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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - RTV

Any recommendations for a reliable RTV gasket brand? There seem to be so many listed but are they all the same? Is the colour significant?
GuyW

Are you looking for something to use with a gasket, or without?
Dave O'Neill 2

Without a gasket.
Its NMC!
A Fiat steel sump pan to block joint. No gasket was used for factory spec.
GuyW

I use Loctite RTV from Halfords. It's the copper coloured stuff and it is good for high temps. I use it on everything, with or without gasket! If you are joining something without a gasket its best to thoroughly degrease both parts with solvent first. Not only does it seal better but it helps stop any 'squeeze out' dislodging.
John Payne

What John said about degreasing. The "RTV" branded stuff that smells vinegary is worth avoiding I think. It exudes acetic acid while it's curing and I don't want that in my engine. Or yours.
Personally I'm a fan of Blue Hylomar, but it needs to be touch dry before assembly.
Greybeard

Grey, I have used Blue Hylomar for years. I just didn't realise it classed as RTV!

But I am aware that one needs to be carefull not to overdo it and end up with snots of RTV exuding into the inside of the engine.
GuyW

To be honest Guy I've never found out what "RTV" means or implies so it's likely I don't properly understand the question.

However FWIW I recently used blue Hylomar on an intercooler housing gasket on top of a 1250hp diesel and that gets good and hot at full Billy! It's immediately downstream of two turbos running 33psi. So I reckon it would be fine for your Fiat sump but I expect there are better options. I'd be interested to know as well!
Greybeard

RTV = room temperature vulcanisation, I believe.
Dave O'Neill 2

RTV - Room Temperature Vulcanising Silicon
Mike Howlett

Guy you can get yellow stuff that's quite odd for sealing cam carrier ladders on the K series. It dissolves in oil, so excess isn't an issue, and is designed for metal on metal joints.
Rob Armstrong

Good Lord what a goldmine of learning this bbs is!
After all these years I finally know what RTV means - thanks guys!
Greybeard

There's a Mazda sealant that's a ripper, specially made for metal to metal joints-It's a silicone but feels 'different' to most, it's more pastey, a bit like thick toothpaste
You can put a bead down and spread it nicely with your finger without it going up your arms and everywhere
It dries when it's starved of air, so you can loosely tighten it (did I say that)till you get a nice bead around the edge, leave it for 10 mins or so then finish scewing it down
It's grey and does a nice tidy job
Mazda Part.no.------R2Y1-10-431
it's made by Threebond---their Pt.no. is--
---1217D
These numbers are for a gun refill tube, so a smaller tube might have different numbers

Well, that was helpfull wasn't it-
willy

it is good stuff though and O2 sensor compatible which is something to be aware of when choosing if that Fiat has a sensor
William Revit

RTV is tolerant of movement between the parts providing there is a groove or chamfer for it to overflow into. You shouldn't use it unless the manual specifies it. If you are just looking for something to stick parts together then you are probably better looking at something else like hylomar.

On K series, I believe RTV was adopted later on the bottom end but I'm not sure about the top. It used to be anaerobic sealant. Refer to the manual

I would always trust Loctite. I'm sure their website gives some guidance.
Paul Hollingworth

I'm in the middle of rebuilding the gearbox on my pre unit Triumph and some joints were sealed with what looks like varnish. I've seen it before on older stuff, it probably worked ok to start with but 65 years on it leaked everywhere! I'll be using my Loctite stuff when it goes back together!
John Payne

John I wonder if that's shellac. I know it used to be used on engine cases but I thought it was only pre-war.
Greybeard

Yes I think it probably is shellac. It's from 1955 but the gearbox is exactly the same as a pre war one so it's possible they could have carried on using it.
John Payne

This thread was discussed between 06/01/2019 and 08/01/2019

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