RT 8431

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Ronald
Posts: 327
Joined: Sun Nov 26, 2006 10:05 pm
Location: Dorset.........

Re: RT 8431

Post by Ronald »

Andrew, first up, welcome to the VMR..........:)

With regard to the lack of compression, bearing in mind that the engine has basically sat for a very long time, it is certain that the bores will be very 'dry' for want of a better word, i would strongly advise before removing the head or pistons, to put a teaspoon full of oil, or a few squirts down each bore, and turn the engine over several times with no spark plugs in it, you may have no compression simply because no oil is there to actually seal the rings!!

It goes without saying that you should use 'new' petrol, as petrol loses its octane over time, so any old fuel should be discarded, well, not literally, but i'm sure you know what i mean.....

Also, as stated, retard the ignition fully, its amazing what difference it'll make to the ease of turning it over, especially by hand!!
Last edited by Ronald on Thu Nov 04, 2010 9:14 pm, edited 1 time in total.
ian judd
Posts: 176
Joined: Tue Jan 08, 2008 6:01 pm

Re: RT 8431

Post by ian judd »

Andrew,
I'm with Ronald here. Taking the thing apart really should be the last resort and only done after it has been running for a while and properly warmed up. Compression problems generally sort themselves out with plenty of oil down the bores and a warm engine. Do as Ronald says, and fill the radiator with hot water if pos. A desertspoon of oil in each bore will work wonders for starting although a bit smokey to begin with.Check the cam is in the right place - it's easy to get it wrong. Once it's running you will be able to use a compression tester - with oil seal and without.
Lying under the car trying to get pistons back in is difficult to say the least and not recommended - the rings are the problem. .....and you will get oil in your hair and eyes!

Good luck,
Ian
RLucke
Posts: 20
Joined: Tue Nov 21, 2006 3:13 pm
Location: Cambridge

Re: RT 8431

Post by RLucke »

I had a vintage motorcycle which had not run for many years, and would not start. Having checked the ignition and valve timing, I put a teaspoon of petrol in the plug hole and it started for the first time in 40 years. Once it had run, it was not a problem in future.

Roger.
Roger Lucke
Toby
Posts: 1017
Joined: Tue Jan 09, 2007 4:49 pm
Location: New Forest

Re: RT 8431

Post by Toby »

slightly off subject, but, all this talk of easy start etc reminds me of a little benford tip up mixer i owned with wrap round starter pull rope. when cold it only started by putting lighter fuel in the plug hole. once warm it was fine. my brother and i disconnected the governor and ran it flat out to see if we could kill it but we gave up in the end! We redexed it too and that didn't help but did fill the clients house with smoke :lol:
if it's got wheels or chips - it'll cost you dear
mowersman
Posts: 66
Joined: Mon Nov 01, 2010 8:43 pm

Re: RT 8431

Post by mowersman »

Well, had it going for about 5 seconds tonight, but just wouldn't keep running. I think the carb is the problem, the plunger is quite stiff when fitted, but slides nicely when removed. I think a spare carb may be the way to go as the pivot for the mixture lever has been broken off a some point as well. Are bits for the carb available?
Thanks
Andrew
RLucke
Posts: 20
Joined: Tue Nov 21, 2006 3:13 pm
Location: Cambridge

Re: RT 8431

Post by RLucke »

Hi Andrew.
Yes, all the parts are available from Burlen fuel systems at http://www.sucarb.co.uk/, although I think the problem with the carb piston sticking could be one of incorrect assembly.

Regards. Roger.
Roger Lucke
Trevor Wilkinson
Posts: 161
Joined: Sat Dec 02, 2006 4:44 pm
Location: Bedfordshire UK

Re: RT 8431

Post by Trevor Wilkinson »

Sounds like you need to centralise the jet. :idea:
Ronald
Posts: 327
Joined: Sun Nov 26, 2006 10:05 pm
Location: Dorset.........

Re: RT 8431

Post by Ronald »

Try leaving the two screws on the side loose, it might aid the plunger moving, at least it might show up what the fault might be.........

Did you try the oil in the bore trick...??????
mowersman
Posts: 66
Joined: Mon Nov 01, 2010 8:43 pm

Re: RT 8431

Post by mowersman »

If I loosen the screws, it moves a little more freely, but still wont return to the base position. I tried the oil in the bores and it made a great difference. It fired pretty much immediately. However I'm worried that that there is something seriously wrong with the engine. It is very very stiff to turn over. To start with I assumed that it was just slightly stiff, from not having been run since the rebuild, but it doesn't seem to be getting any easier to turn over, if any thing, even tighter. Am I best to have the sump off and investigate as I don't want to damage the engine if and when it starts.
Thanks
Andrew
Ian Grace
Site Admin
Posts: 5035
Joined: Sun Nov 19, 2006 12:55 am
Location: USA

Re: RT 8431

Post by Ian Grace »

Have you nhad the engine running long enough to thoroughly warm it? I'm thinking if it is stiff it is more likely to be the pistons than the big ends or mains.

It would be worth getting an oil pressure gauge on there and seeing if it is normal.

These come up quite often on eBay but there isn't one at present of the correct type on offer, but there is this one:

http://cgi.ebay.co.uk/Old-Smiths-oil-pr ... 230b842d16

This would do the job and you could replace it at your leisure. But it would give you a good indication as to what is going on inside.
Ronald
Posts: 327
Joined: Sun Nov 26, 2006 10:05 pm
Location: Dorset.........

Re: RT 8431

Post by Ronald »

Andrew, if the engine is that stiff, what about removing the plugs, and towing it in gear around a field a few times, or up and down a farm track if you have one..... that would rotate the internals without the loading of combustion..... then see if it feels any easier to turn over, it is fair to say that when 'new' they are quite tight, its not until they've done several hundred miles that they start to free up.... and that is along with plenty of warmth...... running for a few seconds won;t do much at-all...... you do however as Ian says NEED an oil pressure gauge..... as none will ruin whta might be a perfectly good engine
The engine in My car has only done a few hundred miles since full rebuild, and everytime i run it and drive it, it feels better and better.... it felt horrible and gutless the first few times i drove it..... all i could see was wasted money.... but thankfully its getting better all the time....

Ronald.
mowersman
Posts: 66
Joined: Mon Nov 01, 2010 8:43 pm

Re: RT 8431

Post by mowersman »

Ok, I will get a Pressure guage sorted at the weekend, I might nick the one off our tractor for the time being. As for getting a permanent one, all the ones I seem to be able to find, including the one Ian linked to, are 2" in diameter. Does anyone know where I can get a period looking (not too worried about it being original) one that is 1 5/8" diameter.
Thanks
Andrew
Ian Grace
Site Admin
Posts: 5035
Joined: Sun Nov 19, 2006 12:55 am
Location: USA

Re: RT 8431

Post by Ian Grace »

Here's the correct one for the SV Minor - 42 mm Eureka:

http://cgi.ebay.co.uk/Austin-Morris-Cus ... 3f049e1df8
mowersman
Posts: 66
Joined: Mon Nov 01, 2010 8:43 pm

Re: RT 8431

Post by mowersman »

Brilliant, thanks
Not quite sure how I missed it, I've searched a couple of times on eBay and only found 2" ones
Andrew
Highlander
Posts: 489
Joined: Fri Nov 24, 2006 12:52 am

Re: RT 8431

Post by Highlander »

Have found a couple of prop shaft couplings. I might have an oil guage. Give me your address or phone 0208 393 6732 (Epsom, Surrey) Highlander.
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