Imndeep

Hello,
I'm wondering if anyone here on the C5 forum has run Marvel Mystery Oil or Seafoam through there crankcase to clean up their engines? I have a LS1 with about 82k on my C5 and it makes some lifter noise in the morning and after warm up. I heard that these engines are inherently noisy. I'm within 3% of an oil change and need to figure something out soon. TIA

73Corvette

Good luck, you may need to do a valve adjustment and take a look before a little problem becomes a bigger problem...

jakecol

I too would be interested in the results of this process. Good luck.

Imndeep

I'm an old MoPar gearhead use to playing with Big Block's. This LS1 business is new to me. So You're telling me I have adjustable Hydraulic drivetrain in my LS1? I just drive and enjoy my Vette, I have my wife's BMW X5 for maintenance worries. I have never had the need to look up LS1 issues before, they're pretty damn reliable.

Sigforty

I have done both and even used Amsoil Engine flush. Not sure I noticed any difference though. I do like to use the Seafoam as a top end cleaner sucking it through a vacuum port into the intake.

Imndeep

So a buddy of mine who was an Automotive Engineer sent me this:
http://www.rjsmith.com/gm-1206539.html
I got the car at 20k miles on it and now have approx 82k and all along it has made the same noise. Maybe my step dad didn't care about it when was new, or he didn't notice it.

73Corvette

Seems to be a fairly simple straight forward fix..

LoneStarFRC

It is not. The valve-train assembly is what's referred to as a "net build" design, meaning you assemble all the parts and tighten the rocker bolt to the specified torque. All clearances, tolerances, dimensions, etc, are designed into the parts.
Of course I'm speaking of OE assemblies. This can (possibly) change when people modify by using aftermarket parts, i.e. valves, springs, pushrods, rocker arms, etc.

HTH

73Corvette

From what I've read so far.. no real world experience with the LS1 valves but that being said They should be torqued to 22 lbs and they can back off...someone correct me it that is wrong please.

Question...the stock LS1 comes with Hydraulic Roller Lifters and Roller Rockers and the only adjustment is the torque?

LoneStarFRC

IIRC, that torque value sounds correct, but LS engines do not have a history of rocker arm bolts "backing off" or "loosening". The rocker arm needle bearings are more likely to fail (introducing slop that can be very damaging), than any backing off of a bolt.

For the record here, we are now speaking primarily of rocker arm/pushrod/lifter components and not "valves", correct?

73Corvette

Yes sir...as you can tell I'm pretty "old school" and sometimes completely surprised... like kid on christmas, finding out new things about this car...

Thank you for your patience and help.

73Corvette

This helped me

What Causes a Lifter to Make Noise

There are a number of issues that can cause a lifter to become noisy on startup, or even all the time. Here are some of the more common ones and I’ll go into more detail later in this write-up;
Wrong valvetrain geometry
Lack of supply oil
Debris in the lifter
Before going into details of the causes listed above, an understanding of the reason why we use hydraulic lifters would be helpful.

Why do we use hydraulic lifters? Couldn’t we just use solid, nonadjustable lifters? The answer is yes, and many engines used for racing, aircraft, lawnmowers and such run with solid lifters. The advantages of running solid include reduced valvetrain mass (racing, aircraft), lower cost (lawnmowers). The disadvantage, clearance adjustments are critical for proper valvetrain operation and have to be checked on a regular schedule. This clearance adjustment requires a number of factors to be taken into account to pick the proper numbers. They include thermal growth and wear. The set clearance needs to be adjusted as the engine accumulates time due to normal wear and erosion of valve face and seat. There is a procedure that needs to be followed to set the initial clearance and for the scheduled checks.

The advantage of the hydraulic lifter is easy to understand. Properly setup they will self-adjust for wear and erosion over the life of the engine without any manual adjustments.

I won’t go into the detailed history of the hydraulic lifter other than to say it was one of the biggest advancements to the four stroke engine.

The current hydraulic lifters are nothing short of amazing. The machining and assembly details are astonishing feats. They have the tightest and most detailed specifications used in the LS engines compared to all the other engine components.

So, how can any manufacture mass produce something with these demanding specifications? Just holding tight machining tolerances isn’t good enough. The only way this can be pulled off is using select fit builds. After the machining and cleaning, each component of a lifter, is measured and cataloged in a computer inventory. During assembly the computer will match the proper parts to achieve a perfect fit. Then each assembled piece goes through a series of test to insure proper operation. Part of continuous improvement, the tolerances once reserved for high performance engines, like the LS7, or LS9 are now shared for ALL LS engines. If you order from a dealer a set of hydraulic lifters for your 10 year old plus LS1, you will receive the same exact lifter found in a new LS7, or LS9. Some folks that market so called “performance lifters” might not want you to know this little fun fact.

Noise due to wrong valvetrain geometry

The modern hydraulic lifter is capable of operation in a large dimensional range compared to any solid lifter. This range is about 2.5mm (.098”). Anything out of this range can make noise. Things that cause this include improper valvetrain geometry, failed components like cam lobe, or rocker, and even a bent push rod. A weak or broken valve spring may cause the valvetrain components to be out of phase with each other allowing them to separate and impact as they crash together again.

Noise due to lack of supply oil

One of the side benefits of the hydraulic lifter, due to their sensitivity to oil pressure, they are one of the first clues that your engine has lost oil pressure. The lifter noise made when there isn’t adequate oil will get the attention of even the non-mechanical folks. Just by the sound they know something bad is happening. Shutting down the engine soon enough can save it.

Other reasons for lack of oil include bad oil pump, stuck oil pump relief valve, low oil level, or something wrong with the oil pickup tube system.

Noise due to oil aeration

This might still falls under lack of supply oil. Oil is capable of holding air in suspension. At high engine rpms the windage from the crankshaft and other moving components can aerate the oil enough that once the engine is shutdown, the oil inside the lifters can release this entrapped air into the high pressure chamber of the lifter. Now, on the next cold start the lifters can compress enough to allow valvetrain components to separate during initial start and clatter for a short time until the air works its way out. Normally this only takes 30 seconds to no more than 2 minutes.

Debris in the lifter

This is far less common compared to other reason for lifter noise. In fact I’ve only seen this on new builds. The lifters found with this issue were traced back to plastic fragments matching the lifter carrier. When the lifter is inserted in the carrier the body of the lifter could scrape plastic off and fall into the pushrod sock. The part I never could understand is how this could find its way down into the high pressure chamber of the lifter.

73Corvette

In the past I've had good success locating little ticks or pecks putting a broom handle in different locations on the engine to pin point where it is coming from...it actually works pretty well, if your patient and keep poking around till your sure of the origin.
Of course the other end of the broom handle is put on your ear..


A LONG screw drive works well too..

You can usually get right on top of the culprit and have a really good idea what to expect when you pull a cover. Works well for other noises/sounds also especially the ones that travel...

LoneStarFRC

GTH if I can. FWIW, I too have learned a great deal about the LS family on CF over the years and from doing some wrenching myself. There's also a couple really good (and very reasonably priced) books worthy of purchasing, dealing with LS engines, their history, difference between years, parts illustrations, etc.

Check Amazon if interested.

Sigforty

The LS series of engines also have noisy fuel injectors. It could be those just as much as the lifters. A mechanics stethoscope would be a good tool to try and pinpoint the noise.

73Corvette

I totally agree we found a bad injector on a buddy on mine, son's car. Using the poor mans stethoscope.

Is that a fancy word for broom handle?

LoneStarFRC

GM obviously agrees, as the introduction of the LS2 in 2005, brought with it black, molded-foam sound deadeners, attached to the underside of the engine "sight covers" (AKA "fuel rail covers").

I'm not sure to what degree, if any, this practice has continued with the OE LS7s or LS3.

Sigforty

Yep.

C66 Racing

If your car has had regular oil changes with a decent synthetic, I don't see the value in a flush. I personally have never used one.