7MGTE engine knock: need help

[psupra]

Hey everyone,

I just got a new motor put into my ma70, had the 7mge before and decided it was time to upgrade to a 7mgte. now that the motor is swapped its working beautifully expect that there's a knocking noise around the centre of the engine, it increases with the revs, which is kinda worrying. does anyone have suggestions as to what it might be?

thanks psupra

[Supra-Jim]

Silly question, but are there any dngs in the sump? Had a very similar thing happen with mine and turned out to be a ding in the sump.

[Shifty]

Motor's fucked mate, big end bearing.

Pull it out and rebuild it before you cause any more damage.

[fatboy13]

My 7M had a knock for around 6 or so months before i blew the HeadGasket, so depends on how bad the knock is i guess. I used to run a bit more oil and it didnt seem to make any difference.

My knock was from 2000 to 3500 rpm or so...

May not be fucked.... fingers crossed!

[psupra]

well i just topped up new oil the other day, plus the motor and the car both havent been driven for around 8 months. i put in a new metal head gasket and also got it sand blasted

[Jin~Jah]

knocking from a 7m is alwyas a bit worrying. Mine had rodknock pretty badly, although no spun bearings. One of the rod caps was loose (number 2), so it was wobbling around the crank, and also the piston joined to it looked like it had smacked the head a few times too.

it didn't knock when it was on boost beucase everything (pistons/rods etc) was being shoved down by the positive intake pressure

here is a short video for your viewing pleasure of what it was like in it's heyday (heyday being the period of time before the rod punched a hole through the block)

http://www.youtube.com/watch?v=JkcLnbOls1M

fresh 20/50 did make it quieten down for a short while, but the problem got worse and was just too much for the oil to mask.

[neal]

Ive got 2 7mgte with rod knock...you should be able to hear it clearly when you get under the car, obviously when its started. i wouldnt drive it untill i find out whats causing the knock. "You can cause severe rod and crank damage and cost you more to fix"

Check your harmonic balancer, they tend to make a knocking sound when loose.

[doobs]

knocking from a 7m is alwyas a bit worrying. Mine had rodknock pretty badly, although no spun bearings. One of the rod caps was loose (number 2), so it was wobbling around the crank, and also the piston joined to it looked like it had smacked the head a few times too...

That video sounds VERY bad... Knocking in any motor is no good , 7Ms are generally prone to it because of unrepaired oil leaks / bad turbos / ect, causing it to run low, and the owners dont check it until its too late...

There was a thread on supramania, listing everyone who has suffered rod knock, and 95% of them were low on oil when it happened...

psupra, I hope its not rod knock / spun bearing, a video would be helpful...
Seems like you've just put some effort into the motor, Im assuming you have just changed to a MHG because of a BHG? Did the oil and coolant mix? that could have damaged your bearings...

Cheers

[psupra]

I haven't checked for dings in the sump yet, but I will do so soon. Had a look at the harmonic balancer but it seems to be fitted pretty well/tight (couldn't establish that it was loose and the knocking sound doesn't seem to be coming from there). The turbo is still in good condition and I've been checking the oil levels regularly...no sign of oil leak or anything (also couldn't notice that the oil and coolant mixed).

Another interesting thing is that just after I swapped engines, the knocking sound was very noticable in neutral (low-end revs) and there was barely any oil left in the motor. After topping up 8L's of oil the knock kept increasing with rpm's (mid-range revs). And since today the knocking noise is very faint and only noticable at higher rpm's (high-end revs).

doobs,
when I swapped motors I thought I might as well go for a MHG, since my old 7M had a few BHGs and I wanted something a bit more durable and hassle free.

Anyway, I uploaded a video on youtube to give a better idea of what might be going on, I hope it helps: http://www.youtube.com/watch?v=UlOtAOO0mvY

Thanks again for helping me figure out whats going on everyone,

psupra

[Kedderz]

since it gets louder with rpm im going to say its rod knock sorry mate

edit - video confirms it,

[RA35GT]

Another interesting thing is that just after I swapped engines, the knocking sound was very noticable in neutral (low-end revs) and there was barely any oil left in the motor

Dood, if it was starved of oil, it woulda killed the bearings in very little time. At this point I'd be pulling the sump and checking the bearings.

Rudi

[Jin~Jah]

oh man that sucks to hear psupra

to me it sounds like rodknock, and chances are it probably is rod knock if it's hard to pinpoint where the sound is coming from.

do you still have your old motor? maybe for a temporary quick fix you could frankenstein the pair of them... although that depends largely on the condition of both.

whereabouts in NSW are you?

[psupra]

got rid of my old motor, was hopeless and at its end. im from maroubra jin