So it begins

Singles, twins and fours.
T.J.Falloon
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Re: So it begins

Postby T.J.Falloon » Sat Jun 08, 2019 2:09 am

Thanks for your info John, will pass that on I am sure the bloke who is doing the job will / should know this. Just to confirm though, are you saying that the white metal bearing is not really necessary and that a plain bronze bush would suffice?

nevhunter
Holder of a Golden Anorak
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Re: So it begins

Postby nevhunter » Sat Jun 08, 2019 8:02 am

The main advantage with white metal lined bearings is they usually fail without hurting the shaft, and bronze likes to run on a HARDENED SURFACE, (nitrided or chromed) and have a bit more clearance to allow more oil to flow and cool it as it's got a higher coefficient of friction than babbit metal. It will also carry more load. When I had a ZA 7 BSA and rode like a fool it think I replaced the timing side bearing about 3 times. I would just heat the case pop the steel part out remetal it including the thrust face and radius and bore it to size and heat the case and insert it. The white metal only ran about a half thou clearance and machines to a nice accurate smooth finish. To align it carefully use an arbour that passes through the other side ball race so you don't gouge out the surface of the alloy case where the bearing is located if it's not aligned accurately. If you are careful you don't lose the interference fit by using heat and care. Same with ball races removal and install. Nev

Gui.dorey
Holder of a Nylon Anorak
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Re: So it begins

Postby Gui.dorey » Sat Jun 08, 2019 2:27 pm

T.J.Falloon wrote:Thanks for your info John, will pass that on I am sure the bloke who is doing the job will / should know this. Just to confirm though, are you saying that the white metal bearing is not really necessary and that a plain bronze bush would suffice?


I think what John is saying is to make a bronze bushing to go between the white metal bearing and the case. But only if the bore for the plain bearing on the case is somehow damaged and you can't fit the plain bearings properly or you lost interference fit.

Hopefully this isn't the case. The glue might just have been added as an extra measure to the peg to make sure the plain wouldn't turn. If he can remove the whole mess carefully, the bore in the case for the plain bearing is hopefully still sound.

Cheers
Gui

T.J.Falloon
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Re: So it begins

Postby T.J.Falloon » Sun Jun 09, 2019 3:34 am

Hey Gui,

Yes after after rereading Johns post that is what I think he was alluding to as well. Upon reflection when I re-examined the photos of the bearing area , I can see no damage in that area so am hoping as you have said that whoever did the pinning just put the glue there as an extra layer of prevention.
Just pulled the head apart and found that the valves are in good condition but the valve guides are a bit worn so will need to replace them as well.

john.whiting
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Re: So it begins

Postby john.whiting » Sun Jun 09, 2019 5:33 am

Its often a tricky decision between fitting a liner and maybe taking the case too thin,and using an oversize OD,which has no effect on the case...............however as Nev mentions,babbiting a bronze bushing is childs play,and this is the way I would go.The reason I suggest bronze is twofold........bronze expands about the same as ally,and a slight interference will keep it in place,and bronze tins and babbits very easily.

T.J.Falloon
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Re: So the resurrection begins

Postby T.J.Falloon » Thu Jun 20, 2019 12:47 am

Hello again all,

Another small update. I have spoken to the machine shop that I took the engine parts to and there is some good news and some bad news.
Good news is that the crank is perfect and so are the bores. I think I may have already mentioned this if so, sorry for repeating it.

However one of the plain bushes has been pinned and the machinist wanted to look behind it for any potential damage.

That has now finally happened, and there is no damage apart from what a previous owner has done when pinning the bush.
The machinist has said that there is about 4 thou stretch ( indicated in area with yellow arrow in photo ) that will need fixing.

I collected my parts from the machinist ( not my normal machinist ) and took them to my usual machinist who said that he didn't think that it was an issue.

My question to you all is, is this a problem?

The next issue I have , if it is a problem , is getting someone to fix it. To that end if there are any fellow Brisbane dwellers that know of a machinist that is capable of this kind of repair and inline boring of the plain bushes and doesn't charge like a wounded bull, can you please let me know. Thanks for that in advance.
Attachments
IMG_20190620_092058 (1).jpg
Other bearing location
777803972.png
Area where 4 thou stretch is.

nevhunter
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Re: So it begins

Postby nevhunter » Thu Jun 20, 2019 1:55 am

The " accuracy" of the bore in the case must be assured. There's often distortion there for whatever reason. If this is redone slightly oversize but true to the other side bearing then a subsequent oversize OD. bush with the correct interference fit should line up perfectly. Heat the case to about 180 degees C to install the bush. That's way below the babbit melt temp and won't affect any heat treatment done and install it in alignment to the other side so it doesn't dig in. As there's not much "give" in the bearing with it's thick wall, about '002" interference will be about all you can safely use without risking cracking the case. Heat and cool slowly and evenly Oxy etc is not suitable. It's a large case so be careful. Use a suitable oven. Nev

T.J.Falloon
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Re: So it begins

Postby T.J.Falloon » Wed Oct 02, 2019 12:18 pm

Hello again all. Thought it was time for a very quick update on how my rebuild is going.
I have the engine back together and in the frame. Finally sorted the valve timing and happy with it.
Yesterday was the first opportunity that I have had to start her up for the first time. I surprised myself when she fired up with the first kick and sounded beautiful.
This is where the fairy tale finishes.
Once she fired up I was keeping a wary eye on the oil pressure gauge. After about 30 seconds no oil pressure so I shut her off.

I have gone through a check list of things. I do not have a Morgo pump which I understand has to be primed.
Firstly I checked to make sure oil was getting to the pump , which it is. I have taken the pump off and checked to make sure that it is clean and have primed it on the bench, where it spits the oil out, so can only presume that it is working fine.
I removed the oil pressure relief valve and checked the ball and spring. Both appear to be fine. Whilst the oil pump was off I gently blew through the oil ways. Air passes through to the oil pressure relief valve, return tank and I can hear air escaping in the internals of the engine.
I have checked and blown out the oil pipes to the head and gauge, all clear. Gauge is working fine.
I refitted the pump and have turned the engine over by hand and have oil coming out of the oil pressure relief valve (prior to refitting the ball and spring).
With the oil pressure relief valve refitted I have turned the engine over y hand with the union fitting to the head and oil pressure gauge removed ( fitting at the underside of the crankcase under the timing chest) . A small amount of oil and air bubbles came from the fitting.
I refitted the timing cover temporarily and restarted the bike with the pipe still disconnected. No oil came from the fitting. Shut her off gain quickly.

Any ideas what my problem may be?

Thank in advance.

JohnnyBeckett
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Re: So it begins

Postby JohnnyBeckett » Wed Oct 02, 2019 6:48 pm

HI Can it be your pressure relief valve not seating right down and not leting the oil pressure to build up or the pump gasket is sucking air or left a oil bung out somewhere

nevhunter
Holder of a Golden Anorak
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Re: So it begins

Postby nevhunter » Thu Oct 03, 2019 4:24 am

Bit worrying. Hook up a fitting /hose to a tee in the oil pressure gauge line and externally pressure it. Check all is primed. You can't operate it without some positive oil supply. I like to prime all engines I do before the engine fires up. It's a good practice. Nev


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