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Discussion Starter #1
Just sharing my experiences with the RT.

So my RT now has 1800 miles and it sounds like a sewing machine (significant amount of valve train noise at 1000-2500 RPM, more pronounced during down shifts). I have a 2013 5.7l grand Cherokee and that engine has 60,000 miles on it and the valve train does not make a peep, tick or clack and the oil gets changed every 8000 miles with conventional oil. When I drive the RT through a tunnel with the windows down the valve train noise is loud enough to piss me off. I have read a lot of folks switch to synthetic which helps some so I figured I would try it. I have tried mobile 1 5-30W with 20% MMO and it seemed to quiet down. BTW I used the same combination on my 2002 liberty (120,000 miles) and it really made a difference...it not only runs quieter but feels more responsive. On the RT, I now made the switch to 5-20W royal purple and it seems like the noise became a little louder.

Me being a tinkerer, I took apart the passenger side valve cover today to see if the pushrod preload is insufficient. Turns out everything checks out ok. Took off the rocker shafts and no abnormal wear on the rocker or rocker shaft...no abnormal wear on the rocker tips or cups either (although there was a lot of oil build up in the cups where the pushrods sit). Anyways, I took the pushrods out (one actually had a small patch of surface rust WTF?) and measured the pushrod lengths.

Intake -- 6.794 inch
Exhaust -- 8.084 inch

Thought I would post them for the 2015 5.7 without multi cylinder deactivation as I could not find it on the web (only spent 5 minutes looking for it thought). Going to check the driver side next week.

Oh and one last thing, I just notice the rear passenger side axle shaft boot closest to the tire is missing the boot clamp. Looks like a trip to the dealership is in my future.

End rant :)
 

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Discussion Starter #2 (Edited)
Interesting, just found out the 2012 VVT Hemi use stock pushrod lengths

Comp Cams Hi-Tech Chromoly Pushrods for 2009-2012 VVT 5.7L HEMI Engines (8x) 7929 & 7748

intake -- 6.790
exhaust -- 8.120

Could it be my exhaust pushrods are ~0.036 deficient and the reason for the valve train noise?

UPDATE: 2-28-2017
Well I found the source of my deficiency...my exhaust rods on passenger side are bent WTF! I put them on my lathe and the runout is almost 3/8" on number 2 exhaust pushrod.

UPDATE: 3-2-2017
Chrome Moly pushrods arrived...ordered Monday and arrived Thursday...oh snap! :woot: Just installed the passenger side pushrods (cleaned with brake cleaner, dipped in RP oil and dabbed assembly lube on ball ends) and came back from a 10mile run. Valve train noise is definitely quieter when I am in the 2K rpm range. Now when I drive the sewing machine sound is coming from directly in front of me. I want to say the motor feels more responsive and pulls better in the 2-4K rpm range but the temps here are in the low 30F and I have not driven the car since Sunday. I have the driver side cover pulled but the motor is too hot to work on. I cannot wait to finish this up tomorrow evening. Here is the rundown of the old and new rod measurements:

Intake Exhaust
Cylinder Old New Old New
1 6.792" 6.817" 8.084" 8.142"
2 6.794" 6.821" 8.086" 8.145"
3 6.796" 6.818" 8.087" 8.149"
4 6.795" 6.816" 8.085" 8.147"
5 6.792" 6.823" 8.084" 8.150"
6 6.792" 6.823" 8.090" 8.146"
7 6.793" 6.824" 8.088" 8.147"
8 6.792" 6.822" 8.089" 8.148"


The pushrods say 6.800 and 8.120 on them but they are all consistently longer. Checked on the lathe and these suckers are straight!

UPDATE: 3-3-2017
SUCCESS! Just finished installing the driver side pushrod and came back from a 15 mile drive around town. I swear the motor pulls even stronger a 3k. There was one lifter that was still misbehaving but seems to be quieting down. I kept the car in the 2-3k rpm range and all I hear is the roar of the stock exhaust. No to mention I am no longer ashamed to downshift. Revving the motor in the garage no longer sounds like the top end of the motor is going to self destruct. FYI my 2015 hemi does not have any cups surrounding the springs or clips/bushings/collars holding the rocker in place which is tempting me to crack open the wife's 2013 WK2 to see how the valvetrain is setup. So far once of the best repairs I have done. Now my attention is focused on the slight whine in the diff but that's another post.

If you have a challenger that sounds is make a lot of valvetrain noise in the 2k rpm range definitely take a closer look at the pushrods. If the noise dooes come back I will be sure to post an update....end blog.
 

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thanks for publishing this, did you use a guide for the process? Thinking of doing the same thing myself this spring.
 

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6.800" and 8.100" are the published stock pushrod lengths.

5.7 / 6.4 / 6.2 engines '09+ / '11+ / '15+ respectively
 

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Discussion Starter #5
thanks for publishing this, did you use a guide for the process? Thinking of doing the same thing myself this spring.
There was no written guide(s), I just had a suspicion that the preload was off (there was a post in another forum that convinced me this was my problem). I tore open the valve covers and noticed no appreciable play but the pushrods felt like they had zero lash and just not enough preload. I built a few motors back in the day with adjustable rockers where you rotated the pushrods until you just felt some resistance (zero lash) and then you torqued down by "x" amount of turns. I took the pushrods out, measured and I then looked for suitable replacements that gave me about 0.025" more preload. Technically what I should have done was measured the lifter travel with checker pushrods but I was pretty confident that 0.025" would be safe. My only regret was I did not take a before recording of the noise....it was quite annoying!
 

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Discussion Starter #8 (Edited)
6.800" and 8.100" are the published stock pushrod lengths.

5.7 / 6.4 / 6.2 engines '09+ / '11+ / '15+ respectively
HHP was stating 6.790 and 8.120 as stock which is why I decided to measure for myself. I determined the stock ones I had were 6.790 and 8.085-ish.
Comp Cams Hi-Tech Chromoly Pushrods for 2009-2012 VVT 5.7L HEMI Engines (8x) 7929 & 7748

Not to mention the service manual from Alldata (and online mopar parts vendors) shows different pushrods which appear to be longer (7.042 & 8.335).

A2speed stated they were 6.800 & 8.100.
https://www.a2speed.com/p-3172-manley-high-strength-516-pushrods-for-vvt-57l-64l-hemi.aspx
 

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I did this over the weekend. The job wasn't too bad. It's a little quieter but not by much. Most of what I hear is injector noise. I thought I had lost some power at first but I think my ecu needed to catch up after being reset from the battery being diconnected. My pushrods looked ok when I measured them. The new ones from HHP are definatley beefier. Not sure it was worth the effort but I won't have to worry about them bending at the track.

Sent from my SM-T800 using Tapatalk
 

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Well it's been over a year since I started this thread and things were going great until yesterday. The challenger sat in the garage all last week because I was using the wife's GC to haul the kids around. It officially has 25K miles on it and 6 month old royal purple 5w20 keeping it oiled. Well yesterday morning I needed to pull the car out of the garage. I go to start it for a few seconds the I hear significant lifter clatter that went away after a couple of seconds, mind you the garage temp was ~85F. I figured that since the car sat for so long the lifters just needed to fill again. So I drove it around town, stopped at a few stores, topped off the tank and came home. This morning I decided to take the car to work and same damn lifter clatter at startup....are you F'ing kidding me! I never heard this type of lifter clatter, even when it was 10F in the garage. I hope this clears up otherwise I am tearing into the top end and may end up doing a cam swap after all.
 

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I go to start it for a few seconds the I hear significant lifter clatter that went away after a couple of seconds, mind you the garage temp was ~85F. I figured that since the car sat for so long the lifters just needed to fill again. So I drove it around town, stopped at a few stores, topped off the tank and came home. This morning I decided to take the car to work and same damn lifter clatter at startup....are you F'ing kidding me! I never heard this type of lifter clatter, even when it was 10F in the garage. I hope this clears up otherwise I am tearing into the top end and may end up doing a cam swap after all.
It could be the anti drain-back valve in the filter isn't doing its job.

Generally for a car that sat a long time - with injection systems:
-before turning key on, press and hold accelerator pedal to floor (this shuts off injectors as if clearing a flooded engine)
-crank for several seconds (no more than 15 secs) until oil pressure registers (if you have oil PSI gauge - some of the non-EVIC '09 - '14 don't have pressure gauge)

Let the starter cool for a few seconds (windings heat up with all that current) and then crank to start normally.

This will typically preclude the dry lifter clatter
 

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Discussion Starter #12
It could be the anti drain-back valve in the filter isn't doing its job.

Generally for a car that sat a long time - with injection systems:
-before turning key on, press and hold accelerator pedal to floor (this shuts off injectors as if clearing a flooded engine)
-crank for several seconds (no more than 15 secs) until oil pressure registers (if you have oil PSI gauge - some of the non-EVIC '09 - '14 don't have pressure gauge)

Let the starter cool for a few seconds (windings heat up with all that current) and then crank to start normally.

This will typically preclude the dry lifter clatter
I am going to give it a try tomorrow morning. I have another wix filter I may try as well.
 

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If you fix your issue try running 0w40 or 5w40. Your lifters will probably bleed down slower.
 
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Well it looks like it went away. No clatter when I left work yesterday or when I started it this morning. :dunno:
 

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Discussion Starter #17
Anything new on this?

I've had the sewing maching noise for a while.
Nope, valves and engine are still quiet. In fact, started the car last night after sitting for 2 weeks (battery tender plug was accidentally disconnected for God knows how long). There was still plenty of charge in the battery and it fired up like a champ...can't wait for the snow to go away!!!!
 

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Nope, valves and engine are still quiet. In fact, started the car last night after sitting for 2 weeks (battery tender plug was accidentally disconnected for God knows how long). There was still plenty of charge in the battery and it fired up like a champ...can't wait for the snow to go away!!!!
I have the same exact "sewing machine" noise going on in my 392. Been to the dealer multiple times and keep being told that its normal. The noise ruins the enjoyment of having the car and I feel like I cant drive it the way I want to. At this point i'm ready to fix it myself, but not really sure where to go for the upgraded valve train parts. What did you buy and replace to get rid of this noise?
 

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I have the same exact "sewing machine" noise going on in my 392. Been to the dealer multiple times and keep being told that its normal. The noise ruins the enjoyment of having the car and I feel like I cant drive it the way I want to. At this point i'm ready to fix it myself, but not really sure where to go for the upgraded valve train parts. What did you buy and replace to get rid of this noise?
All I did was buy and install the comp cam pushrods I stated in post #2 in this thread. I bought it from HHP but they changed their site not to long ago so the link is a dead end but the part numbers are good. The 5.7, 6.2 and 6.4 use a lot of the same valvetrain parts...i.e. rockers, pushrods, lifters. For me the upgraded pushrods made the noise go away.


BTW there is also this a star case regarding the rocker bolt retainers that Hal brought up in another thread. It was not my issue but something else to look out for.
 
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