BAFFLE SUMP/SEALANT QUESTION

[giorgio67]

Hi guys,

 

I'm doing a little job on my engine and I have just dismantled the freshly assembled and sealed sump....

now I have a doubt, I have the 912 engine baffled sump, a little bit different from the 910 turbo but the way to seal it I think it's the same.

On the manual is reported to put a bead of sealant also on the main bearing panel and on the sump but surfing on the web I've found these two pics of a forum member (don't recall the name sorry) and the 910 baffle is sealed in totally different way.

Sealant also UNDER the baffer and then on the upper where it joints with the main panel.

It's correct?

I need to seal mine in the same way?

Also if you look at the pics, you will see that the sealant is also on the internal joint of the sump, nothing reported on the manual about that,

Any help?

 

Thanks

Giorgio

[molemot]

I seemed to remember using "Wellseal" on my 910...so I've just looked at the manual, and it says that's correct for the 910. It also says the 912 uses Permabond A 136.... Frankly, I think that so long as it doesn't leak, it's not critical. The manual also says that the sealant bead should pass on the INSIDE of the fixing holes....so the photos show it going the wrong side!

[giorgio67]

Hi John yes but you have not answer my question mate

the problem is: sealant under the baffle or not...?

Ciao

 

Giorgio

[molemot]

Giorgio....don't think it's critical. I used Wellseal on the 910 and sealed both side of the baffle, working on the basis that it was effectively the meat in a sandwich and sealing both sides made sense. Since there is no provision for clearance between the baffle, the sump and the bearing plate it seemed appropriate to seal the joint. Using a silicone gasket stuff you would want to be sure that you don't end up with great gobbets of it in the sump, to end up obstructing the oil strainer.... but you know that anyway....(!)

[910Esprit]

Your approach looks absolutely fine (although I would use a slightly smaller bead) - although John is right regarding bolt holes.   As its a zero fit joint you will just end up squeezing out copious amounts of expensive sealant if you put it both sides - 50% of which will sit in sump

[Andyww]

I would go with the Permabond A136 for all engines. 

 

A lot of the time these older sealants such as Wellseal were the best available at the time but have been superseded. There is no need to stick with the original recommendation. IMHO this applies more so to Hylomar which is awful stuff and should be consigned to history. 

[molemot]

I've always found Hylomar to be excellent...it managed to keep the oil in Merlins! Personally, I am not a fan of silicone sealants and the gobbets of stuff one tends to get where one doesn't want them. Blocked the cooling system on my boat with a chunk of that once, left over from someone else's efforts...  I don't think Permabond could be used everywhere that Wellseal is indicated...such as the main bearing panel...as it needs a zero thickness sealant to keep the bearing clearances correct. There are more modern zero thickness sealants, and they are a godsend for such jobs as the cam towers...using silicone here results in disturbing the valve clearances and, even if you make allowances for the thickness of the sealant, you end up with an iterative process. Andy is quite right...these recommendations aren't carved in stone, and better stuff is available these days.

[Andyww]

I remember many years ago at an open day, Pat Thomas at Kelvedon Motors had a 907 engine on display which had been blown up by over-use of silicone, there were worms of the stuff all over the sump pickup. He always said that silicone should be used on baths not engines, and I have followed that advice to this day.

 

I use Loctite 518 mostly. Hylomar I cant get on with at all, it seems to dry out while its being applied and its impossible to get a controlled thickness.

[molemot]

Are you talking about the blue Hylomar? That stuff NEVER dries...I always squeeze a bit on and run my fingertip over it. Any slight excess just squeezes out of the joint when you tighten it. You can even get it as an aerosol to spray on gaskets etc.

 

Hylomar® M

The original and genuine non-setting gasket and jointing compound specified by OEM’s around the world.

• Manufactured under licence from Rolls-Royce
• Dichloromethane free
• Wide operating temperature range (-50 to +250ºC)
• Fuel resistant

Pack sizes – 40ml tube (blister card), 80ml tube (carton), 200ml aerosol, 200ml Autopress, 250ml brush-top tin, 300ml cartridge & 1 litre tin.

 

Technical & Safety Documents

[giorgio67]

Job done sealing both faces of the buffle, very little bead of Wellseal as raccomanded by Steve SJ.

G.