Worth noting that what is generally sold these days are "Booster Cables". They are OK to rapidly put a bit of charge back into a flat but otherwise good battery, plus supply maybe 50% of the current demand when cranking. The resistance isn't low enough to supply full starter current without significant voltage drop, which is very noticable on a system with only 6V to begin with. Many are aluminium for low weight, which puts up the resistance.
True jump leads are very heavy copper, with a price to match.
Joined: Aug 2017 Posts: 683 Threads: 17
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6 Location: The far North East of England
Car type: 1934 Austin 7 AVH Van (in bits & incomplete!), 1936 Morris 8 Series I Tourer
I've posted this a number of times in the past regarding the best cable size for 6v systems - suggest you check yours, if they're cables designed for 12v systems then they won't be thick enough. I've used the cables specified below on my 6v 1936 Morris 8 Tourer.
Attached is a link to an updated video taken earlier today.
After far too many days spent faffing around trying to get the starter to turn over, I finally managed to work out the problem, all of my own making I might add. Many thanks for the very useful advice from one and all, it all boiled down to insufficient cable diamater from the battery. Once enough cable diameter was provided she turned over as she had always done fitted in the car.
I had removed the gearbox on the test rig as a first attempt to isolate the problem and having run her yesterday with no squeal present, I put the gearbox back in place and run her again today, as you can see/hear there is again no squeal.
In trying to get the engine to turn over on the battery to start her, I had turned the engine over many many times on the handle and the bores had been oiled again, so I cannot say for definite that this was the issue, but my very first thought was dry (or insufficiently oiled) cylinder bores.
I will remove the head to check the bores just to be sure all is ok, but if there are no issues, I will put the engine back in the and keep my fingers crossed.
Hope this link works
Cheers
Ruby Engine on Test RigVID20230505154129
Thanks Gary, didn’t think it had worked!
I couldn’t get on to the forum last night on our computer and so posted via an IPad, but couldn’t cut and paste the link to the video.
Thanks again
That sounds great, I had a feeling the noise was coming from the cylinders, I’m so please lubrication appears to have sorted it, pulling the pistons to re gap the rings would have been a pain.
I stripped all the attachments off the engine this afternoon in readiness to reinstall same back into the body, but as previously noted my intention, I removed the head to check all was ok inside.
In a previous thread, "Head bolt torque and block" posted by Keith Smith 11.08.22, I noted that I had originally torqued the studs with a calibrated wrench to 30 ft lbs (360 in lbs) and was advised this was way OTT and that I was quote, "...a very lucky boy" not to have broken a stud or two. So this time I torqued the head to just 20 ft lbs. When undoing the nuts I was able to remove them with just a small spanner and surprisingly very little effort.
Upon removing the head there was plenty of evidence of both oil and water migrating under the gasket and traces in one of the bores.
I had applied and very thin film of copper slip on both sides of a new gasket on installation, but no sealant.
The block and head had been checked at the time the block was honed, the block was found to ok but the head was skimmed 0.005". It could be seen at time that more material had been removed from the outer edges of the head than in the centre.
I attach a pdf document with various photos of the head and block literally as the head was removed. The areas that look like they are rusting are not, it is the copper slip.
All the oil in bores and on the faces of the head and block simply wipe off.
The pistons slide very easily without any noise when turning the engine over on the handle.
So the question is should I increase the torque or should I apply a suitable Loctite sealant, which others have suggested on other posts or is there anything else i should be looking for?
One other thought, is there a chance the sleeves could be leaking.......??
08-05-2023, 09:26 PM (This post was last modified: 08-05-2023, 09:28 PM by David Stepney.)
Dennis,
I accept that you have spread copper slip on the head and block mating surfaces, but (and this may be just the photos) the block in particular does not look to be clean enough for me. When doing any 'head job' I clean the mating surfaces with fine emery until, every bit of crud is removed and the faces are clean and bright. I then go over them with a bit of wire wool. I do the same with the head.You will have to remove the studs to do the job on the block thoroughly, and I chase the stud holes with a tap to make sure that the studs fit properly. It is surprising how cruddy the threads get.
I too use copper slip to coat the gasket on both sides before fitting it and then torque the head nuts down to between 18 and 20 lbs/ft, going round them at least three times until they are all snug and tight. I torque them down again once the engine has been run up to temperature and then allowed to grow cold. It surprising how slack the head nuts can become in service. It may be worth checking them again after a few hundred miles. I check mine every major service (5k) and invariably one or two have come slack.
I last had the head off my car several thousand miles ago (probably getting on for 10k but I am too lazy to check through my records) and I have had no problems so far (touch wood). As with all things engineering, cleanliness is next to Godliness and reliability.
You shouldn't have any oil up there; the head is only a cover to keep the compression in.
Please forgive me if I am teaching Granny to suck eggs, but I hope my comments help.
David, I cannot say that the parts were up to your exacting standard but the block had been decoked and fully cleaned, including degreasing and mechanical wire brushing and a full wire wool to all surfaces. This was all before being sent the machine shop. The studs had not been removed but were fully wire brushed on return the threads were clean. The valves were all cleaned and vacuum tested in the machine shop.
The head was a machined surface, completely bright and shiny when put back together.
Like I said the pics were taken just minutes after the head was removed.
Dennis, I apologise if you thought that I was in any way critical. That was not my intention. I tend to be a bit OTT and indeed OCD about things mechanical. The important point that I make is that the head nuts should be checked for tightness soon after the engine has been run and at regular intervals thereafter as C/A gaskets do tend to settle in service.
Having run classic cars for most of my driving career, many of them pre-war, I have sometimes had to learn the hard way and it is no fun, having spent time and effort doing something, only to discover that there is a problem and one has to do the job again.
