A mixture question

[Gfhug]

Layne, that’s impressive to kill off so many moles with just a quart. Or am I making a mountain out of a molehill?

Geoff

[christopher storey]

By design, it was quite normal for the XK engine to use oil at a rate of 200 miles per pint . Our memories have become clouded by the fact that 75 years have passed since the XK was new , and design clearances have narrowed radically in that time ( and of course lubricants have changed ) so that now it is a rarity for engines to need oil added between changes. I'm trying to think back to my piston engine flying days , but as I recall for engines of similar output to the XK, admittedly air cooled , we would add a quart most days where there was 3 or 4 hours flying .

Mole counsumption was a different matter

[mtnjag]

I almost went back and edited that but thought what the heck, good for a laugh.

I understand the oil consumption history. I was thinking back to another post here where there was great concern with that type of oil mileage (moleage) and ideas on what to do and how to correct it.

Anyway, I would still pull all the plugs rather than just one to check for fuel richness or, if concerned, oil use in the odd cylinder. One cylinder does not a diagnosis make.

[Phil P]

The time of fall of the piston from the dashpot would be done during reassembly of the carb before it is filled with oil. The Burlen web-site for SU carbs is I find good source of technical information. If each piston went back in the original dashpot and they haven't been abrasively cleaned, you shouldn't have a problem. The 5-7 seconds are from section 4 of the reassembly procedure on SU Burlen site -
http://sucarb.co.uk/technical-hd-type-c ... reassembly
Yours,
Phil

[JerryL770]

The time of fall of the piston from the dashpot would be done during reassembly of the carb before it is filled with oil. The Burlen web-site for SU carbs is I find good source of technical information. If each piston went back in the original dashpot and they haven't been abrasively cleaned, you shouldn't have a problem. The 5-7 seconds are from section 4 of the reassembly procedure on SU Burlen site -
http://sucarb.co.uk/technical-hd-type-c ... reassembly
Yours,
Phil

Thank you for that link Phil, very useful and further reading of the instructions informs on the type of oil to use and level of it in the dashpot damper. Excellent. Still waiting on DHL delivery from SNGB, now a day late

On the oil use question, I wanted to change from Castrol XL to Castrol GTX as back in the '70's I found a similar change in my well used Cooper S produced a significant improvement in oil consumption. Engines being from similar era's I hoped for a similar result. But I cannot buy GTX in 20litre "cans" so it becomes very expensive. Also I'm not sure of the currently available GTX blends really being suitable - the same as in the 70's.