High revving Nord 105 hybrid

[Datso]

Hello Fellas
my 3rd post on this forum and hopefully I can get my wires untangled with info.

I would like to build a high revving (8500rpm redline) motor to suit a 105 series 1974 Sprint.

I was thinking of using a 1600 crank into a later stiffer block with custom conrods and pistons.
82mm stroke with 85mm bores.

Can someone tell me the height of the 1600 vs 1750 and 2ltr engine blocks?
I cant seem to find this information anywhere.
I did find the Alfa 1750 and 2ltr conrods are:
Alfa Romeo
1750-2000L 53.7mm 22mm 156.972mm
155Q4 145mm
Twin Spark 75 53.7mm 22mm 156.03mm

Anyone know the 1600 conrod length or info on mains and crankpins?

I cant afford the mono-sleeve conversion so....
Im thinking of getting my a friend's buddy to tig weld a deck plate
to make whichever block a closed deck.
A cheap laser-cut steel Ladder brace for the main caps and some solid
C straight bar with holes for the 2 middle studs so they give the centre
of the block some extra strength. Then will get some stock sleeves fitted
with a sealant then grout the bottom end.

Ive thought long a hard on how to make this block stronger over the years
and this is my input hopefully of some help for the Alfa community.

[aggie57]

Sounds like an interesting project.  Have you spoken to Vin Sharp about this?  He has worked with these sorts of projects for many years and knows as much about 105 series engines as anyone you'll find anywhere. 

Bottom line, little point re-inventing the wheel and you may as well save yourself a lot of time.

[branko.gt]

85 bore witout a monoblock is mighty ambitious

[ItalCarGuy]

I didnt know that you could bore out the 2L liners any more as they are already thin?

This will have some of the 1600 dimensions you are after

http://www.alfa-male.com/giulia-super/technical-specifications/technical-characteristics-specifications/

[Datso]

I think I best stick to 84.5mm, even though the Renaults seem to do it with cast liners
but Im guessing you fellas are totally spot on and its not worth the risk.
Im not even sure the 1.6 crank fits the 2ltr late blocks?

The bore spacings are not easily found

Thank you for the link!

The 1600 rod length is 148mm

[Paul Gulliver]

I would like to build a high revving (8500rpm redline) motor to suit a 105 series 1974 Sprint

Not wanting to be a wet blanket , but to build that kind of engine is not going to be a cheap exercise.

I remember reading a engine builder saying. FAST , CHEAP , RELIABLE. You can only pick 2 and you don't get the third 

[aggie57]

I think I best stick to 84.5mm, even though the Renaults seem to do it with cast liners
but Im guessing you fellas are totally spot on and its not worth the risk.
Im not even sure the 1.6 crank fits the 2ltr late blocks?

The bore spacings are not easily found

Thank you for the link!

The 1600 rod length is 148mm

I was reluctant to call that out without double  checking but I'm pretty sure you're right. Different bore centres.

[Datso]

wont be cheap thats for sure. However willing to do most of the work myself yet not the tigging

[pete barr]

Hi Datso, I have a short stroke 1585 cc egine that will rev to 8500 easily. It runs a 2 litre block with a billet crank to give correct bore centre spacing with a throw of 71.5 mm. Not cheap. Talk to Vin as he built this engine.

[Datso]

Just for interest sakes the rod I had in mind with a tall block
Nissan Z24 conrods
Length: 165mm
Piston End Thickness: 25.4mm
Big End Thickness: 26.8mm
Piston End bore: 21mm
Pistons can be had with up to 25mm compression height.


Anyone know the block height of a Nord or 105 2000cc engines
and the pistons heights?

Edit. 235mm centre of crank to top of deck for the 1750 and 2000cc

Im looking at a 1600 crank into a later 1750 block if mains spacing are right
I want to eliminate the cylinder case studs and replace with solid alloy.
Use 4 x triangular alloy posts for the inside corners of the cylinder casing water
area and 6 x rectangular posts for the rest of the sides, then complete the top
with a CNC'd close deck plate with water passages in the right places.

The sleeves Im looking at later new diesel ones machined to fit.

Alot of work to fit a different but narrower angle 16v head from something else.