Setting ride height for 330 GTC

Thanks Dyke.
So we can assume factory specs for suspension settings were same or close ?

 

Timo: They were the same.

 

Thanks Dyke.

So, if any 365 GTC owner/caretaker/mechanic is willing to share aforementioned measurements from their car, it would be helpful and great addition to my research.

 

Very interesting day at the shop yesterday when two 330 GTC’s presented themselves for my “ride height” research measurements (Thanks TM).

While one has some obvious underlying issues needing attention before I can proceed further with the suspension sorting and cars had noticeably different tire diameters etc, the findings for the “ride height” measurements (i.e. difference between “A” and “B”) on both were quite surprising and not only from car-to-car comparison perspective, but also individually.

So any additional assistance/information/measurements from other 330/365 GTC’s would clearly be helpful.

 

Does anyone have good closeup/detail photos of the OEM upper shock mounts on 330/365 GTC/-S rear frames, with and/or without any strengthening repairs done to them ?

 

When I get my 330 out of FL and up here to NC in my new garage I will take the measurements and forward for your records. Thank you for taking this project on.

I have two sets of rims/tires for my GTC. On the set of Borrani 4039s I have mounted the XWX 205/VR14s [80 profile]. I think they look great as the tire does fill the wheel wells nicely. For driving I have the Campagnolo 7x14 rims w/ Vredestein Sprint Classics 205/70VR14s mounted. I wanted Sprint Classics in 215s but I don't think they were available when I purchased the tires. They don't fill the wheel well as nicely as the XWX. But I think they handle better than the XWXs.

In my experience with 2 GTCs and my late father's GTS the issue of the tire rubbing was not on the fender. On hard bumps or deep swales that pushed the tire up it would rub on the heater ventilator duct located at the top of the wheel well. I have had to repair this on all three at various times. I would do my best to bend the duct to be a horizontal oval shape rather than round to try to squeeze a bit more clearance from the tire rub. The smaller profile 205/70 tires don't seem to rub nearly as often as the 80 series tires.

 

Well, this certainly turned out to be an interesting (& educational) project, at least to me.

While having rather limited access for references, along with somewhat pressing timeline, I managed to sort several* suspension, steering & wheel alignment issues on Jim’s car, including repairs and upgrades for (allegedly) common problem with upper rear shock mounts**, which, like front ones on these cars seem to have been originally made with less than ideal strength materials for this type application/design..

It also seems, at least to my limited experience and informally educated eye/mind, that nearly half of factory (engineering?) drawing details/measurements/specifications for rear suspension in the service manual aren’t necessarily correct or ideal as published***, begging a question of which ones should be used for final settings and alignment, especially since some appear to have counterintuitive effect on accuracy or practicality of others.

One relatively pleasant discovery was that the custom components and methods I developed nearly a decade ago for 365 GTB/4 ride height corrections also appear useable on these and presumably 365 GTC’s & 330/365 GTS’s, perhaps others.

Interestingly (again, at least to me), while 365 GTB/4 rear chassis/upper shock mounts feature some of the same questionable strength components, their design had clearly received at least couple of different changes/improvements during their production, perhaps to prevent failures learned from 330/365 GTC/-S reoccurring (?).

I sure would love to see details of 275 upper rear mounts for comparison, especially later models, like a 4-cam or GTS and maybe even very early 2-cam, just to see what, if any, evolution took place during their production timeline.

All this also made me think what percentage of these cars might have suffered from this quite obvious design flaw and how many have received adequate repairs/upgrades, preemptively.

*A few still remain (like OEM tire & wheel size, etc.), but achieved improvements were clearly noticeable..

** Obviously there can be various approaches to remedy (or prevent) these problems, but each would likely depend on severity of existing damages/problems, if any have developed or are present.

*** OTOH, having experienced plenty of inaccuracies in OEM 365 GTB/4 reference publications, I’m not that surprised.

Finally, I wish to thank Dyke and TM for advise/assistance.

 

Timo: While I have not inspected EVERY 275 on this planet, I have personally not heard of nor encountered rear shock mount failures on these cars. My only thought regarding this is the lighter weight of the 275 cars versus the GTC/GTS cars and the resulting lower suspension stresses on the mounts.

 

Thanks Dyke, that sounds reasonable and I appreciate your thoughts.

Like with my earlier & still ongoing* research studies regarding Daytona suspension peculiarities and possible corrections for them, I’m just curious to learn more.

* I’ve come to fairly reasonable conclusions on some of the causes, but...

 

I think this film on here https://www.longstonetyres.co.uk/classic-car-tyres/ferrari/330-gtc.html demonstrates the difference in diameter of the 205/70R14 compared to a proper 205R14 pretty well i hope.

 

An XWX 205VR14 is the correct tire. That said - others may disagree, but I personally would not call an XWX a "great" driving tire. I keep a set of 205vr14 XWX mounted on borranis for shows, but for driving, I've put Toyo 215/70R14s on mags, as it gives a larger contact patch and a straighter sidewall. It is about 3/4" shorter in diameter, based on my eyeball measurements. Speedo still measures within a few % of accurate, based on my crude measurements (perhaps that means it's wildly inaccurate when using correct diameter tires).

 

Timo did a great job with his repairs to my car. I've since driven over 2,000 miles in the past couple of months with no issues, including driving 500 miles each way to the Nevada Open Road Challenge, where I finished 3rd in the 95 mph class (time variation of 28 seconds). The car is very stable and handles great. He even had the rear shocks checked by Koni. Timo has also been a great source of information about vintage Ferraris in general.

 

Hi there - i know this is an old thread - but was wondering - a friend has a sagging front end on his GTC and we wanted to assess what the proper rede height should be front and back.

With all the great work above, anyone have a few measurements they can share related to this.

This would be a good start to figure out what to do.

TIA.......

 

Hi Ed,
Timo would be your source for this info.

 

Thanks Jim.

Ed: Service manual has all or most of the pertinent information, although some specs for the rear, IMO, appear contradictory, hence likely inaccurate.

Daytona specs OTOH, while IMO grossly off when compared to actual "as built" setups found in cars themselves, at least appear accurately designed/drafted.
I just received another one in quite obvious need of OEM suspension corrections and I'll get it sorted along with few other of its "needs".

 

ok thanks - yep trying to find my service manual rolleyes: ) thought i did see that info in there

 

I’m having the shocks on my 330 GTC rebuilt this winter. I’d also like to install new springs as I have no idea how old the springs are nor if they are proper spec (I can get that checked I guess although I would like to just go with new springs for peace of mind). Does anyone have a good source for new correct springs for a 330 GTC?? I have all the specs from the workshop manual, so I suppose I could find a shop to make new springs, but hoping there is a reliable source for ready-made springs out there? Thought I’d ask before trying the usual suspects

I’ll cross-post this on Tom Yang’s site as well.

Thanks!

 

contact clete - he had some made and right on the money!!

 

Thanks. I’ll reach out to him.

 

Clete used Coil Springs Specialties in KS for his front springs and was happy with the results. I’ve reached out to them and will report back once I’ve heard back from them.

 

I’ve ordered springs from Coil Springs Specialties. Here’s the quote:

1967 Ferrari 330 GTC
Front - coil springs - OEM replacement
Pricing; $ 498.60 pair
Rear - coil springs - OEM replacement
Pricing; $ 492.40 pair
NOTE: Yes, we have the design specifications in our library
NOTE Production Time: 4-5 weeks

I’ll report back once they arrive.