TRExp

Herald & Vitesse Forum

Vitesse 2ltr Mk I power loss

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

mwatts Martin Watts
Ruinerwold, Drenthe, Netherlands   NLD
I have a 1967 Vitesse 2 ltr Mk I. Afaik it is in original condition (dual Stromberg 150CD carbs). I have an issue with it however. Hopefully someone has an idea what the problem could be.

Symptoms: starts easily, revs up quickly when in neutral (does run a little bit uneven stationary, but I have not been able to identify a specific cylinder that's causing this). The car will accelerate quite nicely from still up to about 30 mph, but then all of a sudden the power will drop, and the exhaust will start making a louder, deeper noise. Pressing the accelerator paddle down just a little or fully does not seem to make much difference at this point. The car will struggle to reach 50 mph. Lifting the accelerator altogether will produce some "bangs". Subsequently applying the accelerator will give a short (1 sec) moment of acceleration, after that power will drop again.

It has had these symptoms since I first got the car. Quite a few things were of, so I have been correcting issues and the problem has got a little less, but it's still there.

Things I have done so far:

- corrected the contact breaker point gap
- did a static timing adjustment
- checked all cylinders are firing (by disconnecting the plugs and noticing if it made any difference in engine running)
- cleaned spark plugs
- checked and corrected spark plug gaps
- synchronised the carbs
- filled the dashpots
- centered the carb jets
- checked and adjusted valve clearences

After centering the carb jets I put the carbs in the "initial" setting, that is, from the jet just touching the cylinder, opening it three full turns. After warming up the engine, I got the impression the engine was running quite rich. So I turned the needles up, testing the mixture by slightly moving up the cylinder and noticing a change in revs. Doing so, I found the right (front) carb was running quite a bit richer than the left one (near the bulkhead) and needed a lot more adjusting. But still, the power loss problem remains.

Is this purely a fuel mixture issue, or is a more fundamental problem likely?

Edit: I checked two of the spark plugs today. Cylinder 2 (one behind the carb I adjusted the most) was normal. Nr 6 was black with carbon deposits. So the left most carb definitely needs some more adjusting. Nevertheless, any suggestions for other things to check more than welcome.



Edited 2 time(s). Last edit at 2017-10-16 11:41 AM by mwatts.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
Martin,
You have already checked most things, especially the carbuartion, which was my first suspect.
If it's not fuel, its ignition and as it falters as it speeds up, then I suspect timing, either static, cetrifugal advance or else the firing order.
Check 1-5-3-6-2-4.
Then do the static timing - 7BTDC
Then watch the timing on the crank pulley with a stroboscope as you rev it. It should advance as shown in the diagram, to up to 30BTDC.

I see you are from the Netherlands. Lots of good advice here, although Vitesses are rare in the US, but you might go to Club Triumph's site in the UK. There's a regular contributor there, Saltddirk form your country, who I think has a Vitesse, and others.
http://club.triumph.org.uk/cgi-bin/forum10/Blah.pl/Blah.pl?
Bests
John

mwatts Martin Watts
Ruinerwold, Drenthe, Netherlands   NLD
Hello John,

Thank you very much for the suggestions. I had two last possible suspects in mind myself: the carb diaphragms, and the vacuum tube from the carb to the distributor. I checked the latter yesterday evening, and although it looks ok, I find it does come of the carb and the distributor quite easily. I will try securing it with a clamp or even just a tie wrap temporarily.

Firing order is correct.

The Haynes manual provided two settings for static timing: 13 BTDC and 7 BTDC. I've set it to 13 BTDC. Is that too advanced for modern fuels? Could it make such a difference? My plan was, as I don't have a strobe, to fine tune the timing by doing some test drives, gradually advancing or retarding the timing until there is just very slight plinking when accelerating fast in fourth gear. But I haven't got that far yet. winking smiley

By the way, the throttle is VERY responsive in neutral. The engine will rev up instantly. The problems are only under load. And it's not gradually as you speed up. It collapses quite suddenly. Is that ignition? Not being stubborn, but inquisitive. winking smiley



Edited 1 time(s). Last edit at 2017-10-17 12:58 AM by mwatts.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
13 degrees was for 100 octane fuel, so a bit less at static is best, but my concern was with the automatic advance that a dizzy should provide - is the 'moving plate' that carries the contact breaker and is moved by the centrifugal mechanism, seized? Timing strobes are for sale on ebay for less than £20 - I urge you to get one!

JOhn

mwatts Martin Watts
Ruinerwold, Drenthe, Netherlands   NLD
Ordered one! Will be here on thursday. winking smiley



Edited 1 time(s). Last edit at 2017-10-17 03:28 AM by mwatts.

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
Martin,
Your car appeared on the Facebook, Triumph Vitesse International page, so I posted about our conversation.
https://www.facebook.com/groups/355145157954928/permalink/1131584756977627/
Theo Ourborg has replied, saying he cannot locate you (you have namesakes) but his number in Holland is 0031653290

Hope you can make contact.
John

mwatts Martin Watts
Ruinerwold, Drenthe, Netherlands   NLD
John,

I don't have a Facebook account. So I can't check that page, but it definitely wasn't me who posted the car on there... The pictures were probably taken from the photo's and videos thread.

The number you mentioned is missing three digits. winking smiley

Martin

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
rustbuckit2011 Frank Zappa
auckland, auckland, New Zealand   NZL
Sounds like a classic stromberg diaphram issue to me. Take them both out and inspect very carefully- they only need a pinhole to go bad. You will usually find a fault on a crease.

mwatts Martin Watts
Ruinerwold, Drenthe, Netherlands   NLD
Can you get the diaphragms out without dismantling the carbs?

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
rustbuckit2011 Frank Zappa
auckland, auckland, New Zealand   NZL
Yes, couldnt be easier- do one carb at a time so if you are unsure of reassembly you can refer to the untouched one (but its a synch, dont be scared)

1 remove the oil damper dipstick,
2 Undo the machine screws that hold on the cap top on the carb and lift off.
3 Remove the long spring (before it bounces under the car)

The diaphram is attached to the piston in the middle and sealed around the outside by that cap.

4 Remove the piston/diaphram to inspect taking care not to tip the oil out of the tube.
Really check out these things- I have missed holes in the past and had to do over as the symptoms persisted. If you can get some cheaply Id just replace them as a matter of course- they are service items after all and the rubber does perish over time.

Putting it all back together is just the reversal.
Also check the oil level in the tube- i cant recall how far down it is meant to be off the top of my head- probably about a quarter inch. You dont need to re-adjust the mixture or anything, it should all be fine.
If they've never been looked at before then I am now about 90% certain thats your issue
- The 10% uncertainty I will reserve for the carburettor floats being split-



Edited 1 time(s). Last edit at 2017-10-17 05:24 AM by rustbuckit2011.

mwatts Martin Watts
Ruinerwold, Drenthe, Netherlands   NLD
Thanks. I'll look at them this week and let you know.

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
In reply to # 1492328 by mwatts John,

I don't have a Facebook account. So I can't check that page, but it definitely wasn't me who posted the car on there... The pictures were probably taken from the photo's and videos thread.

The number you mentioned is missing three digits. winking smiley

Martin

Martin, Come on, I'm trying to do my beast as an international all dating agency!!! Register on FaCebook!! I cantdo it al myself!!!
John

mwatts Martin Watts
Ruinerwold, Drenthe, Netherlands   NLD
I checked the diaphragms yesterday. They look absolutely fine and can't be that old by the looks of them. They had a little dirt round the edges so I wiped them clean with a soft cloth and put them back.

I've secured the vacuum tube with some tie wraps around the knee joints. I found it was a bit loose.

My strobe light arrived too yesterday. Hopefully I'll have some time tomorrow to set the timing right and test the car. If the timing is right and advances when the engine revs, what else could it be? Fuel filter or pump?

Britnut Randy DeRuiter
Nacogdoches, Texas, USA   USA
If you have a spare coil a quick swap may help. A failing coil can give similar symptoms

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
Martin,
Theo thanks you for your email address, but points out that it is YOU who seeks advice. To contact your compatriot, and possibly neighbour, I urge you to go to Facebook, and the Triumph Vitesse International page.

John

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions

Members Sign In   or   Create an Account

Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster