What do you think?

[Guest Zbrowser]

I'm going the stroker route. Have spent a couple of days going thru the search mode for information. I allready have some of the parts, was wondering how ld28 crank, 240 rods, 89mm pistons, P90 head and carberator conversion would do? If I shave the P90 and do it correctly, would I be able to leave the 89mm pistons alone? or would I need to mill them to get the correct deck height? If so, is there another way I would not have to mill the pistons?

 

Also has anyone done a 4 barrel conversion for a stroker engine? Is it plausible? or am I barking up the wrong tree? Appreciate all the info I can get on this issue.

 

And just incase I haven't asked to many Questions yet how do Iget to this page I see everyone refering to as the L engine page, where you can try outdifferent formulas? I've seen reference to it but could not find it anywhere. Thanks again

[e_racer1999]

won't the 240 rods be too long?

[Roostmonkey]

IMHO...go turbo!!

[Guest Zbrowser]

from what I've been able to search out, 240 rods are ideal, even though they're longer then the stock ones. However, deck height I believe will be 2mm higher then normal and I think there is a way to get around milling them but I can't seem to figure it out. Anyone? Anyone?

I have heard that taking the pistons down may cause structural integrity issues, so I'm trying to shy away from that. As for going Turbo that is still an option, but I may not do that considering the fact that the f54 block I'll be using may not handle it after it is bored for the pistons.

 

Also still need any info on whether or not a 4 barrel carberator conversion will work with set-up. Anything could be helpful so please don't be shy if you have an opinion

[(goldfish)]

here's a nice stie to read

 

http://www.geocities.com/inlinestroker/

[NZeder]

I have heard of guys running into issue with milled pistons - Like you say " have heard that taking the pistons down may cause structural integrity issues"

I have seen this happen also - years ago at a raceday here in NZ - result = holed pistons x2

 

I have read somewhere on the web (will try locate link and post here) talk about using a 2 mm head gasket.

 

Some links that might help are

http://zhome.com/rnt/3.1HanveyProject.htm

[Dan Baldwin]

You're talking KA24 pistons, right?

Pistons pop up ~.025" (measured mine at .022"). The KA pistons have a raised (.019") ring around the perimeter. Machining this ring off will have zero structural integrity ramifications, would give a popup of ~.003"-.006". Go ahead and machine .025" off to ensure no pop-up. This won't affect CR much (LEngine builder doesn't calculate this properly and will overestimate the CR loss from machining dished pistons).

 

Or, you could leave the pistons alone and use the 2mm HKS head gasket.

 

You will have to shave the P90 ~.080" to get a decent CR (and shim cam towers, and use older N42/N47 valves). Or you could just use a stock N42 head for 10+:1 with the 2mm gasket.

 

4bbl conversion not the best way, IMO. Depending on what you want, street performance vs. all-out track hp, I'd recommend stock 44mm SUs, 2" Jag SUs, or 44-45mm 3x2 carburetion.

[e_racer1999]

another idea may be to find some custom pistons that have a higher wrist pin so as to lower the piston in respect to the top of the deck

[Guest Zbrowser]

Thanks for the great info! great threads to go by also. Imissed the first one shown.I think I'll go with the larger gasket and shave the P90 head ( since I already own one ) I have heard that you can get 10+:1 with a stock n42 but didn't research before I bought it And from all the threads I've read that is a discussion that may be argued for a long time as to which is better

 

As far as the 4 barrel This is for street / mabey a race here and there So mabey I'll look into this a little further. I sorta like the idea of having su"s but was sort of taken back as to whether or not they would deliver as much fuel as needed ( read something like that in the harveyproject thread ) Are they very hard to sycronize with each other?

[datsunlover]

Not sure on the head choices (as Im still trying to figure it all out for mine; 280z head on a zx block, yada yada) BUT; I have 71 SU's and I love them. Not hard at all to figure out at all. I dont even have them synced properly yet, but they are SOOO simple to make work! (me and a buddy spent an hour dissasembling and cleaning with varsol, put them together the next day and had my car running in 30 mins!) I just have mine tuned by ear (as well as my timing.. ) right now but they seam to suply plenty of fuel, and have a cool sound to them to boot. I was woried at first using them on my 2.8, thinking they wouldnt suply enough fuel (seeing as they came off a 2.4L engine) but there seams to be lots of adjustment; I only have my adjustrs out 2 turns and it still runs a bit rich! (I think intitial settings call for 2.5 to 3 turns out..) Id say match the intake ports to the head, and run good/rebuilt SU's.

[texasz]

I too am looking at the 3.1L stroker and have spent much time researching this. Here are links to what I can locate while here at work, I may have more at home.

 

http://geocities.com/zgarage2001/z.html

http://www.geocities.com/inlinestroker/

http://www.ztherapy.com/

http://www.schlaver.com/zCarGo.html

http://www.geocities.com/row4navy/

http://www.classiczcars.com/forums/showthread.php?t=1292&highlight=l6+engine+calculator -> L6 Engine Calculator

 

 

What I have been able to determine is that you want an F54 block, either an N42 or a P90 head (the P90 will need to be worked over whereas the N42 will not but both should achieve the same results), the LD28 crank, 240Z rods (the ones with the 9mm bolt which were only available in '73, the earlier models had 8mm bolts), the KA24E pistons from the 240SX, and the head gasket of the proper thickness for your exact specs (either a 1 or 2mm gasket).

 

Now as for carbs...I'd go with either dual or better yet triples. I do not think that a 4bbl is a good choice for these engines as I have heard too many people say that cyl 1 & 6 tend to run lean and 3 & 4 tend to run rich simply due to the way the manifold and L6 are designed. Go with the dual or triple set up and you will have a much more consistant fuel delivery across all cyls.

 

Turbo...I don't recall hearing anyone turbo a 3.1 stroker yet...that could be quite interesting!

 

Hope this is helpful info for you.

[Guest Zbrowser]

all this is waaaayyy helpful And thanks for the threads and info on the carbs!! It makes alot of sense now that I think about it.

 

I'll try to post updates so that mabey others can benefit

[e_racer1999]

if you haven't already checked out this site, it's really good

 

handy dandy denny's reference

http://www.kaynor.net/v8-240z/240z.htm

[510six]

I have had two 3 liter stroker motors built and one thing I would recomend is to have the motor statically and dynamically ballanced.The first motor which was a NA and FI had the flywheel bolts back out due to torsional vibrations along the crank at high RPM`s.This was fixed to a degree with a NISMO comp dampner.But the dampner bolt had to be checked ever 6 months or so.I was reving the motor to 7 grand on a regular basis and would suggest that if the motor is going to be spun over 6500 RPM that a comp crank worm gear and spindle for the dist drive and oil pump is used.The tortional problem was finallly fixed with the addition of a ATI SFI approved crank dampner, but due to the small crank pully a helper electric water pump was installed as well as a custom pully for the alternator.Both of my motors use 133mm rods and 87mm pistons , the first being stock 240z 9mm rods with ARP rod bolts and stock VG30 core motor pistons.The second using Cunningham rods and 87MM JE pistons.I use a Japanese only N33 casting which would be most similar to a N42.