the old 4 star / unleaded dilemma

PostPost by: RichC » Thu Mar 24, 2011 8:12 pm

Having run on 4 star up to now & having looked at the archives here I am thinking of using the shell optimax variety for a bit. Ipickup 4star in my red 20 litre gerry can .(I'll miss the smell of 4 star.)
probably won't do more than a thousand or so miles in the summer .
what's the general consensus folks? straight optimax ?
As I've the low compression head I'm not expecting to have to adjust the timing advance much & it isn't revved much at all
I gather that the valve seats are not that prone to recession and that in the states they,re quite happy using unleaded ...

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PostPost by: billwill » Thu Mar 24, 2011 11:18 pm

Ever since unleaded fuel became the norm, I found that unleaded plus the lead substitute from Redex, was a MUCH better fuel for my Elan than the crappy 4-star that was around.

I hadn't realised that you can still get anything called 4-star anywhere.
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PostPost by: worzel » Fri Mar 25, 2011 9:37 am

Hi

Why not just use TetraBoost- used with sensible precautions you can make genuine 5 star if you want. I've used it for years.

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PostPost by: kstrutt11 » Fri Mar 25, 2011 11:45 am

For many years now I have used regular 95 octane unleaded and an addative with no problems whatsoever
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PostPost by: 69S4 » Fri Mar 25, 2011 3:21 pm

kstrutt11 wrote:For many years now I have used regular 95 octane unleaded and an addative with no problems whatsoever


Same here. I've got the cylinder head off at the moment (still sorting water pump :oops: ) and a quick first inspection shows everything as it should be - no seat damage etc.

I've not had any problem with ignition advance either but that's because the replacement 43D distributor that was fitted years ago came with 7 degree advance weights. That makes 14 degrees of crank advance + 9 degrees static = 23 degrees total. The Stromberg engine should have 33 max (according to Wilkins) so it's not surprising really.

I thought it would be a simple task to change springs and weights to get it back to std but the http://www.distributordoctor.com/ didn't think it was possible (although I seems to have missed out on the reason why). If it really isn't maybe a file and a protractor may get me part of the way there. :lol:
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PostPost by: bcmc33 » Fri Mar 25, 2011 8:13 pm

Repeating what I've posted before - I use Tesco 99 octane stuff plus a dose of additive to make what I think is the 101 octane that the engine was designed for.
Never had a complaint.
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(1972 Sprint 5 EFI)

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