Here's the real McCoy - GBP500 each inc VAT
https://www.bighealey.co.uk/jaguar/jagu ... aight-port. Plus 180 incl for the flanges/tubes. About 1200 anyhow. You can't have too much breather unless you want to establish crankcase vacuum or meet emissions, but 1100-1200 squid is a lot of money to save small pumping losses. On a big single or 360-degree parallel twin or boxer (and some V-twins) these losses are significant. On a 180 degree twin or multi-cylinder, less so. Still, it looks 'racey' and Jag used this system on all Ds and Lightweight Es. Some people even think it means a wide-angle head and who am I to pop their balloon?
I did invest about 500 for my D-Type from another source, but for a road car I went for a DIY option and made another solution: Old covers plus 200 worth of bits. Note, the ones on the engine have not been milled yet to get the alloy half moons flush with the gasket face for use on a big valve head:
I had half a dozen twin-breather towers for the left cover cast using a pattern not shown and the transverse breather tubes/flanges cast using the red wooden one. This has the cover flange boss that welds to the cover cast integral with the tube and flange that's bolt to it. This was to ensure perfect alignment when drilling breather and fastener holes, prior to sawing into two parts at the point where the flange meets the boss. Sadly (but harmlessly) the cut was made by the foundry at the 'wrong' place, leaving a bit of boss on the flange but this will be trimmed off.
The twin breather tower has two standard tube size pipes protruding (7/8"/nominal 22mm), which are very snug fit and angle back with convoluted alloy/paper breather tube attached, for that 'works team' look
. The pipes have a 120-degree kink and can be rotated to fold close to the cover, before holding firm with gasket goo. You can just use short tumps of straight pipe and let the breather tube take the bend. The transverse tubes and flanges can be made of tube and sheet metal, which is more original or you can buy from Denis Welch and align the holes yourself. The transverse connection here is oil-proof rubber hose, not alloy breather tube. The picture shows left to right: steel tower tubes before trimming, the 'works' transverse fittings and hose, fabricated steel transverse fittings/flanges and 120 degree brass plumbing fittings that could be soldered to a flange or used as breather tower tubes once slipped over a short copper stump into the tower. The standard S1 breather has a 0.5" ID. These conversions more than triple that with 2x 0.8"
The final picture shows my S2 with its crossover, to demonstrate clearance for the tower. Even with the black lid in place the bonnet still shut, so although my engine mountings are due for renewal, you can see the clearance where the tower would be.
Finally, for those who have asked, here's a very fuzzy picture from the shipper (CARS, nr. Bury St Edmunds) of the D-type slung together for shipping, pending disassembly, final riveting and rear skinning/painting/completing.
To recoup my outlay a bit, I will sell the three spare breather towers, each with enough tube and 2x brass 120-degree fittings to make the two breather pipes. The Denis Welch tube set that cost me about 180 inclusive, would sell for the VAT-free price. If we have a lister with foundry connections, they could use the wooden transverse pattern to cast more, and turn a spare tower into a pattern to make more of those. Contact me off list, I suppose.
, what are the advantages of fitting such a cap?
