The Triumph Dolomite Club - Discussion Forum

Hi is there a way of getting decent power from an 1850 engine using bolt on parts ? I want to use the car for targa rallies

Mild head porting + port matching inlet/exhaust.
"Accidentally" stick a TR7 engine in for a few more CC?

Not aware of any off-the-shelf cam upgrades for an 1850 at the moment - I wish somebody like Newman cams did one.

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Change the camshaft and put HS6 carbs from a TR7 on it; the latter will be of limited benefit without the lumpier cam.

Have a look in Terry Hurrell's Triumphtune book in the 8 valve section.

Alun, any ideas on a source for a "lumpier cam" ?

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Newman, Kent, Piper...I believe they all have a minimum order quantity of one...

Fit an LPG system. My 1850 had 110hp at the wheels with std cam so std sprint figures...

It's all in the head and bolt on will not do much. Raising the compression ratio, angled valves and seats and set the cam timing correct is all you need. Hs6 carbs are too large and won't benefit.

Jeroen

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Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com

Newman, Kent and Piper don't list an 1850 cam in their catalogues - is it a case of contact them or is there another model that can be used?

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The cam folk will grind to whatever profile you request; is the TR7 listed?

Do I correctly recall that later 1850 heads had bigger valves?

No tr7 listed for those suppliers. Some list Sprint but I assumed (am I right?) that the geometry of the lobes would be totally different on those?

I've bunged an query in with Newman cams (very pleased with the fast road cam I had from them in the 1500 engine) to see if they can do a TR7/1850 cam even if it's not listed.

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Yes I believe they do, my early 1850 (1973) has the smaller valves. I am tempted to upgrade to the larger valve head but at the same time keep it original.

Malcolm

Back in 2014 I sent a standard camshaft to Kent cams. They reprofiled to "DM1" spec, which is 284°.
125 GBP

I am bit cynical about the benefits of porting. Gas flow is incredibly complex and difficult to model. I find it unlikely that someone working at home with a dremel is going to succeed. In fact I would put good money on them making things worse.

It is certainly more complex than simply making the ports bigger and knocking off sharp edges.

The head castings are different, the water transfer housings between the two types are not interchangeable
so your idea will look different


Ian

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Perfection is almost certainly beyond a man with a dremel and needs at least a flowbench.

But port matching doesn't and gives proven results. Yes, it's easy to go just that little bit extra - and go too far. But if you're sensible, there are gains to be made for very little cash outlay.

Easier on older engines as they were much rougher to start with, modern stuff is made with tighter tolerances because higher efficiency is demanded. That's why a 70s production 2 litre 16v (Sprint) makes 127 bhp and a 2020 production 2 litre 16v makes 250bhp or more. It's still an internal combustion engine with the same basic design, just built better! Nowadays Ford will sell you a 1 litre 3 cylinder car that puts out over 140bhp, I wouldn't buy one as that sort of output can't last long IMO, but what do I know?

Steve

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'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey, Now with RWD and Carledo powertrain!

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