Which head gasket for 1105cc pistons?

[ChrisB]

I've not sussed out how to get photos loaded from my mac but the bore size is approx 73.35mm.
It's a three piece gasket all metal, riveted together in four places. The centre sheet is what looks like stainless steel and flat. The outer two sheets are black with raised pressings around the bores, the camchain tunnel and all four outer stud holes. It cost around £90 from the very helpful lady at Eastwood Racing in Swanley, Kent. She didn't have one on the shelf (they place an order weekly to the States) but took one out of a complete gasket set, to be replaced on back order, and had it to me in two days. They're the UK Wiseco importers.

[DeadZedDave]

Thanks for posting the details of the gasket and the supplier. These things are always good to know for future reference !

[ChrisB]

A disappointing update regarding my motor. Quite noisy on initial start up but settled down quite nicely, however, once the expected smoke from burning off build oil had had a chance to disperse, i took it out for a gentle spin. Plenty of smoke at very modest revs. Home for a good look and there was weeping from the head/barrel joint showing at the camchain tunnel area at the front. Did go for a retorque at this point which slowed it a bit but the main problem was the exhaust smoke. Dropped the pipes and ran it again and there is noticeable smoke from No2 cylinder. Bugger!
So now i'm imagining the possibilities of a busted ring, bad valve seal or head gasket not sealing. Since there was some oil leaking from the camchain tunnel area, i'm thinking I haven't got a good enough seal with the RTV silicon. I did make a very tidy job of filling the groove and cutting it flush to the head (I used the orange 700 degree stuff).
Any suggestions or other things to check warmly welcomed.
When i pulled the head yesterday, the silicon had pulled apart and stuck to both the head and barrels so wasn't in one piece any more.

[zed1015]

Same reply as i posted to your FB post.

With the one piece gasket you should fill the groove proud with RTV ( I use VTech vital black gasket maker ). You MUST then leave overnight for the rtv to fully cure before slicing flush with a new stanley blade. Then apply a light smear of sealant fore and aft of the camchain tunnel where you get oil throw from the cam sprockets as advised in the factory manual. Once the head is on torque in sequence to minimum 29ft/lb and max 32ft/lb with stock studs. Ignore the manuals stated 25ft/lb's if that is what yours says as this is wrong and was ammended to 29ft/lb in later versions . I have never had a gasket leak following that procedure.. Also if the head gasket is an MLS type there's no need to re-torque. If it's a fibre then let the motor cool overnight after first start and re-torque the next day..

[ChrisB]

Thanks Rob, I didnt use a smear of sealant fore and aft of the tunnel as you've suggested here, don't remember seeing that in the manual. I would think that would have been enough for the slight weep at the front i mentioned. What's your best guess regarding oil getting in to pot 2? Should I be looking further afield? I obviously replaced the valve stem seals (never managed to remove one without knackering it, but that's a question for another day!) and the bore looks perfect so I'd guess the rings aren't broken but haven't lifted the barrels so I don't know for sure.

[zed1015]

Without actually seeing it it's hard to say but chances are if it's not ring or guide related or some other anomoly such as an internal weep from the head it's just bad luck with the RTV in the 'O' ring groove and possibly head torque if not tight enough.

[DeadZedDave]

Hello ChrisB, sorry to hear things didn't turn out so well, its pretty disheartening when you get trouble on the first start up after rebuild.
As zed1015 says, its tough to diagnose without seeing it.
Just to be clear, you say you did NOT use sealer fore and aft of the camchain tunnel ?
With the single one piece head gasket, just about everybody always says "use some extra sealer here" - experience tells its needed but the actual reason is that we're going away from the standard Kawaski design - so you don't find this advice in a manual ! As you know, the standard Kawasaki gasket set up has two separate head gaskets, one for for cylinders 1 and 2 and another for 3 and 4 and having a separate o-ring surrounding the camchain tunnel. When you loose the o-ring by using the one piece aftermarket gasket, oil leaks in this area are more likely, hence "use extra sealer".
HOWEVER you also mention its smoking badly on No2 and it could be that we're looking at two different issues here.
As you've pulled the head, the camchain tunnel issue will be solved on the next build I guess, but the smoke on No2 might need more investigation.
Not in any particular order I'd offer the following advice on things to check before a careful rebuild. (there may well be other stuff to check too - this is just what comes to mind)
*Check which locations you can find oil;
Is it just in the exhaust port ? (leaking down the guide / valve stem ?)
Is there oil in the inlet (likewise).
Is there oil in the combustion chamber and how much ? Any traces of burned on oil in the chamber / piston / top land ?
Is there oil spread on the head / block surface and or gasket?
Is there oil seepage between the "layers" of the gasket?
*As zed1015 mentions, check the cylinder head carefully - I recall you used a different head for the rebuild and its possible it had its own problems before you started. (?)

All / any of the above could help signpost the source of the issues!

As you've removed the head you should probably replace the base gasket anyway so lift the cylinder block and check the ring gap positions as per the Kawasaki manual.

With regard to the expensive / almost new head gasket, conditional on being able to get it spotlessly clean / free from oil, you may be able to re-use it. I've done similarly in years gone by with multi layer metal gaskets - but obviously the risk is that it fails to seal.
One more thing - but I'm assuming that neither your cylinder head and / or cylinder block has had anything much machined off the joining face HOWEVER considering whats happened, it would be worth a check to make sure your cylinder head NUTS do not bottom out on the top of the studs when assembled ! Anything's possible with a mixture of 40 year old parts with who knows what history / potential modification !

[ChrisB]

So it's been a while but managed to get back to the zed motor this week. In answer to DeadZedDave, by the time i'd wriggled the head out it was not really clear where the oil was entering the chamber as oil had run everywhere. I suspect a badly fitted head gasket/head but thought id have a closer look atanything else it may be.
I bought a go-no go gauge to check the valve guides and whilst all four exhaust guides are more worn than the inlets, they weren't big enough for the wrong end of the gauge. Three of the guides do have what looks like a crack in the end face visible from the combustion chamber side suggesting maybe dropped valves in the past. This may have ovaled the guide holes but not enough that the no go gauge goes in. Are small cracks common?
The other thing I checked was the orientation of the piston rings and here i found that the offending No.2 cylinder's rings were in with the markings at the bottom, not the top. Cyl 1 rings had no markings on whatever, cyl's 3/4 had markings at the top so this may be the cause? My pistons are marked XA which are the thinner rings (0,8mm?). Worried by cyl1 not having any markings I've ordered another set.
I'll put them all in with the markings at the top. Change the valve guide seals (which were new obvs) just in case, and i've got a cometic one piece fibre head gasket to replace the 3 part metal wiseco one, as advised by Zed1015 as the head mating face does have some small marks on it.
While I'm here, does anyone know if my 1105 73mm piston rings should be marked with a 100 near the end?
The rings, as far as i can tell, have no bevels on any edge and this makes me think it shouldn't matter which way up they go in?
Anyhoo, i'll put it all back together when the new rings arrive and tell you how i get on.

[DeadZedDave]

Hello again ChrisB, it sounds like things are still not right with the motor - not good ! I'm not so familiar with Wiseco but so far as I know, the markings -letters/ numbers- should be on the TOP face of the rings as fitted - so perhaps the rings on No2 have been upside down ? This would certainly cause heavy smoke and residual oil on No2. The fact there are no marks visible on No1 is perhaps a bit strange but as you don't have problems on No1 then maybe all is o.k. Its tempting to suggest a full new set of rings - just so you can start from a known condition but after all you have said, I'm reminded that 40 year old engines - especially modified ones - can often have had all sorts of unexpected modifications along the way so perhaps a new set if Wiseco rings might not be the silver bullet it might seem.
Regarding the exhaust valve guides: If they look like they're cracked my own best advice would be that you should find out 100% certain if they're cracked OR not. If they are cracked then I would say they MUST be changed. Cracks in metal by there nature are unpredictable and its just as likely a cracked valve guide might crack some more and a piece of guide material fall off. If it drops into the engine it will not be good. All the best with this ! Dave

[ChrisB]

As you may tell from the huge time gaps between updates, this bike is not high on my project list but here's the latest;
Rebuilt the motor with a new cometic one piece and another go at the RTV sealant in the camchain tunnel rubber seal recess, this time adding a little gasket sealant fore and aft of the camchain tunnel. New piston ring kit from Wiseco to make sure the rings were in the right way up.
Motor fired up easily and this time, oil tight! Progress has been made but the original smoking problem persists.
So now i'm assuming the exhaust valve guides must be too ovalled to get a decent seal and are sucking oil down past my replaced new valve stem oil seals.
Unless i'm missing something obvious i think it's time to replace the guides.
Question; How much am i looking at to have someone proficient replace the exhaust valve guides?
any recommendations for someone in or near the East Midlands I can take it to?

[DeadZedDave]

Hello ChrisB it looks like there has been no answers to your question:

Question; How much am i looking at to have someone proficient replace the exhaust valve guides?
any recommendations for someone in or near the East Midlands I can take it to?

I am not in a position to answer this myself.
Have you thought about posting a NEW topic on here with the question in the title ?

Dave

[ChrisB]

Admitedly, the subject matter has wandered around a bit Dave!
I now know a bloke who has built Hodna race engines for classic racers who is confident it's something we can do in his workshop, so the latest is I'm going to strip the motor once more, buy some new exhaust valve guides and see how we get on.

[DeadZedDave]

Hello ChrisB, sounds like a plan. I know I'm probably stating the obvious here and preaching to the converted and all of that but just in case it needs saying; if the racing Hodnas were single overhead cam and therefore screw and lock nut valve clearance adjustment, please just make sure your engine builder remembers its shim and bucket valve clearance here and whatever he might cut of the valve seat after fitting the new guide, he needs to take account of minimum shim thickness and if needs be, maximum tipping length for the valve stems etc.
Dave