Headers No. 2 (105)

[Clayton105]

These pistures aren't really needed, but I thought I would put them in anyway. This is the head and engine bay of the 105 group NC race car one set of the headers I made was going into.

It had been a while since the head was off and so we decided to pull it off for a freshen up while I was building the headers. I did not do the head originally as I was too busy at the time.... Man: what a slap-dash job, considering it was supposed to have been done by a respected Alfa "guru". I fixed that up too... But that is another story.





Primaries done, but not secondaries. The stubs were 1 5/8" (pains me to speak in imperial units...), and the primaries are 1 3/4". Three reasons: one is to help with the clearance issues around the top nuts, accepted formulae dictates 1 3/4" should be correct diameter primaries, for one of these and the internal step is supposed to help with anti reversion and scavenging.... whatever! Can't be worse than what was on there. Primaries are all 17 - 18" long.



Correct angle out of the head. Remember that the engine tilts ~5 dregrees to the left. So by my calculations, the header should exit the head at 14 degrees down from the horizontal while installed in the car.



Trial fitting in the engine bay with some extra shielding for the brake fittings. I still had to fix the head at this stage so had not painted them.

[gtv27]

the pictures seem to be AWOL??

[Clayton105]

Hmmm... very strange! I could see all the pictures at work, but not from home. Will try and sort out tomorrow.

[Andrew]

I can't see the pics either. There's an blank indicator where the pics should be.
Andrew

[gtv27]

woohoo - pictures!

nice looking pipes.

[ciscotex]

Beautiful headers. I don't see any welds between segments. Did you bend them by the sand/heat method? If so, could you describe the process?

Paul

[Clayton105]

I just bought off the shelf 180 degree madrel bends and then cut and welded to suit the routing. The welding was done where you can see the shiny areas from the flap/gringing wheel on the angle grinder. The closest to rocket sience in the manufacture was the laser cutting from a CAD file.

[Andrew]

Norman Racing makes customs headers up from store-bought standard straight, 90, and 180 pre-bent pieces welded together on a jig they have. All bending pre-done, plus pre-made collectors, all in beautiful stainless.

Andrew

[ciscotex]

Thanks for your response, the work really is pretty.

The reason I asked was that Alfa was famous in the 30s for their beautiful heat/sand bent tubing on their aircraft engines. Saw a brief segment on the Ralph Lauren restoration of his P3(?) and his craftsmen were using the same technique (authenticity, you know). Supposedly it is quicker and doesn't leave weld bead inside the header, but apparently this is a (pretty much) lost art, as what info I've turned up is rather scant.

Paul

[Alex]

My brother just had some custom sand-bent headers made for his Lotus Europa, with a twin-cam 2 litre Vauxhall engine. Not cheap but a work of art, all done by eye, and not a ripple to be seen on any of the tighter radii. Essentially, a plain tube has a round plate welded to one end, filled with sand and vibrated to compact this filling, topped up as required and then welded up at the open end. The pipes are then bent around a series of mandrels and formers to achieve the desired shape, the idea being that the compacted sand should prevent the metal from buckling. The ends are then cut off and emptied of sand ... et voila!

[Clayton105]

Great if you want a set of perfect headers made in the traditional way (and have the money to have it done).

I had never made a complete set of headers before even though I had done systems on a few occasions, so I sort of took these on as a "tick in the box" job... for my own personal satisfaction. I really made no money from this... I tend to charge a token amount as my time is worth something... I would rather be out skiing, cycling or spending time with my wife than welding and working on cars these days.

As I said in another post, my gear was partialy borrowed, and a bit inadequate. But I am pretty happy with at least the look of them. Neither cars have been dynoed yet, so the jury is still out on the HP increase.

I am also a believer in the laws of deminishing returns, and don't get too fussy on finish as long as it is not ugly as... But my approach is that the design and getting the geometry correct is FAR more important than the details of the finish. Some areas the devil is not in the detail!

These two sets took much longer than I anticipated... if I did more sets, a jig would cut down the time considerably.

I once had a set of 4-1 headers made for a 105 coupe of mine: dropped the car off at 9 in the morning and picked it up at 4.... completely finished and fitted set of headers fitted on the car in under 7 hours!

[ciscotex]

I asked only because the finishing on them is so clean, I couldn't see any welds. Hey, you have my undying admiration for having taken up the challenge and completed it.

My question about the sand/heat bending more or less went to what you were saying about the header shop, ie trying to learn a potentially quicker way to get to the end you achieved.

Thanks for your response,
Paul

[Clayton105]

Quote:

Originally Posted by ciscotex My question about the sand/heat bending more or less went to what you were saying about the header shop, ie trying to learn a potentially quicker way to get to the end you achieved.

[1166]

Quote:

My brother just had some custom sand-bent headers made for his Lotus Europa, with a twin-cam 2 litre Vauxhall engine. Not cheap but a work of art, all done by eye, and not a ripple to be seen on any of the tighter radii.

[iachella]

Just wondering out loud here, but don't exhaust manifolds on Alfas need to have separate flanges due to the vibrations of the engine? All the manifolds and headers I've seen do not have a solid piece across the all the ports as you have done. Aren't you looking at possible cracking later on?