Heads on the 16v's

[PeterMunns 0]

Right i ve been offered a 2L 9a engine. I can buy it complete or just the bottom end...whats the difference between the two heads....is it just the cams or is there more to it than that...?? Need to know as i could save myself swaping the heads

 

Cheers

[andycowuk 0]

just the cams

[PeterMunns 0]

andycowuk,

 

Excellent buy the whole engine then

[aposegil 0]

buy the entire engine and sell the head on

 

as for the head differences its the Cams and the inlet size from what i can tell the was three sizes the 2L 16v being the smallest then two in the 1.8 16v heads

 

not alot of difference between them but they do make a difference

[Kevin Bacon 5]

I'm sure someone once told me VW played around with 1mm bigger inlet valves in an attempt to improve torque on some of the 2 litre engines. Not sure which code or year, and I never sought verification. Steve Creswell of C&R knows a heck of a lot about the 16V engine, he could probably tell you.

[PeterMunns 0]

The chap selling the engine said its from a corrado M -reg ... Wouldn't that make it the Mark 3 2L ... ABF and not the 9a block :?: :?:

[NormanCoal 0]

The ABF was never fitted to the Corrado, so it will definitely be the 9A engine

[PeterMunns 0]

ChrisP,

 

:) Sweet Do you think £350 is aright for a 9a engine or am i having my pants pulled down

[aposegil 0]

that sounds like a great price

 

i paid £400 for mine when i bought it

[PeterMunns 0]

aposegil,

 

How many miles had yours done...?? This ones done 74k.... and did you bother rebuilding it :?:

[aposegil 0]

mine had about 100K abut then i didnt care as i knew i had big plans for it ;)

[aposegil 0]

p.s this wouldnt be Majik engine would it???

[NormanCoal 0]

Thats been advertised on PVW right? £350 is a good price, especially if you here is running and it has proof of mileage and servicing

[flusted 0]

The 9a head had smaller inlet ports to increase torque but bigger exhaust ports i think,but the 1.8 is the otherway round.

I believe theres no power gain to be had from swopping either for 1 another.As for the cams,the exhaust cams are the same so your best off using the kr inlet cam.I dont think they ever changed valves sizes on the 16v heads but vw did state that the overall valve surface diameter was a little larger than needed

[NormanCoal 0]

The 9a head had smaller inlet ports to increase torque but bigger exhaust ports i think,but the 1.8 is the otherway round.

I believe theres no power gain to be had from swopping either for 1 another.As for the cams,the exhaust cams are the same so your best off using the kr inlet cam.I dont think they ever changed valves sizes on the 16v heads but vw did state that the overall valve surface diameter was a little larger than needed

 

He's right :)

 

I know of a 9A in a MK2 with the 9A head, KR inlet cam, and 42mm inlet which has seen over 170bhp on Stealths rollers on many occasions. A very good value mod the 2L bottom end

[MelG60 0]

The 2.0 head (9A/6A/ACE) is a different casting than the 1.8 head (KR/PL) you can see it if you look at the intake. In standard form the 1.8 head will outflow the 2.0 head. The later type ABF/ADL head is the best it flows more on the intake and the exhaust and it has better designed combustion chambers. The new style 16V blocks (based on the alu block for the N/A FSI version and based on the 06A block for the boosted version also have good heads but they need to be machined to use them on a non-FSI engine)

[NormanCoal 0]

The 2.0 head (9A/6A/ACE) is a different casting than the 1.8 head (KR/PL) you can see it if you look at the intake. In standard form the 1.8 head will outflow the 2.0 head. The later type ABF/ADL head is the best it flows more on the intake and the exhaust and it has better designed combustion chambers. The new style 16V blocks (based on the alu block for the N/A FSI version and based on the 06A block for the boosted version also have good heads but they need to be machined to use them on a non-FSI engine)

 

I dont want to argue with you here, but uk KR, 9A, and ABF heads all had the same cast number of 051. The very early KR had a cast number of 027, but there is very little difference between the casts.

There are obvious porting differences between the 9A and KR heads, and the ABF head has slight differences with the valve stem length and actual size, but I have it on good engineering authority that no particular version is a lot better than the others

[MelG60 0]

There is a big difference in the 1.8 the 2.0 and the ABF heads. I will try to get some pictures online.

[davidwort 0]

There is a big difference in the 1.8 the 2.0 and the ABF heads. I will try to get some pictures online.

 

club gti have had some good threads on this subject, the VW vortex has some excellent pics of 16v heads cut up, one difference is some water channels in some of the later heads that make it a bit dodgy if you cut too much away when porting (between the inlet ports I think)

Ported and polished there's nothing in it on any of the 16v's AFAIK but the KR and 9A heads do look a bit different on the inlet ports unmodified.

 

David.

[MelG60 0]

True that the 1.8 and 2.0 will be quitte the same ported but not the ABF!

[MelG60 0]

http://www.scirocco16v.com/tech_gallery/ports.jpg

 

Difference between old type 1.8 and 2.0.

[Ess Three 0]

I dont want to argue with you here, but uk KR, 9A, and ABF heads all had the same cast number of 051. The very early KR had a cast number of 027, but there is very little difference between the casts.

 

The part numbers - and the cast in identifiers - do indeed start with 051, but that menans very little...the suffix is enough to tell you it's adifferent revision, and the revision can be as little as a change in manufacturer to a complete re-design.

 

I can assure you, an ABF head is considerably different to a KR/PL head.

 

The inlet ports are different, the combustion chambers are different, the exhaust ports are different, the valves are different lengths, the valves are physically smaller on the ABF but offer the same actual open area (seat is nearer the edge), the retainers are differerent (VR6 type) whilst the followers and springs are tha same.

 

When you actually explore the differences, there are in fact significant differences...not major perhaps, but enough to provide significantly different results compared to a KR.

 

 

There are obvious porting differences between the 9A and KR heads, and the ABF head has slight differences with the valve stem length and actual size, but I have it on good engineering authority that no particular version is a lot better than the others

 

I would beg to differ...

 

As standard the ABF is slightly better - or perhaps is's better to say, slightly more efficient.

 

When re-worked correctly the ABF tends to provide a 'better' finished product by virtue of it's more efficient starting point.

 

There are not major differences between the heads alone...but in my experience a re-worked ABF will tend to make more torque than a reworked KR head with most things being equal...granted, a lot of this will be down to the more efficient manifolding / injectors / managememt of the ABF.

 

In pure power terms, there is little between the two...but again, normally, the ABF will match the earlier engines in power but be running more efficiently and with lower emissions....a mildy sorted ABF (head work, re-worked manifolds, mild cam / cams and mapping) will run 190+ BHP & about 160 lb-ft with standard or better emmissions and still running the cat.

 

But, in general, people who know what they are doing (of which I don't claim to be one!) have agreed that there are advantages with the ABF over the earlier designs.

If there were not, why would VW have engineered it?

[NormanCoal 0]

OK, I'm not going to get into an arguement here.......

 

You are correct in saying there are significant differences between the head of a KR and ABF, but the flow characteristics of the ports when worked will see very little difference to the same work done on a KR head. Yes the differences in the valves cannot be discounted, but as a generalisation in the amount of air that it moves there isnt a significant difference.

 

I would say that the ABF engine controlled by its OE management is a completely different kettle of fish to a ABF engine on K-jet as often done in a MK2 Golf. I have had both in a MK2 Golf, and would say that there are good and bad points for each. Putting the ABF and a 2L with KR head on the same injection will prove there is very little difference

 

As a side note, the information that I got regarding this was from the man who ports heads for C&R, Stealth, TSR, Grant motorsport et al. He also is the major engineer for headwork for the VW Cup entrants

[PeterMunns 0]

ChrisP,

 

So after all this what head should i use for the most power....??

[NormanCoal 0]

what version have you got now? 1.8 or 2l?

 

What are you buying? Block, or complete engine?