With all of the threads lately about 2.3 and 2.4 stroker motors, I have been doing some research on the different combinations along with papers on the subject.

To make a long story short, 2.3/2.4 motors have the advantage or more displacement and higher torque, but have the disadvantage of a lower rod ratio, which increases engine wear, harmonic inbalance, etc.

Companies like AMS developed their 2.3RR motor to have a stock or better rod ratio (most likely using something like a 87.5 bore, 94 stroke, and 160mm rod, although I don't think they have ever released the specs). This gives you 2260cc of displacement, but with a good rod ratio, so you have all the advantages of a stroker without the disadvantages. So, you should have a nice, long living, well balanced, high revving stroker engine.

I had an idea of just increasing the deck height with some kind of plate or something similar, to give you the extra room you need to run a longer rod and obtain the 1.7-1.75:1 nominal rod ratio, but still have the extra displacement. A quick search on Google found an old bulletin board about a Honda motor where they did just this. I think it was from way back in 1998. They wanted more displacement but a 1.75:1 rod ratio, so from what I gathered, from quickly skimming the article, was they welded on a plate for extra deck height, then stress releived and heat treated the block back to proper specs.

So, has anything similar ever been done to a 4g63 or 4g64? I would love to build a 2.3 or 2.4 eventually, but I just can't being myself to daily drive an current 2.3/2.4 with the disadvantages they have to engine life, harmonics, etc. I know many people run them successfully, but just my own peace of mind and wanting things proper. And instead of the insanely high price of a custom build for something like the AMS 2.3RR, I was wondering if anyone had ever gone this route, or if there are just things about the 4g63/64 block that wouldn't make it feasible and/or cost prohibitive.


Thanks,
Eric

 

That sounds tricky.

Obviously it would have to be an iron piece that you are adding on. I thought that welding iron to iron wasn't good in terms of high strength? Brazing? Also, I would guess that after that the motor would need to be sleeved because of the transition between the factory block and the add on would need to be perfectly smooth.

You're a pretty smart guy, I know that. I'm just adding my .02, certainly not an engine builder myself. Have you called and asked any machine shops?

 

I just started this thread as a general inquiry to see what, if anything, has been done with the 46g3/64. There are a million different ways that I can think of doing it, so I was curious as to what has already been done.

I highly doubt I would pursue a route like this anyway, unless easily feasilbe and there were people doing it. I guess this thread was more of a 'is it feasible...has it been done...and if so, what are the details' type thread. Like what size crank could be fit, what rod ratio could be achieved, what block modifications (how much notching, etc)

I have a materials engineering degree, so I'm familiar with the metallurgy side of things. I know it's possible in that respect. But, since I haven't built the 4g63/64 yet personally, I don't know all of the details about the certain aspects of the block and how much it can be modified before getting into issues like water jackets, thinning too much, etc.

If I were to realistically go with a stroker motor, I would most likely build a custom motor similar to what AMS did with their 2.3RR. But, then you're getting into a lot of customization, etc. So, maybe I will just go with a built 2.0 and keep it simple, quick, and easy.

 

It has been done on Supra and Skyline motors. I had seen it a couple magazines. It's doable. I love to see someone try it on a 4g63.

 

There's a little tiny bit of info here: http://gtrusa.blogspot.com/2008/12/o...ssan-rb30.html

Seems simple enough. The block would have to be sleeved so the sleeve comes up through the spacer so there are no seems.

 

i like the idea. now you get to of run a known thickness sleeve, larger bore diameter, beefier area to support a head gasket / o-ring set-up, more support of the sleeve during high cylnder pressure / crank angle position.... just a few merits....

 

bump!

 

If I had the cash, i would give it a try. It's simple enough. Depending on the thickness of the spacer, may run into a problem with the timing belt. I wonder if you'd have to notch the block to clear the longer rods. I'm sure it could be worked out. I think I would go with larger diameter head bolts. This would be a fun build.

 

I only read your first post. I would think what you want to do could be done a little simpler than you are asking.

My math sucks but I think you'd need about a 6.9" rod to get a 1.7 rod ratio, I did this off the top of my head trying to remember the inches to mm conversion so I may not be right. In order to get that you'd you need about 1" spacer. I'd think the easiest way to do this would be to just CNC a spacer with very good dowel pins to locate it and the proper oil/water passage to go up and feed the head. Then you could, I think, place this new spacer on the ................

Nevermind that **** won't work, I just thought of a huge problem but will leave my initial thoughts up there. I was going to suggest running a new sleeve through it all and then use a head gasket to seal the spacer and then another to the head, hell you know it may just work.

Anyway, I'll tell you the 2.1 really works well, it's a noticable difference in the low/mid range when you drive it around. Not quite as good as a 2.3 but it's good.

 

Appreciate the input, David.

I was thinking the same thing at first with a spacer and two gaskets of sorts, but then I think the rings on the pistons would be too high and interfere with the lower gasket (I'm assuming).

I do agree that the 2.1 is a nice motor, but a 2.3 or 2.4 with that rod ratio would just kick some butt. It's obviously possible to achieve at least 2260cc without any added deck height, since that's what the AMS' 2.3RR motor is.

Maybe eventually this can be some off the wall project that you or some other shop does. Then you can share the info with us.

Thanks,
Eric

 

We have done this, in Russia. with 4g63 + deck. 4g64+deck will work even better.
You will need spacer made from another block, failed is okay. Special glue must be used, block sleeved. Many other small things will come. Exactly, I am not engine builder, but I can give any information needed, if you have any question, direct from builder.
But this all will not last long, and is not for daily drive cars. Just race is okay.

 

My thought was to sleeve the entire assembly with the spacer added Eric, then there would be no ring problem. It's a good idea to do it.

 

Right, exactly how I would envision it being done the easiest while keeping nice cylinder bores. That way the weld surfaces aren't within the bores themselves.

 

im to lazy to post the pics but lllllliiiikkkeeeee this? and no crap its for a rb26!

http://www.rhdjapan.com/kakimoto-rac...rb26dett-27058

 

ERL Performance does this to LSX's.

www.erlperformance.com

requires the spacer and then a sleeve. Doable.