My Purple Project - SE5a 1973

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adamwilkes
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My Purple Project - SE5a 1973

Post by adamwilkes » Sat Oct 17, 2020 2:19 pm

I've been wondering about windscreen wipers - I need some new ones to replace the 30-year-old ones on there anyway, and I wasn't happy about the passenger (left one). The left wiper's outer couple of inches leaves the screen when it goes to it's park position because of the wrap-around shape of the screen. I started a new topic for this, and this is the conclusion I think - viewtopic.php?f=1&t=44111

IMG_3420.JPG
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Here's a pair of new stainless wipers - one is 12", one is 15"; seems to work fine, with little change in swept area since most of the relevant 'miss' area is where the 15" wiper left the screen anyway. The 12"still leaves the screen a little, but not as much as with the 15" so I am happier. Also shiny :D

Purchased at low cost from https://boltonbits.co.uk/. Paid £10.99 for a pair of 12" and £10.99 for a pair of 15", all stainless, inc P&P. Covering my bases (and a pair of spares)! The areas within the red lines and wiper blades are cleared by the blades.


wiper pattern 15 & 12 inch.JPG
wiper pattern 15 & 12 inch.JPG (92.24 KiB) Viewed 314 times
Last edited by adamwilkes on Sun Oct 18, 2020 9:52 pm, edited 1 time in total.


Adam Wilkes
Scimitar GTE 5a 1973, kinda Highland Purple; after months of work, still a ruin!
I can't help myself - I have to ask questions and find out why. Why ? Dunno :shock:

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MikeyBikey
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My Purple Project - SE5a 1973

Post by MikeyBikey » Sun Oct 18, 2020 10:37 am

This is a great thread Adam, just reread a lot of the content. I wish I had your courage re cutting out holes in the bodywork. I need to, to weld up chassis bits and bobs but can’t bring myself to do it.


Is we sideways yet...

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adamwilkes
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My Purple Project - SE5a 1973

Post by adamwilkes » Sun Oct 18, 2020 12:09 pm

Mikey, you have fitted a completely different & modern engine to your Scimitar - something only a few people could complete successfully, how can a few cuts in eminently replaceable glass-fibre panels be a problem ? The paint does look nice though :roll: Try it from the inside first :D


Adam Wilkes
Scimitar GTE 5a 1973, kinda Highland Purple; after months of work, still a ruin!
I can't help myself - I have to ask questions and find out why. Why ? Dunno :shock:

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adamwilkes
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My Purple Project - SE5a 1973

Post by adamwilkes » Sun Oct 18, 2020 7:40 pm

New exhaust manifolds

Background for the interested!
The GTE has a 6-cylinder engine in it, with cylinders placed in a 'V' arrangement (hence 'V6')- three cylinders on one side, three on the other side of the engine bay. This means there are two exhaust systems which in this case are totally independent from each other - so we have two manifolds bolted to the engine, running through to two tail-pipes. The manifolds begin the exhaust system and are - as standard - cast iron, partly because it's a cheap option for the manufacturer. Mine are cast iron, but it is well known that properly-designed 'tubular' manifolds (aka 'extractors' or 'headers') made from steel/stainless-steel pipes are more efficient for the engine. Using them means that you can get more power and better fuel efficiency because the pathway for the exhaust gasses tends to be a lot smoother; the manifold pipes are properly sized in length and shape to optimise flow down the single pipe that then runs under the car from where the three manifold pipes join together.

So what?
The driver's side cast-iron manifold on my car has been repaired before, and subsequently repaired by me to weld-repair where one stud screws in; the mating surfaces are poor and the join needs some more work to be gas-tight when the remaining exhaust pipe is clamped on. I suspected that a new one would be needed in the end, so my thoughts wandered to tubular types to improve the engine as well as replacing the leaking manifold. Some while later and with a happy coincidence I managed to buy a pair of used stainless steel tubular manifolds from two chaps from this forum, one side from each person! One was sold as being holed at the point where the three manifold pipes join to form one but I thought I could weld-repair it. Apologies to that seller in advance! The steel that the manifolds are made from is pretty thin and I botched the weld-repair completely, despite concerted efforts. I don't have a TiG welder which would have been perfect for the job, so I used a MiG welder which proved to be a blunt tool when a delicate touch was needed. Since I saw that the manifold was becoming a right-off I decided to practice brazing some areas of it instead, but I only had a propane gas torch so that was very difficult as well :shock: I couldn't avoid leaving some pin-holes; It's all going very well, isn't it!

An example of cast-iron manifolds for the Ford V6 engine:

Pair-Ford-Essex-30-V6-Exhaust-Manifolds-Capri.jpg
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The good tubular manifold, passenger side:


good extractors.JPG
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I decided to buy an oxy-propane set (a lot like oxy-acetylene but a mini-sized kit) so that brazing may be more practicable. (That oxy-propane kit is also fantastic for releasing stuck bolts, since the heat is terrifically concentrated and hot :D ) The manifold is such a mess now, however, that repair is going out of the window and scrapping or rebuilding look like the only options. The manifold is of a 'short' type, where the three manifold pipes join together before they reach the car's floor level; more common is a 'longer' version where the three pipes join just below floor level after turning around the chassis. There are pro's and con's to each type, depending how you want to use the car. The short ones seem a bit rare, so I feel a bit stuck with one good one and one rubbish one. I am thinking about rebuilding the manifold, but optimum building of manifolds is a specialised job involving lots of pipe-bends and TiG-welding (I still don't have a TiG welder). The Gilbern Invader cars (which have used the same engine as the GTE) seem to have had a short tubular manifold fitted at least sometimes as well, and that one is made of less curvy tubes:

Gilbern invader manifold.jpg
Gilbern invader manifold.jpg (12.41 KiB) Viewed 212 times

The more common 'long' tubular manifolds similar to those used on many Scimitar GTE's:

long extractors.jpg
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I am thinking of using fairly straight pipes in a similar fashion to the Gilbern pipes (above), making one to go 'straight through' from the middle exhaust to the existing stainless steel exit pipe, then making the two other pipes join into the first new one from the side ('scarfed' into place). Rough mock-up of the initial idea shown below, with a stout brace to be tacked on to keep the exit pipe in place relative to the manifold engine-plate; the existing three pipes can then be cut out and replaced:

OS extractors.JPG
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I've not done anything with exhaust manifolds before, so - given I have a scrap manifold - I thought I may as well experiment on this one :) I realise it's not going to be 'factory' but it's going to be interesting !
Last edited by adamwilkes on Sun Oct 18, 2020 10:22 pm, edited 4 times in total.



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Old and Slow
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My Purple Project - SE5a 1973

Post by Old and Slow » Sun Oct 18, 2020 7:49 pm

The book I have, "Scientific Design of Exhaust and Intake Systems" explains why the longer pipes are better. (It was first published in 1972 so I think things might have moved on a bit, but it includes contemporary pictures of the Mays head for the Zodiac engine) .
We used to call them "banana bunches"
I wish I'd learned to weld. Good luck.


Philip Needham
Ashley-bodied TR3; '54 Ford Consul; '55 AC 2-Litre Saloon;'65 850 Mini; '70 Ford Zodiac MkIV; XR3i
'81 911SC Targa, '64 Sabre Six

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MikeyBikey
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My Purple Project - SE5a 1973

Post by MikeyBikey » Sun Oct 18, 2020 8:51 pm

I can post a picture of the essex open headers I have, if it’s any help. And give the lengths from header to collector.

Also I had a 2” system throughout, and no middle boxes. I liked it so much I’ve transferred it to the scimega.


Is we sideways yet...

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adamwilkes
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Post by adamwilkes » Sun Oct 18, 2020 9:03 pm

MikeyBikey wrote:
Sun Oct 18, 2020 8:51 pm
I can post a picture of the essex open headers I have, if it’s any help. And give the lengths from header to collector.
Thanks for the offer Mikey; if anything, at present I'm intending to (roughly) copy the good left manifold, so I'll just keep the sizes as-is. If I end up with a pair of pretty-much-the-same manifolds I'll be happy - what I don't want is one half of the engine working a lot harder than the other because of exhaust flow differences between them.


Adam Wilkes
Scimitar GTE 5a 1973, kinda Highland Purple; after months of work, still a ruin!
I can't help myself - I have to ask questions and find out why. Why ? Dunno :shock:

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adamwilkes
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My Purple Project - SE5a 1973

Post by adamwilkes » Tue Oct 20, 2020 2:36 pm

Back by popular request: manifold making lash-up :D

As can be seen above, the offside new tubular manifold is a write-off, so here is me setting about making something out of nothing so I can have a pair of nice (?) tubular manifolds. The pictures pretty much show the sequence, and I am surprised by how well it went in the end. I'm not sure what difference the lack of a collector will make on the performance (not that I will notice) but the approximately equal lengths of pipe before meeting up at the one pipe may still function to smooth and speed the exhaust gasses out of the engine.

The basis of good manifold design is (I think) good gas flow - helped by the theory that one exhaust gas pulse from the engine has some momentum and helps pull out the next cylinder's exhaust gas pulse. If the pipes are fairly equal in length, the pulses will hit the single pipe at regular intervals and the neighbouring exhaust gases will be pulled out by the single-pipe gas momentum in good time and regularly, optimising flow, helping the efficiency of the engine.

This really is pretty much the end of my stock of garden trampoline steel framework, which I scavenged about 15 years ago 8) It has been handy many times - this time as it is the same size as the exit manifold pipes and because the trampoline pipe has a slight curve which I have tried to use to benefit smooth gas flow. The manifold is a bit of a mis-match of materials, with the top and bottom sections still being tarnished stainless steel and the new tubes being galvanised steel (cleaned up where welded) attached with mild steel MiG weld. I don't suppose I will wear it out !

This isn't a job I've been looking forward to really - prior experience of the stainless welding proving I hadn't got the measure of it when I tackled it a while ago. This time I have a better handle on what settings to use on my MiG welder - fore-warned is fore-armed - and it worked quite well :wink:
The existing manifold was tacked to a rigid section of steel frame to make sure that the exit pipe stayed in the right place relative to the top section.

Let the disembowelment commence:

new OS manifold (2).JPG
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First pipe welded in - and suddenly the job looks a lot easier :)

new OS manifold (3).JPG
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Second pipe:

new OS manifold (4).JPG
new OS manifold (4).JPG (125.94 KiB) Viewed 106 times


After cutting the hole for the last pipe, this is the view past the first junction - it's pretty tidy I am happy to say, having spent some time getting the fit to be almost 'edgeless' so that the exhaust gas isn't roughed-up and slowed down too much:


new OS manifold (5).JPG
new OS manifold (5).JPG (84.24 KiB) Viewed 106 times


The finished article - hopefully a decent match for the good manifold to be fitted on the other side! I kept the pipes that join the central one about the same length , hence they don't join opposite each other - not a mistake! And yes, I have run out of high-temperature paint :(


new OS manifold (7).JPG
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Last edited by adamwilkes on Tue Oct 20, 2020 8:51 pm, edited 2 times in total.


Adam Wilkes
Scimitar GTE 5a 1973, kinda Highland Purple; after months of work, still a ruin!
I can't help myself - I have to ask questions and find out why. Why ? Dunno :shock:

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My Purple Project - SE5a 1973

Post by philhoward » Tue Oct 20, 2020 3:31 pm

I think theory and reality diverge quite a lot when you see OEM manifolds so unless you are after every last ounce of power from it, that’ll be fine 8)


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My Purple Project - SE5a 1973

Post by Old and Slow » Tue Oct 20, 2020 7:29 pm

That's a very neat job you've done there. Like it! :D


Philip Needham
Ashley-bodied TR3; '54 Ford Consul; '55 AC 2-Litre Saloon;'65 850 Mini; '70 Ford Zodiac MkIV; XR3i
'81 911SC Targa, '64 Sabre Six

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adamwilkes
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My Purple Project - SE5a 1973

Post by adamwilkes » Tue Oct 20, 2020 7:59 pm

Old and Slow wrote:
Tue Oct 20, 2020 7:29 pm
That's a very neat job you've done there. Like it!
Thanks Philip - next comes the 'interesting' part, fitting them to the engine :?


Adam Wilkes
Scimitar GTE 5a 1973, kinda Highland Purple; after months of work, still a ruin!
I can't help myself - I have to ask questions and find out why. Why ? Dunno :shock:

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