240260280z

It looks like the top assembly that holds the needle bearing has drop tabs connected to springs may be "user-rotatable" too. I have never played with it so I can't say for sure.

Having problems putting images in line??? Below is a 280z tach module on left and 240z tach module on the right. The adjuster is at ~ 12:30 "o'clock". You can access it from the back of the tach's "can" enclosure. The access hole is between the two lamps.

There is a calibration adjustment on the tachs.

Same issue that Johnc and I discussed a few days ago. Have a look at the post with all the meter photographs here: http://www.thesamba.com/vw/forum/viewtopic.php?t=508798

Those are great tools! You can accurately read rpm as well as advance the timing light to read the mark nulled to 0 on the scale at the damper pulley. The cable is long enough to read rpms from the passenger compartment while driving ... works great when also reading the O2 in the passenger seat in real time road tuning.

Flog that horse:

My understanding is that at cruise in 5th on a highway, the throttle valve is not opened greatly so there is a very high venturi effect near this partially opened throttle valve. This is when max vacuum advance is in play. Moving towards WOT causes the venturi effect to drop off a bit until the rpms are high enough to match the localized flow in the cruise area.

Sounds like fun!

Love the licence plate screw history. You are first class!! Glad you made it home safe and sound. I hope I can get your magazine spread!!!!!

I may be in NJ area in Jan. CO I'll do my best to visit my old buddy and state neighbour.

Sort of... that is the reality of what we are adjusting however, if you want to try to get an approximate bench mark at least ; one that many can use, it will be difficult. For example if a procedure states to set the RPM's to 850 at idle and one person's rpm tester was not the same as another's then it would be difficult to achieve the desired result. I would expect a better level of agreement between $50 test instruments with flow numbers on the case. I now have two flow testers my old EMPI and new STE that I will soon compare for bringing a third into the comparison.

This is an FYI just in case people try to set the same flow number at idle for stock cars, there is no accurate way to ensure the number read is correct.

Dang that is horrible. What a bum to sell you a head with so many problems. I thought that store was doing a good service for the Z community .... what a bum.

it's Steves 260z... I visited with him and we had a blast tuning it. The PO left us scratching our heads/ cursing many times....for example the locking nuts on the rocker (lash) adjuster pivots must have been 100 ft-lbs... some were so tight it took two of us on a wrench to loosen. The vacuum advance canister had a leak so there was no vacuum advance; only mechanical. This makes the 32 degrees observed [AT IDLE] even more difficult to accept.

For the record, I had the opportunity to test an EMPI synchrometer against an STE synchrometer and the readings on each were different. I do not think they are calibrated well. The EMPI read higher at idle.

Well the timing light showed 32 at idle but it did have an adjustable pot as part of the circuit and it had a flakey switch so it may be out of calibration...especially since that was with the distributor in the middle of its adjustable range. I swung it to max for a run and no ping. It just lost power and the typical contrary starting was noted. I also tried minimum range and a loss in power. it worked OK in the middle so I left it there. We did not have time to check that the timing marks on the crank pulley and scale were aligned with TDC so the weird 32 number could have been due to the light out of calibration or the scale being off or a different pulley on the car.

Thanks for the ideas. We sprayed the intake, balance tube and carbs thoroughly with starting fluid... no raise in rpms so no apparent air leaks. The observation that the front carb initially worked better with more fuel and then after the valve adjust, the back carb needed extra fuel to balance would mean an air leak jumped. We did not do anything to the carbs or intake after the valve adjustment so we could not have caused an air leak.

I don't believe that timing light. 32 degrees at idle would surely ping off idle.... or the timing marks are off... we did not verify so the PO could have left us another thing to fix like the cam oiler. As well timing would affect all cylinders.... it is a mystery for the moment.

Thanks! I guess I should add more detail: The power now balances with ~4 extra turns down on the rear nozzle, it was the reverse before the valve adjust. All SU's I tuned to this point power balance within 1/2 a turn difference.... something is amiss. I'm wondering if the odd fuel lines between the nozzle and fuel bowl are causing the grief. JFA had a problem recently that is making me think it could be in common. FYI most intake and exhaust valves were tight and the plugs had a crispy coating. Another guess is that the re-lashed valves may have beat off crust and carbon upon their restart to rise a little and reduce the lash again.

L26 w round tops identical and new needles... jets ok... hoses to jets a bit suspect as they bent a little... pistons moved freely ... no choke cables attached during tuning .... nozzle in correct locations... linkage working fine. Initially the back carb was doing most of the work and it balanced better by adding more fuel to the front carb at the same air flow. After some exploratory work it was discovered the PO did pass the car along with a good valve adjust. The front 3 cylinders were ~ 100psi and the back ~ 150psi. A valve adjust brought all up and mostly ~170psi. After the valve adjust, it balanced better by adding more fuel to the rear carb at the same air flow???? The problem moved... but remained...poor balance Fuel bowl levels were OK. Timing was ok. Any idea? It was interesting to see how valves affected carb tuning.

put a drill bit through it then roll on a flat surface to revive the shape. As long as it is clean and not crumbling it should work fine. Be sure to check the cavity where it fits in the banjo for crusty build up.

Nice Siamesed Pis|ton to match the block casting 0r a 6cyl trying to be a 7 cyl?

PM me with your phone number metalmonkey

I'm in atlanta georga now ! SteveJ and I will meet on Fri. I may be here on the weekend.