Quattroporte III catch-all thread

Mine is earlier so I can't compare. Have you downloaded the manual from Ivan's site yet? <http://www.thecarnut.com/maseratimanuals.html> p133 of the full manual has a schematic of the vacuum connections for the '81 and up cars.

 

Yeah, I actually have the manual. Funny thing is, it looks the hose goes nowhere in the manual, but I might be looking at it wrong.

 

Don't document my half of the conversation either!

I certainly don't know what I'm doing, aside from learning what I can.

Today I spent some time getting better acquainted with the vacuum system and measuring each hose to check for leaks, as well as find what hoses hold vacuum or pressure, and which don't.

I also found a few things that are different from the manual, but much is the same.

As several items under the hood are unknown to me, I have some questions too.

Let's start with the distributor. The "A" line (thicker hose towards one side of solenoid bottom) goes to the distributor vacuum. Opening the dizzy cap and observing, there is a ring with "fingers" that stick up, which rotates to the right (clockwise) when vacuum is applied. Above it is a "starfish" with 8 arms that stick out, and meet up with the 8 fingers on the ring below. Applying vacuum moves the two sets of contacts (if indeed they are contacts, mine appear to have surface rust) further from each other. I would guess that means this is actually retarding the timing, instead of advancing it? As some manufacturers did at the end of the 70's to achieve better emissions at idle?

Cross checking this with the service manual, it states that ignition should be -4 deg "with depression" and +7-8 deg. without for a total of 36 degrees at 5000 rpm. If "depress." is Italian for vacuum (or retard), then it would make sense that with the vacuum applied, the timing is retarded from +7 mechanical to -4 with vacuum retard. Does anybody know for sure?

The vacuum diagram in the fender shows the trumpet actuators (basically valves/doors to the air box) being operated by the second solenoid (furthest from firewall), however on my car this hose goes to two curious contraptions that sit in between the trumpets. They are marked as a "pump" on the half-worn metallic label on them. On the left side one (i.e. driver's side) the hose goes to the air intake upstream of the trumpets (and shutoff valves), the other to the solenoid. The right side one also has a tube to the air box (probably some sort of bypass?) and the other goes to the bottom of the charcoal filter.

The vacuum diagram in the manual (4-2) shows a vacuum switch (number 2), which I don't see anywhere. Could that be the microswitch under carb no. 1 by any chance? Part 3 is labeled "offset valve", but looks to me from the drawing to be the air pump valve, taking manifold vacuum in one side and outputting air to each exhaust header on the other. Yes?

Most of the lines I tested (simply, just vacuum/pressure to see if the held it or not) did not hold vacuum or pressure, indicating either that the system isn't closed to begin with, or there's a leak.

The diagram doesn't show where the vacuum lines go once inside the car, but judging from what I heard I would guess the heater/air con is involved in there somewhere. Since I was under the hood I didn't get a chance to check and see if my "consumption" gauge moved while testing.

After starting the engine and letting it warm up, I tried reading vacuum this time by using the line that joins the cam cover breather at the bottom corner of the air box. Only 5" Hg there, the needle vibrating slightly.

From the reading I've done, a healthy engine should pull 17-22" vacuum off the manifold. Either this car is set up completely different, the vacuum system is broken, or (most likely) I'm measuring in the wrong place/way.

Enough for today, any suggestions or advice is most welcome.

 

Right behind your hand, under the air box baseplate is a metal tube, the large part fits the cam cover breather hose (a short section of 1" tubing), and there is a smaller "offshoot" that the hose you have in your hand fits onto.

See if that doesn't match your car. It does mine.

 

Hello Quattroporte3...

It seems you keep coming back to the vacuum system on your car as PERHAPS being the
root of the issues you are encountering.. Not sure this is of help or not, but on my thread
for my 1982 QPIII, posts 57 - 60, there is discussion about the location of the vacuum pump.
Could it be that the problem lies with the vacuum pump?

Mike

 

Yes, I think it's vacuum retard only and is controlled by the microswitch under carb 1 and solenoid 17 to be effective only at idle. According to some other sites, this was done to make combustion less complete, lowering combustion chamber temperatures to produce less oxides of nitrogen. Then they pump air into the exhaust system to burn the unburned exhaust. That old stuff was pretty kludgy. If you disconnect the tube at the distributor, the car will probably idle better, but the tube will have to be plugged to prevent an air leak at idle. Cars without vacuum retard also had different air correction jets in the carburetors (from Steve Swain) to make them leaner at idle.

Everything else seems to be for the evaporative emission controls. Those "pumps" really are - they're little fans meant to force any evaporated raw fuel into the charcoal canisters when the engine is shut down. The intake flaps prevent it from escaping. It's a complicated mess, but as long as it works, it shouldn't have any effect on the engine performance since it comes into play only when the car is turned off. I think the US cars did not have a clutch for the air pump, so that runs all the time and has no controls. My car lost its air pump before I got it.

I would guess that the vacuum pump on the cam is there to generate enough flow to get the power brakes to work (Mitchell -- might be something to check!). That might explain why some of the distributor illustrations from earlier cars show no vacuum servo at all. With the engine's one-throat-per-cylinder design and short runners, there really isn't average manifold vacuum you'd get from a common V8. I think they tap into just one or two, but I'm not at the office and can't check. Then again, in this car the only use for vacuum is to retard ignition a fixed amount at idle, so maybe it doesn't have to reflect engine load. I'm rambling - time to stop!

 

Since my microswitch is broken, and I've also bypassed one of the solenoids (the one that provides vacuum to the distributor), that would make sense, and also explain why the idle increased when I removed the hose from the distributor, and decreased when attached.

I see several references to Steve and things he's posted about carbs, distributors, etc, but am not sure how to contact him for more info. Does anyone know how to get in touch with him?

I thought the "intake flaps" were active when the engine is cold to close off the trumpets in order to get the engine up to operating temp quicker. No?

The pump does indeed connect to the brake booster, as well as the other manifold vacuum tubes (two on the driver's side of the manifold above cylinders 6 & 7). The solenoid valve is also connected into the brake booster from what I could tell.

Mike - it may be the vacuum pump, but right now I want to make sure the entire vacuum system is functioning to spec. After changing the timing a bit, my brake pressure came back, and the "consumption" gauge now reads closer to "normal". The car is going back to the shop in a week, and I'll have them check and set the timing there so we all know it's correct and can look at other factors in the car's running.

 

I don't know Steve or how to reach him. I have a two page PDF summary of his distributor and jetting information if you need it. I don't know where I found it, or I'd send a link.

On my car, these flaps just close off the air cleaner box - there's no alternate source for heated air.

 

I have the same PDF article, but thanks.

Ok, that makes sense, there isn't any warm air coming in from the exhaust headers, and I don't think the cam breather hose would really help much getting the engine warmed up faster.

Is it normal that a Maserati V8 has significantly less vacuum than a US SBC? Did contemporary Ferraris and Lamborghinis also have low vacuum at idle?

Gonna take a break and sit on it for a few days and think about it.

 

Quattroporte3 / GLB...

What is the PDF article you are talking about? How can I get a copy?
If possible could you PM me a copy of it?

Thanks...

Mike

 

Cam timing is probably a little wilder, but I'm not even sure of that.

BTW, the visor mount came in today. I had almost expected to see a picture posted here by Will. If he doesn't, I'll take some. He opted for the "polished" finish (still white), but it still isn't as smooth as the original, and he slightly over-compensated for wear in the pivot taper, so he'll tweak and re-run. However, it other respects it's an exact copy.

I plan to ditch the vacuum retard but I want to fix the lean idle mixture at the same time. I am trying to order some 1.20 air corrector jets from weberjets.com, but their site is broken for just that part.

 

Hi Mike,

it's at the end of this article, at the bottom, and is part of the last article on the page, about tuning Weber carbs.

iL TRIDENTE Online

If the link doesn't go through, I'll try and PM you a copy.

 

Very cool, can't wait to see pics of the part!

Let me know if you get the air corrector jets, I might just try that myself. It's an easy enough thing to change.

 

This thing is so flat white that it's hard to get the camera to focus. If I hadn't gotten my grubby fingers on it, there'd be no definition at all! We checked fit in the car; the only problem is the noted taper depth.

Will wants to try some things for surface finishing on this first proto. He's made the corrections to the taper and has released the second pass to Shapeways.

The other picture is the shaft for the main pulley: 37mm diameter, four 8mm bolts. It's smaller than I remembered. I think a 1/2" square drive will fit, but it's tight. Notice where the bearing is made -- obviously the De Tomaso influence!
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Wow, the part looks identical to the original, aside from the color! I'm not sure what you mean by taper depth, but it does look good. Great job!

The main pulley bearing is made in Argentina. Who would have thought...he he he.

I wonder if it would be possible to turn the engine by using one of the 8mm pulley bolts. As long as they all turn the "right" way. It's a little off axis from the crankshaft, and I don't know how much torque is needed to turn the engine over if all the plugs are removed.

Is the QP3 the only model that used this setup? Do the other V8 cars all have a regular huge bolt at the end of the crankshaft with which to turn the engine manually? If so, I wonder why they changed it here.

 

The shaft of the visor is tapered, I assume so that the spring can pull it in and make some friction. The first pass has the right taper angle, but the hole isn't large enough so the shaft doesn't go in far enough to install the washer and C-clip. Easy fix, he said.

I'd worry about using just one bolt although I haven't tried. Max torque for a 10.9 grade 8mm bolt is 24 lb-ft; not much. That arrangement is used on at least the QP3 and the Bora. The shaft is from my Bora. I'd bet the Kyalami is the same. I've seen drawings of engines from other cars, but have no direct experience. From those, it seems like there are two basic types: ours, and the front engined cars which have a more conventional keyed extension of the crankshaft. I don't know why they changed, but this design is probably better for side loading.

The Weber jets guy says these are special order. He also said his book says 155, so I'd better take a look.

 

I was going to paint my cam covers, any thing I should beware of?

 

Yes. Underneath you'll find a white plastic type of wing nut that you turn clockwise by hand to loosen it. Don't turn the glass just the wing nut.
Tony

 

Cool, thanks.

 

Bart has a pretty good rundown of the process in another thread here, if you search for "black crinkle paint" I think you'll find it. I'm not sure, but think it's in the Ghibli thread.

Good luck, and take some pics and show us how it goes!

 

drove on the interstate. at 80 the car is a dream. I had not expected that at all. went to 90 but decided I did not need a ticket. drove a whole 20 miles. a note about my tires. I am using Lexus 8x18 with all weather pirelli's

 

Congrats! I remember my first trip. I drove it home the 125 miles from where I bought it. It's in kilometers so I was a bit clueless as far as speed goes but the ride was amazing!
I couldn't figure out how to turn the lights on and it was getting dark. I was pressing all these buttons...
I had to call my friend driving behind me to now get in front because I couldn't see. But soon after that I found the light switch.

This car is best on the highway for sure. It revs higher than I expected in 5th. The transition from 4th to 5th is hardly a difference. She just keeps pulling no matter what gear you're in!

There's a hill near me on the Taconic State Parkway where any car I ever drive needs to downshift to maintain normal highway speeds. Not this car! She trucks right up that hill like it wasn't even a hill in 5th. Well one exception, my DeLorean. She goes straight up that hill in 5th gear also.

Wishing you many more trips!
Tony

P.S. I have the XWXs on the original rims.

 

Hopefully we'll know more in a day or two. I found a mechanic who knows his way around Ferrari's blindfolded, and has worked on his share of Masers and Lambos too. Not on this particular engine or car, but I hope he knows enough about how things were done and can look at the documentation, see what's under the hood and put 2 + 2 together.

I've asked him to check if the vacuum is advance, retard or both. The manual would seem to indicate it's both, as you mention, but I only see the dizzy guts rotate one way with vacuum, and there's no positive pressure in that line.

Let's see what the good doctor says...

 

Dear Quattroporte III Entusiasts

Last one ever to be found. Fully serviced and new Auta 9600. Bought some time ago from a collector who had is fully gone through by a Speedometer shop in CA. This is the black three segment Hirschmann unit with amp as used in only a very few applications.

I will be listing it on ebay as I sold the two cars and the one I have is fine. I paid $250 for it but will likely list it on ebay.

I am currently in Vancouver with the unit for the summer. Let me know.

 

Good luck. It really does look like retard is the only possibility with that distributor. It will be interesting to hear what he finds.

On another topic - the second pass visor mount has been shipped so we should get it soon. Will just did the right side version - it took about three seconds.. We also found some Krylon Fusion paint specifically for plastics. Their beige color isn't quite right, but this paint is a good base coat for any type of second coat paint, so surely there's something out there that is a good match.