330GTC engine breather

Moderators: 330GT, abrent

Post Reply
simonc
Posts: 86
Joined: Tue Sep 03, 2002 6:35 am
Location: St Albans, UK
Contact:

330GTC engine breather

Post by simonc »

We are puzzled because we seem to have a 330GTC (9069GT) in the workshop with no engine breather. It is a 'barn find' 330GTC that has been stood for a number of years, which means we don't know anything about it's history. The car will need a full restoration including an engine rebuild but will need to join the queue so this won't happen for some time yet so before we put it into storage we gave it a quick check-over so we would be aware of anything completely unexpected. The usual rotten fuel and brake lines, bushes, tyres, exhaust showed up but nothing major so we decided to see if it would run.

Before starting it we did the usual checks and noticed that the oil is very milky and obviously badly contaminated with water. It turned over OK so we changed the oil and fitted new oil filters, inspected the bores with a borescope, and performed a leak down test, fully expecting to find some major problems but the test was OK-ish with 9 cylinders at less than 5% and three cylinders between 15-20% with the escaping pressure bleeding into the crankcase. We pressurised the water system and this held 10lb overnight so we decided to try run it for a minute or two. We connected a fresh fuel supply and it fired up and ran OK. Lots of rubbish out of the exhaust but it has oil pressure and sounds good. We shut it down and checked for any external leaks but there aren't any apart from leaking carbs, and no excessive pressure in the cooling system. Now for the strange part......

By chance I decided to unscrew the flat oil filler cap and was surprised to find quite a high pressure in the crankcase - the cap literally 'popped' when I undid it. Our first thought was a blocked breather and then we noticed that this car does not have any breather system on it at all, everything is sealed. This can't be right, of course, so I checked the manuals. It seems some 330s have a vented oil filler cap with a large open tube running down the front of the engine and no vents on the cam covers (we have a 'two mount' here like this), some have two vented oil filler caps with one on each bank (have a 'four mount' here like this), and some have just the usual flat filler cap but have vented rocker covers that breathe into the inlet manifolds (have two 'two mounts' here like this).

Does a GTC have a different system to a GT? Can anyone shed any light on what breather system this car should have? We can create a breather when we rebuild the engine but it would be nice to put it back to how it would have been when new.
Simon in the UK

1973 246GT Dino
1976 365 Boxer
1977 400 Auto
DWR46
Posts: 621
Joined: Tue Sep 22, 2009 8:23 pm

Re: 330GTC engine breather

Post by DWR46 »

Simon: Since nobody has answered you, I will try. The 330 motor you describe with the solid oil filler cap on the chain cover appears to be "Blow-by" style motor. Each valve cover should have a large round housing on the top with two hose fittings. One provides air TO the crankcase from the air cleaner and one vents air FROM the crankcase to the vacuum of the inlet track. Your intake manifolds should have a series of hoses and fittings that connect with these housings on the cam covers. You can see all this illustrated in the 330 GTC Parts Catalog on Tav.7. Maybe the car you are working on has some of these pieces missing, wrong valve covers or intake manifolds, etc.
simonc
Posts: 86
Joined: Tue Sep 03, 2002 6:35 am
Location: St Albans, UK
Contact:

Re: 330GTC engine breather

Post by simonc »

Thanks DWR, that is pretty much what we are thinking. The cam covers both look to have been undisturbed for some time but then again we don't anything about the history or how long it has been stood.Do you know when the 'closed' breather system was introduced?
Simon in the UK

1973 246GT Dino
1976 365 Boxer
1977 400 Auto
DWR46
Posts: 621
Joined: Tue Sep 22, 2009 8:23 pm

Re: 330GTC engine breather

Post by DWR46 »

Simon: Starting around #8700, Factory Build Sheets for 330 cars have a pre-printed "Blow-By" noted on the chassis page. However, this is "marked out" until about #9000. I suspect they were using up the remaining stock of old style parts and that took until about Chassis Number 9000.
User avatar
330GT
Posts: 1640
Joined: Wed Sep 04, 2002 9:30 am
Location: Seattle, WA
Contact:

Re: 330GTC engine breather

Post by 330GT »

330 GTs with power steering had the cam covers with the breathers as the P/S was driven off the LH cam where the normal breather would have gone.
Regards, Kerry
http://www.330gt.com 330 GT Registry
http://www.parrotbyte.com/kbc/ferrari 250 PF Coupe 1643GT, 330 GT 2+2 8755GT, 308 GTS 23605
Post Reply