Genuine help from you experts needed!!

[Forkie]

Well, this guy turned up, and what an interesting 5 hours it turned out to be!! His first question was - ' in D is the car changing up twice within the specified speed range ( thus qouted) - yes! He checks the box dipstick colour, and asked to see the filter that was removed - ' the issue is not your gearbox'. Ok !! Next he asked what fuel pump it was running ( before even going over to the N/S ) - stock, in fact N.O.S. glass domed top. Wanted to check what the fuel flow was being pushed out.....so fuel line off, hand cranked, then off the starter into a measuring jug - 5 mins of maths later ' your pump is within tolerance' - ok so not the 'box nor weak pump. Next up - compression test ( cold), which was one thing on my list , but had not yet got around to doing.

[Forkie]

This was the most interesting piece of the whole 5 hours. So he had to remove the alternator right out of the way , to get proper purchase of the unit into number 1 cylinder. Ok so all ready to go ( he had removed the whole dist cap with all 7 leads right out of the way). Off we go.... # 1 reading - 152 psi. # 2 152 psi #3 152 psi #4 152 psi #5 152psi # 6 152 psi. He was totally amazed, and quite frankly so was i. I have maybe done a dozen or so cars over the years, and NEVER had all cylinders reading exactly the same, and this guy also said he has never ever had that (30 + years in the trade) - he was gobsmacked. All 6 cylinders reading exactly the same psi. So after that point, he remarked my issue is not the gearbox, nor inside the engine itself.

[Forkie]

So he now turned to the carbs. He agreed that there is some wear, to the rods, pistons, and pointed out odd wear to the dampers also - then he asked me what oil i had been running them with when i mentioned engine oil - 20/50 i had my knuckles rapped his opinion is way to thick, moreso when cold. S.U. oil reccommended, but 3 in 1 oil is a fifth of the price..... when he removed the spark plugs he remarked ' wrong plugs, and wrong gap..... my leads are too long, get proper leads the list was endless!!!!! Then we got it built back up ready for a start up - then the real fun began.....

[Forkie]

So he wasnt interested in re -installing the ( as he calls it - the April 1975 Friday 3pm air intake system design) and i am sure i have read somewhere a long time ago the S model is proper strangled of air intake through that system - he got me to fire it up without any of that installed. Complete bag of rusty nails to start with. But using his ear, he was adjusting this, and tweaking that - and eventually i was able to push the choke fully home and retain an idle.Its at this point he asked me to remove myself from the drivers seat and join him to the O/S front.

[Forkie]

So, apparently, the rear carb idle was screwed right down, and the front carb was free from its stop - i think thats what he said! So in effect the idle speed was only being set from the rear carb - he has no idea how i was even able to drive it. The rear carb was running rich, front was lean as suspected. In his words ' this car was last tuned by a monkey without fingers'
So where are we now - without any airtake system fitted at all( bare at the carb intakes) and the the 3 way pipe system from the rocker cover outlet to both carbs also removed - she is an absolute animal when revved - sweet as, and idling nice. Fit that three way pipe system back ( air filter system still removed ) and in his words - ' its unhappy again'. So the general prognosis is that although i have minor set up issues that need to be sorted - thinner oil in carbs, better plugs and leads , the main issue is air flow into the engine - coupled with i now have a free flowing stainless exhaust, but the engine is not able to draw in the required airflow that the bigger exhaust can now exhume. So he is going to draft up a bespoke airflow system to suit the engine and exhaust as it stands.

[Forkie]

So this evening, i thought to go for a simple start up, as it only ran yesterday - no plugs out and wind over to get oil pressure up - nope - just get in, pull out the choke and turn the key. - two revolutions and away she went, purring on all 6 . Let it settle down,warm up then blip the throttle - yep that engine still now twists to the left, and sounds glorious. I feel im finally getting somewhere !!!

[johnnydog]

I'm glad that you appear to be finally getting somewhere Forkie after all your persistence!
I am also glad that Alec and I appeared to be on the right track insisting that the issue appeared to carb related rather than the gearbox!!! I'm surprised to hear about the mixture settings being such a way out, and the throttle linkage being totally imbalanced - I agree about the observations of 'your man' about a 'monkey without fingers'!!
When setting HS6s up, they do run a little differently with the elephants trunk removed (a bit weaker) but not such that that they won't idle correctly after refitting it - you couldn't really correctly tune them with it in situ!
So it basically appears your issue was the throttle linkages incorrectly set, combined with some wear, and incorrect mixture settings on both carbs - but a successful diagnosis by 'your man'....in the end!!
Bet it feels good knowing you have got somewhere near!!

[Alec]

Hello Forkie,

you must be pleased and relieved.
A point about oil, I always understood that a multigrade oil like a 20 50 has the viscosity of a 20 grade oil when cold and has the performance of a 50 grade oil when hot. S.U. do specify a 20 grade oil for their carburettors, and from interest I Googled the viscosity of 3 in 1, which came up as 20, so the same as S.U. recommend.

Alec

[Forkie]

Hi Alec and John

Yes im very relieved to be getting somewhere finally - this guy seems to know his stuff. Regarding the 3 in 1 / S.U. oil - thats exactly what he said. As i had no S.U. here but did have 3 in 1 ( who doesnt have a can!) he suggested to put that in as it is virtually the same viscosity.
I believe we are going to retain the elephants trunk but from there fit a stainless pipe right through to rear of grill with a K & N cone, then fit a couple of small ones on the cars where the rocker breather currently connects ( that pipe set up really upsets the idle for whatever reason), then a catch can from the rocker box.
Sun is finally appeared down here so i may be tempted after work to have a sneaky short drive....
Thank you both for your continued interest and input
Regards, Nige

[Alec]

Hello Nige,

I'm not sure how Triumph intended the breather arrangement of your car but some need a sealed engine breather system and anything that breaks the seal upsets the engine running?

alec