SR20 Engine Rattle. Fresh built motor

[XxOLIVERxX]

hey guys. looking for some advice/opinion on what this probelm could be.

me and my buddy rebuilt a SR20DET Redtop for his s13 from pretty much scratch and now the engine is installed in the car and intermittently rattles its head off. im currently doing my mechanics apprenticeship and from what iv seen and heard in the past it sounds like it could be timing chain slap.

engine specs
S13 redtop block, stock pistons
new bearings rings
cometic gasket kit
DE head that was known working before installation. we removed the valves and replaced stem seals and reinstalled.
de cams and cam gears (checked against det items and the pulleys look the same etc. (cams and head were from the same engine and was running fine
reused oil pump(inspected and seemed fine)
reused timing chain(once again looked to be in good nick)

installed a brand new timing chain tensioner (revised S15 type) and the rattle seems to be less severe. im thinking along the lines of a slightly streched chain. (seemed fine upon inspection) cant really think of anything else that would create that kind of sound. the noise seems like its in the front of the engine.. but sounds echo around so not 100%.

now we all know that the SR timing cover/oil pump cant be changed out with the head/upper sump installed so the motor will have to come back out.

previously people have suggested the lifters could be noisy, removed re-bled and refitted twice doesn't seem to make any difference. the rattle seems to get louder when the engine/oil heats up. at idle on first start its almost silent then when you give it a bit of a rev it starts rattling and then gets worse and worse to the point we have to shut it off incase something gets damaged.

just wanted some confirmation that this is actually the problem before we pull stuff apart!

[jdm-specs]

Damn! You ran ur motor without the valve cover on? Thats gangster....mad proprs hahaha

Anyways, if the plastic timing chain guides were worn I can see it happening.... I dont if u replaced it or not.

If I were u I would see where the noise is coming from first before you take it back out...you can use a stethoscope....or put a long screw driver to your ear...so you dont have to run it without the valvecover and have oil everywhere.

If its from the front cover than its propbely the guides or course. ..if its from the pan...then I would check those bearings and bearing caps bolts with a torque wrench....you can try running it with no belts and a battery charger connected to see if its a loose bracket or not.....

But its just friendly advise...up to u...good luck

[Kingtal0n]

Sorry but that sounds like something in the bottom end. The way it knocks when you depression and then knocks again when levleing out is reminiscent of piston slap. But if you are using stock pistons you did not bore the engine, which leaves bearings.

It sounds a little too loud and consistent to be related to the timing chain. Its NOT the lifters or camshafts. You could fool with the timing equipment in the hopes that is the problem.

And I have heard a flywheel/pilot bushing/transmissions make that sort of problem noise. Not quite a rod knock type noise but rattling nontheless. feel the transmission or try stepping on the clutch to see if the noise stops.

[kkaleher]

Unfortunately i agree that does sound like its in the bottom end to me as well. Thats never fun. Why was it rebuilt? (Rod bearing I'd guess) and if so did you replace the rod? Assuming the engine was put back together properly too like bearing oiling holes and grooves all lined up and correct piston #s put back in their correct cylinder. I doubt that would make that noise tho. Have you cheked the oil to see if theres a fun glitter party going down? To me it sounds like you're pulling it back out and disassembling regaurdless. The cause of that noise should be rather easy to find on disassembly I'd think.

[SolTNtuz]

Take off the upper and lower timing chain guides and see if that works. I had an issue with my KA that sounded like the rattle of paint balls in an empty can. Runs quiet now.

[Davidna2fi]

Bottom end rod knock...

[codyace]

Originally Posted by SolTNtuz

Take off the upper and lower timing chain guides and see if that works. I had an issue with my KA that sounded like the rattle of paint balls in an empty can. Runs quiet now.

While I know your intentions were good with the advice, I can say it's very wrong at the same time with the SR20.

You can't just 'take the guides' off the lower end of an SR as they are integral with how the chain works. Now you can take the upper guide off (which this guy already has done as it's not there in the 2nd video) but only in the KA do you take both off.

[codyace]

I'd say that's rod knock for sure.

A quick/dirty way to test:
Pull that valve cover back on so you're not spraying oil everywhere. Disconnect power to coilpack 1, and then rev motor...sure the engine will be stumbly, but see if the knock goes away. If it doesn't, plug coilpack 1 back in, and then disconnect 2, and repeat.

When the sound goes away, or gets very very quiet, you'll know that is the cylinder to inspect.

However that noise is very very common...sounds like you'll be yanking her out and going over it all.