Piston rings are toast? (1 Viewer)

[DocJD14]

First and foremost, this is my first post here after lurking for quite some time. Thank you mud for the wealth of knowledge! A few months ago, I flew across Europe to purchase my HJ60 and drove big red home from the UK to Italy. Let’s just say we bonded for 16 hours and I dreamt I was driving for several nights after returning… Aside from a noisy belt, we made our way back across the Alps without any major issues.

Fast forward to today, a couple buddies and I are enjoying some cold beers and bourbon while doing some routine maintenance on the fuel system. This was nothing wild, just draining the water separator and inspecting the full lines and such since I’ve been noticing some loss of power under load in 3rd & 4th. When I cranked the engine to move the truck back to the side of the drive, there was a solid amount of blow by on the ground behind the tail pipe. My basic mechanical knowledge tells me that the rings are likely toast, but again, my mechanical knowledge is rather basic. What am I looking at here? Full engine rebuild? Just trying to prepare myself here…

 

[OSS]

Maybe all your driving blew out all the soot accumulated in the exhaust pipe. Maybe if the humidity was high it provided enough moisture to blow that junk out.

I’d just drive it. If you discover something super obvious, then maybe a rebuild is in order.

The Diesel section on this website has more knowledgeable members of diesels. The 60s section here (for some reason) is almost all gasoline engines.

Diesel Tech / 24 volts

BJ/HJ diesels (3B, 13BT, 1KZ, 1HZ, 1PZ, etc) and other diesel conversions (ie: Isuzu, Hino, 4BT, 6BT, etc)

forum.ih8mud.com

 

[bigredmachine]

if the rings were that bad i would expect that you would have low poer in all gears, not just 3-4. drive it, grt used to it since its a new truck to you and itll have its own temperament and oddities that youll learn over time. for now drive it and enjoy, if theres a rebuild in the future deal with it then

 

[Lead Head]

That is not blow by. Blow by is combustion gas that gets passed the piston rings, and comes out the engine breather (or PCV valve). That is water and carbon coming out of your exhaust. Water is normal, as every liter of gas or diesel you burn creates a liter of water (in the form of water vapor). But since the exhaust is cold, a lot of the water vapor condenses into liquid water. Then you get water washing the exhaust off and spraying out the back. Both are pretty normal things for a diesel engine to do in the cold.

What you're looking for is heavy white smoke that smells like raw or partially burned diesel fuel. Don't mix it up with the normal condensed water vapor.

 

[DocJD14]

That is not blow by. Blow by is combustion gas that gets passed the piston rings, and comes out the engine breather (or PCV valve). That is water and carbon coming out of your exhaust. Water is normal, as every liter of gas or diesel you burn creates a liter of water (in the form of water vapor). But since the exhaust is cold, a lot of the water vapor condenses into liquid water. Then you get water washing the exhaust off and spraying out the back. Both are pretty normal things for a diesel engine to do in the cold.

What you're looking for is heavy white smoke that smells like raw or partially burned diesel fuel. Don't mix it up with the normal condensed water vapor.

This actually makes a lot of sense. There is no white/blue smoke while driving, even when having the power issues. I’m mechanically inclined, but very new to Diesel engines especially. The engine runs and sounds great. In fact, my mechanic was quite impressed by the overall state when I had him baseline the rig with new fluids, filters, etc. I’m currently working on building my capabilities (tools & knowledge), but also preparing for a long trip with the family in a few months when we move from Italy. My buddies and I did some (unexpected) snow wheeling a couple weeks back that turned a mild trail ride into a long and quite technical day without any mechanical issues. I’ve only run into this power loss in 3 & 4 on a couple instances now with normal driving. It feels like I’m going up a hill and the accelerator is pretty much non-responsive. I’m pretty convinced this is a fuel issue at this point and will continue to diagnose and pinpoint the source.

 

[FordPrefect]

This actually makes a lot of sense. There is no white/blue smoke while driving, even when having the power issues. I’m mechanically inclined, but very new to Diesel engines especially. The engine runs and sounds great. In fact, my mechanic was quite impressed by the overall state when I had him baseline the rig with new fluids, filters, etc. I’m currently working on building my capabilities (tools & knowledge), but also preparing for a long trip with the family in a few months when we move from Italy. My buddies and I did some (unexpected) snow wheeling a couple weeks back that turned a mild trail ride into a long and quite technical day without any mechanical issues. I’ve only run into this power loss in 3 & 4 on a couple instances now with normal driving. It feels like I’m going up a hill and the accelerator is pretty much non-responsive. I’m pretty convinced this is a fuel issue at this point and will continue to diagnose and pinpoint the source.

 

[FordPrefect]

Hello
I’ve been through a similar exercise on my 12ht 61
There’s a mesh screen on the side of the lift pump inlet that can block and is easy to clean.
There’s another small filter located on the fuel pick up pipe inside the tank. Have to remove tank to access.
Mine was blocked up with sediment
Causing power loss, especially in higher gears, excess smoke and soot exactly like you describe all caused by diesel restriction.
Changing This filter and cleaning out the fuel tank made a huge difference to mine
Hope it works for you too
Regards Alex

 

[Freewheel]

How many kilometres on your HJ? The one major flaw of the 2H (maybe the only flaw) is that they have non reinforced piston ring lands. On some trucks, after about 350,000 kilometres, there will be a wear gap where the pistons hold the rings. Basically the steel rings are eating their way through their grooves in soft aluminum piston.

One clue for this problem is increased blowby and hard cold starts, and a compression test that shows low compression in one or more cylinders. (this wear does not usually happen evenly, often one or two pistons will be quite worn and the rest will be totally fine - the truck will likely run fine after its warmed up, as well)

The correct fix is to do an engine rebuild, using all new Alfin pistons that have a steel rimmed ring land.

Lots of information on this 2H issue if you search for "Alfin pistons" or "ring land wear"

I hope this is not your problem, but thought I should mention it, since its not uncommon as our engines get older...

 

[DocJD14]

How many kilometres on your HJ? The one major flaw of the 2H (maybe the only flaw) is that they have non reinforced piston ring lands. On some trucks, after about 350,000 kilometres, there will be a wear gap where the pistons hold the rings. Basically the steel rings are eating their way through their grooves in soft aluminum piston.

One clue for this problem is increased blowby and hard cold starts, and a compression test that shows low compression in one or more cylinders. (this wear does not usually happen evenly, often one or two pistons will be quite worn and the rest will be totally fine - the truck will likely run fine after its warmed up, as well)

The correct fix is to do an engine rebuild, using all new Alfin pistons that have a steel rimmed ring land.

Lots of information on this 2H issue if you search for "Alfin pistons" or "ring land wear"

I hope this is not your problem, but thought I should mention it, since its not uncommon as our engines get older...

Roughly 270k km.. the truck seems to start right up in cold weather, and performance seems relatively linear until the loss of power in higher gears after warmed up. I haven’t done a compression test, but it’s certainly on the list of things to do.