ariel 500 pistons

[mark2]

Just building a spare Ariel motor, when did Ariel change to the split type of piston shown here? The none split one is the one I’ve removed from the motor \
\

[iansoady]

Dunno about Ariels, but Norton Commandos were fitted with the split type for a while and were notorious for dismantling themselves along the horizontal slot just below the oil ring land.

I believe the vertical split was intended to reduce piston slap.

[chaterlea25]

Hi,
I dont know if they changed form solid to split or was it an alternative used on different models?
The split skirt piston runs a much tighter bore clearance, 0.001 - 0.003in
I have an all alloy Ariel HT5 and the trials 5.5:1 piston had a split skirt, current 6.5 is split as well
I have seen theas crack but not disentigrate
I have come across solid skirt high comp pistons, HS maybe ?

Cheers
John

[mark2]

thanks motors back together now , split at the rear im told , will see if I ever have to use it if it fails ,

[iansoady]

I thought the split was at the front as on the firing stroke the reaction from the combustion pressure acts on the rear of the piston / bore. I can't find a reference for this though.

[mini-me]

yes split at the front, time to repeat the exercise?
and if here are any valve cutaways inthe top of the piston, they may well be of different sizes.

from the looks of the scuffing on the other piston, if I were you I'd review my choice of oil used.

[that does not mean I am trying to start or get involved in the great wotoil debate.]

[mark2]

 split to the front it’s in dragonfly’s literature on line ) id put a note on the engine incase I ever used it that the pistons the wrong way round but it might fall off over time so will turn it back round now, good thing it’s not that big a job, still wasted time when I could be doing what the wife tells me to do. The old piston has done a few thousand fast for a ariel miles so im not about to change oils (I use 20/50) no cut aways

[mini-me]

old piston has done a few thousand fast for a ariel miles

and a few slow rattley ones from the look of that lock up scuff?

I speak from experience.

[mark2]

its never locked up to date touch wood , but it does look like its got very close , I have seen some with extra oil being feed to the rear of the cylinder but only when used on the track , I must stop trying to keep up with my mates they ride triumph twins

[mini-me]

Always ride well behind Triumph riders when out on a run, the bits that drop off them pay for your petrol if you bung them on ebay.

I have had pistons like that as long as rings aren't stuck but they'll always run if a bit rattley.
For myself I am a great believer in the oil grade I've always used and Filtrate  Colloidal graphite when you could get it, I am half way down my very last Gallon tin of it.

Also in a well run in  motor STP works well for me, whether its snake oil or not.

[iansoady]

Also in a well run in  motor STP works well for me, whether its snake oil or not.

But unless you do a true double blind trial you never know if it's working or not.

[mini-me]

I am a suck and see type.

Back in the late 1970s I used to trek backwards and forwards to Barcelona in an old  Ford Thames 15cwt van, 3 speed box and all.
I fitted it with Cord rings, and ran it on straight 50 [I got it cheap] and STP.

It had two big batteries for starting on cold mornings in the Pyrenees in October once running warmly and  ticking  you couldn't hear a thing, had to keep blipping the throttle in traffic hold ups to ensure it was till running.

I can't prove anything either way, but it never siezed......... .
I still miss that van.

[mark2]

http://www.ebay.co.uk/itm/750-ml-Colloidal-graphite-in-oil-/261999598003?hash=item3d006499b3

[wink]

I built a VW beach Buggy in 1985 to take to Spain in 1990. did 16000 miles in UK during which time I had to rebuild the 1600 cc motor with Cord Rings and ran it on straight 50 same as in my classic bikes, Norton 19S. Triumph twins BSA singles. In UK it needed a good battery to start in winter, in Spain no problem, Only changed the oil once in 24 years, never used a drop. Sold it at Easter this year to a poser, he´s very happy.
I´ve still got fathers 350 Bullet engined Lambretta running on straight 50 and got about 3 gallons left. I´ve got bad arthritis and can´t work the levers on a bike or get in and out of the buggy so everything has to go.

[mark2]

I still have a beetle but sold my van , run them both on straight 30 , they are a good motor