Another Plus 2 hits the road!

[stugilmour]

Just got the car through MOT this week. So far just taken it back from the shop and a quick scoot around the neighborhood.

Malcolm, my local Lotus tech, really did some magic on the tuning. It is FAR better than I recall from two years ago. The Pertronix II ignition installed well and seems to work. The non-stock SU's appear to be very well suited to the engine now. All trace of mid-range hesitation is gone. Did not require changing the needles from what the PO has installed. Malcolm did strip them down and address a bunch of minor stuff. Main problem appears to have been air leaks in the blanking plate for the removed Federal cross-over pipes, and subsequent rich settings to compensate.

Just getting used to the clutch take-up and the MT75 ratio's, but so far seem fine.

Kind of wondering if the tach is reading correctly, as it sure doesn't feel like it is spinning as fast as indicated. Wilkins book mentions RPM limit of 3000 for first 500 miles, but mine feels way more comfortable at an indicated 3800 or 4000. Are there inexpensive servicing tach's available that would provide a check of this?

Minor items to sort include charging (volts look low), one headlight winking on and off, adjustment of fan on & off temp, radio has loose power feed, reverse lights still stubborn, and a few squeaks and noises to get used to or check out.

Will post pic's this weekend.

[summerinmaine]

Congrats on the progress!

As to the RPMs, you know that Lotus tachs are notoriously sketchy when fitted to electronic ignition, right? Is that a factor?

Charging should be in the range of 13-14 volts (13.2 is the target IIRC). Have you checked the system for output? Gen or alt should be pretty straightforward to test.

[Galwaylotus]

I've calculated the mph vs engine rpm for my Elan and neither the speedometer (jumps around a lot) nor the tachometer seems accurate. The tach is smooth and steady but seems to read high. I'm not certain but I think the reading varies whether due to temperature or voltage I'm not sure. Maybe this winter I'll send both to Speedy Cables for refurb and calibration. Will probably convert to negative earth at the same time so I can replace the dynamo with an alternator.

[Frank Howard]

Kind of wondering if the tach is reading correctly, as it sure doesn't feel like it is spinning as fast as indicated. Wilkins book mentions RPM limit of 3000 for first 500 miles, but mine feels way more comfortable at an indicated 3800 or 4000.

Stu,

Most cars with tachs including modern ones are set up so that when the gear ratio between the engine and the drive shaft is 1:1, the tach needle and the speedometer needle are parallel to each other no matter how fast the car is moving. For Lotus owners, this would mean that in 4th gear, the needles would be parallel regardless as to whether you have a 4-speed or a 5-speed because in most 5-speed transmissions, the 1:1 ratio is achieved in 4th gear.

Unlike most manufacturers, Lotus offered multiple differential ratios. Obviously, a higher or lower differential ratio would upset the relationship between the two needles. Assuming that you have a somewhat accurate speedometer and a "standard" differential, to test your tachometer, I would drive the car in 4th. If the needles are parallel, I would assume the tachometer is functioning properly. If nothing else, this is a simple and inexpensive test. Let us know your results.

[peterako]

Always great to hear of another +2 hitting the roads again.

Enjoy!!

Peter

[leifanten]

most timing light tools have an rpm function that you can use to calibrate your dash tach.