djtimodj

Im looking in to assembling my short block at home. The block will have been bored to 96mm to take the forged 96mm cosworth pistons, heads will have been inspected and skimmed.

Apart from working in a very clean manner and torquing things to the correct spec's are there any other things i need to take into account when putting my short block together??

Any of the shop's on here please chime in as im not sure if there are any special tools/assembly methods you guys use?


Thanks for any tips.

westpak

iTrader: (19)

nothing special, get yourself a copy of the Nissan Manual to follow the right steps and torque values, except for aftermarket things like head/main studs, rod bolts....

I assume you had the block honed for proper clearance with the piston skirts, the assembly balanced and the bearings measured for proper clearance.... basically all of the machine type of work

djtimodj

I have not yet had any machine work done at all.. The block is stripped down and aps turbos bubble wrapped and boxed while i get the long block sorted.

Ive been reading engine building books but there not VQ specific. Things like crank float and just general assembly methods im looking at.

Im looking to build the bottom end and fit the heads back half of the timing cover and let my shop set the timing up and refit/map the motor.

Once the machine work is done it cant be that hard to just bolt the inturnals together?? Just take your time and be clean ect....??

str8dum1

iTrader: (11)

ya its easy.. thats why you see hardly any blown built motors


But in case you missed it, there's prolly at least a half dozen built cars right now that are paper weights becuase of blown built motors.

You might be able to follow the instructions in the FSM, but doesnt mean its going to last.

Good luck!

neech

iTrader: (2)

Don't be scared of it. It's not rocket science like some people may think.

Take your time, read the FSM, the entire engine build section before you actually do it. Print it out and have it with out. Make sure you understand every step and why you do it. You're gonna need measurement tools (wouldn't recommend cheap ones) like a good micrometers, feeler gauges, calipers, dial indicator, blah blah blah.

The machine shop will probably need your specific pistons so that the can match the cylinder to get the tol's right. If they do this for you, you wont need a bore gauge. Have them file the piston rings too while they are at it, or else you'll need a piston ring file and feeler gauges.

I'm sure you're having them balance the rotating assembly right? You'll need to order bearings that are specific sizes.
If you don't feel comfortable doing this, I would just pay the machine shop to assemble it. Most of those guys can do it in their sleep, but there's no telling how careful they are or if they care to get the tolerances right if it means spending an extra 20 minutes on something. That's why I like to do things myself

My machine shop is nice enough to always measure everything for me and order all the correct size bearings, but I still double check it when I get her home. Can't be too careful!

djtimodj

Yeah i understand there are lots of things that can be done wrong and its not "easy" to build it wright so there's no need for any sarcastic smilies! lol..

Doing anything like this for the first time will be hard but like some one already stated its not rocket science. Im still learning about engine building so i may get to the point where i want to leave it to the pro's but half the fun of going FI is getting my hands dirty building the engine!

djtimodj

Just another quick question? How long (approx) does it take a pro engine builer to assemble a short block?

Also how do you balance the rotating assembly? Crank pistons ect... I have used machines to balance shafts and pump implers at work but these are all one piece items ?

terps

iTrader: (2)

^from my knowledge can be done in a day or two when all the machining is said and done correctly and all parts are there

streetzlegend

iTrader: (2)

Im no engine builder, but I did build my own engine. Few tips I could offer you based on my experience, it being my first engine ever to build. TAKE YOUR TIME!!! dont rush through any part no matter how easy it may be, the smallest thing, is what ends up being the cause of a major issue.

Get yourself a bottle or two of assembly lube (they come in a red see-through bottle with white cap) this thing is awesome, if you use oil to lube things while assembling them, the oil will run and eventually end up with dry parts by the time you get to crank ur motor. fill your cams with it, as well as your timing equipment(sprockets, all over the chains, etc...), use the lube provided by the manufacture of w/e Rods your using, for bearings lubrication, ofcourse make sure the back side of the bearings are completely dry! First time i put an engine together (VQ30), i didnt lube the timing equipment nor cams, when i started the motor it sounded like it was going to fall apart. with the built 3.5, it turned over as if it had been running already, not a single noise (so use the assembly lube).

When you put the heads on, make sure the head bolt holes are completely clean, no metal shaving or anything, this is obvious stuff but can be missed.

When you torque down the rod bolts, first call the manufacture of the rods, and ask them the torque spec, and how many times to tighten and loosen. Eagle rods with ARP2000 bolts required to retorque like 3-4 times to get the proper stretch (this is what i did), and make sure you put the assembly lube they provide on the bottom of the bolt head, and on the thread, to get the proper friction when torquing. When your doing this, get a paper and write down which bolt you just did and how many times have you retorqued it. Any distraction will really throw you off lol.

When your putting in the piston, make sure the crank journal for that piston is at the bottom, so when you hammer it in the rod dosnt hit and scratch the journal, also make sure the dot on top of the piston is pointing to the front of the engine. You should also get your piston rings file fitted. Also, try finding a shop that will use a torque plate to bore/hone your block, if you dont know what torque plate is, basically its a plate you bolt onto the block to mimic the heads, since when you torque the heads down there is some stretching of metals and warping going on, so when the plate is bolted down to spec, they then bore and hone it, resulting in perfectly round bores given the torque of the head bolts.

Setting the timing is not hard at all, i got the thing memorized (since iv done it like 4-5 times lol), but the FSM gives you the best instructions you can find. Study that thing like if you had a test (well you do, when you crank the motor is when u get ur test result lol. BOOM = fail), if your going to end up doing timing urself, the tensioners for the chains, put oil on the inside part of them, and release and press on the tensioner lil piston, this will suck the oil into it, and provide pressure on the piston, I do this to prevent the chain's from skipping when you initially crank the motor.

Like I said, I am no expert, nor do I even have a shop. I did this stuff in my room, and backyard and had my old man holding the motor while i torqued things down lol. Just trying to give you a few tips i found very useful. goodluck

accordfreak

iTrader: (15)

great tips. thanks for that.

djtimodj

What a fantastic response!!!! The way you described that build is how i see it in my head. I need to read and read again the FSM on the build and take my time.

Is the engine you built still running???

djtimodj

Guys this is a quote i have from a good UK engine builder. The units at the end of each stage or hours of labour needed.

Is this a fair qoute ??? Im hoping Hal or any one that does this sort of work can chime in and say if this looks like a fair estimate.


Nissan VQ35DE

Used engine to be provided striped but complete, check and inspect all parts to be reused, rebuild with a low compression ratio and uprated rotating assembley, install turbo system and prepare engine for reinsertion.

Process Est Labour Hrs

Clean all parts to be re-used and visually inspect 4.00
Clean block after machining 4.00
Check deck faces, measure bores and check ovality, rods and main journals, weight match rods and pistons, measure compression ratio. 2.50
Mock fit crank and check all main bearing clearences, measure and set piston ring gaps 3.00
Fit rings to pistons, fit rods to pistons, fit pistons to block, check big end bearing clearences, if ok torque to spec, torque main gurdle to spec and fit head studs 4.00
Strip heads and measure valve guide clearences, if good re-seat valves and re-assemble valve springs and retainer system 6.00
Check all valve clearences 1.00
Fit oil pump and pickup, fit sump and rear main oil seal, fit cylinder heads and mock fit turbo kit to check fitment 3.00
Final fit turbo's, fit rear portion of chain cover, fit water pump and lower intake manifold 4.00
Fit cams and cam chain, set cam timing. Fit injectors and fuel rails, mock fit turbo heat sheilds to check fitment and investigate possible pipework paths for turbo water cooling system 4.00
Final fit all turbo heat sheilds, manufacture water cooling pipe system for turbo's and final fit all. 6.00
Final fit rocker covers, front timing covers, turbo intake pipes and upper intake manifold portion, fit spark plugs and coils, re-fit engine wiring loom ready for re-insertion 4.00

Total estimated hours 45.50

Workshop labour rate £80+vat per hour, for purposes of this estimate discounted to £72+vat per hour.

Sub contractor cost's

Machine (bore and hone) cylinder bores to execpt new pistons. £250.00
Acid clean an zinc passivate all engine fasteners £40.00
Cost of hot pressure washing large componants £100.00

Total estimated Sub contractor cost £390.00

Estimated final labour/sub contractor cost total inc vat £4,215.90

These are labour estimates based on previous similar work.
There are no parts cost's included in these totals.

neech

iTrader: (2)

Good info Streetz! I also recommend lots of assembly lube.

Right before first start up, I like to take the spark plugs out, and turn the engine over with the starter until oil pressure builds. On a brand new engine with no oil in any of the passages, it can take a good few seconds for oil pressure to build. This is where the assembly lube is critical. It's important to turn it over with the starter and build oil pressure first without any loading on the bearings that a running engine creates.

DJti, how comfortable are you with doing some of that exterior assembly? Like fitting turbos, manifolds, timing stuff, etc. Lots of that stuff is pretty easy compared to building a motor, if you wanna save some money (a lot of money haha) you could have them do the basic motor work, then do the rest yourself! And you have the satisfaction of knowing that you did it all yourself

Also, how many miles are on the heads? If its not very much, you could probably skip stipping the heads to check the clearances on the parts. Any oil consumption?

djtimodj

Im fine fitting the turbos's and manifolds ect... but im still not happy i could set up the cam timing correctly. Ive not really looked at how its done on the VQ but i just dont want to bugger the whole engine up.

I would be good having a shop build the bottom end and me assemble the long block but dont want to remove my motor and swap over the new motor because i dont have the space to have my car in bits and motor parts every where!

streetzlegend

iTrader: (2)

Oh yea, the engine still running strong. I have 4k miles on it, and its currently at 15-20psi of boost

as for the quote you got, thats pretty expensive, but it is alot of work. Im going to look up a post I made with my quote. its alot less work than what your shop is quoting you though. Considering all the turbo/manifold stuff i did myself.

Edit: here is the link to the thread with all my parts and labor: https://my350z.com/forum/7281098-post15.html
I kept my heads stock, so only the short block needed the machine work.

go-fast

i usually don't respond to this type of generic thread but here goes anyway.....there are specialists within the industry for a reason,to think we can infuse you with the knowledge to properly build a performance engine within the confines of a forum is insulting to say the least.

it's not as "easy" as some imply,going through the motions in the service manual is far from building a performance engine and could only be used as a loose guide.most if not all of the factory specs go right out the window and if used will lead to an early demise.

can i read a book on heart surgery and get everything back in the right place when i'm done?probably,but i have no idea if the patient will live.same thing here,if you want to be a budding engine builder start with a little less ambition and rebuild your lawnmower.if you can still mow your lawn when your done consider yourself coordinated enough to experiment with performance assembly where the book gets thrown out the window and your working off experience.

i know i'm coming off strong,but at the end of your journey into engine building you will realize my honesty has real value.

streetzlegend

iTrader: (2)

I strongly agree with your point, how ever putting together an engine is not as hard as it may seem. There are factors that do require experience and experties such as file fitting rings, checking if journals and bores are within spec, then getting the proper size bearings, and obviously the machine work needs to be done by an expert as well. If someone is going to do a build themselves like I did, then ofcourse some kind of coordination and experience is needed, and not just being able to change oil. In my case it was my first time taking apart and putting together the actual block, but I did have experience doing head gasket change, timing, etc...

But to the OP, if in doubt, dont do it. I actually did mine because I did not trust the actual shops with certain things (local shops here), so I took it upon myself to make sure it was done right, except those things that require experties.

neech

iTrader: (2)

Perhaps they just want you to think that it REALLY IS that hard so that they can charge fools an absurd amount of money for doing relatively simple things. How do you think THEY learned? I can guarantee they didn't spend 7 years at an engine building institute to figure it out.

And whats the worse that can happen? What you throw a rod? It's not like someone looses their life as in your heart surgery example, you just loose a bunch of money, figure out what you did wrong, and do it again. It's a learning process.

And since you are such an expert, what "factory specs" go right out the window? I'm not saying they aren't different, I just wanna hear what YOU think happens.

I'm not saying its as simple as changing your spark plugs, but like I said before it's not rocket science. You definitely need experience and to be mechanically inclined, but it's not like you have to have a bachelor's degree, or even a certificate from UTI/DADC/any mechanic school, to figure it out.

And in addition, when you do it yourself, you can insure the specs are right, whereas a shop that is going to be more concerned with the time spent building it, rather than how close the tolerances are, might not care as much.

I also have lots of mechanical experience, as with streetz. I have built multiple built motors, none of which the bottom ends failed, and frankly, its not black magic.

But hey, if you wanna pay an "expert" $1000 dollars to put together your motor, go right ahead.

go-fast

you likely have natural talent that you take for granted,coordination between the mind and the hands is not a universal skill.to the untrained just pulling an engine takes 8 hrs and it looks like a gorilla went nuts in there,an expeienced vq guy can perform the same task in 3-4 hrs with everything tagged,bagged and no destruction.my whole point is both got the job done,but it's two totally different levels.....don't practice on your performance project.

MardiGrasMax

iTrader: (8)

For the head torque procedure I do somthing different. Since we cant easily get into our cylinder heads to re-torque the fasterners I do this. I torque the heads to ARP spec/procedure, then let the motor sit a day. I then take a heat gun (or a good hair dryer) and heat the heads up. It takes a while, but lay the heat gun blowing into the exhaust port and let it sit for a while until you can feel the top part of the head, the part inder the valve cover, get hot to the touch, again it takes a while... Do this to each cylinder and let it sit a day to cool. If you have the time, do the heat up and cool down again a few times over a few days. After this is done, with the motor at room temp you back the fasteners off NO MORE THAN 1/4 turn and re torque up to spec using the same procedure when first assempling. Doing this psudo heat cycling allows the fasteners to set and unset a few times, so if a fastener was going to loosen up, and they usually do a bit, you have addresed this before you put the motor completely together. Its an extreme thing to to, but its essentially a no cost thing to do.

And with out a doubt assembling a motor is an easy thing to do provided you attain the correct tools. Read the service manual. Read a few other motor assembly books. Ask questions when you dont understand somthing. Take your time. Enjoy the experience building and taking pride in that you did it your self!!!