A5 Stelvio engine replacement with A8

[Jdcooper]

The internal knocking in my 09 Stelvio engine has gotten intolerable. Using a stethoscope I can confirm it's knocking from the lower end; and I assume a bearing is dead (I've experienced car engine bearing failures in the past...and this sound is identical). I've purchased a running A8 and intend to swap them out, thereafter replacing all the bearings in the A5.  While I've plenty of wrenching experience, I'm not very Guzzi experienced; so I seek the 'wisdom of the hive' on a few issues before I get started.

First:   The A8 is flat tappet. I've previously rollerized the A5 with a C kit.  My A8 is serial number 013406. I believe that requires a B kit, correct ?  I also believe that the A8 has the valve shim installed in the head, and consequently I should be able to swap the roller actuators out of the -5 into the -8 without pulling the head. Has anyone done this before to help steepen my 'learning curve' ? Visually they look like a direct swap...but the devil is in the details, as they say.

For those who have pulled engines before, which seals did you replace/reuse.  I intend to order them all at once to consolidate my parts acquisition. 

WHILE I HAVE THE ENGINE ON THE STAND:   Is there anything "chronic" to the A8 which needs to be checked before I reinstall ?  The clutch plates look very good; the engine had low mileage before the previous owner stuffed it.

Thanks for reading and considering my "project" . 

Coop

[pete roper]

Firstly, bad luck! Bottom end failures subsequent to the tappets going west is rare but it does happen. I have no idea what is the actual trigger or whether it's just dumb luck. I've had three go bad out of 80+ engines I've rollerised so the attrition rate isn't high.

As to your question as to parts interchangeability the answer is yes, you can use the 'C' kit assemblies but unless I'm mistaken you'll also need to swap out the plug tubes and rocker covers as I believe that the A8 motor uses the later system with short tubes that go between the head and cambox/rocker carrier casting and the thick neoprene gaskets between the cambox/rocker carrier casting and the rocker covers rather than the long tubes of the A5 that are sealed bottom and top by o-rings in the head and rocker cover.

As to your question about the shims? This is more difficult to answer as it will depend on what bike the motor came out of. If it was a Sport 1200 then it won't have the shims! The identifier is the drilled 'Dots' in the paint adjacent to the date stamps in the head casting. If it has those you're golden. If the paint is untouched then you'll need to pull the heads and swap the shims. Not a big deal if you're swapping the camboxes anyway and a breeze with the engine on the bench!

As for rebuilding the other one? The only fly in the ointment is that the front main bearing is now a pushed in item that is supposed to be integral to the case and non replaceable. If it is damaged you are supposed to throw the case away and get a new one! How about 'No'! My mate Ron has a mob in Sydney who are currently using my original case as a prototype and I hope to be able to offer a bearing replacement service for others suffering front main damage shortly!

Basically though before you buy anything for the old motor strip, examine, measure and inspect.

Pete

[pauldaytona]

engine comes from
ZGULSU022CM111465 GU9032440USC01 GRISO SE MY12 US VERDE
made 31.01.2012

[pete roper]

Thanks Paul. It should have shims then.

Pete

[Jdcooper]

Pete and Paul

You gents are lifesavers. Thanks for taking the time to help me. I'll follow you advice, Pete; I appreciate it !

The great sense of community shown by the members of this board reaffirms my faith in Guzzista's.

[pete roper]

Just remember, if you have any questions ASK before diving in. It's a lot easier to prevent Fuque-ups than to try and Un-Fuque them once they have occurred. I'm on holiday at the moment and don't always have web access but if you can wait for a day or so after a question is asked I can probably get an answer to you. Very happy to help if I can.

Pete

[pauldaytona]

are head covers the same, since they made a switch to the newer covers somewhere. But suppose you can swap covers with internals too.

[Jdcooper]

Well, I removed the A8's left cylinder flat tappet valve actuators today in the process of getting ready for the engine swap.  The plan is to swap the roller actuators from my (dead) A5 into it during the swapout when both lumps are out of the bike.  Sure enough there was DLC erosion on the tappet face. There was no metal wear on the tappets, but a small degree of heat discoloration on the cam lobe.



I'm not surprised, even though it's a fairly low mileage engine.  Pete is absolutely right: they will ALL fail eventually.

[Jdcooper]

Update:

New lump in and running. The bike runs like a Rolex so far (50 miles).  Had to use the old (A5) valve covers on the A8, but the rollers swapped out very easily. No knocking noise as the engine warms up now. Good thing...I was getting frustrated with this bike. Thanks to all who lent their expertise to this project.  How lucky is it that a used, running A8 is for sale 30 miles from my home ? From what I gather these things can be pretty rare.  I am a blessed guy indeed.

Now.......Ride On !

Coop

[Huzo]

As an outsider looking at your plight I say good on you for seeing it through, and yes, there is a seemingly inexhaustible supply of wisdom available, (  if you know where to ask). Well done, it must feel great to touch that throttle and feel the new response !!!

[River Rat]

good job mate

[pauldaytona]

And now what is wrong in the A5 engine?

[pete roper]

My guess, based on experience, is that it will of lunched its big ends and possibly the front main.

[Jdcooper]

"and now what is wrong in the A5  engine"

That's THE question. Hopefully I'll get the opportunity to tear it down before I leave for winter in Florida. The learning curve is pretty steep for me on this. I'd love to diagnose and fix the motor to be able to have a spare for anyone who needs one and isn't lucky enough to find one locally.