Volvo Penta 4.3GiPEFS replacement?

[M_Dennis87]

So I've been battling with my yard sale special 2001 Cobalt 190 and have come to the conclusion that my motor is toast. Long story short the motor has a serious knocking going on, and after changing the oil multiple times I've found a lot of fine particles in the oil. I probed around with an automotive stethoscope and the noise is for sure coming from the bottom end. Below is a video of the noise after changing the oil twice and revving it up a bit.

I'm pretty sure at this point I have a blown rod bearing or something substantial broken in the bottom end of the motor. There's also a lot of corrosion in the valve train so at this point I'm looking at long blocks. I don't have the space or the time to pull the motor and tear it down, nor do I think it's the most cost effective solution. So the question is, where do I look for a long block? My local shop recommended Quicksilver but their prices were quite expensive. I was looking at Michigan Motorz at the different options, but I'm wondering if anybody has an experience with them. THIS is the motor I was looking at, which I believe is compatible.

To date, I've replaced all the old gas, fresh oil, spark plugs, raw water pump, u-joints and gimbal bearing. Any additional info / advice would be greatly appreciated.

https://youtu.be/KcBowRsw1eY
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[BRICH1260]

I purchased my replacement from Michiganmotorz last year and have been happy with the choice so far.

 

[alldodge]

2nd MM there a good company,and the motor you picked should be a good fit

 

[Saline Marina]

Sounds to me like you have a bad lifter/bad rocker/bent pushrod/bad cam nose and the valve is being launched off the seat and then slamming into the seat. In other words, lost motion/lash in the valvetrain. Have you taken the rocker covers off....then you get these little spring-y things that stop the shot of oil thru the pushrod that would just launch oil drips *all over* with the cover off. Then you can idle the motor, or turn the crank a little at a time and see which valve has a bunch of lash/lost motion.

However I understand the desire for a rock solid solution with no downtime due to teardown. At the same time, you will spend a good bit of time swapping the "covers" over to even a good longblock. Most of it is cleaning everything up shiny and new.

 

[Saline Marina]

This is just another way to think about this. Suppose you have a 600 rpm idle. In 60 seconds the crank rolls over 600 times so 10 revs per second. If it were a crank/piston/rod issue you'd likely hear it 10 times per second.

The valvetrain however is a 1:2 reduction from crank speed, so the valves actuate 5 times per second in the same scenario. If you play the video and think of 1 second's timespan I think I hear the knock about 5x per "one-thousand-and-one" second rather than 10x....

 

[Lou C]

That's exactly what I said on another site when the same question was asked. And I wondered if it could be a bent pushrod, stuck valve, pulled rocker stud any number of valve train issues that are not that complex for a willing back yard mechanic to check out and possibly repair...the one wild card I am not sure about since my engine does not have one...is the balance shaft...could it be play in the bearings for that shaft? Anyway what I'd do...is pull off the exhaust manifolds...remove the valve covers...remove the spark plugs...and observe the motion of the valve train carefully as you crank the engine over by hand...if the problem is obvious then...you may save the cost of an engine replacement...certainly worth buying a set of exhaust manifold gaskets...to find out...

 

[Scott Danforth]

16 seconds into the video there is a big bunch of marine tex around one of the exhaust manifold bolts....why.

if the manifold is leaking there, it needs to be replaced....Period

it could be the balance shaft bearings, however it could also be a stuck valve-train or it could be a bad bearing (which only rattles when loaded during the power stroke.)

Do a compression test - are all cylinders between 135psi and 155 psi? if they are all good
pull a plug wire at a time with it running at idle. if you find a plug wire that you pull and the knocking goes away, you have an issue with that cylinder
pull the valve covers and look at all the rockers. any one sitting really high? or really low? any pushrod issues?. this would be obvious if its rocker/pushrod related. if you cant find anything then time to pull the motor and yank the pan

if the knocking is still there after you have pulled a plug wire on every cylinder, pull the intake, check for play in the balance shaft (there should be about 0.002 radial movement and at most about .010 axial movement) you could have lost a balance shaft bearing, or the timing gears to the balance shaft are sloppy.

 

[M_Dennis87]

Saline Marina are you suggesting it may be an issue in the valvetrain rather than the lower end? Is there a way to diagnose this better without tearing things apart? Also, with the mechanics stethoscope, the noise is definitely louder on the lower end, particularly on Cylinder 6, for what it's worth...

 

[Lou C]

thanks for the spec on the balance shaft Scott! I was curious about that.
I would try what Scott suggested, carefully pull each plug and see how the sound changes...maybe start with #6 since you felt it was louder there. If that's it then you have your answer but if pulling all 6 makes no difference, I'd pull the manifolds, valve covers etc and check the valve train...if no problems...pull the distributor and the intake and check the balance shaft as Scott suggested.

 

[Scott06]

If you do end up getting a new engine vs repairing yours, I also had a very good experience with Michigan motorz. Mine was a new base engine vs reman , as new isn’t much more. One thing to watch if you swap engines is some of the 4.3s with a 090M block casting used metric engine mount, flywheel cover and starter bolts. It’s not a big deal either way I just had to get $40 worth of bolts when swapping a metric for non metric block.

 

[Saline Marina]

Saline Marina are you suggesting it may be an issue in the valvetrain rather than the lower end? Is there a way to diagnose this better without tearing things apart? Also, with the mechanics stethoscope, the noise is definitely louder on the lower end, particularly on Cylinder 6, for what it's worth...

I'd pull the rocker covers and use the oil stoppers or deflectors.

This is what I was thinking of...

https://www.amazon.com/OEMTOOLS-2505.../dp/B01MUE220P

Then idle and see if you can see the problem. The lack of oil to the rockers at idle won't hurt anything.

I would also try to teardown an oil filter to see what's inside. You'd have to use something like a chisel to shear the metal case off a little at a time, sort of like a can opener, rather than sawing it open which would cause fine metal to get inside and confound the results.

Any clues on how this motor got this way? Fail to winterize, ingested water, ran with water in the oil, hydrolocked a cylinder? Just stabbing at possibilities.

When you swap longblocks, the intake manifold, the rocker covers, the oil pan, the exhaust manifolds all have to be cleaned up and then crossed over, as well as retiming the distributor's base setting. And you should probably spend time aligning the crank and the gimbal bearing. If you have a valvetrain issue that can be fixed from the top there's a lot of work that you can avoid. Even having to dig far enough down to change a camshaft would be better than pulling the engine imo.