crankshaft question

[quant55]

I have a knocking inside the engine. It's being heard especially on deceleration. The plane bearings on the crankshaft had been replaced, also the connecting rods bearings. Any ideas?

 

Also, the crankshaft (together with pistons) from the 2nd gen venture would fit 1st gen? Does anyone has any experience with that? I know the PN for crankshaft and pistons are different, but from pictures, those looks to be the same.

[Peder_y2k]

Regarding the 'knocking' and previous bearing replacement, it is possible the bearing fitment size was incorrect resulting in either excess bearing clearance, or, not enough clearance for oil flow. As an experiment, try a temporary addition of a quart of 90wt gear oil added after draining 1 quart of the crankcase oil. This will result in a thicker oil that can take up any excess clearance and temporarily quiet the knocking..... if and only if there is excess bearing clearance that is the issue. If no change in sound, then it is not an excess clearance issue so change the oil to eliminate the 90/30 mix and get back to normal oil.

Another source of knocking on decel could be slack timing chain/s due to worn or damaged chain guides.

-Pete, in Tacoma WA USA

[quant55]

Regarding the 'knocking' and previous bearing replacement, it is possible the bearing fitment size was incorrect resulting in either excess bearing clearance, or, not enough clearance for oil flow. As an experiment, try a temporary addition of a quart of 90wt gear oil added after draining 1 quart of the crankcase oil. This will result in a thicker oil that can take up any excess clearance and temporarily quiet the knocking..... if and only if there is excess bearing clearance that is the issue. If no change in sound, then it is not an excess clearance issue so change the oil to eliminate the 90/30 mix and get back to normal oil.

Another source of knocking on decel could be slack timing chain/s due to worn or damaged chain guides.

-Pete, in Tacoma WA USA

 

Thanks. The knocking was present before replacing the bearings. The new bearings were fitted based on the crankcase/crankshaft/connecting rods markings. The timing chains had been replaced also. Trying to hear exactly the source of the knocking with a stethoscope I found out the noise is coming from the lower side of the engine, approx. from the crankshaft area. Also, the knock can be heard as soon as the engine get hot, not immediately after starting it, and yes, I tried 10W40 and 20W50 mineral oil. The knock is lighter if 20w50.

[djh3]

On decell? I think wrist pins make noise mainly on decell. But if you say its on the left side, possibly stator related?

[dingy]

Attached a picture from another thread regarding this block, if it is the same one. There is some significant damage under the near main bearing in picture.

 

That may be cause noise you are hearing., Maybe not, but a good starting point.

 

Post #15:

http://www.venturerider.org/forum/showthread.php?p=822076#post822076

 

Gary

[quant55]

Attached a picture from another thread regarding this block, if it is the same one. There is some significant damage under the near main bearing in picture.

 

That may be cause noise you are hearing., Maybe not, but a good starting point.

 

Post #15:

http://www.venturerider.org/forum/showthread.php?p=822076#post822076

 

Gary

 

Dingy, that block has been replaced. This story is closed now.

Edited June 10, 2014 by quant55

[quant55]

On decell? I think wrist pins make noise mainly on decell. But if you say its on the left side, possibly stator related?

 

Yes, it is heard mainly on decell and it is heard on the lower side (not left side) of the engine. It is not a high tonality sound like the cams sound or a timing chain sound.