Can anyone suggest a timing setting for an unleaded 1600 crossflow?
My Haynes manual only speaks leaded...
cheers,
David
David,
I'm assuming that the engine now has hardened valve seats etc to make it an unleaded engine.
If that's the case will the standard timing not be satisfactory/appropriate given that the (and this is my understanding) timing adjustments made
to a "lead" engine running unleaded fuel engine are so it burns cooler.
Or is this what you were thinking, and wanting someone else to confirm:-)
ATB
Simon
First - yes, I do have hardened valve seats!
Second - I thought that unleaded has a lower RON value than 4-star, so the timing has to be set back a bit (or should I just use premium unleaded?)
David
Buy some octane booster and put that in your tank. Millers or similar, it works in pintos, definite improvement on unleaded fuel.
yours, Pete.
That's not for me, Pete... the reason I had hardened valve seats fitted was to keep things simple - I can just fill it at any petrol station,
with no additives, or LRP, or whatever.
The reason for my original question was that cars timed for leaded petrol tend to pink when using unleaded. I probably need to come back 1 or 2
degrees, but I'd like a starting point to start off with (literally!).
cheers,
David
definatley dont just use plain unleaded
as the octane rating will result in destroyed pistons in less than 1000 miles
(experience) use super or an octane booster.
Tim
I guess that's why you have to set the timing back a bit - to stop knocking/pinking on a lower octane fuel.
DJ
David, there isnt really a hard and fast figure. The timing depends on soooo much, compression ratio, different carbs, cam, exhaust etc, etc. I would
suggest that 3 to 5 deg less advance than Mr Haynes states initially, and save yer pennys for a rolling road sesh.
HTH Stu.
Backing up what Stu said, I have just checked out my Data Manuals, all the HCS/OHV kent type engines are backed off by 4 degrees when using 95 RON unleaded
Many thanks, Mark & Stu! Sort of what I expected...
DJ