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[HELP!] My Engine is "moving" - Mounts not obviously damaged.

Oosh

By Oosh,
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Oosh Veteran

Oosh

Posted
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EDIT: Now that I've had a better look the mounts DO have some damage, see post #8.

Okay, so basically my radiator died after meeting with my fan, I've given the rad a good shove and can't see anyway it fell in to fan, and the fan itself is secure, so in my mind that leaves engine movement as a likely culprit. Also the major damage is on the drivers side of the rad, which is consistant with the direction the engine tries to move.

Now I've been under the car and the mounts aren't obviously split, so I'm at a bit of a loose end, there's no point my replacing the radiator til i know what's going on as I'll only munch another one... I've considered converting to thermofans but that doesn't

solve the root cause of this problem.

Any ideas on it, and ways to test the mounts, would be much appreciated.

Cheers.

Oosh Veteran

Oosh

Posted
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I had the same problem.  Ended up being the viscous fan hub was shot and loose.
I yanked on it pretty hard and couldn't get the thing to budge even a little bit, how would you go about testing that?
Oosh Veteran

Oosh

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I yanked on it pretty hard and couldn't get the thing to budge even a little bit, how would you go about testing that?
Been giving this some thought, the fan's viscous coupling only engages when it gets warm enough yes? So i need to get it hot and then see if it wobbles about, I figure i can slap it in the oven to do this, but at what temperature, 70-80 C ?
blind_elk Grand Master

blind_elk

Posted
Posted
Now I've been under the car and the mounts aren't obviously split...
Try jacking the engine. Use a block of wood between the jack and the sump, and GENTLY lift the engine. You should be able to see the engine lifting off the engine mounts if they are broken.

But I wouldn't expect that the engine could move forwards enough to allow the fan to collide with the radiator. That would mean the gearbox mount was knackered as well.

Oosh Veteran

Oosh

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Try jacking the engine. Use a block of wood between the jack and the sump, and GENTLY lift the engine. You should be able to see the engine lifting off the engine mounts if they are broken.

But I wouldn't expect that the engine could move forwards enough to allow the fan to collide with the radiator. That would mean the gearbox mount was knackered as well.

I did jack up slightly from where the engine and bell hosing mate, the engine moved a BIT then the car started to rise too, but i'll try it at the sump with some wood too (it's dented anyways).
Oosh Veteran

Oosh

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Okay, lifted the car up by the sump (found a paver exactly right size/shape) and there's definately some damage to the engine mounts, passenger side in particular. But, are they bad enough to need replacing? They certainly don't look like they could allow the type of movement necessary in this case.

I've attached pictures of the damaged rad & the engine mounts.

The gearbox mounts are a bit "crazed", in that dry rubber type way, but appear to be solid. I need to look over them better tonight if i get the chance.

Now on to the fan, since my rad is completely useless i can't safely get the car up to temp to test it, so after i cooked tea i slapped the fan in the oven @ ~100C. However, I still couldn't get the hub to bend any...

blind_elk Grand Master

blind_elk

Posted
Posted

In DrvrFrnt.jpg, it looks like the rubber is separating from the metal. If that's the case, then the mount is ROOOTTED. Time to replace (both of them would be my recommendation).

As for the fan, I think the heat causes the viscous clutch to allow the fan to "free-wheel" at higher rpms. How are the blades? Is it possible they moved forwards. You didn't hit some water or something did you?

SteveL Mentor

SteveL

Posted
Posted

There's does appear to be some tearing of the rubber. You should also check the rear (gearbox) mount and the gearbox crossmember bolts/rubbers. I'm not sure about GTSt's, but in earlier designs the rear mount played a part in limiting forward movement of the engine/gb assembly. On the Z-car I added a restraining wire cable arrangement to 'hard' limit forward movement under heavy braking.

Oosh Veteran

Oosh

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Engine mounts, I'll be replacing these for sure, now i have it in my head that RB series mounts are common across the range, so i could use RB30 items? I know Rowdy32's RB20 ones, including the bracket, bolted up to the side of his RB26 and dropped back in to his GTST no worries...

Also, can i realistically replace these WITHOUT removing the whole engine, ideally without even needing a hoist, maybe lifting the engine up by the sump like i did to get those shots, or am i playing with myself?

Gearbox mounts, I will have to have a better look at them, but if i remember correctly they look something like this

      CHASSIS

___   ______   ___

  | |  __  | |

  |_|R|  |R|_|

_______|  |_______

     GEARBOX

Side-on, with R="rubber bits", so it would be arresting front-back movement, that cable setup might be a good idea (for my piece of mind if nothing else).

Fan, i still can't see how it's getting out of shape, but then I'm not in a position to apply the sort of forces rotating it at it's usual few thousand RPM. It's not overtly damaged, and nothing came up and hit it, water or otherwise. All of that said i still don't trust it.

Bl4cK32 Grand Master

Bl4cK32

Posted
Posted

Ive got a genuine nissan drivers side engine mount here at my place somewhere here u can have for cheaper than i bought it for.

when i pulled out my rb20det, the engine mount rubbers were shagged, so i bought both sides to replace em. Drivers side was impossible to get out, so we left it in, and replaced the passenger side one that was stuffed.

It pulled the metal away from the rubber (and the stud with it) like yours, meaning your motor is just resting on the passenger mount :) Take it easy till you fix it....

Pm me if you want the drivers side mount.

Id agree with the gearbox mount, as mine was also stuffed when i pulled the box out with the motor. I replaced it with a urethane mission mount, but i must admit it does add some vibrations to the ride....stick with std, or Nismo ones if you must upgrade.

Oosh Veteran

Oosh

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Thanks Bl4cK32, i may well be in touch, could you tell me where you got them so i can price up the others? I've been on Nengun and can get Nismo mounts, 2x engine & 1x gearbox, for ~$315 (+GST) delivered.

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