9 replies to this topic

[Boab]

What do these letters mean? I know that standard chambers on a 1275 head are 21.4 cc so is 21cc even more????? ie 42.4cc???

Edited by bigbadboab, 06 March 2007 - 09:22 PM.

[Jordie]

at a guess the 21cc is the chamber size

dont know the others

[WEBER45]

The U is usally referred to the head being unleaded!

No Idea other than that possible the 21cc is dish size, did you get any history with the head? sometimes its just coded from special tuning place.

could cam timings

endless really

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[Boab]

It's my mates head, I guessed it was 21cc chamber size, but is that above and beyond the standard 21.4cc?

GW is the engineer's initials as it is on the block too, but as for the SU????????

[Dan]

If the chambers were 21cc bigger than standard then the engine wouldn't run at all and essentially the head would be ruined, in fact you wouldn't be able to make them that big I don't think. More likely that they have been measured as 21cc after skimming. It all looks like coding done by an engine re-conditioner and 2 98 could be when it was done. As for the rest, who knows.

Just read your reply and if you know the GW is the engineer then the SU could be for Standard Unleaded or something.

Edited by Dan, 06 March 2007 - 09:39 PM.

[WEBER45]

I guess it would be the carb? might even be a number of a needle for the SU, someone will probably know what the GW stands for and where they were based etc
Good luck tracking this one.

[Big_Adam]

maybe guessworks has had at it!

...although prob not too likely.

[Boab]

If the chambers were 21cc bigger than standard then the engine wouldn't run at all and essentially the head would be ruined, in fact you wouldn't be able to make them that big. More likely that they have been measured as 21cc after skimming. It all looks like coding done by an engine re-conditioner and 2 98 could be when it was done. As for the rest, who knows.

I never took into consideration of the head being skimmed which could equate to 1 thou being taken of the head, no??
Block and head have the 2 98 on them so that must be the date.

Anyway thanks for the replies, I just wish enginners could have the same system for doing work so it is recognized by everyone

Cheers

[Jammy]

My best guess for the SU is either as Dan says, or that the inlet ports have been modified to suit an SU rather than a webber?

[The Matt]

For info, I think I read that the biggest chamber size you can get from a 12G940 is around 28cc, but the turbo boys will no more about that than me.

It'll be what Dan says I'd think.

21cc chambers, Feb '98, SU??? Maybe Standard Unleaded? Who knows? I dunno who GW would be though, other than some engine builder somewhere!