trainwreck517

iTrader: (1)

So I got my fresh rebuilt engine in, got it fired up first try, after priming the oil system of course, but when I had the engine running, it was making a weird, semi loud clunking noise coming from the main pully area.

I have ran the engine for a few seconds with out the belts so that only the main shaft spins, and the engine is still making the noise, so its not the water pump, pump etc.

I have no idea what it could be. I'am stumped.
"
Thinking maybe a the oil pump is bad? I had 80psi at idle 1k rpms.

Any one have any suggestions or ideas??

Thanks.

trainwreck517

iTrader: (1)

Okay, things done so far:

Took apart the front cover, took out and inspected the oil pump. Oil pump, bearins, counter weight were all fine with no signs of scraping, wear.

Put everything back together with same noise present. Noise is coming from front of engine, using a estetoscope it was stronger at the front main pully, and weaker as you went to the front housing and weaker at the rear housing.

Anyone have any suggestions?

Just a knocking noise that that is consistant with the rpms of the engine, faster rpm faster knocking.

Has anyone ever heard this before? Or any ideas what it could be?

I talked to the engine builder, and he has no idea what it could be. The chain is brand new from mazda, and oil pump looks good.

So any ideas or suggestion?

RX-7 From Heaven

iTrader: (4)

i'm the one that built the engine guys, and everything was done perfectly. we took apart the front cover area yesterday as he said above, and we thought it was the oil pump, but we don't think it is any more. it's a little klatting noise that comes from as he said the front cover area. please help fast....
-erik

viperkiller7

iTrader: (11)

two things...

did you check the endpaly?

are all the bearings and thrust plates on? and correctly

ok one more thing... did the spacer get put in crooked sometimes theyget caught on the bearing below it..

just a few things to check..

RX-7 From Heaven

iTrader: (4)

the bearings and thrust plates are all good, the endplay was good, and the spacer is on perfectly. we thought it might be one of those things or the oil pump yesterday, but we took apart the front cover and all of it's components yesterday and we didn't find anything, so we don't think it's any of those. this engine was in my own car before, and it had a fresh rebuild 800 miles on it before i decided to take it apart and give it a rebuild myself to insure everything. when it was in my car, there was no noise like that, so this is something new. thanks for the help so far dude....
-erik

Wargasm

I had an engine that made that noise, and it turned out that one of the main bearings had spun. Check the oil for fine copper dust in it.

RX-7 From Heaven

iTrader: (4)

hmm. i was actually thinking that it might be the main bearing. you think it could be that? we'll take a look the next time we take it apart, but we wouldn't want to take it apart again and put it together again and find out that we need to take it apart yet another time, haha. we'll definitely take a look at that though, thanks. any other suggestions guys?

GoodfellaFD3S

iTrader: (213)

How did you verify that the bearings were 'good'? Also, how did you check the endplay, and to what spec?

RX-7 From Heaven

iTrader: (4)

the bearings only had about 800 miles on them, and they were checked and thoroughly for any wear. the endplay was checked with a dial indicator and was within spec. would the engine make that noise if let's say the endplay was somewhat messed up? may i remind everyone again that the noise does not come from the irons or the housings; it comes from the front cover, and around the main pulley.....
-erik

trainwreck517

iTrader: (1)

Okay, other things I noticed today.

The noise is diffenilty quiter today then was yesterday. The noise seems to disapear if reved over 2.5k rpm.

Checked compression, constant 86psi on the front on all faces, constant 93psi on faces on the rear rotor.

There are 0 miles on the motor, with about 8 min of total run time. I'am afraid to leave it running risking damaging the housings, rotors... etc.

RX-7 From Heaven

iTrader: (4)

assuming that let's say i somehow fucked up on the endplay, would the car make that noise if the endplay was messed up? also, keep in mind that the noise stops over 2-3krpms. all help is greatly appreciated guys....
-erik

supraturbo1987

iTrader: (4)

83psi for a rebuilt? Maybe I am nuts, but isn't that semi-low?

Trev

trainwreck517

iTrader: (1)

Keep in mind the engine has zero miles, with used housing. Compression should build up to the 110+psi range once the engine is fully broken ~3k miles.

RX7 RAGE

iTrader: (22)

Do you have a streetport?

GoodfellaFD3S

iTrader: (213)

Any smoke out the back? What kind of vacuum at what idle rpm? When you free rev it at idle, does it feel smooth at low rpms or choppy?

Turblown

iTrader: (12)

I've never experience a noise resulting from endplay being out of spec, and I've seen some crazy amounts of endplay...

Hate to say it, but only you guys are going to be able to figure this out. Sounds to me like you guys need to look harder at the parts.. Its not always going to smack you in the face and tell you whats wrong...

villision 1revin7

That is what my motor sounded like when I spun a bearing. Stick a magnet up in the oil pan to see if you get any copper like shavings.

RX-7 From Heaven

iTrader: (4)

when your motor had that problem, did the noise go away after 2-3krpms? i'm thinking that's the only thing that could be the problem, the front main bearing is somehow spinning or out of spec or something.....
-erik

villision 1revin7

I don't know I immediately shut it off when I herd the noise. I put a magnet in the oil pan and their was copper flakes. If you spin a bearing it can destroy a lot of ****.

GoodfellaFD3S

iTrader: (213)

.

trainwreck517

iTrader: (1)

Little bit of blue smoke at start up, but clears up after about 1 min of idling.

Idle is bit rough when cold, but once warmed up idles around 900rpms at about 16in Hg.

There is also something wrong electrically, as I found out friday when driving it for the first time. Anything over under 10in Hg while driving and the car will just "pop pop pop" and hesistate with no power.. need to drive in vac between 20in Hg - 10in Hg. Tested the coil packs and seems as though maybe the leading coil pack is bad. Will be taking it and testing it with inducatance meter at work to see if it is in spec.

Drove it about 10 miles from my friend house, to my house with no major problems, only that hesistation.

Noise was still there when I got home, with no signs of being louder or quieter.

Will update once I got this hesistation issue worked out.

trainwreck517

iTrader: (1)

Yes, the engine is street ported.

RotaryResurrection

iTrader: (8)

Sounds like it's in limp mode...thus when you try to apply throttle it bucks and stops until you let off. You should have an accompanying CEL, and most likely a TPS, OMP, CAS, or knock sensor code.

You sure that the trigger wheel is not hitting something on the front cover?

A spun bearing will result in a pretty quick loss of compression (down in the 70's or below) due to the sides of the rotor rubbing the iron and chewing off the side/corner seals. It will also be a rod-knock type internal sound between 2500 and 3000rpm in most cases.

The only way to get a spun bearing on a new motor with no drive time would be to run it dry of oil...I have seen it happen once where the oilpump drive sprocket key slipped out the back during assembly and once the oil pump primed, the shaft slipped and the pump stopped turning. Motor lasted about 20 seconds and locked up dead.

Does it happen when you turn it over by hand?

You've already checked things out in the front cover and eliminated all that. IF you can't find the cause externally, then I would just run it for what it is. Every once in a while I happen upon a similar mysterious issue, but if I go through everything once or twice more and can't find it, and I can't find any affect that it is having, then I just let it ride because it can't be much at all.

trainwreck517

iTrader: (1)

Don't feel anything when turning it over by hand.

Check the engine codes, and knock sensor came up. Not sure it the knock sensor is bad, or if it just being triggered by the knocking noise. Going to un screw it and see how it runs then.

supraturbo1987

iTrader: (4)

my suggestion is not to unscrew the knock sensor and try running it. First, clear the codes in the system. I know with my supra, if i got a KS code, it would run limp...and once in a while, the KS code would be tripped somehow, and I needed to give it a good clearing, or else it was always in limp mode...

so, clear the codes first...then try it. i wouldn't unscrew the KS, just unplug it...a lot easier.

Trev