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68Datsun510

VG30 crank pulley "wobble"

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Hey all, long story short I have had a EFI VG30E from an 87 300ZX in my car since August. Among some teething issues, is a mysterious metallic sound on cold starts only, accompanied with what can only be described as a wobbling crank pulley. Bolt is to spec, all woodruff keys were new, etc. 

 

Not terribly easy to view the tiny amount of runout, but heres the noise at least. 

 

Anyone else ever experience this?

 

 

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The VG30 was used in the Mercury Villager van and it had problems with the nose snapping off the crank. They went to a larger diameter snout. 

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Cody, that motor don't sound too good...

 

Sounds like a low oil pressure rod knock, or a bad hydraulic lifter (did they use hydraulic lifters?). Either way, it doesn't sound good.

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Dan sure loves that 1900 you sold him. I bet you wish you had it back right about now.

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Im not gonna admit defeat that easily...lol Dan had the connections and money to get that engine where it needed to be. Could I have done the same with the money spent on this engine? Probably... But I am still having fun with it, completely changed how the car drives, all that torque! LOL 

 

The noise isn't (at least i THINK) a rod, as is wouldn't go away once that warms up. And i have thrashed on it quite a bit, kinda need to to feel more confident with it over time. I doubt it will ever be as durable as that 1900 though lol Gonna pull the crank pulley and check the keyway and everything next weekend... Hopefully its just something dumb.... The ticking later in the video is just the injectors. 

 

It sure does sound nice though...lol

 

(freezing cold weather, not head gasket steam)

 

Edited by 68Datsun510

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4 hours ago, Stoffregen Motorsports said:

Cody, that motor don't sound too good...

 

Sounds like a low oil pressure rod knock, or a bad hydraulic lifter (did they use hydraulic lifters?). Either way, it doesn't sound good.

 

Yes they have hydraulic lifters, and thanks to Mobil1 they dont all tick like old pathfinders lol

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Not too familiar with that engine but the end of the crank usually has some kind of harmonic balancer and they deteriorate over time. Again I don't know if this engine has one. Just throwing it out there.

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A piston pin knock can sound like that and they do tend to go away once the engine comes up to temp.

 

I couldn't see the wobble in the video, but yes, if it is a vulcanized harmonic balancer, that could definitely be the cause of the wobble.

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2 hours ago, Stoffregen Motorsports said:

A piston pin knock can sound like that and they do tend to go away once the engine comes up to temp.

 

I couldn't see the wobble in the video, but yes, if it is a vulcanized harmonic balancer, that could definitely be the cause of the wobble.

 

 This later model engine is supposed to have full floating wristpins so I really hope that's not the issue. The strange thing is if you remove the V belt off the crank all the noise stops immediately.

 

 It does have a harmonic balancer but the pulleys are bolted straight to the actual sleeve around the crank. The balance ring is independent of any pulleys. After some fiddling yesterday it appears that the pulley is actually bent which can definitely give the optical illusion of having a bent crank. the pulley is stamped steel which is bolted to the machine hub around the crank snout.

 

I'm on the hunt for a complete set of 88+ pulleys for it.

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I think the crank is toast. Wobbly lower pulleys usually indicate a broken crank. And yes, they can still run like that. 

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That noise is external and at a certain rpm at 0:08 you can hear the distinct slight ringing sound of stamped metal, not the deep nock of a bent or broken crank at all. If removing the V bolt stops it, that's pretty much case closed. I say break out the big hammer and get to work.

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