1600cc boxer conversion - 1.7 crank or 1.7 block???

[rain902]

hiya all!

had a fun day @ sandown yesterday - unfortunately i managed to let the low oil pressure light come on at the bottom of the hill at dandenong road and now my engine sounds like it has a couple of tin cans rattling round inside it

now im in need of a big end rebuild and i thought that i would take the opportunity to increase my capacity to 1600cc.

1700cc is not an option due to class limitations.

the question is will i find a 1700 cc block and put a 1500cc crank in it, or will i put a 1700cc crank in the 1500cc block?

1700cc crank advantages:
more stroke, more torque.
less revs, hopefully more longevity
more flexibility in gear as the engine will have more torque.

1700 block advantages:
bore will be bigger than stroke, so i can spin her like hell


both of em will be hard to find - 1700 cc engines are desirable and rare here.


what are your thoughts? any suggestions would be welcome.

[PSk]

Quote:

Originally Posted by rain902 1700cc crank advantages: more stroke, more torque. less revs, hopefully more longevity more flexibility in gear as the engine will have more torque.

[rain902]

thanks Pete - forgive my not having a clue, but why would i need new pistons? (aside from the idea of replacing worn ones)

Im guessing that there would be different length stuff required if i fitted the 1500 crank into the 1700 engine - what else would i need to change if i went down this path???

manymanythanks

[PSk]

Quote:

Originally Posted by rain902 thanks Pete - forgive my not having a clue, but why would i need new pistons? (aside from the idea of replacing worn ones)

[kaBOOM]

I'm going the other way, I'm useing a 1.5 Litre crank in a 1.7 litre block. This is more to drop the compression tho.....

The problem with putting a 1.7 litre crank into a 1500 block is that you nee to do a bit of machineing to get the crank throws to clear the block. Also the 1.7Litre cranks have a very poor oiling setup. The 1.5 Litre Serries 3 Sud I suppose is the "hot" crank of the lot with a full cross drilled crank from the factory.

[rain902]

cool - thankyou for the advice and info, much appreciated!

the latest good news is the clattering from under the bonnet was the sounds of gasses escaping from one exhaust header which had worked itself loose during the run - seems funny that the noise started at the same time as the oil light showed its head.

thats a relief to my hip pocket! also we can take the time to build the engine right during the off season...


I can get my hands on 1700cc 16v motor - its needing a rebuild, and is in a crate or two in the back of my mechanics, has been for years. I read Petes thread on the race engine with interest - but heres a question - 8v or 16v? I have heard that the 16v need a lotta lovin when it comes to looking after their belts etc, and of course they need to be made to fit - the reason im looking at the 16v head is its there, ready to be stuck onto an engine. Any reason I shouldnt go down this path???


cheers,


teruo

[PSk]

Quote:

Originally Posted by rain902 I read Petes thread on the race engine with interest - but heres a question - 8v or 16v? I have heard that the 16v need a lotta lovin when it comes to looking after their belts etc, and of course they need to be made to fit - the reason im looking at the 16v head is its there, ready to be stuck onto an engine. Any reason I shouldnt go down this path??? cheers, teruo

[rain902]

our series is modification based and capacity based, i guess a 16v head would count as an engine mod (ie not standard) but a port and valve job on an 8v head would count for the same thing...

[dicko]

Quote:

Originally Posted by kaBOOM The 1.5 Litre Serries 3 Sud I suppose is the "hot" crank of the lot with a full cross drilled crank from the factory.