how much silicone to seal the sump?
Discussion
Called in my mates over the weekend to see him re-fitting a sump on a punto.. no gasket in there just RTV silicone... it said on the tube (right stuff for the job) to put a 8mm bead around the floange.. on bolting this up, it pushed a far bit out of the joint on the outside, so the assumption is it did the same on the inside?... okay, he left it 24 hours before putting oil in so it was fully cured... and if you get a bit of this stuff once it's gone off, its very hard to pull it off cleaned metal or even pull it apart... but whats your thoughts on having 'bid beads' of this inside the engine?.. it can olyl get in the oil pickup if it comes off.. but will it ever come off?...
I used Loctite 518 when i dropped the sump on my Saab 9 5 Aero.
Its anaerobic so doesn't set as such, if it goes in the sump/oil it wont cause any problems
For example http://www.uksaabs.co.uk/UKS/viewtopic.php?f=2&...
Its anaerobic so doesn't set as such, if it goes in the sump/oil it wont cause any problems
For example http://www.uksaabs.co.uk/UKS/viewtopic.php?f=2&...
Tyre Tread said:
Have a look on the Chimaera forum and ask Siliconekid about it - Any guesses how he got his name?
Yes.. I know Daz.. and its this that made me think he was using too much... But also knowing Daz.. what else did he do?.. and did he let is cure??Got to say, a sample run I did on a un-cleaned washer stuck like mad after 24 hours and I could not pull it apart or snap the bead?...
the sump he took off had the same sealer on it.. and it was still flexable and you could not pull that in bits either...
The sump had rusted through
thats why he was doing it.. only 40K on the car... appears to be a commomn problem!! 
Tyre Tread said:
Have a look on the Chimaera forum and ask Siliconekid about it - Any guesses how he got his name?
Chimaera engines and silicone? Don't talk to me about Chimaera engines. I rebuilt a 4.0ltr V8 last year. The engine was full of black RTV sealant from the manufacturers. Low mileage, in superb condition, just full of bloody RTV where the muppets can't be arsed to use correct grade gaskets. The sump area was full of it. The water galleys had black sealant in them...and RTV had been used in nearly every bolt thread, rather than using a light thread sealer to act as thread lubricant/sealer and torque correctly.OP, if you really must use RTV, do not use masses of it as any that sits engine side of the sump will find its way into the oil sump filter and restrict oil flow. Personally, you are far better off using a suitable gasket material and for belt and braces 'smear' a light coating of flexible sealant on both sides of the gasket. With any sealant you must let the sealant part dry before component fitting. If you're looking for grade one gasket material, buy sheets of Klingersil and make your own gaskets.
if it were a flat face I’d make a gasket... but it aint... it goes around the crank both ends so it’s not possible....
I suppose it depends on the RTV used also.... if it fully cures / remains flexible / how good it is at sticking to clean metal... I’ve used some RTV before that just peels off.. but this stuff does stick like **** to a blanket !
I suppose it depends on the RTV used also.... if it fully cures / remains flexible / how good it is at sticking to clean metal... I’ve used some RTV before that just peels off.. but this stuff does stick like **** to a blanket !
TVR Beaver said:
if it were a flat face I’d make a gasket... but it aint... it goes around the crank both ends so it’s not possible....
I suppose it depends on the RTV used also.... if it fully cures / remains flexible / how good it is at sticking to clean metal... I’ve used some RTV before that just peels off.. but this stuff does stick like **** to a blanket !
Are you saying the crank shaft ends protrude through the side walls of the sump? If so, there should be an oil seal to stop any sump oil escaping; though this is an appalling mechanical design. You can still make a good gasket[s] to seal the majority of the sump to block underside. You need to post pictures for us to see. Post pics of the block underside, the detached sump, and the two temporarily bolted up.I suppose it depends on the RTV used also.... if it fully cures / remains flexible / how good it is at sticking to clean metal... I’ve used some RTV before that just peels off.. but this stuff does stick like **** to a blanket !
Spanglepants said:
I used Loctite 518 when i dropped the sump on my Saab 9 5 Aero.
Its anaerobic so doesn't set as such, if it goes in the sump/oil it wont cause any problems
For example http://www.uksaabs.co.uk/UKS/viewtopic.php?f=2&...
This ^^^Its anaerobic so doesn't set as such, if it goes in the sump/oil it wont cause any problems
For example http://www.uksaabs.co.uk/UKS/viewtopic.php?f=2&...
I recently helped rebuild a Caterham K-series engine which had been sealed with RTV and the amount of small black fragments around the engine was staggering - would never use the stuff again in any circumstances.
When putting it all back together we used some Hylomar Aerograde as the main mechanic worked with it in the aerospace world and recommended it .
When putting it all back together we used some Hylomar Aerograde as the main mechanic worked with it in the aerospace world and recommended it .
Mr2Mike said:
I agree, 8mm is grossly excessive. You only need a thin smear of the stuff provided the mating surfaces are clean and flat.
As above-smear it around with your finger, enough to provide a good seal but not great clumps. It'll squish out a bit when the sump is mated up but not excessively-maybe by 1mm at most.TVR Beaver said:
Is this on a pressed sump or cast sump. The Punto one is deep pressed and has about 1mm deep indents around the flange between the bolts to make it stiffer. You must at least fill these.
There's usualy a continuous raised section all the way around the sealing surface, which only needs a small amount of sealant. The channels are pressed in to add stiffness to the sealing flange, but unless the channel cross the sealing surface you shouldn't need to fill them with sealant.Gassing Station | General Gassing | Top of Page | What's New | My Stuff