As above, i am after the deck height of the PY block with standard pistons, the cc of the combustion chamber in the afh head and also the cc of the dish in g40 pistons.

Many thanks,

Dont suppose you've looked on www.polog40.co.uk?

I don't have any of those numbers (and not sure anyone will have them to hand) but I assume you're trying to work out the compression ratio you'll end up with if you put an AFH head onto a g40 bottom end. I don't know the numbers but it'll be too low to even run since g40 pistons with a flat head gives 8:1 and the afh has combustion chamber in the head the resulting compression ratio will be very low. You'll need some custom made pistons which have much less of a dish on them.

I don't have any of those numbers (and not sure anyone will have them to hand) but I assume you're trying to work out the compression ratio you'll end up with if you put an AFH head onto a g40 bottom end. I don't know the numbers but it'll be too low to even run since g40 pistons with a flat head gives 8:1 and the afh has combustion chamber in the head the resulting compression ratio will be very low. You'll need some custom made pistons which have much less of a dish on them.

Yeah, I was wanting to know how much of a dome or flat top on the custom pistons i will need. I'll just have to keep looking. cheers anyway...

I don't have any of those numbers (and not sure anyone will have them to hand) but I assume you're trying to work out the compression ratio you'll end up with if you put an AFH head onto a g40 bottom end. I don't know the numbers but it'll be too low to even run since g40 pistons with a flat head gives 8:1 and the afh has combustion chamber in the head the resulting compression ratio will be very low. You'll need some custom made pistons which have much less of a dish on them.

Yeah, I was wanting to know how much of a dome or flat top on the custom pistons i will need. I'll just have to keep looking. cheers anyway...

no need for custom pistons, you need the ones from the early polo hh engines, I've looked into doing a 16v g40 myself, almost have te block and head mocked up at the workshop, the problem using the afh head is the cam belt arangement

afh cambelts to long

g40 is to short

afh belt is wider than the g40 one, I've think I've found a cambelt from a audi 100 which is the width of a g40 belt to fit round the water pump etc, but has the additional length to go round the afh heads extra cam pulley and the extra auxilary pulley which would need fitfing on to block to divert the cambelt from the engine mount. But if the afh cambelt wider for a reason, could be a bit of a risk using a narrower one

using the later avy style 16v heads would be slightly easier due to only having 1 cambelt pulley, but thay just arent as good a afh heads at the end of the day

another problem with both 16v heads is weather you can still use a g40 charger mount, both 16v heads sit futher forward on the block and the exhaust ports are futher left than the 8V heads

hope that helps

thanks

will

Edited 3 July, 201016 yr by willsalter1000

that's interesting. what CR do you end up with when using the hh pistons? I assume they are normal 75mm bore. Just how much longer is the AFH cambelt? could you not stick an idler pulley and/or tensioner in there to take up the slack?

Almost any length/width belt can be obtained so don't let that stop you.

that's interesting. what CR do you end up with when using the hh pistons? I assume they are normal 75mm bore. Just how much longer is the AFH cambelt? could you not stick an idler pulley and/or tensioner in there to take up the slack?

yep, there normal 75mm bore, I'm not to sure about the CR but it should be about right, i have a hh and a afh head at the workshop so ill have a go at measuring the size of the chambers, hh engines are 8.2:1 iirc so if the chambers are around the same size it should be ok

the problem with using the afh cambelt is that it is to wide for the g40 waterpump pulley so the belt overhangs the sides of the pulley which wouldnt be to healthy, I've already tried putting the afh water pump pulley on the g40 waterpump and there a completely different arangement.

something else to add is that I've been in touch with poloace who atempted this and he says that you can use a g40 engine/charger mount in conjunction with a 16v head, it just requires a bit of spacing off and modifying

Almost any length/width belt can be obtained so don't let that stop you.

dont worry, I've got a gates cambelt data book to hand with all the dimentions i need to help me, from the info I've found I'm 99% a audi 100 belt will do the job, ill get one bought and see weather its long enough

thanks

will

Good info right there! may have saved me many £100s!

So the HH pistons will create suitable compression ratio? Is the combustion chamber partially in the head of the HH engine then? Otherwise i'll be back to square one as with g40 pistons.

I need to find a suitable piston that will leave me with a compression ratio of 8.5:1 and still have clearance for the valves on the afh head.

Belt wise, i know of a company that do custom belts, for not a lot of money bearing in mind it is custom. So that can be taken care of. Width wise, i think vernier pulleys on the afh head the same width as the g40 bottom end pulleys will solve that problem.

I need to get hold of an afh head to work out the size of the combustion chamber in the head so i can calculate what pistons will be suitable. I'm not convinced HH pistons will have a thick enough crown to put up with the heat generated...

Just thought about that properly, g40 pistons with flat head is 8:1, so the only way hh pistons will help is if the hh has the combustion chamber slightly in the head. Even then you have to find some pistons, i'd want new ones, and for that money, i could go custom!

Edited 5 July, 201016 yr by .Joe

Just looked in to it, the HH engine does have the combustion chamber in the head and flat(ish) pistons. Now I just need to see if they are suitable and will accept the heat of boost... If not at least i have the measurements for custom pistons....

Second off topic question.... anyone know the suitabilty of the standard afh cams, for a supercharged application? Or anyone know the a suitable set of cams?

iirc hh pistons are completely flat and i dont see any reason why they shouldnt be able to cope in a forced induction application, they cant be manufactured much different to standard g40 pistons and theyve been used up to nearly 200bhp with little problem, with the help of aquamist etc, hayasey's is a good example, I've also heard of germans whacking g laders strait onto standard hh lumps due to the low compression.

as said previously i have a hh and afh at my workshop, when i get some time ill measure the chamber capacity and let you know

have you got some contact info for the custom belt company? looked everywhere on the web for custom belt when i first started thinking about a 16v g40 but found nothing, thats why in refering to the gates cambelt book instead

i know of no camshafts for the afh heads specfic for turbo/ supercharged application, you would have to have one custom made most probally. although there a quite a few people around who have supercharged vw engines on N/A cams and they have seemed to have ran well, if you were going to run a turbo the standard afh cams should be more than up to the job due to mild lift N/A cams quite liking abit of boost, just the same as using a gt cam in a 8V g40 turbo

I have pm'd the guy on here with the 6n afh eaton as he has cat cams and will most likely know the profile. Yeah sure, i'll dig out the info for the belt guys and pm you.

I think vernier pulleys will be the way forward at the top end dont you? Also allowing for maximum tunability. I need to find some HH pistons now! Anyone got some?!

I have found an engineering company that will modify the afh head for next to nothing and get it to match up with a g40 gasket as i believe there are differences in waterways. The g40 has 3 less than the afh iirc.

I'll pm you with the info...

You'll deffo need custom spec camshafts if you want to get the full potential from any 16v G40.

My 8v still flows well on 190bhp @ 8psi with a G40 blower.

ye. it would be nice to hear back from this guy to see what cams he's running, i know of someone elso who had a afh running a g60 charger, ill send him over a pm tomorow

ye, vernier pulleys would be good although you could use the stock items at first, my worry was using a narrow belt to fit round the g40 waterpump, there must be some reason why vw used a wider belt, it should be ok anyway

one thing i know you cant do is cut and shut the inner afh pulley with the standard g40 outer with a adustable centre because the g40 pulleys are so much bigger than the afh pulleys that they would touch one another when fitted, if you get what i mean? so you would need a custom set a verniers making up if you needed them

no need to modify the afh head, all of the water/oil ways match up to the g40 block, its only the late avy roller rocker heads which need the three extra waterways welding up, as you say, if your picky you can drill the g40 block for the 2 dowels which locate the afh head as found on the standard afh block

look forward to the pm

Edited 5 July, 201016 yr by willsalter1000

Custom cams arent an issue nick, as I'm sure you know, newman will grind you any profile cam you like, its the development going in to working out the profiles needed that will take the time.

I am now desperately in need of hh pistons! Or anything similar... Anything else they came in?

I'll get on the case of the belts as soon as i can. The only other option i suppose is running the verniers, an audi 100 belt and a tensioner/idler to take up the slack in the belt... Trial and error i suppose.

I have a spare block i can work with, its just a case of having the time to build it up and see...

Yep its the R&D which takes up time and money, hence why most people go down the easier turbo route for more power. The G40 blower is probably gonna be lost on a 16v head, its starting to run out of puff on mine as mentioned above. You don't get anywhere without trying though....

HH pistons are rarer than PY pistons. They came in a few MK1's, namely the GT and some early 1.3 saloons.

ye, nicks right, hh pistons are pretty rare although they pop up now and again, youll probally have to buy a full hh bottom end/engine though

ye, nicks right, hh pistons are pretty rare although they pop up now and again, youll probally have to buy a full hh bottom end/engine though

Sod it, i had planned on custom pistons, i may aswell just buy some. I dont particularly want to wait for ages until some pop up. Does anyone know where i can get the details from? Or will someone like wossner or wiesco know anyway? As we are still guessing here if HH pistons will even give the correct ratio... It may well be custom only anyhow.

Yep its the R&D which takes up time and money, hence why most people go down the easier turbo route for more power.

Easier? As opposed to bolting on a VW designed supercharger with the VW designed bracket for that engine? Supercharged cams for the 8v heads are available off the shelf and have been for years - turbo cams are a fairly recent development! For the 16v heads neither really exists, so it makes no difference.

If you're going supercharged I'd consider getting an exhaust cam with more duration than stock and swing the cam timing about to give more overlap. Probably best to start off with the stock cams and see how it goes though before you spend any cash! Plenty of info on the 'net and in the tuning books on selecting cams - "Forced Induction Performance Tuning" by A. Graham Bell has some useful info on the subject.

BTW - a good reason for going turbo on a small block motor is more progressive torque delivery - it's much kinder on the drivetrain and makes it easier to get the power down.

Also worthy of note: Another source of "HH" pistons is the equivalent mk1 golf engine, code GF. I just sold a HH engine with a 5-speed box out of mine for £100. Didn't realise the parts were in such high demand!

I have just picked up an HH engine for exactly that. Does anyone know if the rods and crank are any use like the majority of the 1272s, are they the same?

Well i spoke to Cat cams earlier about profiles etc, and they have recommended me some.. From the information I have the standard cams are 245 / 245°, 201 / 201°, 8.50 / 8.50mm max lift, 0.20 / 0.50mm lift @ tdc.

The catcams recommendation was : 247 / 237°, 215 / 206°, 9.50 / 9.00mm Max Lift, 0.65 / 0.55mm Lift @ TDC

Having said that, i have no idea how they have come to this as they have never supplied any for the application i am using them for. Also another downer being the fact that with vernier pulleys, the whole lot comes a few pennies short of £1k!

And no one can still say for definite if HH pistons will create a suitable compression ratio! I'll have to take some measurements when i pick up my afh head...

Edited 6 July, 201016 yr by .Joe

Yep its the R&D which takes up time and money, hence why most people go down the easier turbo route for more power.

Easier? As opposed to bolting on a VW designed supercharger with the VW designed bracket for that engine? Supercharged cams for the 8v heads are available off the shelf and have been for years - turbo cams are a fairly recent development! For the 16v heads neither really exists, so it makes no difference.

If you're going supercharged I'd consider getting an exhaust cam with more duration than stock and swing the cam timing about to give more overlap. Probably best to start off with the stock cams and see how it goes though before you spend any cash! Plenty of info on the 'net and in the tuning books on selecting cams - "Forced Induction Performance Tuning" by A. Graham Bell has some useful info on the subject.

BTW - a good reason for going turbo on a small block motor is more progressive torque delivery - it's much kinder on the drivetrain and makes it easier to get the power down.

Andy not sure wires have crossed somewhere, its easier to build an 8v turbo than a 16v supercharged from a PY lump. Pretty much plug'n'play nowadays for turboing 8v bits out there.

Will,

If you have a 16v problem, and no one else can help and if you can find them, maybe you can hire.....mr tull

I have just picked up an HH engine for exactly that. Does anyone know if the rods and crank are any use like the majority of the 1272s, are they the same?

Well i spoke to Cat cams earlier about profiles etc, and they have recommended me some.. From the information I have the standard cams are 245 / 245°, 201 / 201°, 8.50 / 8.50mm max lift, 0.20 / 0.50mm lift @ tdc.

The catcams recommendation was : 247 / 237°, 215 / 206°, 9.50 / 9.00mm Max Lift, 0.65 / 0.55mm Lift @ TDC

Having said that, i have no idea how they have come to this as they have never supplied any for the application i am using them for. Also another downer being the fact that with vernier pulleys, the whole lot comes a few pennies short of £1k!

And no one can still say for definite if HH pistons will create a suitable compression ratio! I'll have to take some measurements when i pick up my afh head...

got your pm, thats an awful lot of money to spend, i would just try and build as much as you can using vag parts, it should come togeather pretty well in the end i should think, it would be nice to see it actually running before spending mega money on it and at the end of the day i was only interested in having ago because I've never seen in done before, something a bit different really, you probally wont gain a lot more power than running a 8v head.

Will,

If you have a 16v problem, and no one else can help and if you can find them, maybe you can hire.....mr tull

lol, cheers

Yeah, I'm not too fussed right now about taking that sort of money out my pocket. I just want to get it up and running and see what happens. I'll update my build thread in the photo section, the build commences next weekend!