Here's a bit of a mystery.
>
>A friend and I both have V8s.
>
>This is mine:
>
>An '86 3.5 litre 110 with LPG, Strombergs (from a Rangie), RPI
>Advance-by-Retard ignition amplifier / standard ignition amplifier (they're
>on plugs-and-sockets so I can swap them around), Magnecor leads, Bosch
>4-electrode plugs, etc. The engine was rebuilt (to standard spec) about 10K >miles ago.
>
>This is my mate Bill's:
>
>An '89? fully rebuilt 4.6 litre 90 with LPG, Holley? 4-barrel with plate
>mixer for gas, pancake filter on the top, RPI cam, RPI Advance-by-Retard
>ignition amplifier, Magnecor leads (I think), and lots-and-lots of other
>expensive bits. You may have seen it in one of the mags (LROI?) a few months
>ago. It's bright yellow with a safety devices roll cage.
>
>Anyway, they both have a tendency to run like a dog and the symptoms are
>_so_ similar, we're convinced it's the same problem. Trouble is, neither of
>us has managed to find out what it is. Generally speaking, we reckon both of
>them are down on power. The main problem, though, is that when you're trying
>to get a wriggle on, all of a sudden there's a significant drop in power.
>Bill describes it as someone throwing a huge rubber band over the towball.
>There's a hill on the A5 between Shrewsbury and Telford. If it happens there
>(and it often does), it's a real struggle to climb - often to the point of
>having to change down to second and crawl up it at 25-30MPH. If it doesn't
>happen, we'll usually get up it at around 70MPH in fourth - though in the
>past I'd have no problem at over 80MPH in fifth. The problem is evident on
>both LPG and petrol, though it's _much_ more pronounced on petrol. With
>mine, if I'm running on petrol, it usually kicks in about 20 minutes after
>setting off. It ticks over fine, but there's no 'go'. It sounds as though
>it's missing, but I'm not convinced it is.
>
>Here's what we've tried:
>
>Engine wear: we've had mine apart, checked for anything obvious, put it all
>back together again with new gaskets and tested the compression. All looks >fine.
>
>Fuelling: Bill's tried two different carbs, plus a strange carb/injection
>hybrid. I've stuck with the Strombergs. Nothing's made a difference. >
>Ignition: I've replaced most ignition parts with higher-spec bits. The
>dizzy's been changed for an RPI recon. Recently, I rewired the ignition
>amplifiers so that I could have them both in and quickly switch between
>them. Nothing's made a difference, though as a general note, it's slightly
>stronger on petrol with the more advanced ignition (using the standard
>amplifier with the timing advanced for LPG) and there's no pinking. >
>Exhaust: Bill thought that it may be a restrictive exhaust problem, so he
>cut the brand new back box in half to take a look (!). Reckons it looks
>fine, so he's put it back together. Mine's a standard mild steel system. No
>apparent problems there.
>
>Bill's current thinking is that maybe the hydraulic lifters are pumping up,
>so he's considering trying solid lifters and adjustable tappets.
>
>However, we're still really grasping at straws and we've been going around
>in circles like this for over around 2 years. Any insight would be greatly >appreciated!
It sounds very similar to the fuel starvation problem I had with the
101. We never managed to nail it down 100%, but after a lot of heartache and time it was sorted after a top-rebuild with new gaskets. This was after several sets of fuel lines, new fuel pump (in various locations), new Mallory dizzy and full electrics. So we reckon it was an inlet manifold leak causing it to run lean, particularly when warm and on full boot as it would bumble along on the flat at low throttle without any hassle. Show it a hill and it would be a first gear job (if I was lucky).But if yours has been apart then that won't be it. You may have the same symptoms with different causes. From experience it is very easy to get tied up on an initial assumption (we assumed fuel delivery problems on the 101) and overlook another option.
So perhaps Bill should rebuild his top end (which he sounds like he's about to do anyway).
Have you replaced your fuel lines and filters? I would replace rather than blowing through. If you blow through, blow in BOTH directions as a nick may only close the line in one direction. If you have the problem on LPG then it won't be this, but again you could be experiencing TWO problems or just be imagining the LPG issue!
We were one step away from booking a rolling road, but that is not a cheap option and won't necessarily fix your problem.
Tim Hobbs
'58 Series 2 '77 101FC Ambulance '95 Discovery V8i
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