iamjustincase

hey everyone.

been a decent amount of time since I've been on these forums.
I've been raping the search button last couple of days preparing for my rebuild after I developed a rod knock.
I got the engine all torn down today and ready to go to machine shop on Monday.

Instead of just rebuilding with oem equipment I have decided to buy some upgraded things while I have it all apart. I am on a budget of about 2500$.
i can replace bearings and bolts and put it all back together for under 500 but i don't feel comfortable at all doing that as this engine sees extreme amounts of abuse both on and off of the street.

so far my parts list consists of -

ACL rod bearings (shooting for a clearance of 0.0025")
ACL main bearings (shooting for clearance of 0.0025")
ACL thrust washers
ARP rod bolts
ARP main bolts
ARP head studs
rev-up oil pump
JE piston rings
Complete timing set with new chains/tensioners/guides
complete gasket set with MLS headgaskets
Manley valve springs

that puts me at just under 2200USD for parts.
I'm having the block and heads hot tanked, the cylinders honed, and crankshaft polished.
so with that cost included I'm still under 2500$ and I'm building it myself so labor is free obviously.

I am going to be reusing my oem rotating assembly (rods,crank,pistons) as i don't have money to spend on forged internals and re-balancing at this time. Wasn't exactly prepared for this engine to need a rebuild.

So I have some questions for everyone on what you think this build would be capable of in the future as far as high-revving it while it's still NA and/or future plans for forced induction (likely single turbo).

First question would be, how far would you be willing to push the rev limiter with this build?
I added the manley valve springs in there in the hopes of preventing valve float, if that is even a concern, And I am going with the rev-up oil pump because I have read its stupid to put the DE one back in when you are at this point, and its also rated for higher rpm.
I have also read about the rod bolts not liking high rpm so I'm using all ARP hardware to help this.

I am also using all arp hardware because i plan on taking the motor out and reinspecting my bearings after about 2000km since i am experimenting a little bit with oil clearances and weight, and i want to make sure this motor will last as long as it can without me holding back on abusing it.

I would like to see it hit 8000rpm once or twice, but I want to leave the rev-limiter set at about 7500 after I have tried 8000 at least twice.
That being said, I am aware the stock cams will not make power at these rpms, but I will be shifting at about 7200-7400 on the drag strip just to get it more into the power band for the next gear on my 1-2 and 2-3 shift.

so what do you think? is 7500rpm safe with upgraded rod bolts, revup oil pump, and upgraded valve springs on a DE?

I'm also opening up my oil clearances to allow for slightly thicker oil, better oil cooling and less chances of a bearing spinning in the future because of how much regular stress i put this engine through. And becuase i hope to have enough money set aside in a year or two to do a single turbo setup and I would like to not have to rebuild my engine again before doing that.

I plan on running 15W40 synthetic oil with 0.0025" clearances on mains and rods.
I have made this decision after doing some extensive reading about oil bearing clearances, and measuring my current clearances.

My current clearances are 0.0017" for rods and 0.0015" for mains
I've determined that those tight clearances from the factory, paired with my rear timing cover gasket failing (causing loss of oil pressure), and extensive abuse were the main culprit of my current situation. (spun rod bearing) (and extensively worn bearings all around).

Sorry about the stupid long post and a bit of rambling, I'm just trying to put as much info about this as possible to help with opinions.

so recap on my first question, can i rev this motor to 7500rpm?

my second question would be, will this setup be ready for forced induction with a goal of about 450-500whp with a single turbo, no meth injection.

I'm open to any opinions about my build, if you have any reasonable suggestions or recommendations for me i welcome those as well.

If you want to just say that I didn't search enough, or if you feel like posting links to other build threads or threads on this topic, please do, i will read them.

I'm ordering the parts on Tuesday, its all overnight shipping. reassembly is planned for this upcoming weekend.

Thanks in advance for reading my super long post. Here are some pictures just for fun.

Conway_160

iTrader: (1)

Save your money its very much pointless reusing stock pistons and rods. You are limited to ~420whp just like stock since the rods are the weak point in the motor. Also with stock cams the motor will not make power 7000+.

If your serious about wanting to build the car but cant afford it, buy a $500 beater and drive It untill you can do a proper rebuild.

Thats my .02

dkmura

iTrader: (64)

Unfortunately, you're trying to do two separate things with one engine rebuild. I applaud you for trying, but hate to see all that effort wasted. First, take a closer look at the torque curve of a stock VQ35DE and you'll see that shifting at 7500-8000 is a waste of time. Shifting at closer to 7000 -7100 RPM with a standard DE will keep you in the power band, as long as you can shift cleanly. Can you shift at a higher RPM with your setup? Yes- but you won't go any faster...

The other item I don't see on your list is any head work. You don't list your mileage, but assuming it's high, a standard three angle valve job s/b on your list. If you want better flow, a skilled machinest with the ability to port and polish s/b considered to improve the top end. Then you'll want to get some cams to improve performance, but wait, you're hoping to go FI so that's up in the air...

I agree with Conway 160 on the pistons and rods, you'll need forged components to be ready for even a bit of boost on a regular basis. What you're doing now is rebuilding the VQ to stock specs, which is fine, but you won't be ready for FI if you get around to it. Even limiting the output to around 400 HP without building the shortblock makes little sense- it'll eventually degrade the components you have in place.

I can appreciate your idea of trying to hold costs down and doing much of the reassembly yourself; we've done much the same on many of my NA Nissan race engines. Opening up the rod and main clearances may help, but the VQ was designed to use the specs we have and without any specific guidance, I'm at a loss to say whether it (and a higher weight oil) will be successful. If you must put this engine back together as a NA engine, I'd look at what's needed for clearances AFTER the crank is checked for straightness, magnafluxed and micropolished.

Buy another used engine and rebuild it for FI at a later date if you must, but don't try doing two things at once. It doesn't work..

iamjustincase

i appreciate the input.

I'm at an estimated 110k miles on this engine, its actually unknown as this is the second engine in this car and i bought it used with an estimated 70k miles on it.

I also still have the other engine from the first time a bearing was spun on the original motor. So I'm going to keep that so that if i want to i could build that engine with internals and go all the way with that engine, on the side, while still having my car drive able during that.

I didn't totally realize that the rods were the weakest point in the bottom end, i thought spun bearings were the most common failure which is why i was wanting to open up my clearances to prevent that in the future if i did go FI with this build.

I don't want to buy cams as its very limited gains when N/A and putting in cams that are aimed at boost is also pointless as ill be staying N/A for at least another year or two.

I was always trying to stay away form valve jobs and major head work, because again its decently expensive (although i have not actually priced it out) and i was trying to stay under 2500$ which i have been successful in doing with this current list of parts and work being done.

From my understanding doing just a port and polish and 3 angle valve job will have very limited gains for what it will cost unless i buy cams to allow more air in at high rpm, but again i cant by cams because of cost and future hopes for FI.

Do you think i should still buy all of the ARP hardware at least? so that in the future i can disassemble this block, build with forged internals and at the least reuse the fastening hardware so im not wasting a ton on ARP studs/bolts?
Keep in mind i also want to inspect the bearings on my engine again after a summer of drag racing and launching from redline. so i like the idea of being able to open it, and close it back up with the same hardware.

dkmura

iTrader: (64)

With the unknown mileage on this VQ, you're doing the right thing to rebuild it. Why not build this engine as a strong reliable NA version with minimal mods. Since you have a second motor, you've got a good idea of building it as you can afford to. Put it on an engine stand and keep it dry and clean and install the ARP hardware for the future. It wouldn't be a complete waste to use ARP hardware on your stock engine either- but that might be overkill. BTW- forget about doing a lot of headwork on the NA engine, but at least get an estimate on a three angle valve job. That'll be worth it to have both the top and bottom ends rebuilt so you KNOW they're reliable.

iamjustincase

Update :

alright so i dropped the block and crank off at the machine shop today to have the block, front timing cover, and upper oil pan hot tanked and the cylinders honed. Also having the crank polished.

last night I ordered all of the parts.
I decided to ditch the idea of buying arp hardware and upgraded springs, and instead im going to build this engine with oem hardware and save my money to start building my second engine on a stand in the meantime.

Last night i ordered

OEM rod bolts
OEM main bolts
OEM head bolts
JE Piston Rings
All three timing chain tension adjusters
Complete gasket kit for entire engine and intake.
Clevite Main Bearings
Clevite Rod Bearings
Clevite Thrust Washers

All of those parts should be in tomorrow.
The block should back from the shop in 2 - 3 days.

I still have to remove all of the cam buckets from my heads, then i will drop those off at the shop tomorrow, to have them cleaned and checked for flatness.

If all goes well i should be assembling the engine on Friday or Saturday.

dkmura

iTrader: (64)

Sound plan- although I'd pay a few bucks more and have the crank magnafluxed and checked for straightness. It's usually well worth the trouble...

iamjustincase

UPDATE -

Picked up the block and crank from the machine shop today.
Crank was inspected and polished.
Block was cleaned and cylinders honed.
Also had the timing covers and upper oil pan cleaned.

At the same time i dropped off my cylinder heads to have them cleaned and inspected for flatness also.

Cleaned my pistons today to get them ready to start filing rings during the week.
Leaving for Edmonton next Tuesday though, so I wont have time to build it until I come back.
Kind of sucks as the first local track day is the weekend i come back oh wells.

I also want to paint some things before i put it all back together, remaining patient is key i guess if i want it together how i imagine.

I included a picture of the stock casting marks in the head, can't believe how nasty they are, wish i would have cleaned that up before sending them to be cleaned, but i doubt any real gains are to be had without actually porting and polishing. Even then i expect the gains are minimal.

Anyways, here's some pictures of things and stuff.

joshua350z6841

iTrader: (3)

great build. i think u mad the right choices. with the stock valves u can still rev to a safe 7200 rpm

iamjustincase

yeah I'm glad i decided to hold out on pointless upgrades at this point.
save my money for putting the real parts in my other engine when i get the chance.

This was a nice chance to get to know my motor without possibly ruining some super expensive parts in the process. this way if I'm terrible at building this engine, and it blows up again. just a stock rebuild. and i have lots of extra stock engine parts.
I'm pretty certain I'm not going to be terrible at building this. This will be great practice for the next build.

iamjustincase

Without the revup oil pump I'm not sure ill be confident enough in my oil supply to rev to 7200rpm. Last time i had it set at 7000rpm and tried to shift around 6800rpm.
I will probably stick to that with this engine for now.

joshua350z6841

iTrader: (3)

i have ran mine at 7200 stock de for 3 years. on 8 psi

iamjustincase

that makes me feel a little better about it.
ill keep that in mind when im choosing a rev limiter.

gonna be picking up the heads from the shop tomorrow, and im going to try and find time to start painting things before i go out of town for a week.

I have the FSM, but does anyone have any tips, or problems u encountered when setting the timing on these engines?
I have done some searching and reading, but this is my only concern i have about assembling this engine is that i have never set the timing on a vq before and i feel like these timing systems are bit more complex than most.

im sure i'll be able to figure it out with the fsm, just looking for any heads up anyone might have before i get to it.

iideadeyeii

iTrader: (6)

Stock oil pump also? What happened AFTER 3 years?

joshua350z6841

iTrader: (3)

everything has been fine. i run Mobil 1 120782 5W-40 Turbo Diesel Synthetic Motor Oil. you cant run that with cats tho. everything has been fine it has 120k on it so i will be rebuilding it soon for boost.

iamjustincase

thats good to know joshua, thanks for the input on the rev limiter and oil usage.

also to update the build thread, i picked up my cylinder heads from the shop on monday.
all parts are in, but i am currently on my way to edmonton for a trip to pickup a car for a friend.

in the meantime i think my friend may start filing my rings for me while im gone, since i was probably going to pay him to do it because i hate filing rings.

so when i return from Edmonton next week i will start lapping valves and prepare for reassembly. i will post pictures once progress is made

iamjustincase

update

i just returned from my cross country trip to edmonton and returned through the mountains on my way home. absolutely amazing sights were had.

now i need to focus on finishing this build.
i will be filing rings this weekend. but i wanted to know if anyone has an input on ring gaps?

i have only been able to find one post related to vq35s about ring gap, and that person was planning for boost so his specs dont exactly suite my need.

i have been told 0.004" gap per inch of bore diameter, i will be going with this equation but i was just hoping to get some input on what others have done.

as stated above this is a stock rebuild with stock internals and JE piston rings.

i'd like to start on this by sunday, hoping for at least one input on this subject before hand.

iamjustincase

update

rings have been checked and filed.
the JE piston rings i ordered came pre-gapped at exactly what i wanted.
0.016" for top ring
0.020" for bottom ring

installed the crank today and started fitting the rings onto the pistons, that's as far as i got today as the pistons needed some extra cleaning to get the rings to fit loose enough. will finish cleaning the pistons tomorrow and get them into the block.

clearances on my main bearings were plastigauged at 0.0015" for front and rear main, and 0.002" for the two inside mains, with stock sized bearings and a light polishing on the crank. not sure why they arent exactly the same, likely from polishing. not too concerned about it though.

heres some pictures of things and stuff.

iamjustincase

update

finished assembling the short block yesterday, all went well.
checked each rod for clearance and they all came out at 0.0015" clearance with oem size bearings, and a light polish on the crank journals.

disassembled the oil pump, hoping to be able to clean out shrapnel and reuse it. Not the case, the bearing material is embedded into the pump gears, so i will be using the oil pump off of another vq my friend has lying around.

started wire wheeling and lapping valves yesterday also. very time consuming, hoping to have both heads done by Saturday night.

more pictures of things and stuff below.

iamjustincase

well i lapped the valves on one of the cylinder heads today.
took a while, learned alot of things and gained some experience in this department.

not much to say on lapping as its boring and time consuming.

here are some pictures of things and stuff before and after.