EFA Posted May 27, 2002 Share Posted May 27, 2002 As you may or may not be aware, I have volunteered to rebuild Crudders Crossflow which he gently simmered on the M25 on Saturday so he can take his presently motionless Seven to Le Mans. Tonight he has deliverd a big box of spare bits to me, amongst which is a 711M block in what appears to be excellent condition. This block was last used with flat top pistons, but the pistons have become damaged in storage. So my questions are: I am not sure if the block has been skimmed to change the compression ratio in the past, and I understand this used to be a technique used by tuners taking the chambered head route. The block measures 208.5mm from the centreline of the crank to the top of the block - is this approx the normal dimension? We anticipate using a 244 cam with hepolite +090" psitons (1690cc). In this setup is it necessary to pocket the pistons? If yes, would using a 234 cam mena I still have to pocket the pistons??? (time is of essence here, we have no time for machining unless absolutely necessary) Thx for any answers in advance. Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Edited by - fat arnie on 28 May 2002 00:06:58 Edited by - fat arnie on 28 May 2002 00:25:52 Link to comment Share on other sites More sharing options...
Roger King Posted May 27, 2002 Share Posted May 27, 2002 Arnie, Your block has been faced about .5mm assuming that by 'crank centreline' you mean where the caps sit and NOT the bottom of the block. You will need to pocket the pistons with a 234 or 244. Generally speaking .100" deeper should be OK, but you must check clearance is OK. Don't recommend those pistons with a 244 though, at least not in the long term. Link to comment Share on other sites More sharing options...
EFA Posted May 27, 2002 Author Share Posted May 27, 2002 Thx Roger, I'll give you a call in the morning - see if you have any suitable bits lying around..... Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Edited by - fat arnie on 28 May 2002 00:25:37 Link to comment Share on other sites More sharing options...
Peter Carmichael Posted May 27, 2002 Share Posted May 27, 2002 This is obviously a bogus topic heading as crossflows predate "technology". Peterid=blue> eek.gifSecond loser, Class 5, Curborough May 2002id=red> Link to comment Share on other sites More sharing options...
EFA Posted May 27, 2002 Author Share Posted May 27, 2002 Actually I am developing a 4wd, 1 crossflow per wheel, challenger for Curborough on the 25th Aug....... Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
Dave H Posted May 28, 2002 Share Posted May 28, 2002 Arnie, Do you still intend to use my Xflow in the rebuild? - it has a chambered head and flattop pistons (but hasn't turned in over 18 months). Phone on 01273 898252 Dave H Link to comment Share on other sites More sharing options...
EFA Posted May 28, 2002 Author Share Posted May 28, 2002 Dave, Did a quick inventory of Richards garage to find he probably has enough bits! Thx anyway.... Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
Dave H Posted May 28, 2002 Share Posted May 28, 2002 Give me a call if you need it, plus I have a copy of the Haynes Xflow book if required, a spare (but used) 234 cam, a high pressure oil pump (used but was working) and a few other oddments which are not on the old engine. Now working at home for the afternoonsmile.gif Dave H Link to comment Share on other sites More sharing options...
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