420A Knocking Noise, Possible Rod Bearing?

[BLACK'98DSM]

I think I got a rod knocking already. I'm not sure yet but there's some sort of knock near the oil pan area. It's really quiet once warmed up but on a cold start it's scary.

Engine literally only has 4.5k-5k miles on it. I used Clevite bearings, standard size since the crank journals were still within spec. Plenty of oil pressure, never seen it fall below 40psi even when hot. 10w-40. I do beat on it pretty hard sometimes. But I still expected it to last a little longer.

Does anybody have any input on how long their 420a rod bearings last on higher performance builds? Are there any better materials than Clevite?

Next rebuild I'll have the crank machined down to the next size bearing. Just wondering if 5k miles of beating is all it takes to destroy the bearings. If that's the case it looks like I need to stock up on a garage full of 420a engines

 

[DSMPT]

Are you sure it's not from hydraulic lash adjusters? Since you mentioned that it's occurring near the oil pan area, so maybe it's rod knock but if it's the very beginning of rod knock, it's generally opposite. You start to hear the knock sounds when the oil temp gets hot and at low rpm/lower oil pressure. And then the knocking sound occurred range would be wider and wider by time, and hotter would be louder. Then when it gets worse, you start to hear it even when the oil is still cold and finally it would occur always.

 

[BLACK'98DSM]

Interesting. I may remove the oil pan and have a look inside. Wouldn't hurt to recheck my torque on everything and check for excessive play on anything. The weird part is, I've been using a magnetic drain plug since the first time I started the engine. Never once have I seen it collect anything unusual. After the break in period it had a little bit of glitter on the magnet, and every oil change since then there has been less and less collected.

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[DSMPT]

How does the oil and inside of oil filter look like? If rod knock, you probably see some sign in the oil or filter. Do you have a video or pic?

 

[BLACK'98DSM]

It sounds a lot like a diesel engine while it's cold. You can hear in just the 1 minute I had it running the noise got quieter. All it takes is 2 passes at the strip or driving a couple miles on the street for the noise to completely go away. I'm starting to doubt it's a rod bearing now that I took a moment to listen to it. It goes away when I rev the engine higher. A rod knock would still be present and knock faster as I rev it. What would worn out main bearings sound like? I doubt they're worn either but I can't rule them out until I know.

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My camera was right next to the crank pulley, not much to see but that's a good spot for the mic to pick up the knock. That metal banging noise you heard at first was me closing the door and opening the hood, not engine related.

 

[DSMPT]

Yeah I heard it. can't be 100% sure by just seeing the video but according to what you described and the video sound, my first opinion would be piston slap sounds rather than rod/main knock. In case if those sounds are being caused by bearing damage, already you can see some obvious sign from damaged bearing in the oil.

 

[BLACK'98DSM]

It seems to be coming from the top end. I used a stethoscope to listen around. The noise is very faint from the bottom of the oil pan. But when I place it on the valve cover it's loud. Looks like I'll be removing the valve cover to look inside.

 

[DSMPT]

So probably piston slap sound or hydraulic lash adjuster's ticking sound. Not rod knock.

 

[BLACK'98DSM]

Yea, not rod knock for sure. I went ahead and removed the oil pan. There are no shavings in the bottom and none of the rod bolts or main bolts came loose. Everything clicked at the proper torque without turning. I've been planning to build a different head and swap it over anyway. Trying to find a used one in good shape is hard.

 

[EkTsi]

I think I got a rod knocking already. I'm not sure yet but there's some sort of knock near the oil pan area. It's really quiet once warmed up but on a cold start it's scary.

Engine literally only has 4.5k-5k miles on it. I used Clevite bearings, standard size since the crank journals were still within spec. Plenty of oil pressure, never seen it fall below 40psi even when hot. 10w-40. I do beat on it pretty hard sometimes. But I still expected it to last a little longer.

Does anybody have any input on how long their 420a rod bearings last on higher performance builds? Are there any better materials than Clevite?

Next rebuild I'll have the crank machined down to the next size bearing. Just wondering if 5k miles of beating is all it takes to destroy the bearings. If that's the case it looks like I need to stock up on a garage full of 420a engines

To dsmtuners be up players thanks,,..

 

[BLACK'98DSM]

To dsmtuners be up players thanks,,..

I don't understand this. Mind clarifying?

 

[97egl]

On your build it says you have JE Pistons. With forged pistons you normally have to go with a little extra piston to wall clearance because the expand and contract more than OEM pistons. Anyways not sure if you had these pistons when it was cold out last year but I'd guess that they're contracting more now that its colder out and causing your knocking on start up.

You may add some lucas stabilizer and see if that helps. I had an Avenger with about 200K miles and it had bad piston slap but if I added the stabilizer to it the noise would stay gone for about 1500 miles or so.

 

[BLACK'98DSM]

If that's truly the case I'll probably pack it up for the winter and go with some fresh fluids when Spring arises. It won't be too long before the local events die down anyway. I'll probably still pull the valve cover off and visually inspect everything first just for the peace of mind that nothing is messed up for next year. And if something is out of wack I have a few months to fix it up again.

 

[dustyboner]

just wondering, what valve springs are you running. i didn't see any listed in your profile.
The stock springs are weak as f***, you don't even need a valve spring compressor to remove them.
Not what you want with upgraded cams.

 

[BLACK'98DSM]

I'm still using the stock valve springs as of now. I plan to upgrade them as soon as I find the head I want to build. The valves never floated when I had the stock cams but now they start to float around 7k. By 8k I'm losing a significant amount of power.

It looks like Brian Crower is one of the only places that still sell springs for a 420a. They also sell stainless steel valves and stage 2 cams I want. I'll probably build the head using BC parts and finish it off by shaving it down a bit and a P&P job.

Do you think the springs could be shaking at idle and causing a noise? To me it seems like they'd be more noisy in the higher rpm's, especially with such a mild grind cam.

 

[dustyboner]

i was thinking more of a rocker


Mopar Performance DOHC valve springs

Mopar Performance Valve Springs, 95-99 Neon DOHC / 03-05 Neon SRT-4

Installing new DOHC camshafts into your 1995-2005 Dodge/Plymouth Neon with 2.0 DOHC engine? If so, the stock valve springs must be replaced. If the stock valve spring are used, catastrophic engine damage will occur! Mopar Performance DOHC valve springs utilize a higher tensile strength steel...

www.modernperformance.com

 

[DSMPT]

Do you think the springs could be shaking at idle and causing a noise?

If the springs are shaking at idle, you probably don't have a stable idle or you feel something different on the performance from before.

Crower too.

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[BLACK'98DSM]

So I had a couple drinks and started taking things apart. I had to look very close but I found that 2 of my lifters are slightly different than the rest. Which is weird because I ordered 16 of the same part number PT lifters. I'm afraid that if I just order 2 more they might be the same as the 2 that are different. So I'm going to order 16 new ones and set all the current ones aside as spares.

I'm not convinced that was causing my noise issue. But nevertheless it would be helpful to use matching lifters.

 

[dustyboner]

a couple drinks??? maybe you need to get a second opinion on those lifters.

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are you using mopar performance lifters?

 

[motomattx]

That sounds like an exhaust leak of some sort to me.

 

[BLACK'98DSM]

a couple drinks??? maybe you need to get a second opinion on those lifters.

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are you using mopar performance lifters?

I'm using OEM Mopar lifters for a 2.4 PT Cruiser. I bought them from RockAuto.

That sounds like an exhaust leak of some sort to me.

That's a good thought but unfortunately it's not the issue.

 

[dustyboner]

well fukc, the mopar performance lifters and
2.7L rockers are both discontinued

 

[BLACK'98DSM]

I now have a set if 16 matching lifters. I ordered the same ones as before, but this time none are different. Not sure what happened there. I also purchased yet another valve cover gasket set. The 420a is way too picky to re-use something like that. I'll be sure to update the thread next season when I finally dig into it. I'm hoping there's something obvious going on with the top end that I see when taking it apart. I doubt the lifters are that noisy, I'm just replacing them all because I'm meticulous and want the to match.

 

[BLACK'98DSM]

I just received a private message asking what the resolution for this thread is. I can't definitely point fingers at one part, but it was something within the cylinder head or valvetrain. I acquired a low mileage head to rebuild plus new cams, springs, retainers, valves, & lifters. The noise was no longer present after installing this head I built. My observations for the old/used parts were as follows:
- 2 hydraulic lifters did not match the other 14, and appeared to have a slightly shorter height. (This could definitely be problematic.)
- Some of the camshaft journals were deeply scored.
- One of the exhaust camshaft lobes for cylinder 1 had started to round off.
- Too much material had been removed from the cylinder head surface, deeming it no longer serviceable (I tend do this to my 420A race heads to increase compression ratio.)

So those are some things to look for - if chasing this kind of noise. Use a stethoscope as I did to pinpoint whether it originates from the top end or bottom end.