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Messages - Ron Hollis

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And Finally,

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Hi Chris,
            More photos

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Hi Chris,
            I have a neglected flat screen Ace hardtop. At the screen there are three cleverly braised brackets that slide in the screen groove and have a holed flange. At the front of the hardtop there are three corresponding angle brackets bonded to the fibreglass. At the side there are angle brackets that align with the hood stick anchors. At the rear there is an angle bracket screwed to the fibreglass incorporating two holes that align with the central hood "lift the dot" fasteners. It all looks a bit Heath Robinson, see attached motley photos, so may or not be AC; the top is at least 50 years old, sidescreens are AC so it probably is.
 Trust that this isn't confusing
Regards
              Ron   

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Ace, Aceca & Greyhound Forum / Re: Bristol pushrod problems
« on: May 03, 2020, 14:56:29 »
For the record; I removed the head and sure enough it was a sticking valve. No. 1 exhaust guide was cracked at it's tapered end; it looks as though products of poor combustion had been accumulating on the guide, occasionally stopping the valve closing and cracking the guide. A check showed the same on number 4. Based on advice from historic racer, new guides fitted, shorter and without taper and ignition being checked to explain poor combustion.

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I fitted these Weber carbs to my 100D2 engine in 1985, to replace the leaking and worn standard Solex units. They were supplied by Chris Montague Carbs, set for Bristol engines. They bolted straight on using the standard Vokes air filter, fuel connections had to be modified. I recall there were some initial jetting problems and I got advice from Barrie Bird. Since then they have been fine. I still have the bill for the changed jets but unfortunately not the exact description. Barry may still be able to help.

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Ace, Aceca & Greyhound Forum / Re: Bristol pushrod problems
« on: December 29, 2019, 21:14:37 »
Hi Tony,
Thanks for your interest and warnings. No stem seals are fitted. New standard valves and guides were fitted, but this doesn't preclude insufficient clearance. On removing the pushrod an oily/aluminium deposit was apparent around the pushrod head at the valve end. This could be the result of the rod rubbing on the sleeve over time. I don't think it would have occurred after the rod fell, as the rod would immediately stop moving. I am presently investigating the sleeve.         

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Ace, Aceca & Greyhound Forum / Re: Bristol pushrod problems
« on: December 03, 2019, 17:23:15 »
Thanks for the interest and speculation.
Carburettors are the only modification  from standard 100D2 spec.
Camshaft was checked and fine at time of head overhaul and springs were tested. Inspection now shows springs ok. Problem happened at a modest 3500 rpm. so bounce should be relevant
Valve clearances were checked less than 1000 miles ago and are standard at 2 thou. cold. My Bristol Engine Manual states that this will result in a running clearance of 8 thou. So more likely to drop out when hot.
Nick Finberg from Classic Autos has never heard of it either. 

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Ace, Aceca & Greyhound Forum / Bristol pushrod problems
« on: December 02, 2019, 19:35:32 »
Last year the horizontal pushrod on number 1 exhaust fell out? and got bent. On inspection with a replacement rod, I noticed that the rod on the exhaust side, was virtually in contact with the aluminium sleeve and there was a witness mark on the bent rod at this point (which obviously could have occurred after it fell out). The rocker sat central on the valve stem, so that was in the correct position. I did have the head rebuilt about 5,000 miles ago with new valves, guides etc; one job was swaging the sleeves firmly into the rocker covers, so this could have brought the sleeve nearer the rod. Looking at the other rods most are not central in the sleeve due to casting tolerances. Because of the head rebuild I thought a sticking valve unlikely and compression is fine; so made a shim washer for the rocker shaft to move the rocker further from the sleeve (20 thou. thick). Sorted I thought.
Today it happened again, same valve. Before I take the head off is there any useful experience out there?

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Ace, Aceca & Greyhound Forum / Re: Ace Bristol Electric Fuel Pump
« on: December 02, 2019, 17:47:39 »
Apologies for the delayed conclusion. The solution was to refit the original mechanical pump and retain the LP electric pump mounted in the engine bay on the passengers footwell bulkhead. The LP pump primes the osystem ok and the two together satisfy the engine in road use without flooding. Thanks for your advice.
 

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Ace, Aceca & Greyhound Forum / Re: Ace Bristol Electric Fuel Pump
« on: February 20, 2019, 21:09:26 »
Hi TTM,
Don't know and tricky to establish, I would have to turn engine/pump off as it cut to 4 cylinders and expose the three float chambers, roads too busy round here. My engine has Weber carbs and float levels are as makers settings.
I ditched the old pump when Burlen's seemed confident. Now they are understandably reluctant to be specific on a pump for an engine that didn't have one originally; that's why I tried the forum.
Their high pressure AUA25 has a lower duty (7gph), so not encouraging.
Burlen's data is also confusing, giving the duty of AZX1332 as 15gph in their duty schedule (technical section) and 7gph on the sales page. In a mail they confirmed it as 7gph. It would be interesting to know if Keith's engine runs on the electric pump or if he just uses it as a primer like you.

Thanks for your interest.             

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Ace, Aceca & Greyhound Forum / Re: Ace Bristol Electric Fuel Pump
« on: February 18, 2019, 15:43:52 »
hi TTM, thanks for the explanation and your interest.
symptoms are- under acceleration, say on a long uphill (only because this is more convenient than running at high speed) after say 20 secs the engine cuts to four cylinders, we then potter for a short period whilst the affected float chamber refills and return to six. I have checked tank intake, renewed and enlarged the fuel line, replaced/cleaned all filters in line and carbs and checked needle valves/floats in carbs. A flow check to an open end at the carbs gave a flow of 7.5 gallons/Hr; this would reduce if flow was through  the needle valves.   

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Ace, Aceca & Greyhound Forum / Re: Ace Bristol Electric Fuel Pump
« on: February 17, 2019, 17:53:10 »
Keith, Thanks for the information and tips. Some motorsport cronies suggested Facet pumps but they only seem to be available with negative earth.

Hi TTM thanks for your reply. Burlen's suggested AUA25LP which they say was standard on the Aston DB2/4, mounted under bonnet. if you run with the electric pump off then it must become a restriction in the line, which the mechanical pump presumably overcomes.

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Ace, Aceca & Greyhound Forum / Ace Bristol Electric Fuel Pump
« on: February 15, 2019, 21:57:11 »
My car ran perfectly for decades on a nondescript SU pump mounted under the bonnet, instead of the original mechanical unit. It recently gave up the ghost. With no part number I replaced it with one suggested by Burlen Services. This is inadequate. Does anyone else have this configuration and could advise a pump specification?

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