1966 thunderbolt A65 big end questions

[Bigmac]

After a lot of cleaning, cleaning more cleaning and honing the top end, I am about ready to put the bottom end together.

Two questions.

1. Sludge trap, I dont have this part and noticed the slot for the sludge trap had a big bolt through the centre of the tube, any idea what is the exact model or part number of sludge trap tube I would need for this bike?

2. Big end shells, I measured these all around and they aren't oval, but needed a lot of cleaning, is there a chart for this model of bike so I can make sure I get the right size shells? I saw one for the A10 but not the A65. Its been rebalanced so I am thinking it also had a regrind at some point.

Thanks again for the help I have my hylomar ready for when I finally get these last two pieces.

[Nanonevol]

No parts manual?  The sludge trap itself is 68-0185

The info you need on the rod bearings is in the manual.  If it's dirty it's surely worn.  May need a regrind.
Use Plastigauge and carefull measuring to insure correct bearing size. 

How's your timing side bearing?

Do yourself a favor and download a parts and a repair manual.

[DAVE BRADY]

Hi,

I think I would go bit further.  Unless you are really confident doing the measuring yourself get an engineer to do it.  Personally I think I can measure a big end but I'm not 100% confident so I would get an engineer to do it just to be on the safe side.
As Nanonevol said, get a proper BSA manual and you will have the specifications for the journals.  It is important when getting a crank ground that machine operator understands the need for the specified radius on the journals.  This is necessary to prevent stress points that could lead to failure of the crank.  Again the spec. for the radii are in the BSA manual.
Also, don't skimp on big end bolts and nuts.  There are those who will take a chance but it is not worth it.
I did this once when a penniless youth and got away with minimal damage to one con rod.  It could have resulted in the destruction of the engine.

Dave.

[Bess]

Hi,
    Info on ends and shells, its also advisable to change the 3 flywheel bolts, correct washers and torqued with loctite.

Best wishes...

[Mike Farmer]

 

I'm going out on a limb with this.

My thoughts are that the existing BE shell would have the size stamped on the back. or a checkable Pt No. Then all that is needed is the crank ground to the next undersize. If you have the sort of wear that you need to consider plastigauge then I fear that you are not going to get a satisfactory result without grinding. Or at least not a long lasting one.

Take into consideration the time and expense of pulling it all apart and re doing it all a few thousand miles down the line and regrind makes sense to me.

Mike

[Bess]

Hi Mike,
            I agree, I have only ever used plastigauge or the more accurate lead wire process on bearings that needed fitting by scraping the bearing surfaces, or because you cant measure the journal (usually because the journal is still in the engine in horizontally split cases).

The maintenance manual directs to checking the journal size and its surface condition, if within tolerances replacing the shells only, if outside the given tolerances opting for a regrind with the next oversize shells.

Best wishes...

[Bigmac]

Hi

I do have the manual but thanks Bess for posting the chart, its exactly what I was looking for, and thanks nanoneval for the part number, I am doing this in the shed so things are a bit upside down, just to clarify the cleaning was mainly for the entire bike but the crank which is old but not too bad once cleaned up.

I guess I will have to take the bolts off for the sludge trap installation and get some locktight and maybe new washers.

[Bigmac]

Whilst digging in the old laundry basket full of parts just now, I found one stray shell that fits amazingly the only marking I saw was 4004, any idea what these could be in terms of size?
If not I dont suppose there is a way to measure?

Picture attached

[Bess]

Hi,
    That looks  like a Vandervell insigna. Worth giving them a call or just measure the journal and decide which size  shell you need.

Best wishes...

[Bigmac]

Thanks Bess I couldnt find the logo online anywhere!

[Mike Farmer]

 

I was speaking to SRM earlier and mentioned this. Vandervell reputed to be as good as they get have been taken over by another company. He has no idea of their numbering system.

Mike

[Bigmac]

OK thanks Mike appreciate you asking I will reach out to
them

[chaz]

https://vandervell.co.uk/
you might have to contact them for older bike applications , only current bikes listed in catalogue