The Triumph Dolomite Club - Discussion Forum

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PostPosted: Tue Dec 18, 2018 12:48 pm 
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I've got some close-up photos of the head on the injected Sprint engine in the SD2 engineering development car at the British Motor Museum in Gaydon. Unfortunately, I can't post them here without paying a fee - not sure how much even.

Anyway, these show some additional parts screwed into the head above each of the exhaust ports. They appear to be a threaded insert about 3/8" dia. sticking out of each of these is about 3/4" of about 1/4" round bar, flattened from, more or less, where it comes out of the insert.

Has anybody got a suggestion what these might be for? I wonder if they're to measure the exhaust gas temperatures remotely - though there's nothing connected to any of them.

The other question is, would anybody know how to identify a 16-valve version of the cost-reduced Triumph slant-four engine being developed for SD2 upto about 1975 or so?

Graham

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The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Tue Dec 18, 2018 1:16 pm 
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Air injectors to meet US smog regs? Was a common way to do it back then, air pump driven off the front pulley pumping air into the exhaust manifold to get more complete combustion and cleaner emissions.


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PostPosted: Tue Dec 18, 2018 1:21 pm 
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A charge? Surely that would only be if you publish the photo for profit? There are a few pictures of the SD2 floating around but they always seem to just show the injection side.

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Current fleet: Triumph Dolomite Sprint '75, Daihatsu Fourtrak, Honda CG125, Yamaha Fazer 600, Shetland 570

Disposal fleet: Golf GTi 16v MK3 Anniversary

Past fleet: Triumph 2000, Lancia Beta Coupe, BL Mini Clubman, Austin Metro, Vauxhall Cavalier MK1 & MK2, Renault 18 D, Rover 216 GSI, Honda Accord (most expensive car purchase, hated it on pickup from dealer, was made out of magnetic metal as only car I've ever been crashed into, 4 times), Golf GTi MK3 16v x 3


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PostPosted: Tue Dec 18, 2018 1:34 pm 
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A charge? Surely that would only be if you publish the photo for profit? There are a few pictures of the SD2 floating around but they always seem to just show the injection side.
It's because I had them take the pictures for me, so they retain copyright. If I went and got them to lift the lid and I took pictures I could do as a would, but between the petrol and the cost of a new ear after the wife'd had her say, it was just easier.

None of the other photos showed what I wanted to see - the exhaust manifold.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Tue Dec 18, 2018 1:36 pm 
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Air injectors to meet US smog regs? Was a common way to do it back then, air pump driven off the front pulley pumping air into the exhaust manifold to get more complete combustion and cleaner emissions.
That would make sense, as the SD2 was supposed to be able to meet US emissions requirements. In which case, the bits of round bar would be just plugging up the holes?
Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Tue Dec 18, 2018 1:43 pm 
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Air injectors to meet US smog regs? Was a common way to do it back then, air pump driven off the front pulley pumping air into the exhaust manifold to get more complete combustion and cleaner emissions.
Also, it seems that air injection wasn't enough on its own because, according to David Knowles' TR7 the untold story, the carbed version couldn't meet reqs, and the injection system was also needed.
Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Tue Dec 18, 2018 9:08 pm 
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Air injectors to meet US smog regs? Was a common way to do it back then, air pump driven off the front pulley pumping air into the exhaust manifold to get more complete combustion and cleaner emissions.
This sounds like a very likely explanation to me! Ive had a couple of 80s American cars and this featured on them. they had holes in the head above each exhaust port with a threaded adaptor screwed into it and a metal pipe leading off which eventually wound up at the affectionately named "smog pump" I'm not sure that carbs in general couldn't meet US emission standards, my 85 Oldsmobile Custom Cruiser station wagon had the full smog pump kit, electronic ignition and a hulking 4 barrel Rochester carb on its 305 cu in V8, all of it OE. Not sure why they bothered, the rotten thing only produced about 140bhp and did around 8mpg, I didn't keep it long! A later Cadillac Seville that I inherited from my father in law had a fuel injected but smaller V8 that was positively eco friendly by comparison, according to it's trip computer, it could do 26 miles per (US) gallon at 65mph cruise. This car also had the full emission gear fitted and working. But the results it produced on British MOT testing equipment were not all that good!

Steve

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2 door '73 Toledo with Vauxhall Carlton 2.0 8v engine OWF 797M (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 45 years and home of Maverick Triumph.PM for more info or quotes.


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PostPosted: Tue Dec 18, 2018 9:40 pm 
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Once again, I'm going off what David Knowles says about the carb version of the Sprint not being able to meet US requirements.

As I remember, and I'm not certain I've got this right, the California Spec TR8 had to be injected because of the higher requirements there, and still only made 135 hp. I think it gives a bit better than 8 mpg. Maybe ever twice that.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Tue Dec 18, 2018 10:12 pm 
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:lol: Well I guess you can understand the 8 mpg when you consider the roughly 2.5 tonne weight of a "full size" US wagon and total absence of anything resembling aerodynamics. So a TR8 would be at an instant advantage. But there's NO excuse for only getting 140 BHP from a 5+ litre V8!

Maybe there's somthing inherent in the SU design that kept them outside the US specs (or just bloody mindedness by US legislators)

Steve

_________________
2 door '73 Toledo with Vauxhall Carlton 2.0 8v engine OWF 797M (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 45 years and home of Maverick Triumph.PM for more info or quotes.


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PostPosted: Thu Dec 20, 2018 9:44 am 
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I've been back and looked at the pictures from the BMM of these things screwed into the head. And it does look like they are fairly thin walled tubes that have just been cut off and hammered flat. So I think they must be inserts for a smog pump, as suggested by matt of the vivas.

As to whether there's a problem with the SUs specifically, I don't know.

But while the UK spec TR7 Sprint compares very well with (arguably is better than) a US spec V8 in a TR8 (slightly lower max power, but peak torque given at a higher percentage of maximum rpm), presumably, by the time this smog pump's sapped its power, the 135 hp V8 is a clear winner - even with its asthmatic top end.

BTW, anybody know what power one of these air pumps uses up?

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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