Q: Correct 1971 A65L Barrel Part #

[adriancw]

Hi,
    Those barrels look beyond a rebore possibly beyond relining and the pistons unusable.

I would drill a series of holes in the piston, missing the con rods, as close to the bore as possible. Keep drilling and knocking until the piston circumference collapses.


Best wishes...

Thanks Bess, I might give the drilling a try.

Cheers,   Adrian

[adriancw]

Thanks for the pics. She is surely poorly.

You could make a puller/pusher at least about 10mm thick and 40 wide Drill and tap/thread in two places. and bolt across the head, with the use of a couple of big bolts 20mm or so, You may be able to pull the barrels upward over the pistons.

The trouble with hammering is that you will always have the pressure of the "other" piston. Get an oxyacetylene/ torch and melt them. Or MAPS gas

Mike

Thanks Mike,

I am leaning towards something like a puller/pusher.  I actually have a sore arm from all the precision hits on the wood block on the piston crown!!  And a few minor war wounds that occurred during a momentary lapse in focus...

Still leaving it to soak, although I might try something over the weekend!!

Cheers,  Adrian

[DAVE BRADY]

Hi,

Another thought.  I released a very stuck OPRV from A65 cases using an electric welder.  With a high current passing through from the piston to the barrels the stuck parts may well release.  A bigger job than the one I had but it may work.

Dave. 

[Mike Farmer]

 

Dave that is a very good idea. Never considered it but have used it on big bolts 15mm up. As you said previously, in truth it is quite likely only the rings that are seriously stuck. I don't think ally/steel adhesion is usually terribly bad, its normally only a crust.

Mike

[adriancw]

I made some progress   

I left the cylinder soaking, applied more heat, and continued with a block of wood and heavy mallet..  No joy at all, so...

I decided it might be better to split the cases and try it that way.  But in order to do so - I need better access to the bolt under the cylinder/barrels.   

I managed to get the Clutch removed (not easy - and the special clutch puller tool did not work as I stripped the threads, so I ended up using a three legged puller. It worked!!)  The Primary chain is also now removed.  The next challenge to progress is removing the "Clutch Sleeve", which is supposed to just slide off but appears to be seized in place...   I'm hoping that won't be a problem when it comes to splitting the cases.

As mentioned above, I needed access to space under the cylinders to remove a nut, and managed to create that space by using a mix of transmission fluid and petrol in each cylinder and igniting it...  I managed to get the pistons to move 1/2 an inch. The crank now rotates through about 270 degrees.

I re-attached the spindle nut to the end of the crank -but I'm too chicken to apply a lot of pressure and strip the thread while trying to rotate the crank in-situ.

So, the next step will be to undo the nuts/bolts, split the cases, and remove the crankshaft, with con-rods and pistons attached along with the cylinder/barrels. Then remove the big ends, separate the crank from the rods - and have a clear line of attack to continue with each of the pistons.

I've attached a few photo's...

Many thanks all !!

[DAVE BRADY]

Good morning Adrian,

You will need to remove the clutch sleeve to split the cases.  The gearbox stays in the right hand case.  The sleeve is notorious for holding on despite every effort and the pullers tend to come of worse.  You said that you have stripped the thread on your puller so that will not be much use.  The 3 legged puller may work but there is a chance that the sleeve could be damaged but they are available.  Once tight it will be necessary to hit the end of the puller to shock the sleeve off the taper. Sometimes it takes quite a whack to release it and a bit heat can help but not too much as you will affect the hardening of the sleeve and shaft.

I noticed that the primary chain was fitted with a split link.  I would strongly advise to fit a good quality endless chain as the split links have been known to fail with disastrous results.

Dave.

[Mike Farmer]

 

If you have some movement you are half way there. As I sa9id I have split the cases(a long time ago) and getting to that internal nut was a nightmare. I guess I had a bit more slack than in your case. But ultimately I think its the best way if you can do it. Those clutch centres can be a real pig. Have you now managed to completely remove that internal nut.??

You are definitely winning---This will be worth a gold medal!!!!!!!!!

Mike

[adriancw]

Another quick update - and next steps...

I was able to remove the clutch sleeve, and as I have sufficient space under the cylinder - I could get to the nut in that position too. 

I also noted that the oil filter (sludge collector?) had to be removed.

The left side crank case took a bit of jiggling but came off and now I can finally see the crank and big ends.  They look ok - barring some rust.

Next step will be to remove the gearbox cover, get the oil pump off, remove a timing gear and then the crank should be removable.  Undoing the big ends means I will be able to separate the crank from the con-rods.

Once they are (finally) off, I will try some more heat/penetrating fluid and gentle persuasion to separate the pistons and cylinders. The pistons and con-rods will be re-cycled. I hope to salvage and re-use the cylinders (they are the reason why I started this thread in the first place!!!).

Cheers,  Adrian

[Mike Farmer]

 

Thats brilliant. Once you have the B/E bearing undone and claer of the crankshaft your pistons should be a much easier job as individuals where you are only putting pressure on one at the time. Your conrods should also be ok. I cant imagine that you will be able to rescue the pistons, but unless its cracked because its been frozen your cylinders should be renewable either rebore or reline.

So your very close to the gold medal and I'm very pleased this method worked. I was beginning to worry that I had given you a bum steer.

Mike

[adriancw]

Success!!   I was able to continue with tearing down the engine, and got the seized pistons out!!   There are too many photo's to show here, but I've attached a few...

Last night I started by removing the outer gearbox cover, removed the points, the kickstart and gearshift springs - as well as the advance retard mechanism. Not rusted- which was a pleasant surprise!!

After that I finally had access to the right hand side crankcase, with the timing gears. I decided to leave the gearbox intact. I removed the oil pump/tacho drive.

Then I had some fun - I had to undo a couple of nuts on the crankshaft - reverse threaded (clockwise to undo and remove them...) Then some more fun as I eased off the crankshaft pinion and removed the Woodruff key. At last the Crankshaft came out easily from the right side case.

Now with a Crankshaft out, it was a simple matter to undo the big ends and separate the crank from the cylinder head and pistons...

A few "gentle" taps on the Con Rods (not being re-used), and with the pistons fully exposed a quick clean before knocking them back down (well lubricated) and finally removing them...

This was so much fun - I think I'll do it again on another engine... (just kidding...)

Cheers,  Adrian

[DAVE BRADY]

Hi Adrian,

A good result. Now that the pistons are out it is hard to see what was holding them so firmly.  It will be interesting to see every thing when really clean.  Unless the barrels have become pitted then they may clean up with a rebore.  Check the rods carefully as the lefthand one in your picture appears to have a line across it.  Perhaps a sign of an impact at some point in its life.

Dave.

[Mike Farmer]

  

Hi Adrian.

Thats super a good job well done

The usability of your barrels may depend on what their current bore size is. Are there any markings visible on top of the pistons relating to their size. Bearing in mind that you can go up to +.080"(2mm) oversize tho not really recommended and the pistons are next to impossible to obtain  if you still have std pistons you are on the money. In truth looking at your pistons they appear almost undamaged and most likely reusable. Only proper measurements will tell.

Mike

[adriancw]

Hi Adrian,

A good result. Now that the pistons are out it is hard to see what was holding them so firmly.  It will be interesting to see every thing when really clean.  Unless the barrels have become pitted then they may clean up with a rebore.  Check the rods carefully as the lefthand one in your picture appears to have a line across it.  Perhaps a sign of an impact at some point in its life.

Dave.

Hi Dave,

I have to say I'm pretty happy with getting this done.  I agree it will be easier to plan what to do with the barrels once clean, but I saw no evidence of scoring or real wear in them.  I am optimistic that a rebore will really help.

I doubt that I will use either the pistons of the con-rods.  The pistons would be wrong after a rebore anyway.  To be on the safe side, I am probably going to also install new con-rods.

I do not know the full history of the engine, but I don't think it had a high mileage.  It was seized due to weather and pest infestation after being removed from the frame and left outside for an extended period.

Cheers,  Adrian

[adriancw]

 

Hi Adrian.

Thats super a good job well done

The usability of your barrels may depend on what their current bore size is. Are there any markings visible on top of the pistons relating to their size. Bearing in mind that you can go up to +.080"(2mm) oversize tho not really recommended and the pistons are next to impossible to obtain  if you still have std pistons you are on the money. In truth looking at your pistons they appear almost undamaged and most likely reusable. Only proper measurements will tell.

Mike

Hi Mike,

I thought I had responded to you a few days ago, apologies for taking so long (it must have got lost in a PC reboot...) I have re-typed what I said in the "lost" posting below: 

Neither piston crown seems to have any indication of size.   However, the part # on them (partially visible on the side) looks to be 68-785, which would be the original standard size.

I used a couple of micrometers (neither of which have been accurately calibrated in some time) to do some inner diameter and outside measurements on the cylinder bore and pistons respectively.  Both came in at around slightly less than 75 mm, which would seem to confirm the standard size noted from the number on the side of the piston.  I believe the next size up (20 thou, or 0.020") would be an increase to approx. around ~75.5 mm, and 40 thou (or 0.040") would be an increase to ~76mm.

It would seem to mean I may have enough to get a good clean rebore and still be less than the max of 80 thou (or 0.080"), which would be an increase to ~77 mm (i.e. 2 mm extra).

I might start a new posting on that when I get to doing the engine build (whenever that is), and will reference back to this posting.

Thanks for all your help and suggestions !!   Cheers,  Adrian

[Mike Farmer]

 

Greetings Adrian.

That all sounds very good and certainly hopeful. I reckon you should get a sound rebore. Of course if you have lots of time you could always gamble---clean it all up and put it back the way it is and see what happens. I wouldn't now, but may have when I  simply would have been unable to afford the repairs.

I digress, for your general info. +.020"---+.040" and +,060" readily available. +.080" rare but out there somewhere.

If your machine is still on std, the rest -- gearbox etc should be in fair condition.

All the very best and look forward to the next step in this saga (or is it epic). Yep please keep us upsides with it. We all gain a little from these problems.

Mike