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Username Post: piston slap        (Topic#298155)
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
05-31-13 01:01 PM - Post#2350732    

Just purchased an 02 transam convertible. 81k on the odometer. No issues so far except that annoying piston slap ( its embarassing to hear when you start the car cold). It goes away after a few minutes and all I have read says it is normal. Short of rebuilding the engine ( no need for that) is there any real way to reduce the start up noise? I have read about Seafoam, etc. but they all sound like temp fixes or magic. I run 5w-30 full synthetic oil, would a 10w-30 work better? One person suggested using a better oil filter ( with an improved anti-backflow valve). So I ask, is there a real success story out there or is just something I have to live with?



 




models916 
Valued Contributor
Posts: 4785

Age: 68
Loc: Addison, IL
Reg: 05-28-10
06-03-13 05:50 AM - Post#2351439    
    In response to george88gta

Could try an engine block heater. Oil drains and the piston shrinks when cold. It rattles until it warms to size. My old S10 did it for 15 years with no problems. It's not a pressure problem, oil and filter will have no effect. Try some Lucas oil stabilizer with some 10w-30.



 
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
06-04-13 05:52 AM - Post#2351793    
    In response to models916

Seems like an easy test. Next oil change I will switch to 10w-30 and add Lucas. My 2001 S-10 is very quiet. Always dealer serviced and they use 10w-30. Maybe they are on to something. Thanks for the info.



 
fbi9c1 
Frequent Contributor
Posts: 1921

Loc: Los Angeles
Reg: 08-07-07
06-05-13 07:19 PM - Post#2352348    
    In response to george88gta

I would love to hear the theory of why switching to 10W would be of any benefit to an LSX engine. Don't put that Lucas crap in there either. If you want oil to circulate faster and more easily on startup, use 0W not 10W. If the dealer is using 10W, they aren't following manufacturers recommendations. Seafoaming your engine for carbon build-up might be a good idea.

Jim B.


 
fbi9c1 
Frequent Contributor
Posts: 1921

Loc: Los Angeles
Reg: 08-07-07
06-05-13 08:39 PM - Post#2352370    
    In response to fbi9c1

To amplify a bit further, this is a common issue with the LS engines. The piston is slightly too small and as stated it stops when it heats up and expands. Seafoaming every few months will help a bit as will using a top tier gasoline like Chevron and Shell to fight carbon build up. It will never go away but many engines last 200,000 without problems, others will break a ring sooner. Some don't have the slap at all.
Oil, filters, etc. aren't going to have any effect at all. You have been using the right stuff and I wouldn't change, Whatever you do, do not use additives with LS and LT-1(gen II) engines.

Jim B.


 
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
06-07-13 02:34 PM - Post#2352941    
    In response to fbi9c1

OK, good info. What is strange is that I picked up this car in February and the engine was relatively quiet. Brought it home,let it sit in a heated garage until better weather. I decided to change the oil and filter. Used 5w-30 full synthetic and now the engine has a definite piston slap noise. Dont know what oil the car lot guy used, he claims oil was changed just prior to delivery. Anyway, I was wondering if a thicker oil would cling to the cylinder wall, between runs, better than the thinner oil. I have some GM top engine cleaner that I will use with the next fill up. Shell is my brand of choice for all my cars, so that helps with the carbon buildup. So far I have only put two tankfuls in the LS-1 ( 4 vehicles and only two drivers, plus dogs that love road trips, not riding in this car).



 
89RS98Z28 
Contributor
Posts: 680
89RS98Z28
Reg: 10-14-04
06-11-13 04:11 PM - Post#2354252    
    In response to george88gta

Got the 98 ten years ago 85,000 miles.....293,000 miles now. Daily driver. Slapped when I got the car still slaps today. Daily driver that has only had a water pump and battery replaced.
Fuel pump will at times sound like an airplane in the rear but every other tank full add MM Marvel mystery oil 8 ounces per 10 gallons of gas and noise quiets greatly. Started getting noisy at 120,000 but like the bunny just keeps going. Oh just changed plugs for only the second time in 200k miles.
Limited city mostly country driving...averges 23 and on the highway can still get 26+mpg. I use 10w and change every 3 or 4 thousand depends how I've been driving. I call the car bad hay cause its still a real pony killer....

A lesson learned the hard way is not easily forgoten.


 
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
06-12-13 06:03 AM - Post#2354473    
    In response to 89RS98Z28

Thats kind of where I am headed. I added the GM cleaner yesterday and we sill see if it makes any difference. I have enough of the cleaner to do another tankful so it will see at least two applications of the stuff. Next oil change I will try some 10w-30. If no change, I will switch back to the 5w-30. I will post the results.



 
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
06-18-13 02:29 PM - Post#2356420    
    In response to george88gta

Here is an update. I changed the oil to 10w-30, new filter. Slap/noise seems to be a bit less, but it definitely stops sooner than before. Engine gets relatively quiet, not bad for an LS-1. Havent used up the first tankfull of fuel with the GM top cleaner. FYI, the owners manual specs 10w-30 for 0 degrees F and above as an acceptable oil. So for now I will just drive it and listen for any changes. I may do a second application of the top cleaner but not sure of the value to doing that.



 
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
06-27-13 01:55 PM - Post#2358917    
    In response to george88gta

Latest info. I still wasnt happy with the upper end noise around cylinder #2, so I pulled the valve cover. #2 exhaust rocker was very loose ( at TDC) as compared to the intake rocker. I removed the rocker and found that the bearing was very loose and the top of the pushrod was oval shaped, no longer round. Having a complete/new truck engine (LQ4), I started replacing the push rods and rocker arms. The interior of the engine is a brown varnish color, not really dirty or full of sludge. The Carfax showed oil changes at every 7-8k and it was a one owner car. None of the pushrods were plugged or clogged, but there was definitely something preventing adequate oil flow. I think a few low mileage oil changes are a good plan. Time will tell.



 
elcamino 
Dedicated Member
Posts: 5411
elcamino
Loc: Lake Superior-Michigan US...
Reg: 03-30-00
06-30-13 04:03 AM - Post#2359562    
    In response to fbi9c1

I agree, DO NOT USE Lucas. If you are using good oil these additives only serve to dilute it. Just because some never had a problem using it is no proof there is any benefit from it. The only people benefiting from oil additves are those selling them.

The W is the winter flow rating of the oil, its does not mean weight or anything else. Meaning a 0W will flow faster than a 10W. So the higher the "W" number the slower the oil flows when cold. A 0W-30 and a 10W-30 are both the same viscosity oil at operating temps, 30.


PS - I had a 2002 (new) T/A WS6. I always used 0W-30 100% synthetic.

Mike
2017 GMC Sierra Denali Ultimate 6.2L(420hp)/8-sp Z95
2018 Polaris RZR S 900 EPS


 
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
06-30-13 08:04 AM - Post#2359627    
    In response to elcamino

Its all back together, 16 new pushrods and rockers. No more heavy knocking, etc. Valve train is noisey, but I am told that is normal for an Ls-1. I will run it for a few days and then an oil and filter change. Run that for a few days and change oil/filter again to see how oil looks. Thanks for the help everyone.



 
89RS98Z28 
Contributor
Posts: 680
89RS98Z28
Reg: 10-14-04
07-15-13 12:17 PM - Post#2363851    
    In response to george88gta

Glad all the replys that the cars are just noisy did not stop you from finding a serious problem. So now that thats fixed, drive it like you stole it and let us know how much you really like the car.

A lesson learned the hard way is not easily forgoten.


 
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
07-16-13 07:14 AM - Post#2364052    
    In response to 89RS98Z28

So far so good. I have added subframe connectors and an adjustable strut tower brace, both from Spohn. This is in addition to a set of Bilstein shocks/struts and springs. Rides a bit harder than my 88 GTA (I replaced the suspension on that with all GM WS6 parts), but I know I will need tires soon, so I am hoping that new tires will help the ride a bit. Corners well, lots of fun to drive. Who knows, maybe some day I will turn on the radio, for now I just enjoy the car sounds and handling and make sure that I do several frequent oil changes for a while.



Edited by george88gta on 07-16-13 07:18 AM. Reason for edit: No reason given.

 
Black66CK 
Forum Newbie
Posts: 27

Reg: 09-23-13
09-23-13 08:51 AM - Post#2384634    
    In response to george88gta

Does it have a stock cam and everything?



 
george88gta 
"15th Year" Silver Supporting Member
Posts: 1984
george88gta
Loc: new york
Reg: 04-23-03
09-23-13 02:43 PM - Post#2384701    
    In response to Black66CK

Yes, car is completely stock. At least as far as I know. One owner car and no Carfax records of anything but dealer service and repairs.



Edited by george88gta on 09-23-13 02:44 PM. Reason for edit: No reason given.

 




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