Crank Shaft Grinding L28 crank

[be-zed]

Is it possible to grind the big end journals on an L28 crank off set and down to 45mm  to end up with a stroked crank?

If so what may be involved in the process ?

[C.A.R.]

Yes, Crankshaft Rebuilders in Melbourne can do that.

It's would want to be Nitrided afterwards as well.

 

I'm sure Peter Mac will be able to give more info...

[dat2kman]

Aubrey, talk to Dave Stekoven at Crank Eng in Browns Plains, make sure you have correct bearings for big ends, before you specify.

 

What else do you have planned up your sleeve?

[1600dave]

I've been looking into reducing the diameter of the massive journals on an R16 crank (Fairlady convertible engine) to run different rods and reduce surface speed on bearings - one thing I have been led to believe is a possible issue is the orientation of the oilways in the crank. If you take too much off the diameter and the oil galleries are angled, you may change where the oil gallery emerges in the journal (ie the oilway may end up being offset to the centre of the journal, causing possible oiling issues).

 

Just a thought - I haven't looked closely at an L-series crank to see if it is an issue for them.

[be-zed]

Interesting point Dave !  Thanks for the input Lurch .We meet at LAPZ 2011 for a moment ,it was a very busy day that day.

Dusty wants to plan a mini version of that event ,but do it mid week some time soon. But to Jason's request , the last time at Lakeside for me ended in engine failure . Usuall thing, I have talked to you about this kind of thing before. Inlet valves this time but only three. Not easy getting over the Gateway Bridge on three cylinders to get home in peak hour traffic.

So good excuse for a rebuild. I have a turbo L24 which I was going to use parts from to build up some projects . Turns out the rods from the turbo have 45mm big ends and use 20mm pins. So grinding the L28 crank to suit would give it 84mm stroke and using pistons from a

Nissan X-Trail as they are 89mm , use 20 pins and have a height of 31mm.

I haven't done the sums on this but was wondering if it could work . But for now I have stayed with standard L24 rods and KA24 pistons for the next engine.

I will compare the two cranks along side one another Dave to see if there is any see able difference.

[1600dave]

Oilways is probably not an insurmountable issue (if it is an issue at all), just something to consider.

 

Also may not be an issue if all the material is taken off the inside of the journal to increase stroke- I'm looking to take it off evenly all round (can't alter the stroke due to race class regs) in an attempt to reduce bearing surface speed / reduce rotating weight /  use cheap-ish, easily available 6" rods for what is a fairly obscure engine.

 

Keen to see what you come up with !

[peter mc]

Yes it has been done ,  , but the rods you have from the 2.4e are to week , and will bend when you make some good hp , custom rods are needed , rebelo do this mod for there big strokers ,  the oil holes do get a bit messy but its not the end off the world , dont rpm them over 6500 for to long and it will be ok ,

[be-zed]

Thank you for the advice Peter .

But I was just interested in if it was possible as getting ones hands on a LD28 crank is difficult at best. It was just by chance that I have possession of the turbo L24e rods and was wondering if it could be done. Plenty of L28-26 cranks around. As I only do sprints and not very often now going over 6500 rmp would not be a problem.

It is just strange that Nissan would use these rods in there turbo motors from the factory if they may be prone to failure

[peter mc]

they never had them in turbo engines , ever , some one fitted that engine with a turbo, nissan only ran those rods in 2.4e engines