ALFAGTV6.COM

[peter66]

Long time since I visited the forum. I have not been using my GTV 1.8 turbo a lot, because of other classic car purchases that required attention. I have been using NGK BP7ES spark plugs, without any issues. I discovered that NGK now advices BP6ES and in the forum some people recommend 9ES. Should I stick with the 7s and if possible fit the 7ES instead of the BP7ES (protruded head)?

A second long term concern is that my expansion tank pushes out coolant at maximum boost. It's chipped and boost is 1,1 bar. I thought I had it fixed when I discovered that the inlet manifold gasket was not tightened properly, because of a worn stud. I used two nuts with a new gasket and the problem was gone for a while. Now it's back and it also seemed to have taken the alloy radiator with it. It has some small cracks, which the radiator manufacturer now investigates. Did anyone have similar experiences?

Thanks and best regards,

Peter

[Mats]

Sounds like a headgasket issue.

B7ES is what I used without issues, the 'P' indicates a protruding tip as you say.
I'd say that 6 is too hot and 9 too cold.

[jamal555]

NGK is giving u the plug for the regular 1.8ie... 6 is too hot for this engine...

original spark plug for it the Golden Lodge 25HL is somewhere in between NGK heat range 7 and 8... some ppl run 7... some ppl prefer 8 in the summer if driven hard... and 7 for shorter trips car usage and regular driving...

however italians are using 9 in motorsport and for engines over 200hp and hard driving...

so make your choice

[jamal555]

Hey,

my hall sensor on the dizzy gave up i think... car cranks... has fuel and spark.. but just doesn't start... i have voltage reading of 25-26mV while cranking on the hall...

is the hall on the 33 the same? or maybe on the v6 jetronic...

Jim K. mentioned it few pages ago but i'm wondering is it the same as the one in 1.8t distributor...

[Zamani]

I think early GTV6 Jetronic had an optical sensor in the dissy. The later ones had hall sensor. Pretty sure by the time the 75 V6 was out it used a hall sensor. So just be careful which one you get. Either of them might work, but I'm not 100% sure.

[gran turismo]

It would be easier to see if the hall is working if you can slowly crank the engine by hand since it produces a voltage signal twice per crank rev.

[Jim K]

The 33 unit innards are the same. The whole distributor can be transfered to the 1.8T if you take off ~4mm on a lathe from where the clamp fits, so that total distributor neck 'reach' will be same as the 1.8T. If it has springs, weights or vacuum pot, lock the centrifugal mechanism. Regarding the vacuum pot, there's a nice trick you can do to the 1.8T to get much better pickup and drivability in city (no boost) driving. Set timing to 7-9*BTDC at idle with the pot disconnected, then connect vacuum line to fuel regulator port with plastic 'T'. You will have much more advance in low revs and when you boost, the plate locks at the preset value! More economy too!
Jim K.

[Jim K]

Ok, a little update on the daily 1.8T. I installed the ...909 fuel pump and tried the uphill high speed test run with the wbo in-car (LM1). Still weak ~13.3:1, 4th gear, 5500rpm. More fuel was needed so I made an adjustable regulator and found I had to set pressure at 3.4bar (from a std 3bar) in order to read 11.5 afr at 1bar (14.7psi) boost. I reset idle CO% to ~1% and checked that part throttle midrange was still ok so I didn't have to tighten the afm spring. Yesterday, I decided to try 1.3bar (19psi) boost but had pinging. I dropped idle advance from 8* to 5* BTDC and lo and behold, the thing hauls a$$. Since the std boost gauge is a joke, I installed a Racetech unit in the blank space under the left dash vent outlet. Come Friday, I'll see about going to the dyno again and if I do, I'll post the graph. In order to improve low speed response/economy, I got a Hall-effect distributor with a vacuum pot from a 33 (the exact unit mentioned in previous pages) and will install this in place of the 1.8T unit. The reasoning is to have more advance under city driving conditions and when boost is required the unit will zero to the preset value. I believe it'll be much more pleasant to drive. Remember, this is all with stock management, snail, injectors, afm etc.
Jim K.

[xrad]

NIce! It's always a good feeling to get a set-up in running order..it's the simple things too.

Question: cool, medium, or hot plugs?? Stock spark generator I assume(not multispark).

[Jim K]

Champion N2C plugs and my own single spark CD ignition (>200mJ spark)
Jim K.

[Mats]

Cool, so what is the advance at full boost and around 5000? Do you have any clue?
Stock CR, right?

[Jim K]

....No idea Mats, whatever the ignition ecu has in store. The only way one can measure it is with a timing light on the rollers at full load! I'm not about to do that and sure as hell the dyno boys won't let me try!
Hmmmm, I suppose it can also be done by triggering the ecu with a generator, holding the afm and TPS fully open and display the output (ignition coil signal) on the scope screen. Other than curiosity, why would I do that? I have no way of altering the map in these things.
CR is 8:1, I milled the head 1mm for this and installed a 2-piece gasket at the same time.
Jim K.

[jamal555]

You will have much more advance in low revs and when you boost, the plate locks at the preset value!

hmm... so its a advance in the vacuum port... not retard... like in porsche what about this... if the default timing is 8-9* btdc as default... and vacuum port gives an advance to lets say... 1 btdc... the car goes much better... thats for sure... when i boost it will go back to default value... for as long as pedal is pressed >50% as soon as i depress the gas pedal and manifold pressure goes to vacuum again it will again advance ignition by few degrees... right?

what happens if i drive at low throttle at lets say 4000 rpm... the manifold is still in vacuum since im on low throttle... but wont the vacuum port advance my timing again and make the engine prone to pinging... ?

or am i missing something...?

if i lock the mechanical advance, remove the springs, screw the inner parts... will vacuum still operate properly?

[Jim K]

In the case of the 1.8T, there are no springs/weights, the shaft is locked (one piece of metal from top to bottom). So is the 33 unit but with the addition of the vacuum pot. If at 4000rpm you have vacuum (part throttle) you will add the vacuum advance to the preset value. If for example with vacuum tube removed you set at 5*BTDC, when you reconnect the tube you will add another X* from the vacuum pot to the preset 5*. As soon as the boost gauge goes past zero, X* disappears and you begin with 5*. True, on part throttle and vacuum you will have X* plus whatever the ecu gives. If you do hear pinging in this case, you will have to decrease X (mechanically limit rotation of distributor vacuum advance plate) to a point where no pinging occurs (this may be done a couple of times until you get proper results). I can't give you numbers as to how much to reduce since every case differs. Remember, whatever gain in degrees you have in vacuum advance is always an improvement in idle/part throttle. Final regulation of X* is an empirical thing.
Jim K.

[Zamani]

Doesn't the 1.8T have a built in knock sensor?