24seven 104 Posted September 19, 2006 So I've discovered 2 cracks in my 8V head (one from the edge of the exhaust port down to the spark plug thread on pistons 2&3, but the valve seats are 100% still) which will survive for a bit, but in the long term I was thinking of putting an Mi head on instead. I know there's some issues regarding the pistons, but what exactly is the problem? clearance/shape/squish etc? Share this post Link to post Share on other sites
Guest ashnicholls Posted September 19, 2006 Dont know exactly, but I am sure this has been covered before, some or all of the oil and water ways dont match up. Thats a big problem. Things you describe are easy to sort out. Share this post Link to post Share on other sites
taffycrook 2 Posted September 19, 2006 Do a search the subject has been well covered. Basic issues are CR rod and piston design to enable use of suitable cams to make it make some beans. Just fit a complete mi16 it will be all of what you expect for a fraction of the money of a 1.6 mi16. Share this post Link to post Share on other sites
Guest ashnicholls Posted September 19, 2006 Yes fit the 1.9 much easier, unless you are limited by race regulations. Share this post Link to post Share on other sites
welshpug 1,627 Posted September 19, 2006 find out if a 16v head will go on, surely would if an xu10 head does. would be a very interesting project to see with the combination of the flow of a 16v head and the revviness of the 1580 crank, bit like a 16v TU with torque Share this post Link to post Share on other sites
Guest ashnicholls Posted September 19, 2006 Yes didnt think of it like that, it should work. My XU10 head works just fine on my 1.6. Share this post Link to post Share on other sites
B1ack_Mi16 67 Posted September 19, 2006 The head will of course fit fine, the blocks are the same afaik so shouldn't be any problems. Share this post Link to post Share on other sites
Sandy 189 Posted September 20, 2006 Need to modify the block to accept the extra cambelt tensioner, 8v blocks seem to crack between the liners more with high rpm use. Valve cutouts. Share this post Link to post Share on other sites
Guest rick03054 Posted September 20, 2006 The head will of course fit fine, the blocks are the same afaik so shouldn't be any problems. Need to modify the block to accept the extra cambelt tensioner, 8v blocks seem to crack between the liners more with high rpm use. Valve cutouts. Are you saying the oil and waterways match up then? Share this post Link to post Share on other sites
petert 554 Posted September 20, 2006 Need to modify the block to accept the extra cambelt tensioner The same M8 hole is used to hold the belt cover. Another issue is the RH side engine mount if you're planning on using an 8V block. All the galleries and jacket holes line up. It's much easier to put a 1.6 crank in the Mi block. The major issue is getting enough CR, which ever way you do it. Share this post Link to post Share on other sites
24seven 104 Posted September 20, 2006 Well atm I'm short on cash and need a new head, but would like to try an Mi1600 conversion if possible. any modifications to the block/head can be done at work (since I work in a CNC factory with experienced toolmakers, welders and CNC programmers who would help me if needed). If I could get an Mi lump and put a 16V crank in it that would be better, as it would have the weight saving benefit of the alloy block, but aren't they a bit rare now? Share this post Link to post Share on other sites
welshpug 1,627 Posted September 20, 2006 bit confused at what youre saying there! get an Mi lump and put a 16v crank in? its already 16v! plus the 1600 is an alloy block too, which is identical bar some ribs. Share this post Link to post Share on other sites
24seven 104 Posted September 20, 2006 sorry I meant the 1.6 crank. too many 1's and 6's . I mean the alloy block of the Mi engine would be preferable over the cast iron 1.6 block, but since money is the biggest limitation, apart from the 16V head what else would be needed to turn my 1.6 into an mi1600? Share this post Link to post Share on other sites
boombang 2 Posted September 20, 2006 the 1.6 block is alloy too! Just different holes tapped for 16 valve pulley arrangement, different crank, rods and pistons. Share this post Link to post Share on other sites
24seven 104 Posted September 21, 2006 so I'd need mi pistons along with some modification to the block then? that it? Share this post Link to post Share on other sites
petert 554 Posted September 21, 2006 so I'd need mi pistons along with some modification to the block then? that it? did you not read my post? CR is the biggest issue. You'll need custom pistons. Share this post Link to post Share on other sites
B1ack_Mi16 67 Posted September 21, 2006 why? Because if you use standard Mi16 pistons and make them zero deck maybe with custom lenth rods, you'll have an CR somewhere between 7.8-8:1. If you get a thin headgasket like 0.8-1mm, and pistons with approx 6cc dome on you can get to approx 11:1. You would at least need custom pistons for that build. I remember someone earlier talking about the 1.6 gti crank could not coope with more than 7500rpm sustained use, have anyone tried to rev the standard item further, as I find 7500rpm is pretty little with such short stroke. Share this post Link to post Share on other sites
welshpug 1,627 Posted September 21, 2006 aah, I see, is it because the Mi head has the chamber in it, and the 1.6 uses dished pistons to alter the compression? hence you'd have too much combustion chamber, ideal if you want a 1580cc 16v turbo... Share this post Link to post Share on other sites
jimbean 0 Posted September 21, 2006 the 1.6 block is alloy too! Just different holes tapped for 16 valve pulley arrangement, different crank, rods and pistons. if it is any help i have a set of mi16 piston mated to 1.6 con rods sitting in a draw.... the conversion has been done lots of time mostly by grass trackers which is where my piston come from.. but paul broach started it a few years ago by running his rallycross 205 with such an engine give me a shout if you want them Share this post Link to post Share on other sites
B1ack_Mi16 67 Posted September 21, 2006 if it is any help i have a set of mi16 piston mated to 1.6 con rods sitting in a draw.... the conversion has been done lots of time mostly by grass trackers which is where my piston come from.. but paul broach started it a few years ago by running his rallycross 205 with such an engine give me a shout if you want them Any pics of how the pistons are modified? Share this post Link to post Share on other sites
24seven 104 Posted September 21, 2006 if it is any help i have a set of mi16 piston mated to 1.6 con rods sitting in a draw.... the conversion has been done lots of time mostly by grass trackers which is where my piston come from.. but paul broach started it a few years ago by running his rallycross 205 with such an engine give me a shout if you want them Hmmm. may be interested in the pistons alone for future possibilities. Someone suggested I try and get something along the lines of a G40 supercharger (or similar, since actual G40 ones are like rocking horse poop) in there. That would be interesting. Mi1600S Share this post Link to post Share on other sites
