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Old 24-07-2015, 10:08   #1
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Wobbling crankshaft??

Hi all,
The saga continues. I've been advised by a mechanic who was replacing my front seal on a 3jh4e than the new one is also leaking. The report stated a wobbling crankshaft. ????? I can see maybe a wbbling balancer or pully but the crank? I havnt talked to the tech yet but this seems a little hard to believe. The amount of stress that you would think it would take to warp a crank or even bend it would have broken something else no?? At my witts end with this motor. Any suggestions?
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Old 24-07-2015, 10:22   #2
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Re: Wobbling crankshaft??

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Originally Posted by Ten87 View Post
Hi all,
The saga continues. I've been advised by a mechanic who was replacing my front seal on a 3jh4e than the new one is also leaking. The report stated a wobbling crankshaft. ????? I can see maybe a wbbling balancer or pully but the crank? I havnt talked to the tech yet but this seems a little hard to believe. The amount of stress that you would think it would take to warp a crank or even bend it would have broken something else no?? At my witts end with this motor. Any suggestions?
Maybe he put the damper on a bit crooked? I too doubt that the end of crank is bent. If there was some wobble in the crank it would be so small that a new seal could handle it.
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Old 24-07-2015, 10:43   #3
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Re: Wobbling crankshaft??

Thats what i was thinking. Many years ago i worked on a alcohol burning funny car race team. HUGE stress on the crank. Never saw one warp or bend. Burn up, blue from the heat, destroy the barings all day long. Never bend or warp. I wish i would have been there while he was working on it. Just the fact that he suggested a wobbling crank makes me wonder if he seated the seal right, and as you pointed out, mounted the balancer a little wacky.
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Old 24-07-2015, 10:59   #4
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Re: Wobbling crankshaft??

If you had a wobbling crank, by now the engine would have destroyed itself. That's not even a good excuse. Either the seal was not put in properly or you have small pits or corrosion in the surface that contacts the seal. Remove the dampener, inspect closely the surface with a magnifier.
It's not uncommon for corrosion or pits to form on the dampener where it contacts the seal. Dampeners are just mild steel or iron. Better or repaired dampeners have a hard chrome surface where the seal rubs. Also, a slip on sleeve is available in common sizes to put a new surface on damaged shafts.
Another reason boat owners should have some basic mechanics skills, unless they can afford to be taken to the cleaners.
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Old 24-07-2015, 11:07   #5
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Re: Wobbling crankshaft??

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Originally Posted by Lepke View Post
If you had a wobbling crank, by now the engine would have destroyed itself. That's not even a good excuse. Either the seal was not put in properly or you have small pits or corrosion in the surface that contacts the seal. Remove the dampener, inspect closely the surface with a magnifier.
It's not uncommon for corrosion or pits to form on the dampener where it contacts the seal. Dampeners are just mild steel or iron. Better or repaired dampeners have a hard chrome surface where the seal rubs. Also, a slip on sleeve is available in common sizes to put a new surface on damaged shafts.
Another reason boat owners should have some basic mechanics skills, unless they can afford to be taken to the cleaners.
Yeah, the fix might be a "Speedy Sleeve". Very simple to install and probably only $75. You get them at bearing houses.
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Old 24-07-2015, 11:11   #6
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Re: Wobbling crankshaft??

Its funny. I knew I should have done this myself but the boat is 2 hours from me. He sounded like he knew what he was doing and works for a "premier" marina. Should have listened to the little voice in my head. Looks like i know have plans dor the weekend. Thank for the info. You guys arw a great help to aomeone not farmiar with sailboats.
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Old 24-07-2015, 11:30   #7
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Re: Wobbling crankshaft??

Believe it or not but a wobbly balancer is the bane of early model Miata's, it is not a bent crank of course, but that is what it looks like, the early model balancers came loose easily and wobbled, this of course led to a leaking front crankcase seal leak.
Untitled Document
I am not saying this is your issue, but checking the crank bolt for torque couldn't hurt.
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Old 24-07-2015, 11:50   #8
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Re: Wobbling crankshaft??

I think we all agree. Its insane to think the motor runs great except for the oil leak, and the crank is bent. Unless its something really really major, no more hiring someone for something i should or can do myself.
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Old 26-07-2015, 17:28   #9
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Re: Wobbling crankshaft??

Ok so went to pull balancer off and noticed there is some walk and vertical movement at balancer. Crank likely not bent or wobbling but it would sure seem the bearings are shot. Thinking of just pulling motor, popping off caps and crank and as long as the crank isn't scorn, installing new bearings and buttoning it up without messing with anything else......opinions????
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Old 26-07-2015, 18:20   #10
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Re: Wobbling crankshaft??

Wow. What is your oil pressure? You could probably feel maybe .005 +, that is more than should have for sure. To bad it's not something the mechanic did.
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Old 26-07-2015, 18:46   #11
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Re: Wobbling crankshaft??

Well the thought did cross my mind, thought maybe he used a hammer to put balancer back on and broke the thrust bearing. I dont know if that would account for the movement i have though. Probably a 32nd of an inch or less. Dont have gauge. I need to really pick up on the balancer for a little vertical movement, and if I put a screw driver behind the balancer and pry forward about the same. Have like 4 psi oil pressure. Was thinking crank bearings came right out of journal or journals. Just before i bought this boat the original owner did run it close to dry of oil. Thought I might get lucky because the thing runs so well. Even now if i run it for a really short duration it sounds good. Thats why my half witted plan to just drop the pan and crank and just put in new bearings. Not even touch top end or rods. Just bearings and polish crank if needed.
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Old 26-07-2015, 18:55   #12
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Re: Wobbling crankshaft??

Did you say 4 psi? I would assume that is at idle. End play, even when within specs might feel like 1/32. Probably not a broken thrust bearing.
In most engines you can change the bearings without removing the crank. Why would you not change the rod bearings too?
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Old 26-07-2015, 19:13   #13
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Re: Wobbling crankshaft??

Once i open it up and see how ugly it is, I probably will change rod bearings as well. It ran at about 4 psi for about 30 seconds so I hope I didnt smoke the rings or bores. Now i just have to research pulling it out. Any advice on unbolting the drive ? Anything tricky I need to know ?
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Old 26-07-2015, 19:26   #14
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Re: Wobbling crankshaft??

Wait a minute. This thing had good oil pressure before the mechanic changed the front seal? Bearings usually go well before cylinders. 4 psi for 30sec is not going to hurt much. I would need a digital gauge to read 4 psi. You were probably being optimistic or pessimistic.
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Old 26-07-2015, 19:54   #15
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Re: Wobbling crankshaft??

After I repaired the dipstick tube (original problem) i refilled the oil and started it. Had about 20psi at idle and 35 or so at higher rpm. Never looked at tach cuz i was watching the oil. Let it run about 10 minutes and noticed the front seal leak then shut it down until today. I figured the low oil pressure was the front seal. It was leaking pretty badly. Guess the low pressure was a spun bearing or two. Cant even talk to the original owner about normal oil pressure for this motor cuz hes back up north for the summer. Just keep chuggin along I guess.
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