Oh no, not another head gasket thread

[Phil Bishop]

Just a general observation really.

 

As the owner of a 1.6K Supersport, I've obviously looked at the head gasket failures that get reported, and noticed a lot of them seem to occur on or around track days. Not being a track dayer or racer, I've smugly thought to myself: "well if you are going to insist on thrashing what is basically a small saloon engine around a track at ludicrous revs, what else are you going to expect?"

 

But the other day I was thumbing through the CSMA magazine (my other car club ) and noticed a comment in a letter about Rovers being notoriously prone to HG failures. Now, these people are for the most part retired civil servants writing these letters - so have I been wrong? Are we looking at a genuine design fault that could affect any car pottering about, or misuse?

 

(Answers should mainly consist of very short words, as I am not at all techy 😬)

 

And also, if my car came in kit form in November 2004, would it have had the redesigned gasket in it, or is this a pleasure I am yet to experience?

 

I.6 SS, 6 Speed box, BRG/yellow stripe and Brooklands!

[Mark Durrant]

Early cars had plastic dowels (now replaced with steel) to locate the cylinder head and the head gaskets have since been improved. Your car should have both these upgrades however, it is very important to bleed the cooling system correctly as airlocks can cause premature HGF. The header tank preessure caps are also a known weak point.

 

Mark D

Comp Sec

 

[oilyhands]

Primary causes of failure are

 

i) on early engines plastic dowels and problems with the head gasket itself, fixed by improved gasket design and adoption of steel dowels.

ii) on all engines, low liners, if the liners are less than 4 thou proud of the block, gasket failure will occur, it's just a matter of time. Never properly addressed at the factory, vital when replacing following HGF.

iii) head softening due to annealing caused by ill designed cooling system, largely fixed by using a remote pressure sensitive thermostat.

 

If you head gasket fails then you *must* have the head hardness tested, ensure it is flat and ensure you have 4-5thou liner protrusion or it will repeat.

 

Oily

[Phil Bishop]

Now there you go, Oilyhands, doing exactly what I told you not to do. Didn't understand a word of that

 

What does strike me, though, is that plastic isn't a good choice of stuff to make internal combustion engines with. Why did they do that? Did all the chocolate run out?

 

Still, it all makes me eat my words about people thrashing their cars to death at trackdays. It seems it was naff engineering in the first place. Why? Trying to save 50p and ruining a £10k car?

 

I.6 SS, 6 Speed box, BRG/yellow stripe and Brooklands!

[Bozz]

Phil

 

As I understand it the plastic dowels were used to avoid damage (to the head gasket) during initial engine assembly in the factory. Maybe it was Oily who told me this when he was fitting a new HG and steel dowels to my engine a year or so ago. Can't remember now (old age).

 

Bozz

 

 

 

 

McLaren Orange and Black 1.6SS 6 Speed here