918 Side Valve help

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BigBraveDave
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918 Side Valve help

Postby BigBraveDave » Sun Apr 16, 2017 5:05 pm

Hello,
I'm new to this forum and would like some help with my 1951 side valve, I understand the engine is under powered and back in the day the car could manage 63mph, however mine has had an engine rebuild and its top speed is 49mph on the flat, is this correct or should I be getting a bit more?? also on the hills the car is in first gear crawling up. the car has only done 1400 miles since the rebuild.
could there be an issue with the timing or carb set up? or is this the norm??
Thanks Dave
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alanworland
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Re: 918 Side Valve help

Postby alanworland » Sun Apr 16, 2017 5:44 pm

Hi fellow sidevalver!
Your right their not the quickest vehicle on the road but it would seem something is amiss as it should be better than that.
Worth checking timing and fuel mixture to ensure its not running weak and as it not done many miles since rebuild it will still be running in so treat it a bit careful for a few more hundred miles and see how it all beds in.
The little engine does have to work hard but it's quite a strong old beast, mines done about 85k since rebuild and I think runs quite well!

Alan
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RobThomas
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Re: 918 Side Valve help

Postby RobThomas » Sun Apr 16, 2017 5:50 pm

I can get 58mph on the flat in my bog-standard sidevalve with an engine rebuilt in 1953. 45000 miles on the clock.

Sure you have the right speedometer fitted?
Cardiff, UK

oliver90owner
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Re: 918 Side Valve help

Postby oliver90owner » Sun Apr 16, 2017 6:36 pm

Speedos are notoriously inaccurate. How are you determining the speed? If looking at the speedo it may easily be only 45mph.

'Hills' is also very subjective. Where do you live? Mountainous or 'fen' type hills?

If shallow hills and a true 49mph, there is something amiss. 1400 miles should have loosened it up a bit more than that!

What differential is fitted? Are the wheels/tyres still of original sizes?

Does it get to proper operational temperature? What colour are the plug electrodes after a good run? How was the timing set? Is the advance/retard mechanism working correctly? Have the valve clearances been checked/reset since the overhaul?

I would say it is not the norm, but would need more info/data before commenting further.

BigBraveDave
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Re: 918 Side Valve help

Postby BigBraveDave » Sun Apr 16, 2017 7:51 pm

Thanks for the comments,
I needed to know if this was the normal operating speeds of this engine or not, I've been out this afternoon adjusting the timing and fuel mixture, as the manual advises TDC and twelve turns of the flats on the adjustment nut on the carb, this has made a vast difference.
I reached a whopping "55mph" at half throttle on the motorway. I have an app on my phone for the speed can't trust the speedo. I was off the clock at that speed! I live in Wales and we do have the odd hill around here managed the same hill at 30mph today.
I believe with a bit more fettling and a feeler gauge I'll have the old girl skipping along.
Dave.
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colin addison
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Re: 918 Side Valve help

Postby colin addison » Wed Apr 19, 2017 7:35 pm

Hi
Pleased to hear about your MM.
I find your top speed not unreasonable, much depends on wind direction!!
Seriously, timing is critical, I find the smallest tap on the distributor can make all the difference. So find a convenient hill and persevere with small adjustments until you find the optimum. I have a steep uphill going into Maidstone and can normally get up it in second, with favourable wind I might make it in third. The real problem is the lengthy incline before the steepest bit, by then I am crawling!!
With the aforesaid favourable wind I might make an indicated 50-55ish on the flat.
But - persevere.
Colin


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