[cribbj]

This is a topic that has been beaten to death in various places and various threads. But what about putting the differences all in one place in a comparison table?

The following table is a start, and if people who are knowledgeable about either or both models will contribute their knowledge, I'll update the table as we go.

Presently, the table could really use some help in the body and interior sections (not that the other sections should be considered complete!)

And if anyone (Brian?) knows the answers to these points, I'd like to update/correct the table:

1. What material is used for the valves, and is it the same for both the intake & exhaust?

2. The WSM's for the 550 and 575 indicate the valve guides are a "copper alloy" for both engines, however I thought a SiBr guide was used in the 550, followed by a cast iron guide in the 575?

[tazandjan]

John- Cannot really see the chart easily on my Blackberry, but the 575M has sintered steel valve guides and the 550 has bronze. The 550 also has titanium connecting rods, which broke in the racing versions, so they and the 575 use stronger steel connecting rods. If you look in the parts catalogs, I think the 550, 575, and early 612 use the same steel valves. The Superamerica uses shorter valves because of a different valve seat angle.

[cribbj]

Originally Posted by tazandjan

John- Cannot really see the chart easily on my Blackberry, but the 575M has sintered steel valve guides and the 550 has bronze. The 550 also has titanium connecting rods, which broke in the racing versions, so they and the 575 use stronger steel connecting rods. If you look in the parts catalogs, I think the 550, 575, and early 612 use the same steel valves. The Superamerica uses shorter valves because of a different valve seat angle.

Taz, I also thought, as you do, that the 550 had bronze guides and the 575 either had cast iron, or a steel alloy, but according to the WSM's it's a "copper alloy" for both?

About the rods, are you saying they were abandoned for the production 550 in favor of steel? Here again, the WSM for the 550 states they're Ti, and the 575's are steel.

I'm beginning to wonder how much of the WSM is a work of fiction......

[NigelV12]

John,
for the 550 coolant radiator, wasn't there a change, with early models having a drain tap at the bottom, which could be easily broken off, and a later version with the drain repositioned to a "safer" place?
Nigel

[cribbj]

Originally Posted by NigelV12

John,
for the 550 coolant radiator, wasn't there a change, with early models having a drain tap at the bottom, which could be easily broken off, and a later version with the drain repositioned to a "safer" place?
Nigel

Nigel, I've heard this too, but don't know if it's correct. On my '99 550, the drain fitting is exposed, but not really "hanging down" where it could be knocked off. It's still exposed enough, however that the plastic belly pan wears through at that point first and I've had a steel guard installed there to protect it better.

Maybe someone with an early 550 can comment?

[NigelV12]

John,
My 550 is from 11/97. I raised the point, as the radiator was changed in 2004 and I was told that the tap on the orignal radiator had been broken off or been damaged causing a leak and that the new radiator has the drain tap in a different, less exposed position. The parts list however shows no change in part numbers.
Nigel

[bay]

Originally Posted by NigelV12

John,
My 550 is from 11/97. I raised the point, as the radiator was changed in 2004 and I was told that the tap on the orignal radiator had been broken off or been damaged causing a leak and that the new radiator has the drain tap in a different, less exposed position. The parts list however shows no change in part numbers.
Nigel

on my 550 1/98

[tazandjan]

John- On the titanium connecting rods, they were only changed on the racing 550s. The production 550s retained them throughout the run.

Iam pretty sure the 575 had sintered steel valve guides, which were also recommended as replacements for the 456 and 550 if the bronze guides wore excessively. Cannot access the parts catalogs and tech bulletins to confirm until tomorrow night.

The early 575s also had a unique thermostat housing with an extra water temperature sensor. This was changed during production for the 456/456M housing with no sensor.

Also, the front suspension and wheel bearings were a different design on the 575 with no stub axles and reduced unsprung weight. The ABS sensor wires pass through the space where the stub axle was on the 550.

The banjo fittings on the 575 transaxle were also much heavier than those on the 550.

The fuel cooling ECU and hardware were eliminated on the 575 and one other ECU was also eliminated, but I cannot remember which one without reference to a parts catalog. The 550 actually had more ECUs than the 575.

The brakes were identically sized except for one larger set of pistons on rear 575 brake calipers. 575M wheels were lighter weight than the replacement 550 aluminum wheels.

Will add some more when I do not have to do it from memory and can reference your chart.

[bretm]

Man, this is a great thread for 550 dreamers like myself.

So here's a random, and possibly sacrilegious, question... Is it possible to bolt a 550 front bumper onto a 575? ie, is a straight bolt on affair, or would the bumper have to be modified.

[cribbj]

Originally Posted by NigelV12

John,
My 550 is from 11/97. I raised the point, as the radiator was changed in 2004 and I was told that the tap on the orignal radiator had been broken off or been damaged causing a leak and that the new radiator has the drain tap in a different, less exposed position. The parts list however shows no change in part numbers.
Nigel

Originally Posted by bay

on my 550 1/98

Nigel/Bernard, thanks, and it's clear to me now. On my '99, the drain is located in the same place as your pic, but it's been rotated 90 degrees, so instead of facing down, it faces to the rear. See pic below. That downward facing drain is REALLY exposed, isn't it?

Originally Posted by tazandjan

John- On the titanium connecting rods, they were only changed on the racing 550s. The production 550s retained them throughout the run.

Iam pretty sure the 575 had sintered steel valve guides, which were also recommended as replacements for the 456 and 550 if the bronze guides wore excessively. Cannot access the parts catalogs and tech bulletins to confirm until tomorrow night.

Taz, according to the Ricambi parts catalog, and as you said, the 575 guides are shared with the 456 and 612, while the 550 guides are used only in that engine. And that's why I questioned the same descriptions being used for both the 575 and 550 in the WSM. Of course the WSM was probably written at a point in time, well before the car was actually released, so it doesn't take into account production revisions. But if the 575 never had bronze guides to begin with, then it appears to have been an error in the WSM, not a production revision. It would be good to get confirmation of this point from someone who's been into the 550 and 575 heads and replaced the guides. I'd also like to have a tech description of the valves, if nothing else to know whether they're SS, their stem diameters, etc. It would also be interesting to know if Ferrari carried over their penchant for sodium filled exhaust valves or if that was finally phased out.

Originally Posted by tazandjan

The early 575s also had a unique thermostat housing with an extra water temperature sensor. This was changed during production for the 456/456M housing with no sensor.

Saw that in a WSM pic and was thinking how much easier it would be to change that sensor than those under the manifold. Too bad they didn't keep that design. Do you know if that sensor was for the gauge, or for the fans?

Originally Posted by tazandjan

Also, the front suspension and wheel bearings were a different design on the 575 with no stub axles and reduced unsprung weight. The ABS sensor wires pass through the space where the stub axle was on the 550.

Missed that, thanks. Also it looks like the same wheel bearings were used both F&R for the 575, while the 550 needed a different P/N for the front bearings from the rear. It would be interesting to see a pic of the 575 with the front wheel off. Same P/N's for the steering knuckles for the 550/575, so I wonder if the 575 wheel bearings could be used for the 550 ($700 cheaper, and already includes the ABS sensor)? Looks like a different setup on the rear however, with different P/N's for the hubs.

Originally Posted by tazandjan

The banjo fittings on the 575 transaxle were also much heavier than those on the 550.

The fuel cooling ECU and hardware were eliminated on the 575 and one other ECU was also eliminated, but I cannot remember which one without reference to a parts catalog. The 550 actually had more ECUs than the 575.

The brakes were identically sized except for one larger set of pistons on rear 575 brake calipers. 575M wheels were lighter weight than the replacement 550 aluminum wheels.

Will add some more when I do not have to do it from memory and can reference your chart.

Will add the points about the banjo fittings, brakes, and wheels. Had already included the differences in the fuel system.

Bret, I think a 550 bumper could be mounted to the 575, because the reverse has already been done. At least one 550 owner bolted a 575 bumper onto his car because the 550 bumper hangs so low, and the winglets are always being damaged. I think he had to replace the 550 mounting brackets with 575, but in the end it was accomplished.

[bretm]

Originally Posted by cribbj

...Bret, I think a 550 bumper could be mounted to the 575, because the reverse has already been done. At least one 550 owner bolted a 575 bumper onto his car because the 550 bumper hangs so low, and the winglets are always being damaged. I think he had to replace the 550 mounting brackets with 575, but in the end it was accomplished.

Makes sense. One would think that Ferrari would make it pretty much a bolt on affair to save development costs in the facelift that yielded the 575.

We'll see how things go in my 308 rebuild and with a bunch of outside factors (housing, jobs, etc.), but I could easily see a 550 or 575 as my next Fcar. It really is the best fit for my use case, and they're just so darn good looking.

[cribbj]

Here's an update to the table. Hope we can continue to get good participation

I'm posting it as a jpg so it's visible to all, but obviously it's an Excel spreadsheet. I can attach that if people prefer it that way. The print in the jpg is pretty small.....

[tazandjan]

John- Here is the technical bulletin confirming the 575M valve guides and the recommended replacement guides for the 456/456M (and 550, not reflected in the parts catalog because of few 550 problems) and 575M were sintered steel, part numbers 188630 and 188631.

Note that these guides were not fitted originally to the 456/456M, but are the recommended replacements because of wear issues on the original bronze valve guides. The 550 had a redesigned head and did not have as many problems with valve guides, although at least one European 550 owner did have to replace his valve guides because of excessive oil consumption and oil smoke.

There is a possibility some late 456Ms were fitted with the sintered steel guides, but I have been unable to confirm one way or the other.

That section of the 575M WSM was likely copied verbatim from the 550 WSM, error and all, when the WSM was written in late 2001.

Brian Crall says good quality bronze valve guides work fine in the 456/456M (and F355, which had similar problems on some cars).

[Brian]

I went through school on both cars. It would be far easier to list the things that are the same. The first 15 pages or so of my 575 school book is a list of major differences. It is a very long list. I suspect there are few interchangeable parts.

The school notes also have an additional 10 or so pages on what I consider the ill concieved and poorly executed TPMS system. I have never seen so much space given nor attention paid to any other manufacturers TPMS system.

It would be an accurate ststement to say they are different cars with similar body work.

[cribbj]

Taz, thanks for the confirmation on the guides. Do you have any info about the material Ferrari used for the valves themselves? Curious if they're a steel alloy, SS, or something even more exotic like Ti or inconel? Since Ricambi's price per exhaust valve is around $140 each and intakes are $200, it would "seem" they might be a bit more exotic than a run of the mill steel alloy.

Brian, thanks for your input; is there any chance you'd consider putting some of that school info in the public domain? Not any proprietary service info that you use to make a living - just technical descriptions. Some owners may not be that interested in the technical details of their cars, but a number of us certainly are.