I haven't posted on here often but i do spend hours reading and id like to get in on some discussions... I am building an engine for my mk1 and im trying to fit together the best parts to suit me. The engine is not about absolute power, i want to have something fun but also something i can stretch the limits of and try some new things. the main thing it needs to do is rev like a beast - aiming for 9k (remember just for fun and no other reason to do so) Please also bare in mind that i have access to a complete machine shop, welders and all kinds of fabrication. I just dont have access to specialist engine equipment for boring blocks accurately or grinding cams etc. It all started with the EW engine i got with the car. its a 1.6 oversquare engine from a scirocco. sounded interesting and has potential to rev high. i got an abf engine for 50 quid but ended up having to store it outside so the block was toast. so i thought i would make a 1.6 16v which i have mostly built up and looks like its going to work a treat with minor modifications. since i have abf pistons sat around i thought i may aswell bore it out from 81mm to 82.5 and get to about 1.7. BUT then I have been looking at the price and went off the idea for the smallish gain to cost ratio. I was trying to source the correct length rods for this block and head combo (i would have used kr pistons and decked the block) and came across the AKL engine which has the right length rods i think. i then noticed it had the same stroke as my EW engine. pretty exited at this point because an aluminium block sounds awesome. just needed me to drop some kr pistons in and bolt the head on... sort of. speaking to a guy i know about whether i should go for an aluminium block or not, the 2.0 20v came up so i had to check it out. well cut that story short there is an ALT engine in the post to me now. I got the whole engine for less than most people sell the block for so i now have a dilemma. Since im getting it basically free, should i use the 20v head or the 16v head. the short crank is a definite want but i'm not sure if my EW crank will fit in the ALT block so my questions to you guys on here: (i have done lots of searching but im doing odd combinations and cant find the same setups...) 1. Assuming i can rig up the oil pump arrangement somehow, will the EW crank go into the ALT block? 2. If not, will the AKL crank fit the ALT block because they both have chain driven oil pumps? 3. The main dilemma is should i go with 20v or 16v for this setup... i will have both the heads but i could probably get a big bore 20v head and am capable of porting out either. People say that the 20v flows better but what do you guys think with this setup? I will be running it na with throttle bodies I like 16v because it seems more fitting with the car and i can really push the platform with super high lift cams etc. im also familiar with it and have exhaust and other parts to go with it but am i going to be missing out on like an extra 50hp or something blindingly obvious by not going 20v? The setup i have in mind would be: short EW or AKL crank AKL rods ABF pistons - may need machining down but i see that as a non-issue ALT alloy block ABF head high lift cams, uprated springs and solid lifters lightened flywheel and possibly crank probably deck the block a bit if needed to up the compression dual crank pulleys and eventually i will go into variable valve timing throttle bodies with variable intake length may look into dry sump if the EW crank fits the ALT block I have seen people with the small block 1.6 16v polo engine with an AFH head reaching 8-8.5k revs so i shouldnt have much issue meeting my target with the shorter stroke in this engine? Let me know what you guys think about possibilities and any info if people have done it before p.s. i know the 20v and 16v heads have different oilways etc but i can sort that out no problem p.p.s. imagine how killer an anodised gold engine block is going to look
Great stuff, power to your elbow. In my very limited experience the main drawback for the NA 20V is that centre inlet valve. It will not allow a massive amount of extra lift without the valve pocket encroaching onto the top ring. The valve gear has a bit of a 'rep' for falling apart at >8500, if the internerd is to be believed. I have plenty of 16 and 20V lumps around but only experience of 16v race stuff. The 16v is rock solid, you have to really try hard to break it, and that's without carlos fandango race parts inside. Good luck and keep us informed Jon
Another little idea to throw into the mixer is that the audi v8 head has the extra oil ways so could prove to be a better choice...?
From what I've read on here most sport applications go for the ABF head as its pretty bullet proof . Works vag rally teams etc . My race KR uses ABF pistons decked and pocketed so that works going to use ABF pistons in my RE2000 rebuild engine as well . Short throw big bore is what you need for high revs to avoid piston acceleration forces causing rod stretch and bearing failure . With all the engines you've got its probably strip them all down and see what works my knowledge is all from playing with KR engines so can't help with the newer stuff but I'm keen to see how you get on
The on flow alone, the 20v head flows more than a 16v head. The middle intake valve helps to promote mixing needed for combustion. As said by Jon you are limited by the maximum lift on a 20v engine, although that would not be a problem if you already met your desired target. To rev to 9K rpm, you will need a complete valve train i.e valves, spring and retainers solid lifters, along with appropiate cams ( that account for the middle intake cam), internal adjustment gear and vernier cam drive. Your engine will need a bespoke crank, rods and pistons to achieve the desired displacement and compression ratio, plus steps will be needed to reduce engine friction. 16v head, proven and tested. EU tuners have been able to achieve cira 250bhp and a banshee 9500rpm rev limit from a 1.6 16v. Like with the 20v the engine requires many custom components to remain durable It you can tackle this project and find a way to reduce the cost of undertaking such a project we all are looking with great interest.
If it were me building a screamer, the first hurdle to overcome would be losing the hydraulic lifters. Sounds easy enough, but its not a cheap or quick to do exercise.....unless you throw cash at it.. Jon
bumping an old thread with a bit of an update. I have compiled an engine that runs. i have made up the cheapest/easiest combo of parts for now to test out the short stoke oversquare design and see how i like it. the engine consists of the following EW block EW crank AKL con rods KR pistons ABF head using a standard height head gasket for a KR peugeot 205 gti distributor twin 44mm mikuni carbs ashley 4-1 ehaust manifold sportex 2" exhuast system I had to make a modified cam belt tensioner bracket to take up the slack from the lost block height from the ABF - I used the abf oil pump and belt/pulley because they appear of higher performance I have a lightened flywheel and although ive never had one before i must say the engine does seem very keen to rev. its not quite running 100% yet because i need to sort out engine breathers and plumbing but in the next week it should all be coming together (Im driving it to do some laps of the nurburg ring in a couple of weeks!!) from loose calculations based on lots of conflicting measurements online i guess im down on compression ratio. in the region of 10.0:1 or just under. i was going to make up a thinner head gasket but the piston is awfully close to the head at the moment i dont think it will work. could machine the pistons to get it but i just want to get a feel of this engine on the road so i can get stuck into its monster brother if i like it. all importantly heres what it sounds like. Im pretty pleased with how good it sounds. this is just the first run so the fueling isnt right yet but she goes!! edit: video embed didnt work. you are going to have to find it on my instagram account - click the picture
Good effort... If your running an ABF head Inc cams 10:1 will be okay. ..depends on the total cc really. Also...that inlet manifold flows pants for when you start looking for decent power...and longer trumpets will be needed if you run a short type inlet.
Little update. got 15.37 seconds on the 1/4 mile at santa pod the other weekend. hoping to beat that with a bit more practice at GTI inters. not bad for a cobbled together engine. I'm not sure if i can get to my target RPM or not yet because the standard clocks seem to stop at 7k
So I've realised this thread is out of date and due an update so here goes: this is a picture that is almost up to date of where the engine is for now from some shoddy calculations based on my 1/4 mile time im running around 120hp at the moment. first thing to note is the strap over the HT leads. this is an absolute must and i haven't found out quite why the leads pop off. they come out pretty quick from left to right after just one blast to redline. its either due to vibration (solid engine mounts and suspension and a lightened flywheel that im certain hasn't been balanced or seen to properly) or gasses in the head. i made a cutout on the seal to cam cover on plug 1 and it didn't solve the problem so it mush be vibration. you will also notice my very shoddy "quick mockup" throttle linkage that has lasted way too long. thats going in favour of a nice centre pull unit when i get round to making it. vac advance is now off too and im almost on the maximum advance allowable in the distributor slots. however this isnt the correct dizzy for the car so i may not be too much advanced over stock. the engine absolutely rips and im fully happy with the WOT performance but its lacking massively on cruise to the point that i cant maintain 70mph. its going to go on the rolling road in the next couple of weeks to have the carbs set up properly but before then will go some very lairy cams, some decent velocity stacks and a new fuel system these are thought to be old crane cams and i would greatly appreciate any input if anyone knows about them. around 300 degrees duration. i have measured about 12.4mm of lift and by the looks of them they have a serious amount of duration. the top one is an old schrick cam that needs a repair but isn't as wild as the other two. 265 or something I will update after the rolling road to show figures of what this little engine does. I will also be moving over to the aluminium ALT block and AKL crank when i get some other bits sorted to up the displacement slightly with the larger bore. hopefully i can squeeze some more compression out of it at the time too. I don't know about you guys but im keen to see what power it makes when set up properly on the carbs.
I have got near to 200hp on a couple of my 16V lumps with the short inlet manifold, so you may be wiser spending your cash elsewhere before you junk it. I'm not disagreeing with Jason, but the swapout to a longer one wasn't really noticeable to me. Anyway, more importantly, take care fitting your lairy cams and make sure you have enough clearance on the valve springs, as lairy usually means aftermarket springs/top hats/retainers, never cheap in my experience. If you buy aftermarket springs be very very careful to make sure they sit properly inside the OE top hat/retainer, if that's the route you want to go down. And more cam needs more compression... If they are solid lifter jobs you may get away with stripping a couple of mech 1600/1800 heads and re-using the mech buckets and shims. This isn't something I have tried, but can't see why it wouldnt work, and it would be cheap and quick to shim em up. Good luck and keep it coming. Jon
The new cams are in. its all bad! at the moment I don't have a proper vernier pulley so adjustments are limited. with the cams at the correct timing the valves just about tickle the top of the piston. i think its only on the inlet cam. I found that my new cams have both got a keyway for the sprocket but the original abf ones dont. luckily i have a spare schrick cam that i stole the sprocket from and the key but i ended up having to fab up a key for the second one. it seems a bit mad that vw machined the keyway on the sprocket but not on the cams! it now means that there is no going back after removing the sprockets because i have no idea where they are meant to be positioned! to get the car to run and get me home i have skipped the cam back one tooth on the belt. as a result the car sounds weird and is all out crap to drive. no surprises there. however. Jon, it's interesting that you say more cam need more compression because my mid range stumble (that i presumed to be a carb issue) that i have been struggling with is now magnified by these cams. could it be that i just have always been down on compression and this has caused the stumble? what are the causes of a big cam and low compression? since im going to have to machine some pistons im going to bang together the aluminium ALT block to mate to the ABF head and use AKL rods with ABF pistons. Im predicting I ill be way down on compression so may end up having to fit longer rods. does anyone know how much meat can be taken off the ABF pistons? I will get an xray done at work to show the section if i need to and a picture of the current engine bay
With more cam, more duration / more lift , at overlap the exhaust valves are closing while inlet valves are opening. On std roadcars this is kept to a minimum to get good idle and good TQ. On performance cams there is much more overlap and valves are at a higher lift @ TDC.... being longer open after TDC ( exhaust) and before TDC ( inlet) This create some leak and with a std static Compression Ratio, your dynamic compression ratio becomes lower...... thats why you need more CR on wilder cams. Or atleast select the right camshafts to be in balance with the rest of the engine. http://www.hotrod.com/articles/ccrp-9812-secrets-of-camshaft-power/
Thanks for taking the time to respond. Really appreciate it. How is the CR requirement affected by boost. Can you make up for low compression with a supercharger or will it still not be ideal? I'll probably be shoving in 1 bar
Interesting thread i now Keith Murray has build an ALT Alloy block with 16v ABF Head Turbo engine recently 650bhp in the Audi R8 The ALT Alloy block is 24KG lighter than the ABF so a big weight saving for a race care looking to the lightweight route. ABF 16V BLOCK ALT 20V BLOCK They used the 16v ABF for tuning as opposed to the 20v head as far as i understand. anyone know the standard compression of the 2.0L 20V ALT Engine ?
Thanks for the weights. very useful info! Have you got a link to this engine? sounds very interesting. I didn't realise they could take so much power. As a bit of an update, I am now building up the following ALT block ABF head CRANE 300 degree cams 7A pistons (same as kr but for the bigger bore so will need machining slightly to fit cams) AKL con rods AKL crank hopefully dry sump if i can find parts or otherwise a simple chain driven oil pump and not that balance shaft monster that comes in the ALT Rotrex supercharger with a t28 compressor housing and turbine pictures to follow when i make some progress
