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View Full Version : Sr20det crank not spinning freely after build


Vicious Beaner!
11-25-2019, 11:19 AM
What's up guys . Got a sr20det built last year by a shop. Engine ran fan before stock but decided to build to get to 450 to 500 reliably with a gtx3076r . Did pistons, rods , new all ARP hardware. The whole 9. Tried to get it going last week with a tuner etc . Did the proper break in procedures and that crank wont really budge. Spins maybe a 1/4 turn by hand and then just stops. . Engine ran for 10 seconds and shut off. Drained the oil and no shavings . Undid the trans , starter etc and still hard to turn by hand with a 2 foot breaker bar. So yanked the engine out and having another shop take a look at what's wrong . Is it possible for that engine to be complete crap?
I'd appreciate any feed back or similar related issues.

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Turbosauce74
11-25-2019, 11:37 AM
Was the crank polished or machined? Sounds to me like your mains could be too tight of tolerance.

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Vicious Beaner!
11-25-2019, 11:49 AM
Was the crank polished or machined? Sounds to me like your mains could be too tight of tolerance.

Sent from my SM-G965W using TapatalkYea from my understanding builder did say it was machined and polished. That's what I was thinking aswell . Hopefully it isn't anything major. That would be a bummer

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PoorMans180SX
11-25-2019, 11:56 AM
Yep, sounds like the mains were too tight. If you're lucky it'll just require a polish on the crank and resetting the main clearance. If you're unlucky they did some wonky machining and the engine will need a line hone and a new crank.

Turbosauce74
11-25-2019, 12:19 PM
Yea from my understanding builder did say it was machined and polished. That's what I was thinking aswell . Hopefully it isn't anything major. That would be a bummer

Sent from my SM-N960U using TapatalkLuckily you might not need to pull too much apart, a bit of plastigauge and you could check each bearing individually. I'm assuming you didn't get the block line bored?

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brndck
11-25-2019, 02:40 PM
Pull the spark plugs and make sure the cylinders aren’t full of fuel.

I bought a car that the previous owner said wouldn’t run, turns out he replaced the injectors but there was an old oring stuck in the fuel rail causing raw fuel to fill cyl 2. It would crank about 2 revolutions then stop dead.

ultimateirving
11-26-2019, 11:34 AM
Pull the spark plugs and make sure the cylinders aren’t full of fuel.

I bought a car that the previous owner said wouldn’t run, turns out he replaced the injectors but there was an old oring stuck in the fuel rail causing raw fuel to fill cyl 2. It would crank about 2 revolutions then stop dead.

This shit happened on my car too. Started her up and she was idling then just died after about 15 seconds and wouldnt crank any more. Took off the fuel rail and fuel was everywhere.

jedi03
11-26-2019, 01:39 PM
if nothing in cylinders, check with bore o scope that nothing has contacted piston and see if spins freely, if doesn't check timing too before pulling motor apart

RalliartRsX
11-26-2019, 02:06 PM
1) Either the main clearances are too tight (which is why you ALWAYS spin the crank by hand once you bolt up the mains and after every conrod install)
2) Piston to valve contact

Confirm if they align honed when they rebuilt the engine if using stock main bolts. If using aftermarket make sure they align hone correctly and have them issue you the spec sheet before and after align hone. If they did it incorrectly, the engine will have to be torn down.

And make sure they also give you always the measurement bearing clearances and which bearings they used (mains and rod bearings)

11-26-2019, 03:01 PM
is someone seriously recommending plastigauge? lol
crank bearing clearances could have possibly been too tight. tear it apart and if it only ran for 10 sec. your crank could be ok. Get a new shop to redo the whole bottom end.

S14rebuild
11-26-2019, 04:16 PM
is someone seriously recommending plastigauge? lol
crank bearing clearances could have possibly been too tight. tear it apart and if it only ran for 10 sec. your crank could be ok. Get a new shop to redo the whole bottom end.

Whats wrong with plastigauge? Yes are there better tools to.check measurements?

But plastigauge is a very useful tool and many if not thousands of motors have been built using it and ran perfectly

jedi03
11-27-2019, 12:57 PM
there are just better ways of doing things...

brndck
11-27-2019, 02:24 PM
there are just better ways of doing things...

imo plastigauge is a great tool to use to make sure someone didn't put the decimal in the wrong spot when trying to use a dial caliper.

i'm still amazed at how many people can't properly use one, but claim to be engine builders. :duh:

RalliartRsX
11-27-2019, 02:55 PM
Nothing wrong with plastigauge for a DIY to double check.

However, youtube mechanics who have no idea how to use their $800 dial calipers need something to blame......

Vicious Beaner!
11-27-2019, 05:37 PM
Ended up taking it to another shop so they can tear it down and check everything .I have a feeling he didnt line hone since they were Arp main studs and or tight clearances. Just found out hes known for leaving tight clearances through another customer smh.

Vicious Beaner!
11-27-2019, 09:41 PM
Sooo look what I found guys . Head and cams are shot. Smh. Crank spins smoothly still after head is off. So it was the head all along https://uploads.tapatalk-cdn.com/20191128/e6fca1f74b12040d1688274e62411ed4.jpghttps://uploads.tapatalk-cdn.com/20191128/b3f81fa8d417ba97c8bee831445323e1.jpghttps://uploads.tapatalk-cdn.com/20191128/d609964a2741ad6d8103f5195b4a8aee.jpghttps://uploads.tapatalk-cdn.com/20191128/c17d95b572f5e204a3eccd6b7f0577b3.jpghttps://uploads.tapatalk-cdn.com/20191128/82cff825459374c0780cf11d3dc26afb.jpghttps://uploads.tapatalk-cdn.com/20191128/ecf73ab929f3f57d86e78b2531451878.jpg

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S14rebuild
11-27-2019, 10:59 PM
Holy fuk, after seeing that nightmare, id pull the bottom end apart and check EVERYTHING

Vicious Beaner!
11-27-2019, 11:33 PM
Oh bottom end coming apart forsure to get inspected. Damn it I'm deep into this sr20 already smh lol

Kingtal0n
11-30-2019, 09:55 AM
you would notice something like that during installation

which means those parts went in looking fine

which means they were ruined within that 10 second time frame

which means they were installed without any oil (my guess)

Turbosauce74
11-30-2019, 10:58 AM
is someone seriously recommending plastigauge? lol
crank bearing clearances could have possibly been too tight. tear it apart and if it only ran for 10 sec. your crank could be ok. Get a new shop to redo the whole bottom end.Boy do you look wrong now....

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Turbosauce74
11-30-2019, 11:01 AM
Sooo look what I found guys . Head and cams are shot. Smh. Crank spins smoothly still after head is off. So it was the head all along
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Glad to see the bottom end most likely survived, but yeah I'd be pulling it apart and checking every oil galley for shavings. What cams are those?

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RalliartRsX
11-30-2019, 11:29 AM
you would notice something like that during installation

which means those parts went in looking fine

which means they were ruined within that 10 second time frame

which means they were installed without any oil (my guess)

I am leaning this direction. However, the photo with the cam cracked right at the cam gear seems like the shop installed the cam caps with a 500lb torque wrench as it looks like a fracture vs a fatigue (no oil) failure.

brndck
11-30-2019, 07:42 PM
JEEZUS FUCK.
Dude that sucks.

Looks no oil pressure was getting to the head.
Why the cam cracked I don’t know, but FUCK.

Turbosauce74
11-30-2019, 07:45 PM
Possibility that the caps were over torqued or the cam shaft was bent. I had a shitty shop drop one of my cam shafts and bend it. Cam would install fine but tough to turn, ended up having to pay for a new set.

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RalliartRsX
11-30-2019, 07:52 PM
Cams are hardened (brittle). If they are dropped, they shatter, not bend lol

brndck
12-01-2019, 02:48 AM
Possibility that the caps were over torqued or the cam shaft was bent. I had a shitty shop drop one of my cam shafts and bend it. Cam would install fine but tough to turn, ended up having to pay for a new set.


On a KA or SR20 if you overtighten the cam caps, you’ll pull the threads out. Seen it quite a few times when people don’t pay attention to the part where it says INCH/pounds, not FOOT/pounds.

Also yeah I’ve never seen a cam bend. They crack.

crazyorigin
12-01-2019, 09:40 AM
Cams are hardened (brittle). If they are dropped, they shatter, not bend lol

Cams can certainly bend. The hardening on iron camshafts does make them brittle but as long as they are they will easily bend. The can chip or have a piece break off that is partially due to hardening and also partially due to the metal characteristics of iron. The hardening is also just case hardening, meaning roughly the outer .020" of their surface is much harder than the rest. They are not made of carbide...

jedi03
12-02-2019, 10:29 AM
I would reach out to the original shop and have them pay for fixing it...sry to see that...

nick_d_240sx
12-03-2019, 03:10 PM
Anytime an engine is rebuilt or the cams/cam gears or timing chain/belt has been removed, turn over the engine by hand multiple times to verify everything is spinning smoothly.

Sorry man.

Vicious Beaner!
12-03-2019, 08:59 PM
Yea engine is getting completely overhauled fellas/ladies . Had shavings in the pan. Reached out to the original builder and he is dodging me. Had to buy a new head , get it machined and of course tear had the engine tore down to fully inspect any further damage smh. Would it be right or wrong to put the shop out on blast with these pictures I have to save someone else's engine in the future?

brndck
12-04-2019, 09:34 AM
Would it be right or wrong to put the shop out on blast with these pictures I have to save someone else's engine in the future?

if they won't cover their work and their failures, absolutely put em on blast.

jedi03
12-04-2019, 10:23 AM
just don't do it if you think will be pursuing legally as the "slander" could come back and cause issues...

Kingtal0n
12-04-2019, 12:22 PM
I hate to mention this but
if any of that shaving materials got into the block, oil passages and so forth, it could be useless to try and rebuild it. One little bit of metal lodges into a bearing and you have the beginning of a 10k max miles engine with destined bearing failure in 1-3 years.

Not saying its impossible to clean up, but it kind of is for some engines.
Failures because of using blocks with metal grit floating around is a thing.

This is why I don't put big money (as a college student) into an engine. If I was going to rebuild an SR20 at this point I would try to find a tired old engine that still ran (with say 120psi) and perform a stock rebuild in my own place.

Never let a machine shop or anyone for that matter touch an engine in a way that you can't personally measure/inspect, and you will never be disappointed in the rebuild, because even if you screw it up you will learn something. Whereas letting a machine shop screw you over teaches you nothing except to avoid machine shops. Which you have not learned yet. So I suppose thats fine for now. Did you learn yet?
Come back in a couple years and tell us what you've learned about rebuilding sr20 engines.

brndck
12-04-2019, 01:10 PM
I hate to mention this but
if any of that shaving materials got into the block, oil passages and so forth, it could be useless to try and rebuild it. One little bit of metal lodges into a bearing and you have the beginning of a 10k max miles engine with destined bearing failure in 1-3 years.

Not saying its impossible to clean up, but it kind of is for some engines.
Failures because of using blocks with metal grit floating around is a thing.


ultrasonic cleaning is rad.

pulling the balls out of the crank to clean the internal passageways is a damn good idea too

RalliartRsX
12-04-2019, 01:31 PM
ultrasonic cleaning is rad.

pulling the balls out of the crank to clean the internal passageways is a damn good idea too

Yep. Not sure which machine shop King is using, but my machine spot is able to get just about every single miniscule of oil shavings from any foreign object debris

Also, they removed the balls on my crank and tapped them with an NPT fitting in order for them to easily be removed if I ever had to do a tear down again.

Easy peasy. Short block is 100% salvageable. It just needs a complete tear down, inspection, new bearings, proper clearances measured and go. Easy several hundred bucks and a 1-2 week worth of tear, cleaning, etc

I can tear down a SR block in less than 3 hours on a slow Sunday lol!

kyral
12-06-2019, 03:33 PM
Cams are hardened (brittle). If they are dropped, they shatter, not bend lol

this is not true. ive actually thrown a camshaft on to a concrete floor and it did not shatter

Turbosauce74
12-06-2019, 03:37 PM
this is not true. ive actually thrown a camshaft on to a concrete floor and it did not shatterYup, I'll agree that on average they do shatter, but they can bend. In reality the bend is probably a fracture tho.

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brndck
12-09-2019, 03:37 PM
this is not true. ive actually thrown a camshaft on to a concrete floor and it did not shatter

a prince Rupert's drop is hard as fuck, you can smack it with a hammer, till you barely flick the tail and the whole thing shatters.

[YT]/https://www.youtube.com/watch?v=6V2eCFsDkK0[YT]

cams are hardened and brittle.

can anyone show an example of a cam set up in a lathe or v-block showing excessive runout (bending)?

i'm genuinely curious to see an example.

Turbosauce74
12-09-2019, 03:40 PM
a prince Rupert's drop is hard as fuck, you can smack it with a hammer, till you barely flick the tail and the whole thing shatters.



[YT]/https://www.youtube.com/watch?v=6V2eCFsDkK0[YT]



cams are hardened and brittle.



can anyone show an example of a cam set up in a lathe or v-block showing excessive runout (bending)?



i'm genuinely curious to see an example.I could put it in the head and it won't spin, swap cams and it spins. I don't have any machinist tool to show run out unfortunately. It's on the list.

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TheRealSy90
12-09-2019, 06:27 PM
Roll the cam down the driveway on video, pretty easy to see its bent.

jedi03
12-10-2019, 10:07 AM
have seen in the past, pretty sure it can bend from the high heat and tolerances changing somewhere causing it to warp...but they do shatter super easy...I normally rotate them from the sprocket to spin them out and break the oil tension/suction from it, had one snap in half when doing so...

Kingtal0n
12-15-2019, 02:19 PM
I've heard from a friend that you can snap a cam in half, over your leg


I tried it once and it left a bruise. why do nissan people give me bad ideas



they definitely flex and bend a bit as you install them using FSM procedure.
A brittle materials can display a wide range of properties, and so can ductile. Some ductile materials will display a brittle failure when the conditions are right for it to happen, such as when the force is applied suddenly. It has to do with the crystal continuity of covalent bond angles within the material.
There is no clear defined border between the two types of materials, but rather a range of conditions for which either behaves one way or the other.
Also, In engineering textbooks for example, there are many ways to define the yield strength and stress property of the same material.

jedi03
12-16-2019, 11:41 AM
rofl at least wasn't like the can smash on the forehead! its amazing how things fail...I have a few small examples in my garage to help people understand what they may do depending on circumstances! failed rod, crushed ringland...super fun lol!

RalliartRsX
12-16-2019, 12:40 PM
So OP.

Machine shop gonna take care of you or what?? Gonna let us in on who it is??