Club G40 Forum

Technical => Engine and Transmission => Topic started by: Justin14100 on August 06, 2009, 08:55:57 AM

Title: 1273 heads the same?
Post by: Justin14100 on August 06, 2009, 08:55:57 AM
Just read somewhere that all vw 1273cc heads are the same?
Wanting to port+polish one and get some bigger valves in it. Does this mean I can use the head of a 1.3 carb jetta block I have laying around?
Also. Best place for big valves jabba sport? They have them listed for £97!

Thanks!
Title: Re: 1273 heads the same?
Post by: hayesey on August 06, 2009, 12:25:34 PM
1272cc heads are basically the same yes. If you get one from any 1.3 mk3 polo (CL, GT, G40 etc...) then the casting is the same.  The head from 1.3 engines with a carb (polo m2, golf mk2 and the jetta one you have) are pretty much the same but have a hole to drive the mechanical fuel pump, you could block this hole up with a plate though easily enough.
Title: Re: 1273 heads the same?
Post by: Justin14100 on August 06, 2009, 05:29:13 PM
So if I get a 1.3 polo genesis engine the head will fit perfect?
Best head gasket to use?
G40 or 1.3 or GT one? or they the same?
Metal ones from glader-site any good?

Thanks!
Title: Re: 1273 heads the same?
Post by: PeteG40 on August 06, 2009, 05:45:06 PM
metal ones are from an 8v mk4 (1.4 or 1.6 - they are same) use normal mk3 bolts as g40 ones are slightly longer

and yes a genesis will be the same casting but different valves to a g40
Title: Re: 1273 heads the same?
Post by: Justin14100 on August 06, 2009, 05:48:16 PM
Quote from: PeteG40 on August 06, 2009, 05:45:06 PM
metal ones are from an 8v mk4 (1.4 or 1.6 - they are same) use normal mk3 bolts as g40 ones are slightly longer

and yes a genesis will be the same casting but different valves to a g40
Ah score, might have got a free one - Would be replacing everything inside anyway - using all the G40 bits, replacing all seals. So will strip it down to the casting!
why the bolts different? Surely if they are the same casting it wouldnt matter?
Sorry to be a bug!
Title: Re: 1273 heads the same?
Post by: Dan on August 06, 2009, 09:47:02 PM
A GT and G40 will have double valve springs too.
Title: Re: 1273 heads the same?
Post by: PeteG40 on August 07, 2009, 08:19:32 AM
Quote from: Justin14100 on August 06, 2009, 05:48:16 PM
Quote from: PeteG40 on August 06, 2009, 05:45:06 PM
metal ones are from an 8v mk4 (1.4 or 1.6 - they are same) use normal mk3 bolts as g40 ones are slightly longer

and yes a genesis will be the same casting but different valves to a g40
Ah score, might have got a free one - Would be replacing everything inside anyway - using all the G40 bits, replacing all seals. So will strip it down to the casting!
why the bolts different? Surely if they are the same casting it wouldnt matter?
Sorry to be a bug!

g40s normally have a thicker head gasket, hence longer bolts (not cheap at vw)
the thinner gasket means higher c/r and you can use the normal polo headbolts from a mk3 cl etc.

Double valve springs tend to be on all g40s and most gts but some cls apparently still have some.
Title: Re: 1273 heads the same?
Post by: Justin14100 on August 07, 2009, 09:42:53 AM
Quote from: PeteG40 on August 07, 2009, 08:19:32 AM
Quote from: Justin14100 on August 06, 2009, 05:48:16 PM
Quote from: PeteG40 on August 06, 2009, 05:45:06 PM
metal ones are from an 8v mk4 (1.4 or 1.6 - they are same) use normal mk3 bolts as g40 ones are slightly longer

and yes a genesis will be the same casting but different valves to a g40
Ah score, might have got a free one - Would be replacing everything inside anyway - using all the G40 bits, replacing all seals. So will strip it down to the casting!
why the bolts different? Surely if they are the same casting it wouldnt matter?
Sorry to be a bug!
Ah cool, thanks a lot. Got everything from the G40 head so will have to swap them over!

Thanks!
g40s normally have a thicker head gasket, hence longer bolts (not cheap at vw)
the thinner gasket means higher c/r and you can use the normal polo headbolts from a mk3 cl etc.

Double valve springs tend to be on all g40s and most gts but some cls apparently still have some.
Title: Re: 1273 heads the same?
Post by: Tommo on August 07, 2009, 02:20:48 PM
Arent the HG's only aroung 0.4mm thicker though? How much longer are standard G40 bolts?
Title: Re: 1273 heads the same?
Post by: bbspolo on August 07, 2009, 04:15:56 PM
we list (and stock now!) the proper g40 headbolts!
Eurocarparts redhill  ;)
Title: Re: 1273 heads the same?
Post by: Justin14100 on August 07, 2009, 05:44:09 PM
Just took the head of a 1.3 genesis. Seems to be in good nick!
Kept the head bolts from it, dont think I will need anything else from it.
It OK to get it skimmed a little to clean the surface and still use a metal HG?
Title: Re: 1273 heads the same?
Post by: supercharged spaniel on August 07, 2009, 11:57:06 PM
i went to vw to pick up new g40 headbolts and he charged me 5.80 (the cost of one) for all ten thinking that one meant one bag...felt mint..went back the next day to get what wasnt there the day before and he had realised when cashing up..so had the remaining 50 odd quid to pay...gutted lol
Title: Re: 1273 heads the same?
Post by: Justin14100 on August 08, 2009, 11:55:58 PM
Oh, and finaly - before I take the plunge and spend £100 on bigger valves... does it make a big difference a big valve head? Cause at the cost of the valves I can get the ferry to france and afford the petrol to vic sur aisne. A lovely french village!

What you think?
Title: Re: 1273 heads the same?
Post by: breadman on August 09, 2009, 11:50:22 AM
Justin, its not just spending £100 on a set of exhaust valves. You'll also have to cost in the seats being machined.
Then to make it worthwhile, the head will need porting too.
A properly ported and flowed head will work better than a poorly ported head with big valves. Porting is an art and generally best left to the professionals who understand and know what does and doesn't actually work. However, it can be done at home particularly if you read, understand and then follow a guide from a head tuning book.
Title: Re: 1273 heads the same?
Post by: Justin14100 on August 09, 2009, 01:53:01 PM
Quote from: breadman on August 09, 2009, 11:50:22 AM
Justin, its not just spending £100 on a set of exhaust valves. You'll also have to cost in the seats being machined.
Then to make it worthwhile, the head will need porting too.
A properly ported and flowed head will work better than a poorly ported head with big valves. Porting is an art and generally best left to the professionals who understand and know what does and doesn't actually work. However, it can be done at home particularly if you read, understand and then follow a guide from a head tuning book.
ha. Yes I know it's not just the valves. But they are the first purchase of the kit for me! Going to speak to a few machineing places I know next week and see what they will quote me for the work. Cause I'm starting to wonder if I should just spend the money on enjoying that car instead!
Thanks!