New Series III Owner-High Altitude Running

[knac1234]

Hello all,

First post on this BBS :thumb-up:

I purchased a 72 SIII a few weeks ago in pretty good original shape. Mechanically, it is sound, with about 8K miles on the engine, trans, carb, radiator, exhaust.....etc....

It came from about 1000 ft altitude, and now lives in Colorado at 9100 ft altitude. It started and idled fine, but (not expecting a rocket), foot to the floor acceleration was not great.

I figured the jetting on the carb and maybe the timing, so here is what I have done:

-checked the dizzy, which I found to be converted to electronic ignition.....then set the timing to about 12 BTDC
-checked the plugs, which were a nice color, but the gap was a bit off (my .034 guage could easily fit in the gap), so I regapped to factory specs using my .030 guage
-cleaned and refilled the oil bath filter
-jet-wise, Pierce Manifolds seemed very knowledgeable, and suggested a one step down idle jet (50 to a 45); from my main jet of 165 to either a 155 or 160; and an increase in the air correction jet from (I think) 190 to 200

It fires right up, even in the very cold weather we are having, and idles well. I think the acceleration is better, but perhaps I leaned it out a hair too much, so I might try the 160 main instead of the 155 I went straight to.

So, at 9100 ft altitude with a Weber ICH on a petrol 2.25, does my route taken seem sound? Timing right, or a bit more advance? Seems a few people at altitude are using 12 BTDC, but I have heard other variations....including a degree of advance for every 1000' above sea level, which running premium gas, theoretically puts me at 6 BTDC per the manual PLUS an extra 9 degrees to 15 BTDC. Concerned about pinging there.

Thanks for any thoughts....

Julian

[LaneRover]

Welcome to Rover ownership and welcome to the BB!

I think you are headed in the right direction. Not sure about timing. I know that when I went changing jets I found that some of the off-road places that in San Diego deal with dune buggies were very helpful. If you can't find anyone else who can help with the differences for a Rover locally maybe find a local old VW place that may have a guy that is familiar with the differences.

Brent

[knac1234]

Thanks Brent,

I lucked out I think with Pierce Manifolds. They specialize in Webers, and have 2 tech guys on staff. The one I spoke to was most helpful, and was very familiar with the Series Rover, as he had one that he regretted selling!!!


Julian

[meatblanket]

FYI, I'm in Golden and was running a 155 main jet in my Weber 34ICH. It was running too rich at higher elevations with the 155, so I'd be surprised if you aren't getting black smoke and sooted plugs at your elevation with the 160 jet.

You are on the right track advancing your timing. I can't recall off hand where mine was, but it's a lot more advance than you would think. I never had problems with pinging. With too much advance you may experience engine "dieseling" and continuing to run after you shut it off.

Have you had any vapor lock issues yet? ;)

[knac1234]

Thanks meatblanket-

No vapor lock issues, but if I do I will pop an electric fuel pump on it near the tank.

That's interesting regarding your 155 jet and a still too rich condition in Golden, which is lower than me (Divide). Perhaps I should get a couple more jets below the 155 and try those also (they did call it tuning by your wallet!).

Thanks,
Julian

[meatblanket]

To clarify, the 155 jet worked fine in Golden, and was only too rich at higher elevations, i.e., 10,000 feet and higher. For general use on the Front Range, the 155 is probably the right jet.

The electric fuel pump will probably be in your future, that's what I did after being repeatedly frustrated with vapor lock. :thumb-up:

[knac1234]

Thanks....

To clarify also, I am running the 155 jet currently. Originally, when the Rover came from Indiana, it was running a 165 jet. Pierce Manifolds recommended getting the next 2 sizes down.....I have only run the 155 at this point.....not the 160.

I'll be running it between Co Springs (6000 ft) and Divide (9200 ft). So, maybe the 155 is right that I'm using, or maybe a 150 is worth a shot? Would think a 145 to be too small.

Regarding the electric pump, if needed, I happen to have one I bought as a backup for my MGB and Hillman. Only used it once to siphon fuel out of a tank :D

Regards,
Julian

[meatblanket]

I'd probably leave the 155 in, unless you are seeing black smoke in Divide.

Ideally, you'd pull over at Woodland Park and change your jets. Just kidding. But EFI is a boon in Colorado.

[knac1234]

Well, this weekend, maybe I will play with the timing a bit more. Maybe a bit more advance? Might throw in the 160 jet just for the heck of it to see what happens (only takes 10 minutes to swap them).

EFI would be good! The ATV I bought up here even has EFI....for the very reason you mentionned!

Julian