Author: Martin Lucas May 16, 2008 at 03:08:23 from 122.57.171.249 in reply to: Re: 711 M FF 1600cc Block posted by james jordan on May 14, 2008 at 00:51:13
Hi James, The decking of a 711M block by the 1/4" does not result in a block the same height as a 1500 L block. The 711M is 1/2" taller. Any 711M block that is used as you describe will have a 1/4" spacer fitted to the top of the timing chest assembly. Many Lotus Twin Cam engines have been reblocked with 711Ms as you describe. I believe there are now better options available. If you are going to use a 711M block then my preference is to deck the bare minimum off the block as neccessary. The more material left on the fire face must result in a stiffer block and reduced chance of distortion. There are that many piston manufacturers around today that will make a set of custom pistons at a very economical price, here in NZ JE pistons are popular given the strong exchange rate. So JE in the USA must be very afforadable.
If I was to use a 711M block I would suggest tracking down a set of Datsun L18 conrods. These are 130mm long. These will fit a Ford crank and can be modified to run a Ford bearings and Gudgeon very easily. The extra length improves rod ratio and they are extreemely strong. You can retain standard Twin Cam type pistons and need deck only 0.04" from the block. Run a two link longer chain. These are available through Burtons. Or you can run a Cosworth wide journal rod or a Datsun L16 late model rod which is the same length. Again pistons are available off the self to suit this combination. No decking of block is required.
Here in NZ we retain a 1500 block, use a 1600 length rod ( H section available locally), JE Pistons (bore ranges from 83.5 to 85 depending on block) and a modified Datsun L18 crank. I have assembled a TC bottom end with 711M block, Datsun L18 crank, L16 rods and Accralite 85mm short (Cosworth) compression height pistons. No decking of block required.
Lastly ditch the Ford conrods bolts if you retain a standard factory Ford or Lotus Rod. Go for ARP minimum.
Just my 2 cents worth.
Post Followup
Note: Follow-ups should only be used for information of interest to all viewers. For other inquiries or personal communication please send an email if possible or use other contact information provided.
When you return to the board you will need to do a REFRESH or RELOAD to see your followup.