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Complete lack of power under load, V8 Saloon.

Fossil
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Re: Complete lack of power under load, V8 Saloon.

Post by Fossil »

Chris & Robert

Yes, there will be no movement if the baseplate is seized on the distr. top body, and the vacuum capsule can only be properly checked if is disconnected and removed; but at over 50 years of age it would be sensible to have the latter rebuilt regardless unless this has been done already. Also the top body will have to be removed in order to dismantle the baseplate and restore movement. In other words there are good reasons to remove, dismantle and overhaul the distr. if the engine lacks power and there is no evidence that this has been done for some time, but it is relatively straightforward to do provided that there is no major wear anywhere. It's not unusual to find the inner walls of the distr. bottom body caked with old dry grease thrown off from previous over-lubrication of the weights, and the manual does advise keeping the two vent holes of the bottom body clear, I assume to allow any water that might find its way into the device to leave, or perhaps oil that finds its way up from the engine, or down from over lubrication of the cam.

Time for more recollections! Look away now if you're not interested. My first foray into the innards of the 20D8 distributor followed sudden total loss of power 25 years ago one sunny Sunday afternoon returning from an event in Falkirk (I had even won a prize!) along what is known as the "Kippen straight" on the A811 west of Stirling. In a rare moment of inspiration I removed the distr. cap to find that the rotor arm didn't move when the fan was turned. Cause therefore a sheared Mills pin in the distr. shaft. Having been kindly Relayed home by the AA (I'm still a member), the distr. came off and the remains of the pin were drifted out and a new one fitted. It's still there.

Around the same time I had the good fortune to obtain two complete saloon engines from a young man in Norfolk for the staggering sum of £100.00. This was in the pre-fleabay era. Cue hired Transit van, there and back from Helensburgh in one day. They were complete with all ancillaries: the distributors and other bits have been extremely useful. I still have a long term plan to rebuild the later engine and find something to put it in. But the better of the two camshafts is now in the SP, following attention by Russ Carpenter, along with its cross reinforced cam cover, because the original cam had been very badly re-profiled. The earlier engine's block had a huge split down one side between the outer water passages, due to frost I imagine.

But I digress, again, sorry.

Regards

Geoff

Simon Hyslop

Re: Complete lack of power under load, V8 Saloon.

Post by Simon Hyslop »

This model isn't one I know much about specifically but just reading through it all, if there is still trouble as described, I'd take a close look at all the inlet manifold joints. Although a leak in them is often accompanied by a whistle, this isn't always the case especially if the gap is bigger than a pinhole and whereas on a car with a single carburettor the weakening effect is usually apparent at well under 3000 revs, I am wondering if the engine is running out of go because of an over weakened mixture.
Holding a finger to the joint or a small piece of newspaper can help to identify a leak, or some oil and watch for it being sucked in. Had you not said specifically about having the manifolds off I may not have suggested this but it's a problem I have encountered several times on various cars.

HenryC
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Re: Complete lack of power under load, V8 Saloon.

Post by HenryC »

I had a similar problem recently on the Conquest and it was simply due to the timing being incorrectly set. It was out by about 10 degrees and the symptoms were exactly as described in the original post.

Careful setting up using a gauge down the spark plug hole to find TDC and working on from there solved the problem with a dramatic increase in performance at higher revs.

So I recommend you continue with the distributor route, once you are certain the timing is correct.
Cheers, Henry Curwen
Registrar for Conquest & Century Saloons (DJ250/1, DJ256/7, DJ260/1)

Conquest (Drop Head) Coupe DJ252

Phillmore
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Re: Complete lack of power under load, V8 Saloon.

Post by Phillmore »

I agree with Henry that correct ignition timing is crucial but if you suspect that there is wear in the distributor and or parts binding etc I would fix that first otherwise any efforts to obtain correct static timing will be false. Ie your static timing might be set with the base plate seized in a slightly advanced position. I hope that makes sense?
Andy

1954 Conquest Mk1, 1956 Conquest Mk2, 1957 Conquest Century Mk2, 1955 Austin A90 Westminster

KV8
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Re: Complete lack of power under load, V8 Saloon.

Post by KV8 »

I have to join those who think lack of fuel delivery is the problem. It revs freely when static but falters under load with I assume even more dire symptoms when a rising incline is attempted. Been there got the T shirt on my Triumph Stag.

First check fuel flow by examining flow with each float chamber open in turn ( Have container ready to catch fuel -engine cold!) It should gush and require a noticeable finger pressure to close needle valve. Take opportunity to check needle valve settings

Otherwise check back down the fuel line to pump and tank, check main filter and pump filters. Blow through fuel lines with adapted cycle tyre
pump.

If the car has been off the road for sometime then this can be due to fuel degradation. If so try a size-able refill with 97 octane.

HTH

H

Ian Slade
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Re: Complete lack of power under load, V8 Saloon.

Post by Ian Slade »

There is only one filter unless an extra has been added, the easy check is disconnect at the LH carb, and switch on the ignition, if fuels spurts out and the pump ticks like mad then the fuel supply is OK. That leaves the float valves ( a knock on the side with a spanner normally cures this, but it will jam again) but it's quick and will easily determine if that is the problem, with the air filters removed you can see the fuel/ air mix when revved and the dash pot rise so that's simple, no need to rip the system apart for no reason
Owner since the 70's, Genghis is slightly to my left.

Phillmore
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Re: Complete lack of power under load, V8 Saloon.

Post by Phillmore »

You say it won't rev/pull over 3000 under load on the road. Will it pick up and rev over this when in neutral?
Andy

1954 Conquest Mk1, 1956 Conquest Mk2, 1957 Conquest Century Mk2, 1955 Austin A90 Westminster

KV8
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Re: Complete lack of power under load, V8 Saloon.

Post by KV8 »

Ian Slade wrote: Sun Aug 20, 2017 7:31 am There is only one filter unless an extra has been added, the easy check is disconnect at the LH carb, and switch on the ignition, if fuels spurts out and the pump ticks like mad then the fuel supply is OK. That leaves the float valves ( a knock on the side with a spanner normally cures this, but it will jam again) but it's quick and will easily determine if that is the problem, with the air filters removed you can see the fuel/ air mix when revved and the dash pot rise so that's simple, no need to rip the system apart for no reason
My SU pump has a thimble type filter on the inlet in addition to the main filter under the bonnet. The OP has a V8 saloon so unless modified has a single air filter which is a bit more long winded to remove with the elbows etc to view the needle rise etc.

The symptoms described are exactly those experienced on my triumph Stag. It was intermittent and after many red herrings I eventually realised it occurred only when the fuel was low and was found to be an air leak in the fuel pick up due to corrosion. The fuel feed at the carbs under no back pressure looked visibly OK.

H

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Re: Complete lack of power under load, V8 Saloon.

Post by Alpine Daimler »

Hello again all out there.

I must say I am quite flabbergasted at the interest shown in this post of mine and the very helpful responses, I do recognise and appreciate you folks giving up your valuble time and monthly internet data in the interest of my V8 saloon.

Serious family matters have meant my priorities have lain elswhere theses past few days and I am in the middle of a long shift block so its been a matter of gathering advice, reading of manuals, drawings etc, I print out all of your replies and read them over several times in the train to work.
Geoff, thank you for persevering with your computer challenges and writing some terrific and enjoyably digressing stuff which I'm sure we all value, you and your very helpful advice has given me the confidence to dismantle the distributor where I think the problem could lie after a lay up of approx 9 months.
I have even attained a hand operated vacuum pump to test the capsule without sucking directly on the screwed connection and possibly getting ebola or similar from 1967 threads.
Elsewhere Andrew Carpenter has given similar top notch counsel and guidance. Tuesday and /or Wednesday is penciled in for attending to the V8 providing life outside Daimler stabilises.

Right, I should clarify the following : the engine without load sounds really good and attains approx 3000-3500 rpm without complaint, I have not tried to go beyond this speed, as I am reluctant to get the old boy too worked up unnecessarily.

Whilst rebuilding the inlet manifold and refitting the carbs I tried to exercise great care as to the integrity of all joints as I have read of the ease of maladroit re-assmbly and subsequent problems, there appears to be no hissing indicating leaks, at the next idle run I shall check this again.

As mentioned I changed the original and perfectly serviceable filter to carburettors fuel feed pipe for the braided steel replacement as it is so reccomended, especially on the old forum. This, surprisingly, was a bit of a devil to fit, a tad too long between carbs and took careful alignment and fitting to a avoid any kinks causing fuel starvation, I also had to turn down the banjo bolt length by 2-2,5 mm to attain leak free joint at filter bowl as pipe end connection is not so thick as original, all fittings etc checked for cleanliness and free of debris...(problem there?). It was also necessary to remove material by grinding (once removed from engine) of the throttle bracket to eliminate very heavy chafing/masive interference of fuel pipe. I will check fuel flow from this new hose at carb connetions first of all when next in the workshop.

Timing : I suppose it is remotely possible for some people to somehow disturb the timing whilst overhauling the steering column and heater box! Its not much of a job in the now grand scheme of things, I shall look at that as well....could be a long day.

I should add as a grand finale that I have checked to the best of my ability and knowledge the freedom and smooth movement of the SU pistons and all round condition of carbs. I still think the problem lies at the distributor, when last running all was well, its all so sudden and un expected as they say!

Wherever you all are have a pleasant Sunday evening from a dry but mixed weather wise Munich.

rob c.

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Re: Complete lack of power under load, V8 Saloon.

Post by Alpine Daimler »

If it helps and anyone is interested this was the recorded a few days ago!!

:

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