The interaction between the elastomer seals in an engine and its lubricant is an ongoing battle. Referred to simply as ‘compatibility issues’ by the specialists, the damage inflicted on the seal by the lubricant can manifest itself in two ways. The first of these is considered to be the direct chemical attack on the elastomer matrix resulting in its loss of performance (as a seal) while the second is the combined effect of this and the dynamic stresses applied. While the latter can be addressed by thorough dynamic testing, much of Read more…

As many might know to your cost, the cylinder head gasket is high up among those engine components to suffer the greatest stress. Often a weak point in some of the best engine designs, its unenviable task is to provide a robust seal between the cylinder head and corresponding crankcase for the combustion gases, oils and coolant, both between each other and the outside atmosphere. If that were not difficult enough, the component also acts in distributing the dynamic loads between the head and block and as a consequence, has a considerable influence on the forces Read more…

The humble rotating shaft seal may be an afterthought for many a designer but its history is certainly never lacking in acronyms!

Early lip seals were made using a nitrile rubber. Now referred to, as NBR the application was limited to working temperatures of no more than 90-100 degree C immediately under the lip at the rubbing surface. Changes in seal designs at this stage to use much narrower contact points not only improved its performance, but also reduced the amount of heat generated in the first

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While it might be the aim of many engine designers to minimise the chance of any oil leakage by dispensing with the humble rotating shaft seal, it may not always be possible or even desirable. At any point where there is a mechanical take-off in the form of a rotating shaft, an oil seal will need to be present and while race engine designers try to minimise these occurrences, for the rest of us wishing to improve existing OE equipment or re-engineer old engines, that option simply does not exist. However armed with a knowledge of the design parameters around which these seals perform best, there Read more…

One of the world’s leading race engine manufacturers has revealed their design philosophy regarding seals and gaskets to RET Monitor this month.

Dave Salisbury, Chief Design Engineer at Engine Developments Ltd (EDL), told RET Monitor, “It’s a simple philosophy really… we just work hard to eliminate seals and gaskets wherever we can.”

Whilst that sounds straight forward and much like common sense it is actually something which is very hard to Read more…

In this and future issues we will look at one of the most critical seals in a race engine, the seal between the top of the cylinder bore and the cylinder head.

There are of course many ways of achieving this seal, but perhaps the first question we should ask ourselves is whether or not we need to have a joint which needs sealing in the first place.

Race Engine Technology magazine is soon to feature Read more…

In the first RET Monitor Seals and Gaskets article, we started to examine the research which Trelleborg Sealing Solutions, a leading multi-national manufacturer of gaskets and seals, has published into the interaction of sealing compounds with biofuels. This research will cause fuel system designers to rethink material selection for sealing gaskets and O-rings.

In that article we focused on water contamination of bio-diesel, something which is to an extent, almost inevitable. Water contamination has a significant detrimental effect Read more…

Form-in-place gasket technology is becoming widely available.

Every time an engine builder has to lay a silicon bead on a head gasket, he finds himself muttering, “There has to be a better way to do this!”, as he wipes the goo off his fingers. Excess silicone sealant inevitably squeezes out at the joint, creating a freestanding bead of material that is held in place solely by a very thin film at the seal joint, creating the perfect opportunity for it to fatigue off

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High-performance racing engines create a hostile environment with the presence of extreme temperatures and aggressive fluids. The polymers used for rubber seals and mouldings are often extremely costly, where even a simple O-ring can cost upwards of £35. However, recent advances in rubber compounding offer some lower cost alternatives.

For many years, automotive seals were manufactured from nitrile rubber because of its excellent resistance to mineral oils and petroleum solvents and fair

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Trelleborg Sealing Solutions, a leading multi-national manufacturer of gaskets and seals, has published research into the interaction of sealing compounds with biofuels which will cause fuel system designers to rethink material selection for sealing gaskets and o-rings.

Trelleborg evaluated the compatibility of typical automotive biofuels for both gasoline and diesel engines with a variety of fuel system sealing compounds, focusing on hardness, stress-strain and volume swelling.
Initially they conducted standard laboratory tests, which suggested that typical elastomers of Fluorocarbon (FKM) and Flourosilicone (FVMQ) were compatible with commonly used biofuels. Read more…