discovered that a core plug is leaking. It is below the carburettors and can only be seen from below. I am hoping to change this by removing the carburettors and again working with a mirror. Has anyone done this in the car and has any advice?
David

Crossley Stephenson
Posts: 232
Joined: Wed Feb 10, 2016 9:15 pm
Location: Victoria, Australia

Re: Conquest Century core plugs

Post by Crossley Stephenson » Mon Apr 15, 2019 1:39 am

David,
I had a look this am and it looks like it is possible to replace the core plugs with the engine in situ but it will be fiddly and require a mirror and some dexterity. Easier with the manifolds off, in fact a couple of the core plugs probably can't be replaced without removal of the manifolds. I replaced a core plug on my Special Sports last year, luckily the rearmost one, and it was fiddly but did require removal of the inlet manifold.
Good luck,
Michael

David Williamson
Posts: 8
Joined: Mon Feb 15, 2016 10:41 am

Re: Conquest Century core plugs

Post by David Williamson » Mon Apr 15, 2019 11:59 am

Crossley,

Thanks for your advice - much appreciated!

regards

David

pekkak
Posts: 24
Joined: Fri May 13, 2016 7:26 am
Location: Espoo, Suomi - Finland

Re: Conquest Century core plugs

Post by pekkak » Fri May 03, 2019 4:36 am

David,
If you could remove the cyl.head, try to flush cylinder jackets. Protect components at engine sides, carefully protect all cylinder tops. Maybe some some other areas in the engine bay too. Connect small diameter metal pipe to a garden hose. Remove cylinder and manifold drain taps. Place the metal pipe to water ports. Do not let the hose run with full power. Flush cylinder jackets from all six water ports. I used also compressed air. Then dry places with plenty of tissue paper or similar.
This is more like a horse doctor method but I was was mazed how much silt came off. Specially around cylinders 5 and 6. Engine is cooling better now.
Best wishes!
Pekka

David Williamson
Posts: 8
Joined: Mon Feb 15, 2016 10:41 am

Re: Conquest Century core plugs

Post by David Williamson » Tue May 07, 2019 5:26 pm

Thanks everyone for your advice.
I did not want to disturb the cylinder head as the car has been running very well apart from getting hot in traffic. I was able to replace the offending core plug using a mirror and feel, as it was out of sight even with the carbs off. On a quick test run, everything seems to be well and I am hopeful that the recored radiator will have resolved the overheating issue. It is possible that some silt remains at the base of the block, but as the cooling liquid has always been clean (at least in the 11 years I have owned the car) and it used to run reasonably cool most of the time, I believe the radiator should be sufficient.
regards
David

pekkak
Posts: 24
Joined: Fri May 13, 2016 7:26 am
Location: Espoo, Suomi - Finland

Re: Conquest Century core plugs

Post by pekkak » Tue May 07, 2019 8:45 pm

Sure David. However quite a lot silt remains in the base of the block because particles are "heavy" and I belive they tend to pack around cyl. 5 and 6. . I recon I managed to flush almost all out. Only once I had an overheating situation. It happened when I had to turn my DJ251 around in a very tight spot. Plenty of low revs and extremely limited airflow with fan blades only. After clearing the situation she sputtered a little. Then the air flow and higher revs of the water pump began to cool cooling liquid again. I learned to avoid tight spots but sometimes you must drive there.
Good luck!
Pekka

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