Oil Cooler Hose Question

I'm changing the lower oil cooler hose in my 75 308 gt4. This is the one that goes from the lower connection on the cooler to the engine block. I got the replacement from Superformance and I installed it and I had a huge leak from the point where the banjo joint mates to the block via copper crush washers (new also). Bolt was tight so I measured the width of the banjo joint from Superformance against the old banjo joint. The new one is 2mm narrower. So I screw in the bolt without the banjo as far as it will go and measured the gap between the underside of the bolt and block mating surface....sure enough the width of the new banjo joint together with the crush washers was not sufficient to prevent the bolt from "bottoming out"; ie the banjo joint could not be tightened.

Anyone else have this problem before? Would any of you guys have an original banjo joint handy the width of which you could measure by calipers in mm? Thanks, Blaine.

 

Thanks guys, yes that helps. Where would one find thicker copper crush washers? I cant simply grind off a mm or two from the end of the bolt because the problem is that I run out of thread on the shank of the bolt. Anyway I'd like to simply fix it as per stock.

 

The thickness of the Superformance banjo is just a bit over 22mm. If it was 24.8mm it would work no problem. I'd better at least call Superformance for some answers. Any other ideas on where to get this hose. Would Ferrari still stock them?

 

Ok, so I called Superformance this morning and talked Ron (the engine rebuilder there). This was the first he'd ever heard of this problem and was mildly sceptical until he went into the shop and measured the bolt length of a 1975 gt4 block he was rebuilding. Wouldn't you know it that bolt was shorter such that my problem would not exist. He thought I just had a bastard bolt until he went and measured another banjo bolt they had lying around and it was the same length as mine. He was really surprised. Any way he's going to check for some thick washers, but given the math I need them about 2.75 mm thick each. I think I'll just have some made up.

 

OK I talked to a very reputable independant fcar repair shop and explained this problem with the banjo fitting being to narrow. Well...it turns out he has been having the same problem from the supplier of his hoses. So a word of caution....even if you're getting your oil cooler hoses from Ferrari check the width of the banjo fitting as compared to the original. It seems there is a batch out there that is 22mm thick when the originals were 25.5mm thick.

Thicker washer is not the easy fix you might think. Firstly, there is no thicker washer available. They need to be 2.75 mm thick at minimum = custom copper washers. You can't simply "double up" the normal copper washer because it still wouldn't be thick enough...triple??

 

Ok, so here's what I did. I used the Superformance hose with "to shallow" banjo fitting. I doubled up the copper washers on the side that connects with the block. On the side that connects to the underside of the bolt head I used a custom (friend with a cnc machine) washer made from copper that is 2.75 mm thick. So far no leaks. I would have used one of the custom made 2.75mm washers on the engine block side but I was not absolutely sure that the copper I used to make the thick washer was softer than the engine block material. I didn't want to risk galling on the engine block mating surface so opted to try two factory coppers. I did not have the same concern with the nut head underside because they are both steel and as such are without question harder than the copper.

If anyone has gotten one of these oil hoses with the thin banjo fitting I can sell you the thick copper washers if you need them. No warranties and use at your own risk etc. Just PM me and I'll let you know the details.

 

This seems like the best solution. Lee, I'd definately be interested in obtaining this bolt if it's not absurdly expensive.