Today i just heard a weird pop/backfire noise coming from my built d16z6 vitara. i have like 3500miles on it already. it has 75.5 mm vitara pistons/npr rings/acl bearings/ new seals/oil pump/head rebuild/etc. i also dremeled the main gridle cap/and some parts on the block and brought it to a shop after it was bored and re checked if the clearance would be okay. i grind and they said that the clearance is good. at least a small braze rod distance away in the girdle and the block. eagle h beam rods i have.
yesterday i also added a blox velocitcy stack/intake filter to the car.
Today im concerned about the pop sound. ive had a experience with a backfire/pop sound from the air intake before due to a retarded cam gear 1 tooth off ive bought an engine from. but this engine is not off its all aligned.

when i revved my car in a parking lot i thought it was that sort of noise. from the inside of the cabin.
okay i poped the hood and re reved it a couple of times, ive heard the noise, but cant exactly pin point where exactly the noise was comming from.
i reved about 2k to 4k open/close/throttle. and noise in between revs i heard the pop noise sounds like a loud knock sound?

WTF.... its more a knock sound than a pop/backfire sound. i thought it was maybe something loose since i have solid mounts, but would anything cause that??? exhaust header donut gasket? engine mount it sounded like a loud knock kick from the intake manifold side or some sort? a solenoid??? idk.
im worried. i spent alot of money to this supposedly cheap build. i took a while to build this motor.
im concerned and don't got time to check.
is it a bearing failure? or just some something major i don't have time for swaps/ rebuilds anymore.
i tried to replicate the sound for a while but after like 3 to 4 times ive heard the weird sound i couldn't seem to make the noise anymore when i try to rev it. i couldn't .
my oil pressure seems fine and okay.

what caused that sound??
do vitaras 75.5mm with eagle h beam rods make that sound?
did i spin a bearing or is it like fuel related?
i don't got time to check yet.
what could be the cause of the weird knock.

 

Whats the bearing clearences, how much oil pressure, and does it obly happen when the engine is cold/hot?

Try and get a video of it.

I know my engine sorta creeps me out when its cold from piston slap, not used to forged slugs with large p2w clearance for boost. Once its warm is quiet

 

morning i comp tested about 150psi across the board? 1-2-3-4

sucks today it still had very hard time starting. the thing i did was used my old cap/rotor,ignition wires. from my old motor but looks old and slightly same to the one in my rebuild motor. the thing i changed where the spark plugs brand new. i started it it started up. i i put the old air box intake back and it started better. but still rough idle with up and down revving. and seems to die out. the fuel pressure is about 40psi fuel filter/ and fuel rail. then i heard a loud tick like a noise something banging against the block intake manifold areas.
okay i have a vx motor on the side. i thought that the IAC valve was causing the very jumpy kill throttle and sounded like it was choking air or too much air.
when i put the oem box intake on with the VX IAC valve it seemed to run slightly better but still run rough. but also the VX iac valve diffrent mount but mounted okay. it has a solenoid inside the IAC VALVE i thought its like a loud solenoid sound or something.

i reset the ECU and restarted same rough idle and weird i have to give it gas to let it run. it idle but roughly.
i begin to hear the loud tick/knock like sound back/block intake manifold areas. i just let it idle and run. it makes the loud knock tick noise. im worried it don't make that noise before. the noise is like a ratchet hitting at the back of the intake manifold or block. the noise came worse loud when slightly reved or at idle.



my bearing clearances are .002 .0015 around there rod/main std size. i ran 5w30 and supposed to change the filter/oil when next weekend but plan turn out something else. supposed to change to 10w40 oil but now this problem? whats the knock noise.

i removed the engine oil pan/gasket
checked if the rods or anything where loose.
the rods had some play side to side. but i remembered when i assembled it had some play i cant do anything about side to side . feeler gauged and it was still within specs.
i didn't check the endplay again under the vehicle i don't have tools.

the cyl/bore looked the same as before when i rebuild the motor etc.
the engine oil is very old black/brown, thin. oil pressure when running where like around 40 psi etc.
i saw some sparkly dirty in the oil. could that be some brake in stuff?


F**k my head is twisted i don't know where to start to check what cause the stupid loud like a ratchet is hitting the metal part of the manifold block area?

 

Sparkly = not good. H beam rods can sometimes end up wider than the factory rods enough that they can contact the block as they come around. To be honest I have also heard this same type of sound once, when the pistons on an engine protruded out past the deck of the block by .020". My advice to you is take the head back off and the pan off. You should be able to see some indication of your problem. Its the only way to know for certain.

 

Yea take the pan off and look. U might want to leakdown test first to make sure tge valves are good so u dont have to worry about the head

 

Sparkly=uhoh. You shouldnt have any metal dust after 1000-1500 miles from the engine breaking in.

I woukd inspect everything for any signs of contact. I know you said you clearanced the block but maybe there wasnt enough room somewhere.

 

could the metal dust be extra dust from the places ive grind such as the girdle/ block i had to notch it. but the noise is killing me. can ignition make those noises? the cap/rotor looks messed up. but i only changed the spark plugs and now only cylinder #2 & #3 spark plugs are fouled. the 1&4 cyl spark plugs are not?
should i fix ignition or something or find why spark plugs are fouled b4 starting the engine again?


but if i cleared the block why would.

 

Dude just take the thing apart and look at it. You will know right away and can get on track to fixing it. Speculation is just going to mean u have a car that makes noises for a longer period of time

 

are these pistons for d16z6 worth the money ? and does it make a crazy difference in power/rev?

 

I'm suprized noone asked if the ecu was stock or not! So.. is the ecu stock or? What's the a/f look like?

 

Hate to be the bearer of bad news, but from what you're describing it sounds like you have the beginnings of a bearing failure... =/

 

the ECU is stock P28 d16z6 manual, but i had to convert the 5 wire o2 sensor to the 4 wire o2 sensor. i took off some wires de pin and pinned in a o2 harness conversion harness with the 4 wire o2 connectors. i followed the instructions on how to rewire the sensor.

 

which is really easy to see when you take the rod cap off!

what were your bearing tolerences? i hope nothing much under.0015"

 

my bearing clearances where like all close to .002 rod clearance
and my mains where close to .0015.

ok do i need to take the mains to remove the rod cap? and will the crank come off while its in the car?

 

Post a vid of the noise. It would be much easier to diagnose with.

 

no u dont have to mess with the mains at all. just the pan, oil pickup and windage tray come off. you can get at all the rods by rotating the engine over. a vid of the noise, compression and leakdown test are all a good idea before you tear into it. good luck hope its nothing major

 

okay i didn't have time to check it out yet? take off any bearing or something.
but what i did so far i just took off the oil pan/transmission cover.

i rotated the crank and inspected the oil pan. the engine oil pan don't have any big chunks of flakes or so, i see mini bronze like like salt or smaller on the bottom of the oil pan. like bronze anti seize almost the same? the oil is dark dirty.
i was thinking maybe it was from the oil pan bolts because i put some copper anti sieze on the bolts when i rebuild the motor. Then i saw some little chunks silver but not much mini flakes. i presed the flakesand seems soft or something dissolve like.

is this bearing material. i also inspected the rod bearing endplay the bearing endplay seems tight only cylinder number 4?

why number 4 only tight endplay i used the feeler gauge most of all are .0015 endplay but number 4 have .014 endplay and feels tighter then cyl/ 1,2,3, and 4???


what could of caused the spin bearing??

also a week be4 i spun the bearing i had a code 22? vtec oil pressure switch?
and i also have code CEL 15 ignition ouput signal?

da heck cause that? i felt i lost power at 4th gear? about 3-4k 80-90 mph? check engine comes on? but i turn off and restarted motor light goes off?




what caused the light to go on? and is this the casue of the spin bearing? i don't have any oil pressure light on?

 

Bronze dust/salt looking bits=bearing material.

Vtec pressure switch code probably cause garbage from the bearing being chewed up is clogging the vtec screen thing. Ignition code is probably unrelated.

Obd1 doesnt store codes so itll wipe out the codes till it detects it again.


Also after grinding on the block you should have cleaned it all. Any contamination be it grinding dust, diet, or even hair can cause problems during assembly.

Stop driving it, dont even start it up. Drop the oil pan and remove the rod caps. You may have already destroyed your crankshaft if a bearing is spun

 

Agreed 100%. And remember, you don't want to waste your time trying to grind down a Honda crankshaft for oversized bearings. I can pretty well promise you that if you've spun a bearing, the crank is toast.

 

bronze bits crank bearings, so the crank is toast. how about the block/head etc material? if the vtec code CEL is caused by bearing material or bits is the head etc is savable? or i should dump the motor F**k i spent alot on this motor
i didn't have the time to tare it apart again. or check it.
do u think its possible to save the remaining parts etc?

 

It's going to depend mainly on how long you drove the vehicle after the metal particulate matter started to circulate through the oiling system. Those metal particles are highly abrasive and can cause damage to camshaft & journals, oil pump gears, rocker assemblies, cylinder walls & pistons, etc. Basically any components that are metal-to-metal that rely on oil for direct lubrication will be adversely affected by the bearing material circulating through the system for any length of time.

Its possible you will be able to salvage much of the components, but you will not know for sure until tear-down and inspection.

 

I put 300 miles babying a rod knock before it wore paper thin and had no damage to the cylinder head, camshafts, or anything besides the crank and rod (dunno how well the oil pump fared) ymmv but I havent heard of anyone trashing a head by bearing failure.

Good oil filters help.

Anyways, crank is toast and that rod may be trashed as well depending on how bad it spun.

I wouldnt know about damage to things like the cylinder walls since I overbored it to 81.5 during the rebuild

 

did u end up rebuilding the engine you spin the bearing on?
how manny rods did you replace bearings did u spin?
if i spin only 1 rod bearing do i replace all rods or can i just replace the 1 particular rod? are the rods usually reusable after spinning it?

 

Had to replace the crankshaft. The rod was garbage, no way in hell could it be reused.
I replaced the rods and pistons with new forged pieces, all new oem bearings, new everything. Basically replaced everything except the block, head, and a few sensors, etc.

 

BUMP help......


Ok i tore apart the motor heres what ive found.
i did compression test
i had all 150 psi through number 1-2-3-4 cylinders.
i did leak down test
i had
15% cyl 1, 5-10% cylinder 2, 10% cylinder 3 and 10% cylinder 4? they are all within the Green percentage of my leak down gauge tester.
ive heard some air noise

i checked the valve lash play with a feeler gauge. they where all the same specs about 3k miles ago since ive rebuilt the motor.
ive removed the VTEC-solenoid. found small metal curled up shavings like 3 little pieces or so.


i removed all main bearing gridle/cap. looks okay? bearings seems nice. i see a line slightly but no deep scoring grooves with my fingernail that would hook up too. seems normal even ware. assuming its okay i used the ACL bearing the colored copper seems slightly there or gone.

ive checked rod endplay number 4 cylinder seems stiffer side/side flywheel to crank endplay. compared to the 3,2,and 1 cylinders.
3,2,and 1 cylinders rod endplay side to side seems to have more side to side endplay.


inspected rod bearings seems worn no notice of metal particles or shavings or deep scoring in my crankshafts journals? also no coloring in the Eagle H beam rods? but the copper ACL coating seems to be broken in i don't see the protecting look as if it came out of the box as well as the main bearings.
but comparing to the mains the rods seem more broken.
the rebuild machinist told me before the ACL usually wore off if broken in?


WTF????

please help me i don't know what would cause the weird no start condition, engine knocking sound rough idles etc????