- Oct 4, 2013
Why did Triumph dispense with the splayed head in favour of the parallel port head on the T140E in 1978 ?
Anyone know ?
Anyone know ?
It was a more efficient combustion chamber design:Thanks LAB but unfortunately the question still stands...
A ‘revised head’ due to ‘emmisions’ as quoted in the article is a tad vague on detail.
As far as I know, the head changes where:
1. A move to parallel ports
2. a ‘revised combustion chamber’.
What I’d really like to know is why they did those.
But, do you mean T140V and single carb?I always thought that twin carb heads and single carbs heads were a different casting, having differences around the intake port areas.
That’s a good question...Was there something wrong with the prehistoric copper head gasket?
Meriden seems to have thought so.Was there something wrong with the prehistoric copper head gasket?
That reads like something between forlorn hope and sales talk.L.A.B. said:Quote from 'Triumph Service Bulletin 9-79' (Jan. 79) :
"... the Klinger cylinder head gasket was introduced to prevent failure to which the copper gasket was prone."
Possibly swirl induced by the splayed inlet ports directed incoming flow to exit straight out the exhaust port during the valve over lap period, not good for emissionsI thought that cylinder head was the earlier single carburettor version modified (manifolds) to take twin Mk2 Amals not a new for the 1978 model item in total but the Mk2 fitment might have been ?
There was some mention of the straightened inlet port adding to swirl as far as the splayed exhaust port but that might have been wishful thinking after the fact.
Even though 500 unit construction had stopped before 1978 I wonder if the 500 and 750 head had anything in common, the 500's did go well on the track.Possibly swirl induced by the splayed inlet ports directed incoming flow to exit straight out the exhaust port during the valve over lap period, not good for emissions
The straight inlet ports would send the intake charge at the exhaust valve face and not at the open area of the exhaust valve inducing tumble instead of swirl