Author Topic: A10 Engine Rebuild Checklist  (Read 1763 times)

Offline rowan.bradley

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A10 Engine Rebuild Checklist
« on: 26.08. 2016 15:03 »
Does anyone have a checklist of things to be inspected, parts to be routinely cleaned or replaced, and other tasks to be done when stripping down and rebuilding an A10 engine? Just to help me prepare for this task. I don't want to get it all together again and then find there are other things that I should have done...

Thanks - Rowan


Current bike: 1958 A10 Super Rocket (in bits), purchased in 1967.
Previous bikes: M21

Online Greybeard

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Re: A10 Engine Rebuild Checklist
« Reply #1 on: 26.08. 2016 22:26 »
Crankshaft sludge trap MUST be clean. Crankshaft timing side bush MUST NOT be slack. Crankshaft endfloat must not be more than a couple of thou. I know you are going to get some more tips but try to spend time browsing old threads on this forum;  every aspect of these bikes has been covered already. Don't rush; enjoy the process; you will probably miss it when it's over.

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Re: A10 Engine Rebuild Checklist
« Reply #2 on: 27.08. 2016 11:51 »
G'day Rowan.
To add to Greybeards list. Replace the anti wet sumping ball & spring, crank journals, co rod little end, valve guides, all the bushingss.
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Re: A10 Engine Rebuild Checklist
« Reply #3 on: 27.08. 2016 22:10 »
Hi Rowan, the key items that get missed are listed above, in my opinion what's is most important is getting the bottom end checked and fixed up as necessary, as for me removing and splitting the crank cases because I'd missed something would be a pain! Rebores and head work etc can of course be done with the bottom end left in situ. Small ends are easier to replace with the rods out so there is a case for replacing them as part of the bottom end refurb as well.

If you have the crank cases split I think it would be worthwhile renewing big end shells and the drive side main bearing regardless of condition, the timing side bearing would have to be in excellent condition for me not to renew that as well (using correct line boring method). As per prior posts the sludge trap and anti wet sump Spring/valve (very often missed) and all oil ways  should be checked cleaned etc. and the crank end float checked. All internal case threads should be checked and cleaned out, with a tap if necessary.

Bushes on the timing side should be carefully checked particularly if the cases need to be split to replace them, for the same reason the camshaft and its bushes should be checked as well. Cam shafts are not cheap but if it is showing wear I would replace it and get the followers refaced if also showing wear, and so they don't wreck your new cam.

The oil pump should be checked as you don't want a worn one to ruin your work!

Few people will replace every bearing and wearing part in an engine (even if you could get the parts)  so I don't think the aim is to end up with an "as new" engine, just an engine with everything important "within tolerance".
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Offline edboy

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Re: A10 Engine Rebuild Checklist
« Reply #4 on: 27.08. 2016 23:03 »
the hardest and most important part is getting to all the nooks and crannies to spotlessly clean the cases and crankshaft. i recommend steam cleaning but know nothing of any other blast process.

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Re: A10 Engine Rebuild Checklist
« Reply #5 on: 28.08. 2016 15:33 »
Hi All,
Quote
the hardest and most important part is getting to all the nooks and crannies to spotlessly clean the cases and crankshaft. i recommend steam cleaning but know nothing of any other blast process.

+1

The oil way from the PRV to the timing gear and cam trough can easily be forgotten
There's a alloy plug  which would have to be drilled out to clean out any blasting media if the cases were blasted without securely blocking the ends and mid exit to the timing gears  *warn*

John


1961 Super Rocket
1963 RGS (ongoing)

Offline rowan.bradley

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Re: A10 Engine Rebuild Checklist
« Reply #6 on: 15.11. 2017 20:54 »
Replace the anti wet sumping ball & spring.
By this do you mean what the parts list calls "oil retaining ball" (part 1-4675) and "oil retaining ball spring" (part 67-1400)?

If so, do I need to replace these with genuine parts (if so, who sells them?)? Or can I replace them with a ball of the right size and a spring of the right dimensions and pressure? If so, what are these dimensions?
Replace the crank journals, co rod little end, valve guides, all the bushings.

Do you mean "regrind the crank journals"? They can't be replaced, surely...

I was expecting that I would inspect all the bushes, and only replace ones that looked damaged or that had too much clearance. Is this a valid approach, or should I plan to replace them all as a matter of course?  Remember that this bike only had about 9 years on the road. The odometer shows 39K miles. Of course I have no way to know whether this is genuine, but it seems to me that there is a good chance that a lot of these bushes and bearings are still in good nick, and still have  a lot of life let in them. I already had a reply from someone saying it is normally not necessary to replace the little end bushes when replacing the gudgeon pins (which I am). Same question about valve guides - can I just inspect and only replace if badly worn, or should I plan to replace anyway?

The oil way from the PRV to the timing gear and cam trough can easily be forgotten
There's a alloy plug  which would have to be drilled out to clean out any blasting media if the cases were blasted without securely blocking the ends and mid exit to the timing gears  *warn*
Are there any other oilways that can't be got at without drilling out plugs? And what approach do you use to reblock the hole where the plug was after cleaning out the oilway?

Thanks for all your advice - Rowan


Current bike: 1958 A10 Super Rocket (in bits), purchased in 1967.
Previous bikes: M21

Online chaterlea25

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Re: A10 Engine Rebuild Checklist
« Reply #7 on: 15.11. 2017 22:14 »
Hi Rowan,
If you drill out the blanking plugs, or drill and tap a hole in the plugs and use a slide hammer to remove them
Suitably sized plugs can be turned up and pressed back in or tap the holes and fit screw in plugs
I purge out the oilway without removing the plugs, but do not media blast the cases in the first place

Usually the camshaft bushes do not wear badly so if ok leave well alone, make sure to clean out the inner end of the cam bush in the drive side case
Aerosol brake cleaner is good for blasting out nooks and crannies (not crank sludge traps though!!)

As to what to include in the rebuild ? the sky's the limit but you need to make conscious decisions based on future use and maybe financial considerations

I would opt to send the oil pump to SRM or someone else with a test rig for rebuild and performance check
(I now insist on new pumps for customer engines)
Have the conrod big end bores checked for size, if OK polish the rods to a mirror finish, then fit ARP big end bolts
28ft/lbs torque for the 5/16in bolts on original rods
Or fit new rods
I feel its worth modifying the "oil retaining ball and spring" setup to the A65 setup where the ball seats on the back of the oil pump ( that way it can be serviced without an engine strip down)

Make sure the drive side mainshaft is to size for the roller bearing and that the cushdrive splines are in good condition

A lot of crankcases have damaged threads, the 5/16BSW threads that hold the primary cases suffer a lot
"Time Sert" inserts are the best fix

Make sure the oil pump mounting surfaces are absolutely flat,
Remove all the case studs and flatten out any raised areas around the threaded holes

Enough for now *eek*
John


1961 Super Rocket
1963 RGS (ongoing)

Online JulianS

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Re: A10 Engine Rebuild Checklist
« Reply #8 on: 16.11. 2017 10:12 »
Use best quality parts when choosing new. Some new valves and guides at the cheap end of the market are made to poor tolerences and may be worse than the old ones being replaced. Some new "hepolite" rings have a very poor reputation for quality.

I would only replace that which proves to need it.

Spray carb cleaner also good for cleaning.

If the sludge trap plugs have been removed with a chisel be careful of any sharp marks left on the crank web which could become stress points and lead to problems.

Offline rowan.bradley

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Re: A10 Engine Rebuild Checklist
« Reply #9 on: 16.11. 2017 17:01 »
Thank you for these suggestions.

Suitably sized plugs can be turned up and pressed back in or tap the holes and fit screw in plugs
If I drill out the plugs and replace them with threaded hex socket set screws (Loctited in), can anyone recommend what size screws will work best (i.e. how big a hole I will be left with) and what thread to use? Is an M series thread OK, or do I need something coarser?

I purge out the oilway without removing the plugs, but do not media blast the cases in the first place
Since I don't currently have a compressor, is there any reason why I shouldn't use water to flush out the oilways? I know I would have to be very careful not to let water get anywhere it shouldn't, and everything would need to be scrupulously dried afterwards (maybe stick it in the oven for a while).

Have the conrod big end bores checked for size, if OK polish the rods to a mirror finish, then fit ARP big end bolts
28ft/lbs torque for the 5/16in bolts on original rods
What is the reason for polishing the con-rods? What benefit does this provide?

I feel its worth modifying the "oil retaining ball and spring" setup to the A65 setup where the ball seats on the back of the oil pump ( that way it can be serviced without an engine strip down)
Where do I find a drawing of the A65 arrangement, and what parts would I need?

"Time Sert" inserts are the best fix
I'm not familiar with Time Sert inserts. What are the pros and cons of these w.r.t. helicoils? They look as if they will require larger holes for the same size inner thread than helicoils (which I would have thought in general was not a good idea).

Many thanks - Rowan


Current bike: 1958 A10 Super Rocket (in bits), purchased in 1967.
Previous bikes: M21

Online JulianS

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Re: A10 Engine Rebuild Checklist
« Reply #10 on: 16.11. 2017 18:18 »
I would avoid drilling out the plugs sealing the oilways you could do more harm than good. It is difficult to identify the centre of the plugs and the angle of the drillings, with the sole exception ofthe plug sealing the oilway at rear of camsaft trough where the plug is clearly visible.

First photo how do you identify where to acurately drill this plug, with red arrow. to open the oilway?

Blue arrow shows the enlarged oil hole to take A65 ball and spring.

I use aerosol carb cleaner to flush these oilways, why use water which would not act as a solvent to any impurity found.

Polish rods to remove a nicks which could lead to fractures - its is for reliability.

Last photo provides dimension of the cam trough plug.

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Re: A10 Engine Rebuild Checklist
« Reply #11 on: 16.11. 2017 18:26 »
If clearances for any wearing parts are within tolerance, reuse them. You are better to keep using original parts than embark on expensive and unnecessary replacements. With only 39,000 miles on the clock, the bottom end should be good for a lot more miles yet.
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Online chaterlea25

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Re: A10 Engine Rebuild Checklist
« Reply #12 on: 16.11. 2017 22:02 »
Hi Rowan,
Julian has answered most of the questions

"Timeserts use the same size tap as helecoils so no extra metal is removed
The inserts are solid with a little shoulder on the outside that fits into a counterbore
It inner thread is finished with a "roll" tap that expands the insert locking it in place
If a helecoil is fitted to the drive side case there is a possibility that it could be wound inwards when the screws are fitted or refitted causing the helecoil to foul the crankshaft

The crankcase oil hole is enlarged and the same spring and ball assembled in reverse so to speak
If I remember I can measure the diamater over the weekend

John
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1963 RGS (ongoing)

Offline rowan.bradley

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Re: A10 Engine Rebuild Checklist
« Reply #13 on: 24.11. 2017 12:42 »
First photo ... Blue arrow shows the enlarged oil hole to take A65 ball and spring.
Please can someone provide more details of the modification to fit the A65 type non-return valve behind the oil pump? What size does the hole need to be drilled? How deep should it be? Which ball and spring does one use, the A10 type or the A65 type? What size is the ball? Does the ball simply press against the opening in the oil pump body? If so, does this opening need any kind of finishing (e.g. a light counterbore) to enable the ball to seat well? Presumably one should remove the old ball and spring? Is this compatible with the SRM oil pump? Any other details that I haven't thought of?

Thanks - Rowan


Current bike: 1958 A10 Super Rocket (in bits), purchased in 1967.
Previous bikes: M21

Online JulianS

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Re: A10 Engine Rebuild Checklist
« Reply #14 on: 24.11. 2017 13:49 »
Remove the old ball and spring from inside crankcase. You should be able to see/measure the plain bore of the hole containing ball and spring.

Open the small diamter to match that.

Use the A65 spring and 1/4 ball.

Should seat satisfactorily against the SRM pump. Old mazac bodied pump will need the ball seating aganst it by gently tapping ball with hammer against pump.

Use an SRM gasket at pump/crankcase joint. Avoid nasty cheap gaskets with small oil holes which some are selling. Also avoid gasket claiming to fit A10 and B25 the mounting holes are bigger to accomodate dowls used on B25 between pump and crankcase - gasket can move on assembly part masking the oil holes.