9a Vs KR block

Hi there, im currently assembling parts for a mk1 16V G60 project.  Im at a bit of a crossroads now regarding which block i should use.  I have been told for best results i should opt for the 9a block with the KR head.  I have already purchased a bahn brenner integration kit which was intended to be used with the KR engine.  Obviously i want to use as much of this kit as i can.  Can anybody tell me what the differences are between the two blocks?  I know the oil cooler is slightly different but just wanted to know if anyone can tell me if much else is different?.  If the blocks are almost identical does anyone have one for sale? Cheers.

As far as i know there i dentical. Oil coolers aswell as everything else can be changed over. Sadly not selling mine!
If you can find a audi 6a as these tend to be better looked after. Mine had done 130k. Still had honing marks and no wear internally.
Obvioulsy bore size is different so id go for that.
You doind a build thread? Whats the kit like. Do you think its worth he money?
What are you doing to lower comp? Or does the kit cover that

You don't want to be using either one to be honest. The 9a/6a are 2 litre engines and KR 1.8, tall v's short blocks, 144mm v's 159mm rods etc etc

Get an ABF 16v with it's more modern engine management and it's better rod/stroke ratio and larger inlet plenum runner diameters, still cheap enough and you do not need any of BBM's "IM shaft conversion" parts because they are standard on the ABF and the USA never got those engines. Waste of money buying half the conversion parts over here. Get on the bay for one.

ABF has semi-sequential management, far more advanced than old k-jet, so for cost and tunability maybe add Megasquirt?

For the engine you want to use a spacer plate and the ABF layered head gasket, ARP hardware (rod/head/main studs & bolts)

Also, ABF 16v head and block flow more than any of the others (standard) with greater valve lift, no need to chop and change anything really and helps the torquey characteristics of the supercharger conv with rod/stroke.

Abf is tall block with longer conrods. Kr & 9a are the same only bore size which is different so for that reason why not have the extra 200ccs. Makes sense

Ah, 9a is short block is it? With the ABF you get some meaty 159mm rods and 21mm bolt dia, bit sturdier than others for FI, plus the engine management benefits. Valve lift is 10.2mm inlet and 10.8mm out v's 8.8 and 9.6 for others, ABF much better for flow, anyone know the KR/9a hybrid flow measurements? You could always drop a 95.5mm crank from a TDI in too for a 2.1 (ish)  8O

Just seems a bit much doing a hybrid when you could buy a more modern one for peanuts, mine only cost £150 all in

Its not a hybrid really though vw used 3 heads, all can be fitted only problem is valve cut outs in pistons is only on abf block.
Anyway the charger kit has been built around the g60. so you use the g60 management like the kit says. Its not a aftermarket kit thats needed it uses vw side.
Id look into wether the kit will be anle to work with the extra 200cc. You dont want to build it to find out your not getting enough fuel/air into the cylinders.
I would use the 9a/6a block

were did you find that for 150?? bargain.. I know what your saying. I would probably do the same if i was building it from scratch. But the kit has half the work done

9a has the valve cut outs in the pistons mate.


As far as i aware, kr/9a/abf heads all perform the same. Its the cams that make the difference. abf cams are best, then kr.

No need to compare standard management of the abf anf the old k-jet as that'll be binned for the G60 digifant management normally found on an original 8v engine.

Abf has wrong inlet manifold for G60 aswell, you need the rare scirocco 16v inlet so the TB is on the right side of the engine and not the left like the abf and common mk2 golf 16v's

Thanks for all the input so far guys.  I should have included a few more details really in my original post.  The reason im asking about the 9a block is i have been talking to john mitchell of JM Racing who has been building 16V G60 engines for the last 15 years or so.  He has found that he gets the best results by using a 9a block combined with an ABF crank.  This gives more dispacement than a standard KR block (about 2litre). If i was to use the KR block and increase the CC id have to ditch the oil squirters which i dont want to do.  If the blocks are identical near enough externally im happy that the integration kit will work.  
  The kit is quite expensive but its high quality.  It includes brackets for relocating the alternator, coolant outlet brackets which avoid the charger, throttle body elbow, throttle cable, spark plugs, crank/water pump pullies etc etc which allow the KR block to be G60`d.  To reduce the compression in the engine i purchased a spacer gasket from BBM but ive had a rethink on this and think i want to get hold of a good set of pistons designed to lower the compression which is a much better way of doing it.
  I havent started a build thread yet and still have bodywork issues that need to be dealt with.  I bought a restored mk1 gti but some of the work will need redoing so im looking for a bodyshop to do that in the north-east.
  There are so many choices with this engine that i decided to contact a specialist. Im happy to follow his advice but i wanted to retain as much of the stuff i had already bought as possible.  As it stands i have a fully rebuilt KR block on my engine stand with new pistons, rings and bearings all fully lightned and balanced.  Im at a crossroads now as to which  block to use (i got this engine with another mk1 gti i bought years ago) so the KR block might have to go.

I have also been told that the audi s2 manifolds work very well with this conversion.  They need to be modified however and also this will probably mean the throttle body elbow which came with my BBM kit will be redundant as it was to be used with the scirocco inlet manifold.  This option isnt cheap either as obviously they need TIG welding which would be a job for a specialist unless your lucky enough to be able to do it yourself.  Its such a difficult engine to get right which makes me all the more determined.  I love the sound of the g lader and its such a rare conversion in a mk1 golf.  Plus with the set-up i have described 350bhp is more than achievable, delivered in a smooth linear fashion associated with superchargers as opposed to turbos.

Slightly exaggerated information here, the differences in output between these engines really is not that great. What you are really looking at is characteristics of the drive train in question. Shorter stroke = easier revs. The ABF might offer a touch more torque but revs are lessened. If you want to achieve the goal figure you suggest then you definitely need to go for a 9A/ABF 2litre block. 350bhp is very optimistic but achievable, don't expect it to be easy. The engine will need a lot of work to reach that kind of output.

Personally I'd sell the KR block for a good price and pick up an ABF for around £250. Go to town get the head on the flow bench and lighten and balance the whole thing. Better cams and management then you should be good. How deep is your wallet is the question really?

The comparisons between heads was done on clubgti, all about the same really a KR head with ABF cams will perform almost the same to the standard ABF.

I would keep the kr block, and 1800cc, with a charged application the extra 200cc will be less needed and torque figures will be good anyway, also while you can chase any bhp figure you like i think 350 and front wheel drive would be fairly pointless.

With the right gearbox and diff i would have thought there would still be some fun to be had in it.  Plus if the engine proves to be too much for the mk1 ill pop it in my corrado.  The plan has always been to build a high powered engine.  Im sure ill be able to live with traction problems for the power thats available once on the move.

Abfmk1. whats the differnce between 9a / abf blocks? just the block not the internals. Just interested to know thats all!
Heard some good recomendations on quaife diffs but sadly not got one myself

Sorry i have never had/seen a 9a block, but abf is obviously taller and i know its internal but it has the timing wheel which is very handy for after market management.

Surely if your fitting a G60 you want to lower the CR, none of which you can do using these pistons. KR/9A/ABF are all high compression

There is a good selection of aftermarket pistons that can be used with the 9a block designed to reduce the compression ratio the the correct level.  The reason im asking about KR vs 9a is i want to get around 2.1litres which means id have to lose the oil squirters with  a KR block (im not even sure if they can be bored to 2.1) and i have a bahn brenner integration kit (allows the g lader to be incoorporated) which was designed for the KR/G60 block.  Im sure the blocks are similar enough externally for me to be able to use most of the kit.  I know there are many different options and ive spoken to somebody who has been building the 16V G60 engines for over 15 years who recomends the use of a 9a block with ABF crank which is probably the way im going to go now.  So anyone want to swap a KR block for a 9a block?

Cero said

Surely if your fitting a G60 you want to lower the CR, none of which you can do using these pistons. KR/9A/ABF are all high compression

Yes this is why a stacked or thicker gasket is used to lower the static CR, not everyone can afford a set of forged pistons.

So what advantage does the abf crank have over the 9a?

abfmk1 said

So what advantage does the abf crank have over the 9a?

Longer stroke so effectively more combustion volume, but you will run in to problems with possible valve interference and will prob need a thicker gaskest or low comp pistons with crown recess. This also means you'd need make sure you get your measurements right if you want to use a high lift cam.

thought they were both 92.8 stroke