engine sounds like a an old Mercedes diesel

[DMANFROMNOWHERE]

I got an issue, my engine sounds like an 80's Mercedes diesel. not exactly sure what it is but im afraid its a valve issue, doesnt exactly sound like valve tick, it also gets quicker with higher rpm but it doesn't get louder, is fairly faint. i got oil pressure and its not overheating. has anyone experienced this before? not sure if im describing the sound enough

[Mr. Man]

Does it go away when the car heats up?

[DMANFROMNOWHERE]

Does it go away when the car heats up?
No it doesn't, sounds the same from cold to warm. its kind of like a muffled tick but I hear it near the drivers side head area

Maybe a bit more information will help. I swapped my heads to some 9 thread heads, but I used the hydraulic lifters from the old head because the new ones didn't have any spring to them. the old lifters or whatever you want to call them had 130k miles, I used the old rockers as well but did not touch the spring or valve

[RubberCtyRauder]

Heads have a poor cooling passage at cylinder 8 which makes it run hotter over time and can cause issues with a bent valve or build up on valve. Not just Marauder but Cobra guys too. There is a head cooling mod out there but it won't fix it if already bad. Compression test on cyl. 8 can help determine. Not saying that is it, but it can't be ruled out either just yet.

[DMANFROMNOWHERE]

Heads have a poor cooling passage at cylinder 8 which makes it run hotter over time and can cause issues with a bent valve or build up on valve. Not just Marauder but Cobra guys too. There is a head cooling mod out there but it won't fix it if already bad. Compression test on cyl. 8 can help determine. Not saying that is it, but it can't be ruled out either just yet.

I did the cooling mod when I installed the new heads

[justbob]

Sounds like a lash adjuster not pumping up.


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[DMANFROMNOWHERE]

is there a certain brand of lash adjusters that people here recommend?

[blazen71]

is there a certain brand of lash adjusters that people here recommend?

OEM. If it's a timing chain issue, plan to do a full timing chain replacement. It's a lot of work but can be done with the engine in the car.

For reference:
https://www.mercurymarauder.net/forums/showthread.php?102630-Parts-List-to-do-your-Timing-Chain-Guides-Tensioners

https://www.modularmotorsportsracing.c om/cart/index.php?main_page=product_in fo&cPath=4_9_51&products_id=168

This is not necessary, but if you have OCD like I do, this flips the pass secondary tensioner so it tensions the chain on the correct side:

https://www.modularmotorsportsracing.c om/cart/index.php?main_page=product_in fo&cPath=4_9_51&products_id=455

[DMANFROMNOWHERE]

I replaced the timing chain not too long ago, at around 115k miles I believe, I have 130k now, replaced heads and inspected timing chain and everything seemed fine so I reused it.

where can I buy OEM lash adjusters? mmr sells some but idk if thats the best place. from what ive seen its all pretty marked up

[justbob]

Tasca normally has decent prices.


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[DMANFROMNOWHERE]

UPDATE: I found the issue. I know you're not supposed to swap parts until the issue is fixed but instead diagnose and replace only what is needed but I still went and bought the Hydraulic lash lifters. Wasn't it, but at least I got new parts on my new heads so it isn't that bad.

The issue was the timing chain. I took apart the front and found that the passenger side chain was a bit loose. there was tension where the tensioner was but it was loose where the guide was. everything still looks brand new and undamaged but I have extra new parts so I'm going to replace those and reinstall the tensioner, hopefully better this time. I'm sure this will solve the issue but I will keep you all posted!

This cars been down since April with a month or 2 of it finally working only to make a noise and be out of commission. I could've had a shop fix all of this by now but its all a learning process so no regrets

[justbob]

That’s normal. Dumb design.

Rotate the engine and you’ll see it tense up, then slap around depending on where the valves are.


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[DMANFROMNOWHERE]

UPDATE: runs like new. I replaced the tensioner with another new OEM tensioner and it fixed the issue.
Not exactly sure why this happened. it might be because the heads got resurfaced and thus the tensioner needed more tension?
maybe I didn't install it right the first time? but if I didn't, why did the noise start happening months after everything was reassembled instead of right away?
I had fresh oil and oil pressure.

beats me, but if your car ever sounds like a 80s German diesel, might want to look into timing chain tension.

[DMANFROMNOWHERE]

not fixed, never mind... not only that but a bigger issue arose.

[justbob]

Details?


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[DMANFROMNOWHERE]

the noise came back with a vengeance, whatever the issue was... it broke my valve cover.

[justbob]

Front of cover? Did you replace the tensioners when you did the chain?

I did a bone head move years ago where I didn’t install the cam sprocket spacer. Oops.

It was trouble free all day including three hour round trip to the dyno, dyno time at 20 psi boost, and ran errands all afternoon.

Two miles from home and zero warning, snapped the cam sprocket in three pieces, imploded the tensioner, and sent all the shrapnel into the oil pan.. I had it all back up and running to perfection three days later and heading to the Louisville meet. [emoji16]

Mistakes happen.


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[DMANFROMNOWHERE]

yeah, I had bought the timing kit from adtr.net so everything is new


so a bit more of an update, it was the drivers side exhaust
camshaft bolt. it completely sheared off and broke the valve cover.
it also broke the camshaft position sensor and both the head of the bolt and the plastic of the camshaft position sensor are somewhere in my oil pan probably.
I have to fish it out somehow, I'm probably gonna take the timing cover off, remove the remaining piece of the camshaft bolt from the camshaft, replace it with an ARP bolt i bought and fish out the bolt with a magnet and hopefully the plastic with something I can scrape it with if it doesn't come out when I change the oil.
not sure exactly why it sounded the way it did but there was something moving there.
luckily the timing sprocket is still there and in position, I'm pretty sure timing is still good so there was not a lot of damage other than the valve cover and camshaft position sensor. there are some scuffs and scratches here and there but nothing that would affect the performance of the car or on any mating surface.
I pray that this is it and im finally able to drive my car once again.

[justbob]

Wow, quite the mess. I fished all mine out the front of the pan with the timing cover off. Lots of brake clean to wash any remainder towards the plug.

I forgot to mention the five brand new stainless valves that I also bent..

I ended making a clock out of the nuked parts on that car.

Keep us updated!

https://uploads.tapatalk-cdn.com/20230207/42ff52544dee2354c9051920e612e7 fb.jpg
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https://uploads.tapatalk-cdn.com/20230207/d6149493975176cc6a6fef5ce333f6 7a.jpg


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[blazen71]

Sounds like the cam sprocket bolt came loose. That's probably when the noise started. Then after running loose it broke. My guess is a TTY bolt was reused?

[DMANFROMNOWHERE]

Sounds like the cam sprocket bolt came loose. That's probably when the noise started. Then after running loose it broke. My guess is a TTY bolt was reused?

that was my guess too, however I wouldn't know if it was since i bought the head already assembled with the cams on. I replaced the hydraulic lash adjusters or lifters and the rockers but the cams were still on, didn't touch them.
I haven't had a lot of time on my hand so I haven't been able to do much but i have taken the timing cover off and found the plastic piece from the camshaft position sensor, however I haven't found the camshaft bolt yet. I got a magnet that bends so hopefully with some luck ill be able to fish it out fairly quickly. the only thing left to do after that is remove what's left of the bolt, replace it and seal everything back up.

[DMANFROMNOWHERE]

That clock is so cool man! awesome conversation starter!

Wow, quite the mess. I fished all mine out the front of the pan with the timing cover off. Lots of brake clean to wash any remainder towards the plug.

I forgot to mention the five brand new stainless valves that I also bent..

I ended making a clock out of the nuked parts on that car.

Keep us updated!

https://uploads.tapatalk-cdn.com/20230207/42ff52544dee2354c9051920e612e7 fb.jpg
https://uploads.tapatalk-cdn.com/20230207/6c60080838a75d19fde71ad9cea7d4 88.jpg
https://uploads.tapatalk-cdn.com/20230207/d6149493975176cc6a6fef5ce333f6 7a.jpg


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[blazen71]

that was my guess too, however I wouldn't know if it was since i bought the head already assembled with the cams on. I replaced the hydraulic lash adjusters or lifters and the rockers but the cams were still on, didn't touch them.
I haven't had a lot of time on my hand so I haven't been able to do much but i have taken the timing cover off and found the plastic piece from the camshaft position sensor, however I haven't found the camshaft bolt yet. I got a magnet that bends so hopefully with some luck ill be able to fish it out fairly quickly. the only thing left to do after that is remove what's left of the bolt, replace it and seal everything back up.

Freedom Racing has these cheap. Or use ARP reusable bolts

YF7Z-6279-AA Camshaft Sprocket Bolt (Torque to Yield)
F1AZ-6278-A Camshaft Sprocket Washer