Info on building an 1840 84mm crank crossflow?

[db69]

As title an info ,how much work is involve, any one done it ?

[Miniliteman]

Use 5.10" rods plus you need to make clearance for the crank in the block, camshaft and the sump.

[racing escort]

To much hassle in my opinion, and why would you do it ?

[Erikmex]

To much hassle in my opinion, and why would you do it ?

Lots of reasons, lighter than a pinto, nice revvy engine, more torque than a 1700, the reasons to build a big cc xflow are endless.

[Pushrod King]

Long stroke will mean more torque but will have a less revvy feel. Along with what's already been mentioned he cam will need some work to allow clearance of the big ends.

[racing escort]

Don't get me wrong, I love the crossflow engine, but the long stroke of 84 mm will create so much building problems that the benifits are gone.

Here in Belgium we have a crank making firm called : Nuyts . They do a steel crank with a stroke of 78,6 mm for the lotus twincam/crossflow. Shorter pistons do the trick, stroke to rod length ratio stays almost the same. All there crankshafts are on this site :

http://www.crankshaft.be/

[e321]

Seems an expensive way to end up with a sub 2 ltr 8 v engine.

[MemphisTwin]

Don't get me wrong, I love the crossflow engine, but the long stroke of 84 mm will create so much building problems that the benifits are gone.

Here in Belgium we have a crank making firm called : Nuyts . They do a steel crank with a stroke of 78,6 mm for the lotus twincam/crossflow. Shorter pistons do the trick, stroke to rod length ratio stays almost the same. All there crankshafts are on this site :

http://www.crankshaft.be/

Hmmm... that's only 1mm longer stroke crankshaft than standard and only adds 21cc.

[racing escort]

Yes, but when using a larger stroke, the first thing to alter is the sump (which can be done easily)
I wouldn't want to grind the block and the camshaft to make room for the conrods.

A bigger stroke also creates more sideways force on the pistons and makes is less revvy (and that is why the crossflow is such a nice engine)

[Miniliteman]

Hmmm... that's only 1mm longer stroke crankshaft than standard and only adds 21cc.

That one is meant for the Lotus Twin Cam and adds approx. 6 mm to the stroke (std Lotus is 72.7 mm or thereabouts).

[racing escort]

Yes, but that's the same kind off crank, it fit's a crossflow (I know someone driving with it)

[Fridgeman]

heres a way you may have not seen before, i have a lotus twin cam novamotor 2ltr , the block is a modified L block FVA .they used to fit a spacer plate on top of the block so they could use a 84mm crank x 86mm bore .15-1 compression mild cams 200bhp/180ft lb

[GCCR]

Many years ago I built a 1960 cc Crossflow. Fantastic engine! Won numerous MN Rallies with it in the back of a Darrian. Blew away Pinto's no problem - lighter and revved like stink despite a 90 mm crank. Used Carrilo rods and forged pistons and a gear driven A6 Cam with an inclined valve Vulcan head, huge valves, and holbay roller rockers. dry Sumped on 45's.

[racing escort]

also with a spacer plate on top off the block ?