Heads off

[Andy B]

Hi guys,

Been putting this job off for nearly two years now. The missus rides the monster whilst I follow behind on the Guzzi normally (and I get to take it out when she's not looking)... Once thing I have noticed is puffs of blue smoke when she pulls on - not all the time, but more than i'd like anyway.....

Last few months its been a big boggy when pulling on too - I assumed crap in the carbs, plug starting it always a pain in the ass....

So, I thought I'd pull the heads and barrels, expecting to replace the rings and hope the barrels are ok...

Front cylinder is definitely the worst culprit - was a right bugger to get the barrel off as well as the case studs had built up a fair old bit of corrosion (vertical cylinder just pulled straight off no hassle), and the head was carbon'd up something rotten....



Started cleaning with a wire brush to get the worst off...



Leak down check with some carb cleaner failed...



And top of the inlet valve was coked up too...



So anyway, I've cleaned up as best I can with the valves and started lapping them back in - planning on getting the heads and barrels vapour blasted so not going to use too much elbow grease on them... but taking the piston off, any tell tales for checking worn rings?

I bought a set of rings from Germany via ebay after a bit of research and i'm not sure i've gotten the right things... (https://www.ebay.co.uk/itm/291624459815)



these are the new rings, but they are slightly different... I'm assuming i'm not going to be lucky enough that they are interchangeable?



Also noticed some light scoring on the piston skirt, there's no major scoring on the barrel, but again, there are some slight marks...



At least the piston cleaned up nice enough....



And then just to add a bit of drama - bloody cam belt tensioner guide bearing on the front cylinder decided to grab some ali right at the tip and damaged the thread all the way down (D'oh!)



I'm hoping I can re-dress the thread or at the very worse use a timesert....




So big questions i guess are - piston rings - If they're the wrong'uns - is there anyway i can tell if the old ones are even shot? and If i can't sort out the threads in the barrel - does anyone have a spare horizontal barrel going?

[Mark64]

Hi Andy, were the rings in line like in the pic when you removed them? If so you will be losing a fair amount of compression due to gasses slipping past them - the rings should be evenly spaced - every 120 degrees to prevent this, also when rebuilding, it is much easier to fit the piston to the bore and then fit the whole assembly to the conrod, beware of the gudgeon pin circlips dropping into the crankcase (stuff it with rags first).
Good luck & happy monstering ��

[Mark64]

The cambelt tensioner bearing thread will probably dress up ok, run a gap down it & use some low/medium grade loctite & jobsa guddun.

[Andy B]

I lined the rings up just for the photo to make a better comparison pic... Can't see any issues with them visually, and they all moved freely and everything... Still concerned with the interchangeability of the/new ones mind...

Thanks for the rebuild tip - I was planning on putting them back on the rods first before the barrel and struggling that way...

Taking the heads and barrels for vapour blasting tomorrow.. Looking forward to seeing the improvement with valves that actually seal

Hi Andy, looks like a big job broken out there!, better than watching the queens speech tomorrow anyway.

Who are you using for vapour blasting? Would be interested to hear your feedback...and see the results ,

[Andy B]

Yep yep... If someone puts on the speech I'll be busy cleaning some carbs

Taken the heads to red dragon vapour blasting yesterday. Said they should be done by Saturday.. Nice and quick eh? Will post up photos when I get them back

...ah as recommended by Phil Morris ....look forward to seeing the results, they are on my radar too....(gs engine)

[Andy B]

Well that was a quick turn around. I've just come back from Wrexham and picked up some brand new looking heads!









Dropped off on the 24th, and they're back with me on the 27th.... now if that's not good service, I don't know what is....

Dave who runs the place rang me up and said he was bored over Christmas so came in and finished off my bits... top bloke.

If I can get my project suzuki running i reckon i'll be giving him the whole engine in bits to do

Next job - lap in the valves and wait for a few bits to arrive in the post before I throw them back together.

Looks like the rings I bought wont fit so back to the drawing board with that one. I'm gonna refit the old ones and hope my problems are all valve related and the lapping will cure it... if not, i'll save up for some high comp. pistons and rings and throw them in next winter (or the following winter since I like putting things off )

[Mossleymonster]

Very nice. Just out of interest, have you checked the ring gap?

[Andy B]

Originally Posted by Mossleymonster

Very nice. Just out of interest, have you checked the ring gap?

I haven't to be honest... at this point, I didn't want to remove the rings to measure them only to put them back on and risk breaking one....

If i was putting the new ones on I would, but I've heard the horror stories of prices for rings coming from Ducati dealers... so i'm going to bury my head in the sand, and see how it goes with improved valves.... and to be fair, the state the valves were in, there's going to be a helluva improvement....

Worst case scenario, I do it all over again in a couple of winters time

Hi Andy, they look brilliant mate, I am picking up the vibe that you are well pleased with them,and the service was brilliant too.............will send you a PM shortly

[Mr Gazza]

Very nice... They look like metal again!
Can't wait to get the Commando heads done, but I might try ultra-sound cleaning first. My guru friend says it's just as good and much cheaper, but the peening of the beads does seal the metal and go a long way to stopping oil and road grime staining.

Seems an awful shame to put that engine back together with crappy rings... If indeed they are shot? Must be worth asking round the club to see if anyone has some spare rings. I think Albie might have some? I know he regretted using duff rings on his rebuild.

Yours don't look superficially bad. It's going to be worth having them gently out to check the gaps and definitely to make sure the ring grooves are spotless.

Looking good..

[Mossleymonster]

[QUOTE=Mr Gazza;561768]Very nice... They look like metal again!
Can't wait to get the Commando heads done, but I might try ultra-sound cleaning first. My guru friend says it's just as good and much cheaper, but the peening of the beads does seal the metal and go a long way to stopping oil and road grime staining.

Seems an awful shame to put that engine back together with crappy rings... If indeed they are shot? Must be worth asking round the club to see if anyone has some spare rings. I think Albie might have some? I know he regretted using duff rings on his rebuild.

Yours don't look superficially bad. It's going to be worth having them gently out to check the gaps and definitely to make sure the ring grooves are spotless.

Looking good..[/QUOTEr



Agreed Mr G.



I wouldn't go this far and not do the rings, just the thought of doing all that good work and then having to do it all again would really take the shine off for me.

https://moto-renzo.biz/en/Tecnical-G...Ducati-92.html

[Andy B]

Well, you convinced me only managed to do the top ring on the front cylinder before realising i've left my feeler gauges in work....



But using a razorblade and vernier a rough guess brings me to 0.47mm What are the gaps meant to be?



I've been in touch with the company in Germany that I got my rings off and they're happy to refund me or swap for the correct rings if they have them, so fingers crossed at this point...

Did some further cleaning up since I had some garage time today.... I wanted to get the oil feed mounts off the barrels to make sure all the media from the blasting was out...

aaaand... front cylinder again - 2/3 bolts seized solid!



That Mig is a god send!



I was quite surprised just how much media was left over...



that was just a coupld of light scraped with a tiny screwy... A lot more came out with the carb cleaner.. Glad I checked it now...



And just had enough time to lap in all the valves... (before and after on the exhausts)

[350TSS]

I hope this helps - may not apply to a plated bore
http://blog.wiseco.com/everything-yo...about-ring-gap