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SequenceGarage
08-09-2005, 08:35 PM
yay for learning. These are questions that you wouldn't think about having until you come up to them, when you think "[censored].. this isn't the kind of thing i want associated with Trial and Error in any way" that brings me here. I'm not an engine builder but ive done a bunch of SR swaps, changed diffs, clutches, turbos blah blah blah all easy stuff with nuts and bolts, but building an engine is scary to me. Seeing professional engine builders have motors that fail and to think that mine wont seems nothing but cocky, anwyays im being super carefull on each step of the way so hopefully we'll be aright.

SO I got my block back from teh machine shop, im going to clean it out with a b unch of WD40 and papertowels anythign else I hsould do to the block to make sure its ready to go? I dont have an air compressor but I was thinking about buying those computer air spray co2 things to clear out all the openings and make sure there is no [censored] in there - however my builder did clean the thing for me so it shouldn't be too bad.

Piston Rings - the CP pistons came with piston rings and looking at the stock pistons both compression rings are squares, however the CP pistons I got, one of them has a taper to it. Reading on the net it looks like this is the 2nd ring and the taper should be on the bottom to scoop oil downwards on the way down, is this correct?

What piston ring gaps should I be running for a 400rwhp SR dedicated race car?

Those are my main concenrs for now, however im sure i'll have more questions tommorow and the day after as I put everything together. This is the only question i can forsee myself having now but who really knows

driftin240
08-09-2005, 09:30 PM
Taken from S14 FSM, will be same for any sr20det piston ring end gap.

Top Ring:
Standard
0.20 - 0.30 mm (0.0079 - 0.0118 in)
Limit
0.39 mm (0.0154 in)

2nd Ring
Standard
0.35 - 0.50 mm (0.0138 - 0.0197 in)
Limit
0.59 mm (0.0232 in)

Oil Ring
Standard
0.20 - 0.60 mm (0.0079 - 0.0236 in)
Limit
0.60 mm (0.0272 in)

That is strictly by the manual, I would go any tighter or looser just because it's a 400 hp track car. I think you engine should be clean enough, if you want to you can always pressure wash it out with some good simple green automotive and spray with WD-40 immediately afterwards.

Kingtal0n
08-09-2005, 10:31 PM
yay for learning. These are questions that you wouldn't think about having until you come up to them, when you think "[censored].. this isn't the kind of thing i want associated with Trial and Error in any way" that brings me here. I'm not an engine builder but ive done a bunch of SR swaps, changed diffs, clutches, turbos blah blah blah all easy stuff with nuts and bolts, but building an engine is scary to me. Seeing professional engine builders have motors that fail and to think that mine wont seems nothing but cocky, anwyays im being super carefull on each step of the way so hopefully we'll be aright.

SO I got my block back from teh machine shop, im going to clean it out with a b unch of WD40 and papertowels anythign else I hsould do to the block to make sure its ready to go? I dont have an air compressor but I was thinking about buying those computer air spray co2 things to clear out all the openings and make sure there is no [censored] in there - however my builder did clean the thing for me so it shouldn't be too bad.

Piston Rings - the CP pistons came with piston rings and looking at the stock pistons both compression rings are squares, however the CP pistons I got, one of them has a taper to it. Reading on the net it looks like this is the 2nd ring and the taper should be on the bottom to scoop oil downwards on the way down, is this correct?

What piston ring gaps should I be running for a 400rwhp SR dedicated race car?

Those are my main concenrs for now, however im sure i'll have more questions tommorow and the day after as I put everything together. This is the only question i can forsee myself having now but who really knows



Here are some things to do/watch out for...

First of all, I wouldnt use WD-40 or air spray C02 on anything inside the engine. Just FYI, it contains abrasive that *may* scratch important things up. Just use regular mineral engine oil to keep the rust away. When assembling parts i.e. main bearings and connecting rods, DONT use any oil UNDER the bearings (install them clean and dry) and use a non-residue solvent like BRAKE CLEEN to wipe away dirt, oil, and grease, from anything you are installing that shouldnt have oil on it. When using BRAKE CLEEN or similar, let it AIR DRY do not WIPE with towels which may leave behind filiments... this goes for any surface you want to be CLEAN. Obviouselly, when inserting a piston into a bore you will want oil on nearly everything (dip the piston upside down into a deep dish of oil right before applying the ring compressor to it)-
use vacuum hoses on the rod-studs as the piston goes down the bore to prevent the rods from scratching the cylinder walls.
check your clearances with a dial bore gauge and micrometer. do this by torqeing the mains to factory spec with bearings installed but NO crank installed, use dial bore gauge to check the inside size of the mains. then use a micrometer to check the size of the main journal on the crank.. subtract to find your main clearances. If it isnt in spec, dont install the crank, order new bearings. do the same for the rod bearings. too large a clearance will promote low oil pressure, bearing failure, engine knock... too little clearance will promote bearing failure, premature wear, oil pump failure, and possible engine seizure.
Standard main bearing clearance should be .0002" - .0009" with .0007" being average, and .0020 being the MAX clearance on a high mileage motor. ROD bearings should be .0008"-.0018" with .0013 being average. .00256 is the LIMIT MAXIMUM.

CP recommends bigger ring gaps than factory, DONT go by the factory ring gap specs for your pistons, OR piston to wall clearance. DID your machine shop KNOW to use a larger than factory piston to wall clearance? Use a dial bore gauge to check the size of your cylinder, then mic the piston's size, subtract to find difference. The actual wal clearance and ring gap is determined by CP's recommendation. call them or check online what they recommend for your application.

I assume you balanced your entire assembly together? CP pistons weigh different than factory pistons... and if not balanced your rotating assy will eat power, vibrate, and possibly come un-glued at high RPMS.

when installing studs or bolts that are to be torqued to a certain Ft.Lbs... be sure to lubricate them with engine oil otherwise you wont get an accurate torque reading. Dont use anything super-thick like assembly lube, or moly, it will change your torque readings. Speaking of moly (grey lubricant with teflon) dont get any of it on your bearings it will scratch them similar to what WD=40 can do.

Happy240sx
08-10-2005, 06:36 AM
yay for learning. These are questions that you wouldn't think about having until you come up to them, when you think "[censored].. this isn't the kind of thing i want associated with Trial and Error in any way" that brings me here. I'm not an engine builder but ive done a bunch of SR swaps, changed diffs, clutches, turbos blah blah blah all easy stuff with nuts and bolts, but building an engine is scary to me. Seeing professional engine builders have motors that fail and to think that mine wont seems nothing but cocky, anwyays im being super carefull on each step of the way so hopefully we'll be aright.

SO I got my block back from teh machine shop, im going to clean it out with a b unch of WD40 and papertowels anythign else I hsould do to the block to make sure its ready to go? I dont have an air compressor but I was thinking about buying those computer air spray co2 things to clear out all the openings and make sure there is no [censored] in there - however my builder did clean the thing for me so it shouldn't be too bad.

Piston Rings - the CP pistons came with piston rings and looking at the stock pistons both compression rings are squares, however the CP pistons I got, one of them has a taper to it. Reading on the net it looks like this is the 2nd ring and the taper should be on the bottom to scoop oil downwards on the way down, is this correct?

What piston ring gaps should I be running for a 400rwhp SR dedicated race car?

Those are my main concenrs for now, however im sure i'll have more questions tommorow and the day after as I put everything together. This is the only question i can forsee myself having now but who really knows



Here are some things to do/watch out for...

First of all, I wouldnt use WD-40 or air spray C02 on anything inside the engine. Just FYI, it contains abrasive that *may* scratch important things up. Just use regular mineral engine oil to keep the rust away. When assembling parts i.e. main bearings and connecting rods, DONT use any oil UNDER the bearings (install them clean and dry) and use a non-residue solvent like BRAKE CLEEN to wipe away dirt, oil, and grease, from anything you are installing that shouldnt have oil on it. When using BRAKE CLEEN or similar, let it AIR DRY do not WIPE with towels which may leave behind filiments... this goes for any surface you want to be CLEAN. Obviouselly, when inserting a piston into a bore you will want oil on nearly everything (dip the piston upside down into a deep dish of oil right before applying the ring compressor to it)-
use vacuum hoses on the rod-studs as the piston goes down the bore to prevent the rods from scratching the cylinder walls.
check your clearances with a dial bore gauge and micrometer. do this by torqeing the mains to factory spec with bearings installed but NO crank installed, use dial bore gauge to check the inside size of the mains. then use a micrometer to check the size of the main journal on the crank.. subtract to find your main clearances. If it isnt in spec, dont install the crank, order new bearings. do the same for the rod bearings. too large a clearance will promote low oil pressure, bearing failure, engine knock... too little clearance will promote bearing failure, premature wear, oil pump failure, and possible engine seizure.
Standard main bearing clearance should be .0002" - .0009" with .0007" being average, and .0020 being the MAX clearance on a high mileage motor. ROD bearings should be .0008"-.0018" with .0013 being average. .00256 is the LIMIT MAXIMUM.

CP recommends bigger ring gaps than factory, DONT go by the factory ring gap specs for your pistons, OR piston to wall clearance. DID your machine shop KNOW to use a larger than factory piston to wall clearance? Use a dial bore gauge to check the size of your cylinder, then mic the piston's size, subtract to find difference. The actual wal clearance and ring gap is determined by CP's recommendation. call them or check online what they recommend for your application.

I assume you balanced your entire assembly together? CP pistons weigh different than factory pistons... and if not balanced your rotating assy will eat power, vibrate, and possibly come un-glued at high RPMS.

when installing studs or bolts that are to be torqued to a certain Ft.Lbs... be sure to lubricate them with engine oil otherwise you wont get an accurate torque reading. Dont use anything super-thick like assembly lube, or moly, it will change your torque readings. Speaking of moly (grey lubricant with teflon) dont get any of it on your bearings it will scratch them similar to what WD=40 can do.






Well sh!t Sasha...if you were a little apprehensive before...

I'm not even building a motor and this post just gets the hair on the back of my neck to stand.

Good luck with the build bud.

chunk
08-10-2005, 08:42 AM
Speaking of moly (grey lubricant with teflon) dont get any of it on your bearings it will scratch them similar to what WD=40 can do.



Moly lube = a molybdenum based lubricant, hence the name "Moly"

TS4l
08-15-2005, 11:22 AM
When you install the pistons/rods do it one at a time and torque it down to spec and then slowly rotate the crank, it should be smooth and fairly easy to turn. If it sticks or is hard to rotate then something is wrong. Check the cylinder walls to make sure the rings aren't scratching and if they are take it back out and figure out why.

Also it sounds weird but I message oil into the piston skirt, I was told by lots of engine builders to do this and the pistons will soak up some of the oil.

Make sure and keep everything clean, I would see if you can borrow an air compressor from someone and blow out all the oil gallies, and the ball bearings in the crank. I think keeping everything clean is a very important part of a good build.

Once you install the head don't turn the engine upside down, if you do make sure and check the HLA's to make sure they don't need to be re-bled. Also make check them all before installing the cams and if you have any doubt then bleed them.

Have patients, taking your time and following the specs and making sure you do everything right will keep you from having to do it again soon. Its a good learning experience so listen to what others have had success with and take that into consideration. And have fun! Assuming everything works out you'll have a really fast car soon!