Hi all, been using this site for information for a while now. however, i cant find a definate answer to my problem. I have a mk2 16v golf which im restoring. 20 years ago it was my favourite car. so when i saw this one looking sorry for itself in my mates yard, i decided to swap it for an old air rifle. lol Anyway, im in the process of doing an engine conversion. chose the 9a block and using a kr head. wanted to keep it looking original. My problem is, i bought a 9a block off ebay. after having it rebored and buying new pistons etc, it turns out my 9a block is infact an abf one. realised when i went to put the pistons on the rods. after having the rods rebushed, they are in engineers now, the 9a pistons will sit half a mil to a mil lower in the block. what problems, if any will this cause. the head has had a light skim, reconditioned, port and polished with 276 kent cams. will also be using a 4 part metal head gasket. any information would be a great help. thanks.
Compression will be too low and performance will be cack! You could have the block decked to suit which is the cheapest easiest option, or you could fit a diesel crank and make it 2042cc. I gotta ask, didn't you look at the code on the front of the block?
lol, i didnt. wish i had! to be honest, i bought it as a 9a corrado bottom end. compared it to a spare kr engine and it looked the same. didnt think any more of it. foolish i know. too late now though! i read on here that i could take the thick part of the gasket out? both the block and the head had a light skim. so maybe that would bring it back close to where it should be? would the pistons usually be level with the top of the block then? i also heard there could be an issue with the vaves from a kr head hitting the pistons in a normal abf block and that you might have to use an extra head gasket. so i was thinking it might be a blessing in disguise! lol. thanks for the reply too hotgolf.
lmaoooooo! such a helpful site this ent! think i will try somewhere else. 99 views and one answer! lol
One answer and the correct one. Maybe you would prefer a lot of horse sheit being spouted instead? Plus you may have had more of a response if you put the question in the engine section. Neither ABF or 9A were fitted to mk2s in this country.
lol, fair comment danster. ive looked at so many threads on different sites and they generally seem to conflict. thought id ask a simple question and get a simple reply. guess i did. not sure how to move it the the engine section either. think i will just try taking the thick part out of the gasket. if it doesnt work, i will just have to buy another set of pistons. right ones this time! lol. thanks for the reply.
With compression that low would a supercharger or turbo not be a good idea, albeit not very OEM. There, that's a reply that doesn't help.
lol, ok ok, stop busting my b*lls! my earlier comment was just a bit of sarcasm! supercharger would be great. however, this is the first time i have done any kind of rebuild and as you can see, i already made a massive mistake by not checking the engine code! t**t i am, but im just trying to remedy it without losing too much money. can you imagine if i tried to supercharge it! id probably end up with one off a jcb or something! lol
might just have to do that melg60. although i think the cambelt will be ok. will only be about a mil. im surprised at how much a mil could make with regards to compression. but as my title says, Newbie! lol. anyway, gonna try the gasket route and see what happens. engine will need to be run in anyway. anyone tried the kent 276/276 cams on this set up?
Good to see you stuck around. You will need a vernier cam pulley to dial in the cam timing after skimming the block a decent amount to regain compression.
nice one danster. thought i might need one, so will put that on my new list. lol. how are these cams on tickover? coming back to the gasket thing, the difference from the top of the piston to the top of the block is the same as the thick part of the metal head gasket, not including the other 3 parts, so they will be used. the block was refaced and the head was skimmed. do you think i could get away with it? how much compression would i lose? i guess it would make for a revvier motor, im probably wrong ther, but what might i lose average bhp wise? any ideas? was also wondering, if i skimmed the block, would the head bolts hit the bottom? soz for all the questions guys.
It would be a good idea to get the clearance volume accurately measured to see what the compression ratio actually is at the moment. Then it can be calculated to see how much is required to get it spot on. The engine has been re-bored so that will increase the swept volume of the cylinder a little. This would normally raise compression by itself. The fact the block and head have also had a skim alters things too. Sounds like you have got involved in a decent engine build cost wise, it would be a shame not to optimise it. Stripping out the spacer in the gasket maybe an option. As would the diesel crank swap mentioned already. Neither are horrendously expensive options. But it would make sense to see where you are at the moment with the compression ratio. Cam choice is pretty much linked to compression ratio. Are going to be running Kjet, carbs or standalone management? I am sure a Mod can move this thread to the engine section.
what should the cr be? i had it rebored to 83 ml. i will be running on kjet for the time being. i considered using a diesel crank after hotgolfs suggestion, but because ive already had mine polished and ballanced decided to try the easier route. i have my work done at northampton automotive services, simon measured everything up and also came to the conclusion that removing part of the gasket would even things out. but would i have problems with the gasket afterwards? would rather not have the blocked decked anymore incase i do something different with the engine. which is more than likely! lol. just need to get to grips with the basics really. was thinking of eventually using a standalone management in the future, but thats something else i will need to get my head around. at the moment its just a word to me mate. lol
decided to go the gasket route. if it fails, then abf pistons it will be. there has been well over 200 page views, so alot of interest, so i will put a post up to let you all know how it went. a word of advice, if you buy an engine off ebay, check the engine codes!!! lol. to a newbie like me, they all look the same. and thanks to the people who replied. danster, im gonna be on your case for sure in the future! lol. thanks for your time.
Personally, I wouldn't be going down the gasket route. The laminate gaskets are a 4 piece design, top/bottom and the sealing faces which are thin, and have afine coating of some sort of gasket sealer on them, then there's 2 inner section. 1 about 1mm, the other about 0.15mm (rough estimates) If you take the 1mm section out I'm not sure there's enough integrity in the thin section to keep the upper and lower sealing faces the right shape, as they have raised sections that squash flat. I maybe talking complete bolx and I'm hoping someone else will pipe up with their ideas on it. If the block isn't built yet I dunno why you don't deck the block, it'll only cost 40-50 bucks and it'll be right.
no, your right hotgolf. i think its me just being impatient. ive been getting the parts together for a good few months now. if i take my block back to the engineers, being racing season they are quite busy, so it will probably take a few more weeks. but i think that will be the best and safest route. if i have the block machined, so the pistons are level, will i have trouble with valve clearance considering its a kr 16v head? someone mentioned that they are different to a abf head and that the kr valves will be closer to the piston.
i already have kent 276/276 cams to put in. i had the head reconditioned, p+p too. the inlet manifold was also flowed and portmatched. i also have a 4 into 1 down pipe and scorpion exhaust to put on. crank and flywheel has been ballanced, rods and pistons too. which is one of the reasons i couldnt exchange the pistons. block was rebored to 83ml for the new pistons. small ends have already been rebushed. im going to take the block and head over tomorrow or friday to see what can be done. im hoping to get some good power from it when its done. once it has run in, i will probably take it to stealth for a tune up and rr. hoping to do a few track days next year. if all goes well! lol.
if anyone is intending on using 9a pistons in an abf engine for whatever reason and need their rods rebushing, renault do a small end bush/bearing for their diesel engines which are a perfect replacement for the original abf ones. 5 each and apparently harder wearing than the original. which being a diesel part would be right i guess.
