Ethanol, Timing, Tuning, etc

[HinFL]

I am a relatively recent convert to the Series Rover brotherhood and am about to tackle the timing/tuning of my 1973 Series III NAS 2.25 petrol for my first time. To the best of my knowledge it is a 3-bearing, 8:1 compression engine that has never had the no-lead head conversion (i.e. has the original head) and it has a Weber 34ICH carb.

I have read the threads regarding timing by ear and timing by beer, but also may try my hand with the strobe. I have also seen the figures in the green bible for different octane fuels. I've been running unleaded premium in her, but would rather not unless it's necessary. I guess that makes a difference with the timing values. My question is: with fuel nowadays containing up to 10% ethanol, does that change those figures? I assume that the ear and beer methods are unchanged, but what about the green bible's values?

One more point (pun intended) of information. A mechanic friend installed and timed a Pertronix electronic distributor and coil a while ago. I hope this won't become a referendum on the wisdom (or lack thereof) of doing so; just wanted to mention no points to gap or deal with.

I am very grateful for all the knowledge I've gleaned from other threads regarding getting the timing correct before adjusting the carb, etc. Any other advice for this new guy who is by no means an experienced wrench would be greatly appreciated. Thanks in advance (pun intended).

[LaneRover]

Unleaded premium is not need by any means in a series Rover as these are designed to run on 3rd world fuel. The petrornix does take a bit of the work out of timing some love them some avoid electronic ignition like the plague.

Others on this forum know much more about the effects of ethanal on seals, diaphragms and so on.

Where are you in NE Florida? I just moved to the Jacksonville area

[HinFL]

Hi LaneRover and thanks for your input. It's funny, but just this morning I saw in the "What did you do to your Rover today" thread your Rover on the flatbed in SD headed across the country. Welcome to the area. I'm in Fernandina Beach, as far northeast as you can go in Florida without venturing into Georgia.

I'm sure you are much more adept at Series Rover maintenance than I, but wanted to mention that James at British 4X4 is the mechanic I spoke of earlier. His shop is on/near St Johns Bluff and he's been a great help to me as a newbie.

I saw another forum guy is in Hilliard; more of us in this area than I thought... Where in Maine for you? We just got home from Vinalhaven a couple of weeks ago.

[jac04]

Ethanol has a higher octane rating, but I don't think that will come into play with timing because the fuel octane rating remains at the pump stated value. Ethanol blend fuels have a lower energy content by volume, so you may need to adjust idle & main jets as well as the accelerator circuit to allow for higher fuel flow.

[Nium]

Octane means "detonation resistant" so the higher the octane rating the more detonation resistant the fuel. As previously stated Landy's will get the most bang for the buck using the lowest octane fuel you can find. Premium (92 octane for example) will not give better mpg.

Higher octane fuels require the timing to be more advanced then lower octane fuels. That's why the lower the octane the closer to TDC the timing is usually set because it explodes faster.

I've wondered which octane rating the Green Bible was originally written for because in England the octane rating is RON which has higher numbers for the same PON rating (which is in use in the US). So setting the timing to the octane rating in the Green Bible maybe incorrect becasue is it in RON or PON? It will at least get you close to the correct timing then you just have to tweak it by ear, beer, or whatever till it's spot on. If you are getting pinking the timing is to advanced.

[LaneRover]

Hi LaneRover and thanks for your input. It's funny, but just this morning I saw in the "What did you do to your Rover today" thread your Rover on the flatbed in SD headed across the country. Welcome to the area. I'm in Fernandina Beach, as far northeast as you can go in Florida without venturing into Georgia.

I'm sure you are much more adept at Series Rover maintenance than I, but wanted to mention that James at British 4X4 is the mechanic I spoke of earlier. His shop is on/near St Johns Bluff and he's been a great help to me as a newbie.

I saw another forum guy is in Hilliard; more of us in this area than I thought... Where in Maine for you? We just got home from Vinalhaven a couple of weeks ago.

Maybe slightly more adept, slightly - when I get around to doing it. The 109 is here in Jacksonville now and I have to figure out why it isn't charging. This is a truck I had someone else restore (it was in Maine, I was in SoCal) and when the generator went Ted put in a alternator but retained the original voltage regulator, a bit strange but for years it worked perfectly.

Ocean Park Maine is where I spend time when I head up there. My 88 is kept at my Mom's and I have a few other Rover's on some property in Old Orchard.

I may have to check out British 4X4, though I can do quite a bit there are times when my work takes me away and it is nice to come back and have something else already done!

Brent

[gudjeon]

I ran an 8:1 at 6 degrees BTDC with no problems on regular fuel. Ethanol lowers fuel's boiling point somewhat, especially at altitudes. Not an issue with modern high pressure fuel injection, but is an issue with open atmospheric system like carbs. I went to electric pump with recirculating filter like 80's Chrysler spec. No more prob's.:thumb-up:

[HinFL]

Thanks to all who have given input so far. I just looked at Section 17 of the Green Bible that covers emission-controlled engines (my 1973 North American Spec engine has most of the devices) and it says set dynamic timing to 6° ATDC with no mention of fuel octane.


_° BTDC, TDC, 6° ATDC. Now I'm REALLY confused. Am I missing something? Or should I just do the ear and/or beer methods and not be concerned with timing indices? Please remember that I'm new at this and don't assume that I know what I'm doing.

[Donnie]

Thanks to all who have given input so far. I just looked at Section 17 of the Green Bible that covers emission-controlled engines (my 1973 North American Spec engine has most of the devices) and it says set dynamic timing to 6° ATDC with no mention of fuel octane.


_° BTDC, TDC, 6° ATDC. Now I'm REALLY confused. Am I missing something? Or should I just do the ear and/or beer methods and not be concerned with timing indices? Please remember that I'm new at this and don't assume that I know what I'm doing.

I time by ear or with a vaccuunm gauge. By ear , you are taking into all the above mentioned concerns: all the alcohols, worn rings, comp, timing chain wear. carb float leval etc. etc.. Just bring the engine speed up to the rpm's that you drive at the most, if U have a vac. tool use it . if not hold the speed constant & dial the dist back & forth until U R at the best operating feel.. Valve ping or hard start cranking indicates that U R 2 far advanced.....Timing light does not consider any of the above wear factors or fuel mix.
poor perf. indicates that you R 2 retarded.. a retarded timed engine will run hotter too,
as the spark is firing too late & heating the cyl walls

[73series88]

To much thought.
you guys are making my head hurt.
aaron

drive and enjoy!