ProjectSQ

Driving home the other night my car would start to slow down even when giving it gas and in boost. I would have to down shift just to keep moving. When I came to a stop at the gas station it would stall out as soon as I clutched.

The engine is an sr20 that's mostly stock with exception to cp pistons (stock compression), arp head studs, apexi 1.1 head gasket, and acl race bearings. I was just coming up on the 500 mile oil change for engine break in.

https://www.youtube.com/watch?v=PC11...ature=youtu.be

Any and all help would be appreciated.

ixfxi

sounds like rod knock to me, or some other internal issues amigo

you better break it down and take a closer look before more damage occurs

silviaks2nr

sounds like somebody made a boo boo installing those bearings or you starved the motor of oil. Rod knock for sure.

ProjectSQ

Thank you for the insight. I am definitely waiting to do a rebus at this point. Bearings were all installed correctly by myself (doesn't ran much to most but judge if you must) I am in the military and will go on deployment soon enough and will rebuild her with the spare money. It's just strange to me that a newly rebuilt motor would have these problems.

Kingtal0n

many rebuilt sr20s wind up this way. And yet, everytime I mention these statistics along with the warning "do not attempt a rebuild. buy another long block" I am told otherwise.
As if, as if I dont know.


It isn't your fault; they are extremely sensitive engines. Both with respect to the spaces between parts, and the filthy air we breath. You should be building this engine in a clean room with a running HEPA filter, as if you are painting a car. And that is assuming you can actually get decent machine work done to it; which I want to say is the primary cause for failure to begin with. Something the owner has no control over, isn't that just perfect? You can be the best engine builder in the world and have it fall apart because the guy in the machine shop doesn't specialize in tight engines, and thinks that .0022" is close enough to .0014" for it to work.

Ill add you to the list I recently started keeping track
http://zilvia.net/f/showthread.php?t=535520
http://zilvia.net/f/showthread.php?t=569861
http://zilvia.net/f/showthread.php?p=5765974

KiLLeR2001

My SR was rebuilt in 2007, been running fine ever since as my daily driver. Has about 43,000 miles on it now. Had my friend's SR rebuilt last year, still running strong with no issues.

Guess we are the lucky ones.

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DJ 21o3

so one shouldn't try building the SR20 as their first ever engine machining project? Yay...lol owell, I will continue to double check tight clearances.

Sorry for your bad luck OP, everyone always says the SR is a very picky engine. Tear it apart and let us know what you find!

ixfxi

you have no fucking idea what youre talking about

DJ 21o3

Sadly I do think he is partly right... A lot of SR's seem to fail shortly after being rebuilt, and I have read a few post from a few notable engine builders on other SR forums about how they can be extremely finicky when getting rebuilt. I just have confidence that as long as my tolerances are checked, double checked, plastigauged for lolz, then remeasured yet again, mine will stay together.

OP, do you have any measurements from your rebuild? I would like to know what failed and possibly why.. Maybe tolerances were a little too off?

ixfxi

if a motor fails shortly after its been rebuilt, then it hasnt been rebuilt...

if you cant handle the job, then take it to a reputable machine shop that can.

you dont need a hepa filter to rebuild a motor, thats for sure

fatduece

#ohmygoodness. Im getting close to rebuilding my sr20 soon. This thread does not make me feel good. That hepa filter thing better be a joke.

ProjectSQ

Ok everyone let me start off by saying this isn't my first engine build. Though not to say I'm an experienced engine guru either. My problem is likely because the machine shop I had gone to for machining the crank aren't experienced with these motors and assured me 0.0025 clearances would be fine. I'm pretty sure I had looked it up at some point and seen a few other rebuilt sr's running this loose so at the time I didn't think anything of it.

I'm fairly certain this was my issue and I'll be sure to change my approach on the next rebuild. If anyone agrees please keep your negative comments to yourself and just post some insight. Maybe with enough gathered info we can repost this as a sticky for sr engine rebuilds, kind of a "do's and Dont's" list.

fatduece

What is the correct clearance 0.0014?

Kingtal0n

I left 85,000 words out of my post because nobody will read an 85,000 word post. So when you read it you take cliffs, its not the whole story. If you have questions like this one, simply ask. I will be happy to clarify with more words.

So here is the low-down on the filtration. normal air has millions of particulate per cubic unit. Million of particulate, everything from pollen to fungus, viruses, bacteria, dead sloughed cells, and more. Let that sink in. Its in the air you breath, the air your engine breaths, the air your dog breaths, you can not get away from it. Its been with you since birth. How does your body handle it? Well, you have millions of white blood cells patrolling your lungs looking for this stuff, they eat it up and most of them carry it up to be swallowed, riding the "mucous escalator" powered by the beating cilia that lines the epithelium of your respiratory tract. Swallowed debris normally becomes harmless once it hits the low PH of your stomach. Other defenses include nose hair and sharp turns (the sharp turn at the back of your throat is designed to free larger mass particles from the incoming air, there is a peyers patch, a congregation of lymphocytes, positioned perfectly to deal with those large threats)

How does an engine deal with that same threats? Air filters. Oil filters. And it is sealed up. Exactly like a body, we can relate such things as nose hairs to air filters. You might consider the spleen an oil filter, something you can live without yet it helps clear certain dead/dying cells from the blood. things that should not be there because they might cause problems.

Now consider stationary objects, anywhere in the world. You let anything sit still, check the top of your doors or fridge, and it will collect this debris. This pollen/fungal spores/dead hydrophobic fragments/etc will be inside your engine if you let it sit anywhere in the world, and the amount is directly related to the length of time your engine is exposed. to make matters worse, the hydrophobic film associated with oil that is certainly coating many surfaces of the inside of your open engine that you are building is perfect for trapping and holding these particulate debris. Millions of particulate are being trapped and held inside your "freshly rebuilt engine" per unit time, they will be there when you first turn the key.

An ounce of prevention: to avoid the nasty air we breath, build the engine in a sealed room with a running filter, just like painting a car. One truest component definition of high performance is attention to detail, tiny details, molecular details. You may find through searching that behind every true high performance engine build, there is some kind of protection from airborne debris.
random high perf. book snippet:


random googles (I am sure there are 1000000 results)
http://www.egmcartech.com/2013/08/02...our-engineers/
http://www.rdpmotorsport.com/engines.aspx
http://www.pettitracing.com/pettit-engines/
http://books.google.com/books?id=zff...20room&f=false


You can build an engine in your garage, sure. Do your best to keep it clean of course, we don't all have filters setup. But ideally, with an engine like the sr20det, you want a filter going. It depends heavily what you are building, what the intended application is.
I am sure the GT-R engine's are assembled in a clean room. You try to tell those guys it isn't necessary, they don't know what they are talking about.

"Watch how the Nissan GT-R's engine has been assembled by four engineers ... which is assembled in a hermetically sealed “clean room,” ""

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5.3/4l80e/turbo 240sx playthrough:
https://tinyurl.com/turbo240

ixfxi

Sorry, for a second I thought this was NAGTROC

The SR20DET is not a hand built motor. I dont see why this level of sophistication would be mentioned. In the end, you always rant like some gaddamn lunatic...

Here is what you do:
Step 1) Get an FSM
Step 2) Follow the directions in the FSM
Step 3) Use good quality parts

My friend busted his cherry building his first motor (a 100% stock SR20DET build) using all OEM components: pistons, rods, bearings, etc... in his fucking garage. Yes, cleanliness matters but where in the FSM does it say we need a fucking CLEAN ROOM. We're not assembling mechanical hard drives here.

Read the FSM, Spicoli

LEARN IT...
KNOW IT...
LIVE IT...

KiLLeR2001

This guy thinks you can only successfully build an SR in a sealed room with a full hazmat suit on like they do with the Intel microprocessors, lmao.

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silviasandbeer

check my sig/quote lol

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IG: @3SoulXX
"I never fucked a ten. But one night, i fucked five twos ”

ixfxi

im not even discrediting the guy, i just think a lot of his posts are....


nevermind, he's fucking out of his mind.

DJ 21o3

His post are usually spot on, but he takes the long way to get to his destination.

KendallH

Pretty sure he's an aspie or something

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DJ 21o3

I am assuming you mean inches with your crank clearances. The limit in the FSM states 0.05mm, or .0020 in. Sounds like that was the killer, but let us know what you find. I know I measured mine before and believed I was clear of the limit (0.035 mm) but I will be double checking all of mine yet again before final assembly.

Hopefully we can create a thread that is a "Do and Don't" list for future engine builders other than simply stating "USE THE FSM", even though the FSM should end up with a solid engine.

pacotaco345

Lol I assembled my SR in one night half drunk in my friend's garage that had dogs running around everywhere. Knock on wood its still running great. I did take it to a machine shop that specializes in motorcycle/japanese engines though

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OBEEWON

I like you.
I only read the first and last sentences of your posts, but they are the best.

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Matej

Engines are really crude and primitive technology with pretty high tolerances. It is likely that a rebuild will not last as long as a motor coming directly from the factory, but that may be attributed to countless other factors besides air purity of the workplace. When it comes to doing a garage rebuild, that is probably the last of the things that will affect how long the motor will last.

ProjectSQ

Alright let's leave the guy alone. I mean Clair Patterson was a clean freak but if it wasn't for him we would still be using lead supplemented gasoline and poisoning ourselves. (Thank you The Cosmos)

On the topic of clearances I'm pretty certain that the gap was the issue. I was referring to inches so 0.0025" and 0.0005 beyond the fsm's limit. Also contributing the possibility the bearings wore in slightly increasing that clearance and the shitty oil that was ready for a change. (Like I said I was right around the 500 mile engine break in oil change). all that together could have been the cause and I hope that's all it is.

I agree we should gather up some silly facts for those wanting to learn. For example I will never use the tube of RTV that came with my oem gasket set. It cured way too fast and became "crumbly" where as the black RTV from advance or oreillys works great. Also with metal head gaskets be sure to get copper gasket adhesive (I think that's what it's called). Always spend money on new oem (or equal quality) oil pumps, water pumps, timing chains, and timing chain tensioners. BEFORE TRYING TO BUY SOME SILLY PERFORMANCE PART! (No point in upgrading when your engine's foundation is weak). I can't think of anything else.

Also I can't stress enough the use of a proper knock sensor, a functioning maf, and a good tps. Without knowing these are all good you will spend WAY too much time trouble shooting for no reason.

Kingtal0n

If you take some time to think about it, what I am suggesting is simply taping up your work area with a clean tarp (as if you intent to paint), which is cheap, and including one or two box fans with $13 home depot filters strapped to the side, or on the vacuum side where there is no fan.

how was it you put it, "people that skimp on these little things shock me" ?
what shocks me is you can say something like "the sr20det is not a hand built motor" and get away with it. What are you using to build yours?

DJ 21o3

I am building my SR20 in my college class. They are used to small block chevy and ford engines, so my teacher was impressed when I explained how anal Nissan was with their bearing and piston grades. lol

Regardless of what engine it is and what it came out of, it all comes down to clearances. Who cares if you are in a sealed chamber running a HEPA filter. If your clearances are wrong, the engine will probably fail.

DJ 21o3

Did you change the oil at all after its first fire up or did you actually go 500 miles on the same oil before first fire?

Also not really relevant to the rod knock but what was your break in procedure? Run it hard or baby it?

ixfxi

I dont have an SR20DET. Doesnt anyone remember?

Broadfield helped me install a 1LR-GUE in my S13.

Standard

This is what I was thinking, I was always told to change the oil and filter after the first 30 minutes of run time, then again after 500 miles. Bearing clearances was probably the real issue though.

Good question too though, I've heard not to baby a new engine, but to beat on it a bit right away