3.1, 3100, 3500?? build options

[Mach 5]

gotcha yeah it was late when i looked at the link. Now that I think of it its definitely do-able since the lifter bore are essentially 350 lifters. Im gonna talk to some people at my local speed shop -SK Speed- and see what they say.

oh and after thinking what abouit 3500 heads and lower intake along with the 3500 crank stroked .240 on a 3100?? Is this possible? This would make 208ci on the 3100 bore. or just leaving the stroke the same but still using the 3500 heads and intake and just grinding the rod journals down to accept sbc rods??

Thats a cool link Thanks!!
-Jarek

[ericjon262]

IIRC, lifter springs go inside the lifter, a rev kit goes outside, around the pushrod, controlling the lifter. which allows the valvesprings to control the valves, not the whole valvetrain.

[Mach 5]

I thought they had lifter springs for sale on here.. Wouldnt that eliminate the issue?

[ericjon262]

would it be possible to run a "rev kit" on a 60*? that'll keep the spring pressure down and keep the hydraulic lifters in check, it's be a one off piece, but you might be able to sell them...

http://www.airflowresearch.com/index.php?cPath=75

AFR claims a 100hp increase in power through better valvetrain control, and AFR isn't some fly by night company...

[trotterlg]

I think to get to 7,500 you will probably need solid lifters, the standard roller lifters are heavy, so spring pressures will need to be high and lifter pumpup I am sure will be a problem. There is a good reason most high spinners are OHC engines. Larry

[Mach 5]

I would say 7k would be the max and I would be happy.

Does anyone have experience with the turbo race cam on here?? and the heads too??

[Jonpro03]

Yes with a stroke that will still be under 3.5" 7500RPM will not be an issue. Piston speed will be well within a safe limit. You should be more concerned about a light valvetrain that can take the RPM and not the rotating assembly. An inline 6 engine will never have the same harmonics as a V6. The 60 Degree V6 does have a secondary imbalance but it is very small.

Exactly the concern I had. I don't know if a steet built pushrod valvetrain is capable of 7500rpms.

[geoffinbc]

Yes with a stroke that will still be under 3.5" 7500RPM will not be an issue. Piston speed will be well within a safe limit. You should be more concerned about a light valvetrain that can take the RPM and not the rotating assembly. An inline 6 engine will never have the same harmonics as a V6. The 60 Degree V6 does have a secondary imbalance but it is very small.

[Mach 5]

7000 RPM is realistic. But there is no reason to sacrifice that extra stroke to do it. You can spin the 3.31" crank to 8000RPM and be well within a safe piston speed. So reducing stroke will in no way allow your engine to spin faster.

If I was into this build and spending my dollars o custom pistons and rods then I would stroke the crank to the max the journals would allow. Spec a piston with solid ring lands with plenty of margin from the top of the piston to take the heat from the boost and then get a set of rods to zero deck the pistons.

As for the stock oiling system it would provide oil at any RPM the engine could handle. The priority main feed will keep all the bearings happy. The only thing I would consider is oil restricting pushrods and full roller rockers so I would not have to worry about excess oil up top.

so you feel that this crank given 25psi more or less depending and 7500rpm should be ok with this 3500 crank..?? I am very concerned about this I do not want to over rev this motor either. I also would think that given that rpm I would have to start worrying about the secondary harmonics starting to take play to which with a shorter stroke even if its only 1-2mm shorter will greatly reduce the chance of this being an issue. Ive been reading on issue with the rb motors having this problem at around 8000rpm with bolts coming loose and bearing failure more of an issue on the larger stroke motors.

I am very happy just throwing around ideas right now starting next month the build will actually start

[Mach 5]

just showing some links to what I feel are good websites for intake design for my personal build
I already know that there is a thread on intake design

http://horsepowercalculators.net/intake-manifold-design/intake-manifold-design

http://www.200sx.lv/forum/viewtopic.php?t=818

http://www.homemadeturbo.com/showthread.php?t=93372

[geoffinbc]

7000 RPM is realistic. But there is no reason to sacrifice that extra stroke to do it. You can spin the 3.31" crank to 8000RPM and be well within a safe piston speed. So reducing stroke will in no way allow your engine to spin faster.

If I was into this build and spending my dollars o custom pistons and rods then I would stroke the crank to the max the journals would allow. Spec a piston with solid ring lands with plenty of margin from the top of the piston to take the heat from the boost and then get a set of rods to zero deck the pistons.

As for the stock oiling system it would provide oil at any RPM the engine could handle. The priority main feed will keep all the bearings happy. The only thing I would consider is oil restricting pushrods and full roller rockers so I would not have to worry about excess oil up top.

[Mach 5]

I never said 10000rpm but I was taking the idea that all of the high powered motors like the supra and the skyline heck even the vq series 350 and 370z's all have in common are short strokes. i think having a little lower torque can actually benefit me since I have traction issues out of the hole.. that and my stock 5700 redline of my old motor kinda made my shifts very short and the high torque gave me wheel spin in the first 3 gears after the downpipe change. Im sure a tuned suspension can help greatly I still need to do the Koni upgrade

I was thinking a realistic goal would be between 6800- 7500rpm with a destroked crank. I dont even think the stock oiling system could hold more than that anyway. I already have a high rpm screamer in my ae86.

example:
RB26- 86mm bore 73.7mm stroke
RB30- 86mm 86mm

1JZ- 86mm bore 71.5mm stroke
2JZ- 86mm 86mm

VQ37VHR 370z
95.5mm bore
86mm stroke

VQ35HR 350z
95.5mm bore
81.4mm stroke

granted these are all 4valve motors but just the concept of small stroke large bore and they peak around 7000- 8000rpm

GM 60 degree v6

2.8- 89mm bore 76mm stroke

3.1- 89mm bore 84mm stroke

3.5- 94mm bore 84mm stroke

[geoffinbc]

Not gonna happen sorry. Your not going to spin a pushrod motor that high and have it last. If your strictly drag racing then go for it. But if it is a street/endurance motor its not going to run for long spinning that high. Start building a realistic motor for your car and not something your going to dump $15,000 into on fancy parts that do nothing to increase reliability. 7000 RPM potential is more than enough for any street/endurance motor. If you want to make a few trips north of that then it can be done. But get 8000RPM+ street motor dreams out of your head. Stroke the motor it will make more torque all over the RPM range and the small increase is not going to hinder high RPM performance at all.

If you really need a motor that can perform at 10,000RPM then you should start with a 2.8L or 3.6L DOHC 60 Degree V6 and not any of the pushrod motors.

[Mach 5]

gotcha, I have been studying plenum design for a while now so I think I can come up with something different. I may actually just use this thread as my build post..
Thanks for the verification of those main bearings I was confused because of the different part# but now I know why. I would actually rather want to de-stroke it.

example of why.. besides my experience with my small stroke 4age 20v ae86

http://www.youtube.com/watch?v=5B1uqQWdw6A&feature=related

[Superdave]

Mains are the same, GM went with the aluminum coated ones in the 3500 but measurements are the same. Of course you should check all your clearances on assembly though. Grinding the pins down for the SBC rods will work fine and it's a great time to add some stroke to it. you could get up to around 3.7 liters out of it.. maybe a little more.

Just keep plenum volume in mind when building your own, that's where the 3500 plenum shines. For the gen3's, it's the best out there.