First engine rebuild fail...

Yodavan · 01-31-2015, 08:29 AM

I've spent the last 4 months or so rebuilding the motor in my 99 Dodge Ram Van 3500. [img]

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Here it is just about ready to go back in [img]

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Took advantage of a nice day and slid it back in hooked it all up add coolant and oil and turned the the key. A few seconds later she fired up and was running, wow I did it! I kept the RPM's up to make certain it had plenty of oil pressure and it ran very smoothly. If fact 15 minutes later I was still gently altering the RPM's not to high but keeping it off idle. Then I slowly let it come to idle when a loud ping killed the motor.

I pulled the valve cover and found a bent pushrod? What the.... So pulled the head and sure enough the valve is bent too.

ok so it's not the best of day's about now... Come to think of it not much went well that day, that's another story.

So I'm still not sure what went wrong? I'm going to pull the other head make sure all is well, also pulling the water pump and timing set cover to try and re-degree the camshaft.

I could use some good advice on some parts of the build that I'm not sure about. Here's what the rebuild included.

Block was cleaned in a hot tank, cylinder bores where honed, crankshaft polished, pistons and rods checked. New cam bearings pressed in all by the machine shop. New crank and piston rod bearings, new rings. New camshaft for more torque, new cast iron engine quest heads with new valves and springs came assembled. New hydraulic roller lifters, reused pushrods and rocker arms. New double roller timing gears and added a tensioner.

So my plan now is to check the cam degree and corrected if needed, replace the valve, replace the pushrods and maybe the lifter?

My question is about the lifters, as I use a pushrods and try to collapse each lifter some give easily and others are rock hard? I did not soak them in oil before installing, I only coated the outsides with oil and then slid them in the bores. Could this be an issue, should I pull them and soak them in oil?

When attempting to degree the cam I was having trouble and ended up setting the crank gear on the 4degree advanced key way and the cam gear at zero, could this be the problem? I've been told the crank gear should not be adjusted to anything but zero key way. But if that's true then why does it have adjustable key ways? The company I purchased the cam from says the cam must be degreed and the factory dot to dot is not good enough.

So if someone has experience and can lead me in right direction it would be greatly appreciated.

1der · 01-31-2015, 10:05 AM

Man, sorry to rad about your bad experience.

You did not mention, was the bent valve from piston contact?

JWA · 02-01-2015, 05:47 AM

Been a long, long time since I've been inside a motor, almost always used factory parts even if they were high performance or improved performance items. The only real aftermarket parts used were superior timing chain and gear sets---all this was with GM stuff mind you.

Having known of a few who bought kits supposedly selected to fit a certain application too often those would have been assembled incorrectly, wrong cam for lifter/push rod packages and so on. This might not be your case but its worth checking the actual parts instead of the list of those included---if you went this route.

Following the manufacturer's recommendations tends to yield the best results. Even though there might be provisions to change such things as the crank gear orientation doing so would very much require degreeing the valve train if only to make sure interferences aren't initially present or could develop.

At any rate time to back up a bit, inspect and/or check everything---replace what's bent and start over. Because the lifters are hydraulic they should "pump up" by oil pressure alone but the oil bath hours before they're installed is a good idea.

Sorry for you mishap and I sincerely hope its nothing too serious, economically or mechanically.

Please let us know what you find.

Yodavan · 02-01-2015, 10:47 AM

Quote:

Originally Posted by 1der

Man, sorry to rad about your bad experience.

You did not mention, was the bent valve from piston contact?

Well the valve and piston did make contact but you make a good point did the valve bend before it hit the piston or did it bend because of hitting the piston. That I really don't know? The piston is aluminum and has a ding in it, I'll clean it up by cutting the high spot down.

Van won't fit in the garage and it snowed last night so I'll wait for better weather to work on it.

Yodavan · 02-01-2015, 11:02 AM

Quote:

Originally Posted by JWA

Been a long, long time since I've been inside a motor, almost always used factory parts even if they were high performance or improved performance items. The only real aftermarket parts used were superior timing chain and gear sets---all this was with GM stuff mind you.

Having known of a few who bought kits supposedly selected to fit a certain application too often those would have been assembled incorrectly, wrong cam for lifter/push rod packages and so on. This might not be your case but its worth checking the actual parts instead of the list of those included---if you went this route.

Following the manufacturer's recommendations tends to yield the best results. Even though there might be provisions to change such things as the crank gear orientation doing so would very much require degreeing the valve train if only to make sure interferences aren't initially present or could develop.

At any rate time to back up a bit, inspect and/or check everything---replace what's bent and start over. Because the lifters are hydraulic they should "pump up" by oil pressure alone but the oil bath hours before they're installed is a good idea.

Sorry for you mishap and I sincerely hope its nothing too serious, economically or mechanically.

Please let us know what you find.

I was concerned about adding any parts that we're not stock so I found a place online called Huges Engines that specialize in MOPAR Engines. They helped me select the right parts that would keep it reliable and provide a bit more torque and hp. The cam is larger then stock but mild and more for torque at low RPM then HP at high RPM. The stock heads are known for cracking between the valve seats which both sides on mine were cracked. In fact you can see the cracks by eye LOL. So I purchased a set of Engine Quest heads that fix the cracking issue and are reported to provide better air flow. I went ahead and purchased them assembled from Huges with the valves and springs already in them. Lifters are new but stock and also from Huges.

Well they say if your not failing your not learning.... So it's a great learning opportunity for me

1der · 02-01-2015, 11:57 AM

Speculating: engine was running fine for a significant number of minutes before failing. If the valve floated just a bit (weak spring, sticky guide: not likely since all new, but?) then it could make contact w/piston. Sounds like the cam has either or both more lift and/or duration than stock to get a bit more torque. This may have caused the clearances between vve and piston to become very tight. A little slip or stretch (break in?) on the chain and you could have result. I also think your thoughts around timing chain position need to be explored more. It may have been a contributing cause. Any other pistons show slight contact? Lastly, are the pistons spec'd for the lift of the cam?
Man, it has been decades since I was inside an engine, you are making my brain work!!!

Yodavan · 02-01-2015, 03:27 PM

Quote:

Originally Posted by 1der

Speculating: engine was running fine for a significant number of minutes before failing. If the valve floated just a bit (weak spring, sticky guide: not likely since all new, but?) then it could make contact w/piston. Sounds like the cam has either or both more lift and/or duration than stock to get a bit more torque. This may have caused the clearances between vve and piston to become very tight. A little slip or stretch (break in?) on the chain and you could have result. I also think your thoughts around timing chain position need to be explored more. It may have been a contributing cause. Any other pistons show slight contact? Lastly, are the pistons spec'd for the lift of the cam?
Man, it has been decades since I was inside an engine, you are making my brain work!!!

Sorry about making your brain work so hard but your input is great!

Yep that's right the cam has a bit more lift and duration. According to Huges the cam will work fine with the stock pistons and rods, rocker arms and pushrods.

I need to borrow or buy a spring compressor and pull that valve out but the spring does not look broken. I will admit that I did not check valve to piston clearance...

maybe it's a good idea that I figure out how to check that to make certain the clearance is at least what's recommended. When I slide the new valve in I'm guessing it should move thru the guide freely with minimal resistance? It's the exhaust valve by the way that hit.

Let's say the timing chain has started to break in and has stretched or settled on the gears a bit. With my timing gears not being set perfectly this may have not caused trouble at first when I was building it and turning the crank by hand. But now that it has loosened up a bit the clearance is gone? Oh hey I added a tensioner where there was no factory tensioner to start with, maybe the tensioner has relaxed a bit? Got to get back in there and look at it. I bought a brand new degree wheel and adaptor so I'll make sure it's perfect before putting it back together.

The number 8 piston on this side is the only one showing contact. I'll pull the drivers side head and have a look.

Thanks a bunch you helping me think thru this thing

Yodavan · 02-01-2015, 03:43 PM

Quote:

Originally Posted by 1der

Speculating: engine was running fine for a significant number of minutes before failing. If the valve floated just a bit (weak spring, sticky guide: not likely since all new, but?) then it could make contact w/piston. Sounds like the cam has either or both more lift and/or duration than stock to get a bit more torque. This may have caused the clearances between vve and piston to become very tight. A little slip or stretch (break in?) on the chain and you could have result. I also think your thoughts around timing chain position need to be explored more. It may have been a contributing cause. Any other pistons show slight contact? Lastly, are the pistons spec'd for the lift of the cam?
Man, it has been decades since I was inside an engine, you are making my brain work!!!

Here's a pic of the valve and pushrod, also of the spring.

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1der · 02-01-2015, 04:04 PM

Yoda,

Please make sure to take lots of pictures of the timing chain, cam and crank sprockets to make sure you have the current set up (relationships) well documented before removing the chain.

I know the hydraulic lifters are supposed to self adjust but is it possible the rocker arm for that valve was over tightened causing the valve to not quite return fully?

The tensioner is not hydraulic is it?

Off to watch the Super Bowl. Will check back later.

larrie · 02-01-2015, 04:27 PM

Bummer, rebuilding an engine can be fun or a problem. Have seen it both ways.

Have you checked with Huges to see if they have seen this before or if they will replace the head?