VVT functioning on a series 4 - Alfa Romeo Bulletin Board & Forums
 
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post #1 of 11 (permalink) Old 09-21-2005, 11:53 PM Thread Starter
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VVT functioning on a series 4

Does anyone know for certain just what parameters initiate the VVT on a motronic. I was out playing with mine today to try to determine just what sets it off. Murray is in need of the parameters...and likewise so do I on my future autronic project.

From my experimenting with an tach/DMM and the throttle under the hood my results suggest that the VVT only kicks in by throttle position and has nothing to do with RPM. I ran the car up slowly to over 5k on the tach without kicking in the VVT at all. Then I punched the throttle and got instantaneous and sustained activation of the VVT solenoid through all rpms.

Can anyone shed some light or factory reference?

On another note...I have come up with another way of replacing the rubber bushing in the VVT support. Ask for details if interested.

Best Regards,
John M

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1978 AR Spider Veloce 2000....the first and still here...Bianco
1984 AR Spider Veloce............the second & gone to the parts bin....Rosso
1992 AR Spider Veloce............the third and still here...Bianco
1991 AR 164L........................the fourth and traded on the SS....Rosso
1965 AR Sprint Speciale..........the fifth...in boxes....sold....Bianco
1978 AR Spider Veloce 2000....the sixth gone to be a parts car...slow black
1967 AR Giulia Sprint GT.........the seventh with Gregg and sold......Rosso
1993 AR Spider Veloce............the eighth with Gregg and still here....Verde Inglese
1982 Ferrari 308 GTSi.............the first and still here....Azzurro
1999 Ferrari 355F1 Spider........the second and still here....TdF Blue[/SIZE]
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post #2 of 11 (permalink) Old 09-22-2005, 08:14 AM
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John M,

Very interesting question but IF YOU DON'T KNOW, WHO ELSE WOULD?? I always thought that the VVT is triggered by pedal-to-metal action which is detected by the throttle position sensor.

Rubber bushing in the VVT support... Is this important for the VVT to function properly? Please let me know your secret!!

Thank you,

Taiga "Tiger" Inoue
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post #3 of 11 (permalink) Old 09-22-2005, 09:13 AM
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Probably the easiest way to fine out is the same test on the L-jet. Just turn the key to the on position, do not start the car, and turn the throttle plate by hand and see if the VVT selenoid activates. I know the L-jets activate via the TPS switch at WOT. (About 3/4 open Throttle.)

Dave
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post #4 of 11 (permalink) Old 09-22-2005, 10:22 AM Thread Starter
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Thanks guys....excellent suggestions and info. I certainly don't know all.....and this one has me stumped. Dave, I'll give your test a try.

Best Regards,
John M

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1978 AR Spider Veloce 2000....the first and still here...Bianco
1984 AR Spider Veloce............the second & gone to the parts bin....Rosso
1992 AR Spider Veloce............the third and still here...Bianco
1991 AR 164L........................the fourth and traded on the SS....Rosso
1965 AR Sprint Speciale..........the fifth...in boxes....sold....Bianco
1978 AR Spider Veloce 2000....the sixth gone to be a parts car...slow black
1967 AR Giulia Sprint GT.........the seventh with Gregg and sold......Rosso
1993 AR Spider Veloce............the eighth with Gregg and still here....Verde Inglese
1982 Ferrari 308 GTSi.............the first and still here....Azzurro
1999 Ferrari 355F1 Spider........the second and still here....TdF Blue[/SIZE]
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post #5 of 11 (permalink) Old 09-22-2005, 10:44 AM Thread Starter
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Lets talk about that support bushing design on the VVT for a second. What the big metal support has is a rubber bushing surrounded by two metal collars. The outer collar presses into the support. The inner collar is threaded and is what the VVT threads into.

When adjusting your VVT...first......don't try to slacken the big lock nut on the solenoid with the VVT/support mounted. Pull the entire support w/ solenoid off by removing the three allen head screws. Then break the big lock nut loose on a bench. If you don't brace the VVT when you slacken the lock nut....you will twist and destroy the old bushing. Then you find yourself in the position I found myself about a month ago.

What I used to rebuild the bushing was two layers of commercial grade rubber sticky tape. This stuff made by Colorado Steel/Norton if I remember right. Its the same stuff used to adhere lexan windows on the sides of fiberglass boats. It is the non expanded type of rubber tape. And its tough stuff. I left the outer collar mounted inside of the big metal support. I thoroughly cleaned to bare metal. Did the same with the inner threaded collar. I ran two independent runs of the tape around the inner bushing. Lubricated the tape with adhesion promoter called Titebond...and slid the inner collar with tape formed bushing into the outer collar. Let it setup a few minutes and whala...perfect. Put probably 800 miles on her since and still in perfect position.

The solenoid can then be adjusted to seat right against the plunger and the tape retains the original bushing's flexibility and proper positioning of the threaded collar to align the VVT with the plunger.

So.....if you have one failing or already failed......and can't come up with a similar solution....send me a PM.

Best Regards,
John M

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1978 AR Spider Veloce 2000....the first and still here...Bianco
1984 AR Spider Veloce............the second & gone to the parts bin....Rosso
1992 AR Spider Veloce............the third and still here...Bianco
1991 AR 164L........................the fourth and traded on the SS....Rosso
1965 AR Sprint Speciale..........the fifth...in boxes....sold....Bianco
1978 AR Spider Veloce 2000....the sixth gone to be a parts car...slow black
1967 AR Giulia Sprint GT.........the seventh with Gregg and sold......Rosso
1993 AR Spider Veloce............the eighth with Gregg and still here....Verde Inglese
1982 Ferrari 308 GTSi.............the first and still here....Azzurro
1999 Ferrari 355F1 Spider........the second and still here....TdF Blue[/SIZE]
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post #6 of 11 (permalink) Old 09-22-2005, 05:38 PM
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Hi John,

We're finally back from Seattle, Topeka, and myriad points in between. Just for my edification (and other BB'ers), what were the symtoms on your car that led you to try to adjust the VVT?


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George Schweikle

1976 Spider (Dedicated Autocrosser, "SPICA, No Carbs")
1991 Spider Veloce (Retirement cruiser)
Scuderia Non Originale
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post #7 of 11 (permalink) Old 09-22-2005, 05:57 PM Thread Starter
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Welcome back George!

Did you see what Budsy has been up to? He made me his manual laborer for a day.

Well....why I adjusted mine....I replaced the valve cover with a polished one. In the mean time I have been hearing some upper rpm valve click (or at least that is what I thought it was). So I had replaced the main fuel filter. I tightened the chain. Both failed to get rid of that click. It hasn't been too long since those clearances were checked....and they were a little tight. So I started brainstorming as to what I could have done. A few weeks went by and I thought....darn it. I never adjusted the VVT to make sure it was where it was supposed to be. I went to loosen the lock nut to adjust the VVT as it clearly was wrong. And the lock nut only worked to rip the bushing to shreds.

Now, that click was still coming through at higher rpms since repairing the VVT. I think I discovered the ultimate cause. The main high tension cable between the coil and the distributor was dislodged considerably at the coil. Just about sitting on top of the coil lip. It had burned the top of the coil. Cleaned the debris off the cable.....plugged it securely into the coil....and the car seems to be running smoother. Seemed pretty smooth before....but still a noticeable difference. So, I'll know more after a thorough test drive.

If its still there...I think it'll be time to adjust those valves back into specs.

Glad to see you are back. Bud has carbs on his ride. He should have it ready to drive by now!

Best Regards,
John M

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1978 AR Spider Veloce 2000....the first and still here...Bianco
1984 AR Spider Veloce............the second & gone to the parts bin....Rosso
1992 AR Spider Veloce............the third and still here...Bianco
1991 AR 164L........................the fourth and traded on the SS....Rosso
1965 AR Sprint Speciale..........the fifth...in boxes....sold....Bianco
1978 AR Spider Veloce 2000....the sixth gone to be a parts car...slow black
1967 AR Giulia Sprint GT.........the seventh with Gregg and sold......Rosso
1993 AR Spider Veloce............the eighth with Gregg and still here....Verde Inglese
1982 Ferrari 308 GTSi.............the first and still here....Azzurro
1999 Ferrari 355F1 Spider........the second and still here....TdF Blue[/SIZE]
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post #8 of 11 (permalink) Old 08-13-2006, 01:00 PM
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Vvt

John,

I changed my distributor cap and rotor yesterday. While doing this, I must have hit the VVT. I started the car and it idled poorly-had been running fine prior to the changing the distributor. Quickly found that the VVT had been knocked about. Went to loosen the VVT nut, it turned into gooey black mush. I now have cleaned everything and taken it all apart. I'm interested in how you remounted the VVT...

Thanks,

Duke
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post #9 of 11 (permalink) Old 08-13-2006, 04:37 PM Thread Starter
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Duke:

You won't believe me...but I used double sided foam tape made by Colorado Steel for Norton....for US Marine to mount lexan windows. Its pretty heavy duty stuff and it works! Not your normal foam tape.

Some people have used a radiator hose cut and wedged between the collars. If you are so inclined....clean your parts (remove all the old bushing), box up the mount and the collars (don't need the solenoid...just the threaded collars and the mount off the valve cover) with return prepaid shipping label, and send it to me. I'll make the repair and send back to you free of charge.

Other options are to source a good used mount off of ebay, APE, or DeNoya. NLA new. If you want to send it out to me...PM me for my address.

Best Regards,
John M

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1978 AR Spider Veloce 2000....the first and still here...Bianco
1984 AR Spider Veloce............the second & gone to the parts bin....Rosso
1992 AR Spider Veloce............the third and still here...Bianco
1991 AR 164L........................the fourth and traded on the SS....Rosso
1965 AR Sprint Speciale..........the fifth...in boxes....sold....Bianco
1978 AR Spider Veloce 2000....the sixth gone to be a parts car...slow black
1967 AR Giulia Sprint GT.........the seventh with Gregg and sold......Rosso
1993 AR Spider Veloce............the eighth with Gregg and still here....Verde Inglese
1982 Ferrari 308 GTSi.............the first and still here....Azzurro
1999 Ferrari 355F1 Spider........the second and still here....TdF Blue[/SIZE]
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post #10 of 11 (permalink) Old 08-14-2006, 05:39 AM
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John,

Being a former Marine, I can appreciate the foam tape!

What's your opinion about machining a threaded collar? That way I can adjust the VVT. Is insulating material used against heat?

Thanks for your reply and offer to repair!

Duke
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post #11 of 11 (permalink) Old 08-14-2006, 09:59 AM Thread Starter
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Hey Duke:

I don't honestly know why they used a bushing. I assume to reduce engine vibration to the solenoid.

The collars on that bushing....the one on the mount side is press in type. The one on the solenoid side is threaded. So I think a threaded solid mount to replace the bushing that will press into the carrier/holder will work.

I can attest that my foam tape solution has held now for nearly a year without having to do anything to it. What I did was to take one course of foam tape and wrap around the inner collar. Then I took one course of foam tape and wrapped around the inside of the mount...or the second pressed in collar...can't remember. I think I used the second collar to reduce the tape amount. The tape is double sided sticky. Then I wet the tape on the mount and threaded collar and pressed them into eachother. See the picture. I tried epoxy prior to the tape...but couldn't get it to hold. But the tape has worked perfectly so far.

Best Regards,
John M
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1978 AR Spider Veloce 2000....the first and still here...Bianco
1984 AR Spider Veloce............the second & gone to the parts bin....Rosso
1992 AR Spider Veloce............the third and still here...Bianco
1991 AR 164L........................the fourth and traded on the SS....Rosso
1965 AR Sprint Speciale..........the fifth...in boxes....sold....Bianco
1978 AR Spider Veloce 2000....the sixth gone to be a parts car...slow black
1967 AR Giulia Sprint GT.........the seventh with Gregg and sold......Rosso
1993 AR Spider Veloce............the eighth with Gregg and still here....Verde Inglese
1982 Ferrari 308 GTSi.............the first and still here....Azzurro
1999 Ferrari 355F1 Spider........the second and still here....TdF Blue[/SIZE]
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