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| mediamab Member Since: 01 Dec 2021 Location: Matlock Posts: 58   
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12th Nov 2023 4:19pm |
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| trickster5000 Member Since: 12 Dec 2015 Location: East Yorkshire Posts: 502 
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An exhaust manifold stud is not a common place for the engine earth to be attached - I believe the correct position is a strap that bolts onto the transferbox or gearbox (can't remember) and then to the chassis rail next to it so that is definitely one thing to look into.
Can't quite make out the alternator wiring but definitely worth keeping wires away from hot components (if it's a little wire it's probably the one for dashboard battery warning light possibly explaining that issue too). Have you got a multimeter to measure the voltage when the engine's running? Is it a factory V8? Matt. '89 90 CSW with a 3.5 V8 conversion (WIP) - http://www.defender2.net/forum/topic46809.html |
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13th Nov 2023 12:53pm |
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| mediamab Member Since: 01 Dec 2021 Location: Matlock Posts: 58
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Ah ok - dont suppose you could point out where it should go to rather than exhaust manifold? I guess those smaller wires I just need to cable tie away from the engine and check wires arent damaged?
Yes its a factory V8 though was rebuilt about 5 yrs (8k miles ago) Ta |
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13th Nov 2023 12:57pm |
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| trickster5000 Member Since: 12 Dec 2015 Location: East Yorkshire Posts: 502
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The earth strap will use a threaded hole on either transfer or gbox casing at one end and a (clean, paint free) hole on the chassis at the other to bridge the insulation gap caused by rubber engine mounts. Your engine earth strap doesn't look standard and may be a homemade jobby so might be worth looking at a new one in the correct position.
As for the proper routing of the alternator wiring it's probably best if someone with another factory V8 can comment - I converted mine myself and ran all the alternator wiring to the nearside wing, P-clipped to engine bracketry and the inner wing itself however V8 front end drive setups vary quite a bit so this might not be appropriate for yours (my alternator is mounted top-nearside unlike yours). Just inspecting the wire insulation isn't already damaged and then cable-tying it safely out of the way should suffice. Matt. '89 90 CSW with a 3.5 V8 conversion (WIP) - http://www.defender2.net/forum/topic46809.html |
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13th Nov 2023 1:20pm |
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| mediamab Member Since: 01 Dec 2021 Location: Matlock Posts: 58
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Is this position/quality of the ground cable on the engine block likely to be a possible cause for my issues? (and checking those smaller wires havent melted)
Gut says the issue came about once engine got warm! |
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13th Nov 2023 3:17pm |
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| TexasRover Member Since: 24 Nov 2022 Location: Paris Posts: 1073  
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I owned and rebuild a 1984 Range Rover V8 and I can tell you that engine is not an easy engine to keep going. There are quite a few weak points and add your typical bodge jobs and it becomes quite a handful. Component quality is not brilliant and things are often substituted rather than replaced with British Leyland parts.
From your picture I see you already lost the original manifold and SU carb setup, this could be good or bad, but regardless being non-standard trouble shooting will require knowledge and experience. Looking at that earth strap, that carb setup and welded exhaust manifold indicates this car has been 'messed with' so you should expect any issues could be related to non-standard/sub-standard installations. Fix whatever looks dodgy and then start measuring and checking the components. Eventually you will find it. Expect this car to keep you busy. I hope you like that kinda stuff. Unfortuneatly I had to sell my sorted Range Rover when I left the USA, greatly miss that car, but at least it made my a good profit to sink more money in another Land Rover product. |
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13th Nov 2023 3:52pm |
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| mediamab Member Since: 01 Dec 2021 Location: Matlock Posts: 58
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Obviously am aware of the new Edelbrock carb but are you saying the welded manifold suggests a bad issue / not the right way of this being done? I’m aware of who did the rebuild and they’re classed as a reputable business from looking at reviews etc… so it’s not a DIY job.
I’ll try and figure out where I need to move the earth too. If anyone can provide clarity on exactly where that would be good  to remove current position do I need to re torque the bolt on manifold to a set figure?
Am I likely to find that may fix my electrical issue? (Also also checking the cables hanging by the alternator are good and then protected) is there anything else I should look for? |
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13th Nov 2023 8:46pm |
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| trickster5000 Member Since: 12 Dec 2015 Location: East Yorkshire Posts: 502
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You can always test if your current earth strap is working by using a multimeter to check for continuity between somewhere metallic on the engine and the battery negative terminal. The exhaust stud position isn't great practice due to the thermal cycling that cable will be subjected to but in all likelihood it's probably doing it's job. I would replace it anyway with one in a better position.
Here's the clearest pic of mine I have during the rebuild, it looks like I just used an exposed stud on the gearbox and bolted the other end using one of the bolts for the gearbox crossmember (black cable above exhaust Y-piece: Click image to enlarge As for refitting the bolt, I believe the torque spec is around 25-30ft-lb, I don't have a workshop manual to hand but go easy - ali RV8 heads are prone to stripped threads on exh man bolts. It's very possible your battery warning light and loosing power issues are entirely seperate - if the power loss was more like bogging down under load it could point to various carb/fuelling issues whereas power loss due to misfiring is likely to be a spark/electrical problem. Matt. '89 90 CSW with a 3.5 V8 conversion (WIP) - http://www.defender2.net/forum/topic46809.html |
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13th Nov 2023 9:38pm |
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| mediamab Member Since: 01 Dec 2021 Location: Matlock Posts: 58
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great thats super useful - yeah definitely keen to get these simple things fixed and solid for sure. I assume one option is to just leave the connector on the manifold but remove the wire then no risks with bolts snapping etc
So im assuming they would be related as the loss of power to the engine is a total loss of power to all electrics. To the point where for about 30minutes I had a total loss of any power at all (was if dead battery but it wasn't at all). Weirdly, it almost appeared that slamming the bonnet brought that connection back to life as I did nothing else that seemed to trigger the power to come back. So based on that im assuming main issue is electrical - though bonnet shutting seemed weird?! There is a small electric cable bolted to the back of the bonnet - im not sure why as it terminates there but assume no relation? sorry appreciate im learning here! |
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13th Nov 2023 9:43pm |
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| trickster5000 Member Since: 12 Dec 2015 Location: East Yorkshire Posts: 502
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Sounds like it's all pointing to an issue with the main earthing between the battery, the chassis and the engine.
I would definitely start with that engine earth strap in that case - if the engine is not earthed the starter motor circuit is not complete, resulting in the complete loss of power that you describe as it can't even crank the engine. Slamming the bonnet is likely just jostling that earth strap enough to coax it into a connection but intermittent earthing will have all sorts of implications for the ignition system too, resulting in the power loss. You could run another earth strap and leave that existing one in place altogether if you wanted, although I would definitely be in favour of whipping it off for appearance's sake. Matt. '89 90 CSW with a 3.5 V8 conversion (WIP) - http://www.defender2.net/forum/topic46809.html |
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13th Nov 2023 9:54pm |
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| mediamab Member Since: 01 Dec 2021 Location: Matlock Posts: 58
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Yeah sounds good. I think I'll definitely start there and get these grounds solid with brand new cables and connections. The only wariness I have of removing that manifold bolt is that it appears to have a number of washers on it - is that normal? I was thinking maybe added cos didnt have the right bolt to allow the earth connection so had to pad out a longer bolt?
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13th Nov 2023 10:00pm |
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| trickster5000 Member Since: 12 Dec 2015 Location: East Yorkshire Posts: 502
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Yeah sounds like a bit of a bodge really, there all sorts of bolts knocking around for RV8 exhaust manifolds but normally a cap bolt or 12 point bolt with no washers. If it's not blowing on that port currently it might be best just leaving it for now until you have it running right Matt.
'89 90 CSW with a 3.5 V8 conversion (WIP) - http://www.defender2.net/forum/topic46809.html |
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14th Nov 2023 12:53pm |
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| mediamab Member Since: 01 Dec 2021 Location: Matlock Posts: 58
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Yeah sounds a good plan thanks!
One thing playing on my mind, the lack of that decent earth, is that likely to be causing the total loss of all electrical power, even to radio, lights etc? Appreciate for starter that makes sense but can that be causing everything, and causing the engine to loose electrical power when it’s already running? Is it simply that’s a key circuit as direct to the battery and without that there’s no earth circuit? (Apologies if that’s a stupid question, just find understanding a problem helps me than just fixing and not knowing why ha!) |
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14th Nov 2023 9:29pm |
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| trickster5000 Member Since: 12 Dec 2015 Location: East Yorkshire Posts: 502
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No you're right - even with a bad engine earth you should still have dash electrics like lights.
Again if you are losing all of them at the same time it's still most likely an earth issue, but this time it's the battery earth cable that runs from the battery negative terminal to somewhere on the chassis, best just start from the battery box and follow the cable underneath the car to wherever it's bolted to the chassis, inspect for damage or questionable condition. If the chassis is not in great condition, a build up of muck and corrosion around the earth strap mount could prevent conduction. The best way to test all of this is with a multimeter in 'continuity mode', hold one probe on the battery -ve terminal and start prodding bits of metal all over the car with the other probe - pretty much all metal bits on the car should have a path back to the battery -ve terminal. Matt. '89 90 CSW with a 3.5 V8 conversion (WIP) - http://www.defender2.net/forum/topic46809.html |
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14th Nov 2023 10:09pm |
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