rear cylinder base gasket oil leak......

[nathanhu]

more work to do .............



anybody done one of these themselves??
is it a paper or liquid gasket ?

ill post a pic later

any hits or tips of what i should be looking out for?
thanks in advance
nathan

[Felix]

If it's a standard motor it will be a metal base gasket. If you need to replace the gasket, you'll need to obviouly take the head, cylinder, etc off.

Where exactly is the leak?

[nelly]

The base gasket is more of a shim to set the squish than a gasket.
The oil leak is likely to be the o-ring on the rear rhs at the base of the cylinder.
When you reassemble the cylinder, coat the base gasket in threebond (rtv sealant) and grease the o-ring well. You can clean the old base gasket up and re-use.
If the o-ring is fitted dry, as it is at the factory, it goes hard and ceases to seal properly...............hence your leak.
Not a difficult job. The hardest bit is getting the circlip back in the piston!!

[nathanhu]

its loosing quite a bit now this is after two days riding, but some flat-out on the motorway/autobahn

nelly ,
injection + exhaust system off, set the cams to timing marks ,remove belts , and judging by your last post leave the piston IN the barrel ;)
do i need the special tool for the head bolts?
and is 45 deg twist ok for the belts?



oh and if your free ill pay for your flight and beer if you come to my place and do it for me :lol:

[nelly]

nat, thats about it.................
Ideally you'll need the head nut spanner, but as ever there are ways around using "special" tools ;)
45 degree twist seems a little tight compared with the tension tool. I'd go for the 5mm deflection between the cam pulleys personally.
It makes life a lot easier if you can leave the piston in the barrel (especially if don't have a ring compressor), but if it comes out, take it off the rod, refit on the bench and refit to the rod when you put it back together. I have a ring compressor that works with piston on the rod, but it's fiddly. For the sake of a circlip it's not worth the fuss.
You won't need many parts. Head gasket, exhaust gasket, o-ring, piston circlip and some rtv.

as for "oh and if your free ill pay for your flight and beer if you come to my place and do it for me "....................... starnger things have happened :lol::o

[nathanhu]

well i started stripping the bike this morning and found loads of metal particles in the oil.......:mad:

isnt it always the case :flame:

[nathanhu]

and heres what i found ----

[TP]

Originally posted by nathanhu
and heres what i found ----

:o

I'm tipping 4.

[rockhopper]

Guys, chrome isnt magnetic so you wont get it sticking to the sump plug. Unless there are are huge chunks of metal on the plug what you appear to be seeing is totally normal and nothing to worry about.

[TP]

Originally posted by rockhopper
Guys, chrome isnt magnetic so you wont get it sticking to the sump plug. Unless there are are huge chunks of metal on the plug what you appear to be seeing is totally normal and nothing to worry about.

Oh yeah, forgot about that. Thanks Paul.

I'll stick to computers shall I!

[nathanhu]

why is that normal ?


is my bike lightening itself!!!!!
:lol:

[rockhopper]

Its just general bits of swarf from around the engine. Thats what the filter and magnet are there for. I've seen them much worse than yours as well! One had a whole gear tooth stuck to it. Little bits that you can hardly feel between your fingers are nothing to worry about. Just clean it all off and check it again next time.

[rockhopper]

Have you looked in the strainer?

[nathanhu]

i got the strainer out last night and it ok with very few particals in it.

just having trouble getting the head bolts undone !!!

[Edited on 16-4-2005 by nathanhu]

[nathanhu]

as its such a tight fit ......
hm best i get my grinder out

[nathanhu]

so progress report.....

i got my hands on one of these---


made the job a lot simpler

[nathanhu]

i removed the cylinder

but couldnt find an O ring there was just a base gasket with sealant on both sides!!!!!!


this job has been done before by my dealer just over one year ago, my next question would be ,has it been done correctly????

[nathanhu]

and lastly a pic of the gasket
in the top left hand side is a grey ring this is just silicone
is this where the O ring should be??

[nelly]

Looks like you may be suffering the parts bin problem.
The engine case appears to be the type requiring an o-ring. the machined area around the oilway is where it would sit.
The base gasket looks like type that does indeed require just sealant, although the hole shouldn't be blocked up with the stuff.
the base gasket that fits with an o-ring has a bigger hole that sits around the sealing ring.
I'd have a word with your dealer. Having the recess for the o-ring means that the gasket and sealant won't seal alone. It'll need a ring in there to fill the gap. Probably the o-ring and suitable base gasket is the better alternative.
I've checked the parts diagrams and neither really tally with your 2001 748E though. Have you got the heads with the lower exhaust cams? 5 bolts holding the rocker pin covers in place? or 4 as per the "traditional" heads?
Ducati are showing the 2000 models with o-rings and 2001 without.

[nathanhu]

Nelly ,
thanks for getting back to me ill go and have a look in the garage.......


maybe the pixies came in the night and fixed it............. but i doubt it :lol:

[nathanhu]

nope still in bits....(dam pixies never come when you want them to !!!)


so the side rocker pin covers have 5 bolts in them ..

i guess that would mean no O ring then????? confused ....just a little

[HANCYM]

Just reading with interest again... If this here hole is supposed to be sealed with an O ring and or free to pass oil. Is the oil on its way up under pressure or down flowing back?

If up, and blocked isn't that NOT good....?

[nelly]

The 5 bolt rocker pin covers indicate you have a "proper" E model. Ducati spread the use of the ST4 and S4 head mods probably to reduce the production costs. some E's use the old design heads.
Anyway, the parts manuals show you have the right base gasket, ie no o-ring, however that shallow recess in the crankcase looks like the older style using the o-ring seal............
Could be a parts bin confusion.??????
Also, at some point the head gasket design was changed and this made it thinner. To retain the squish dimension the base gasket was thickened up.
I guess what i'm trying to convey is that i'd try and use the earlier base gasket with an o-ring in place, but you must ensure the base gasket remains the same thickness as your current one......................if you went down that route.
Alternatively, you could try and fit a thin o-ring below the base gasket you have now. Using sealant won't give a sufficient seal to the recess in the crankcase IMO.
That oil way is a return from the heads back to the sump, so it's low pressure. It will be hot though and that's why the oil will, if it gets half a chance, escape over the back of your crancases. It being blocked by sealant won't help whatsoever though.
If it were me, i'd go for the solution of using your existing gasket, with not too much sealant in that area and try and get a thin o-ring in there, under the gasket. The sealing face of the cylinder should be flat? If you need any help or maybe a suitable ring, mail me and i'll measure the ones up off the older engines and try and select a suitable one to use. It wouldn't need to be much more than 1mm section i'd have guessed.

Hope that made some sense...................i'm confused anyhow
:puzzled:

[Jon]

Well done Nelly, I think this is very commendable of you. I know his Lordship has rang you from spain asking for advice when he had a problem, and you took the time out to help him, also the same with Old Yella. Keep up the good work Neil, it will pay BIG dividends in the end.

Nathanhu, you really should have cleaned all that crap off the block before starting that job!!!!!!!!!

[rockhopper]

Blocking up the hole might be one way of solving the oil supply to the cams problem!

[nathanhu]

hi Nelly,
todays progress report :puzzled:

ive cleaned up all the gasket faces and the gasket itself .
iv noticed that there is no recess machined into the engine cases for an O ring , and on the mating face of the barrel there is no further oil way drilled upto the head , so i can only assume that the gasket sealant actually covers the drilling to seal the oilway ( the oil return from the cylinder head is down the rear of the head either side of the exhaust manifold and then into the crankcase)
got some Loctite 5920 rtv sealant today , should do the trick ?


thanks for all the help Nelly, i thought it would be more fun to do this on the forum , maybe it will give others a little insite into what goes on inside the motor and we can all learn a little.....lol

normaly i fix Landrovers and Hgvs so this is something new and interesting for me

[nelly]

Good news nat. That slight circular machining is where the o-ring sits on the earlier engines. Blocking off the oil way in the cylinder casting is an easy fix!!!!
The hole in the crankcase could still be open to an oil way though, so as it's not needed, i'd make sure there's "enough" sealant around there to make sure no oil gets out ;)
The Loctite sounds like it'll do the trick............RTV is the key. I use Threebond (Ducati use it in production).
It just doesn't need to go hard/brittle over time............

Best of luck finishing the job off :)