Hey guys...

I have a 2000 Ls1 with what i think is some severe piston slap. A little background for u. When the motor was in the car, at startup i thought it was a rod berring, but i know what a berring sounds like and this wasn't quite it. So at cold start it was bad but as it warmed up it quieted some but not all the way. So i pulled it out and put it on the stand. I tore the motor down and found that the main and rod berrings look to be perfect after a 118k.
I will build the motor with home ported 853 heads and exhaust, 3.42 stock gears prolly 3600 stall...and i am looking at the polluter v2, maybe on the 111 lsa. My goals are streetability and strip on the weekends. Trying to be at the 11.5 time so i dont have to put a cage in the car. My question is: withe piston slap like it is do i need to replace the pistons? I'm thinking the block needs to go to the machine shop for the full prep. I also need to have the rods resized for the arp bolts. My machine shop said that if i put them in without resize there will be 8-9 extra ft lbs on tourque down. The motor ran strong with the slap, it was just to much to listen to, plus i thought it was hurt. The cam berrings were wiped bad, the copper was showing all over them. Anyway the engine is sitting on the stand and its telling me to just put some new trimetal berrings in and cam berrings ws6 pump and put it back in. But that wont cure the loud slap. So guys what do i do next?? Thanks Marc.

 

Why not have the block honed and replace the pistons?

 

Is that what i will need to do, replace the pistons? If so i may as well have it bored the small amount these engines can take...yes? But i can't order any pistons till after it would be at the machine shop for a final bore number correct? I don't have alot of bottom end experience mostly top end...but i am learning, and reading alot. Thanks Marc

 

Yes the rods need resized for the ARP bolts, otherwise they will be out of round. You will need to replace the pistons if the slap was as bad as you say. Just have a nice hone put on the block and get the correct size piston. as for the BEARINGS....replace them as needed and get back on the road. Seems like your cam choice might be a little extreme for a weekend only track car, yes the Polluter V2 has good driving qualities, but i bet if you called and talked to a sponser you could find a better fit for your car. 11.50's is not a hard time to achieve.

 

I haven't seen a ls1 that didn't have some sort of piston slap. loose is fast and these motors last forever whether they sound like a cummins or not. if its just a weekender get some domed pistons with a fat relief and run a big cam on a tight lsa and spin it to the moon. e85 is your friend.

 

This piston slap was enough to sound like a rod bearing. I see that some people just put the arp bolts in without resize. I have been told thats NOT a good idea. I REALLY want to just put berrings in it and go, but i dont want the noise that did not fully go away warmed up, and i dont want to put it back together and have any damage and have to pull it out again. Thanks...i'm really torn on what to do!!!!!

 

fwiw a friend of mine tore down his 160k mile motor for the same reason. bearings looked perfect no wear on the cylinder walls. we honed it, put new rings bearings oil pump chain etc in it, cammed it and put a 200 hit on it...same pistons...this was 5 years and 40k miles ago. no noise and it still runs hard. the piston slap is inherent due to the short skirt. my 99 car has done it since it had 35k miles on it. 110 now and no probs.

 

Do it once, do it right.

You need to have the rods resized
You really should have the block honed and replace the pistons with a good aftermarket piston.
You will need to have the crank re balanced for the new pistons.
The cam bearings were most likely not wiped as you said. Most cam bearings from the factory were showing copper. It's just part of the machining process to fit the cam.

 

Thanks for the replies guys...anyone else have an opinion on what i should do next?

 

Heres another thought i had. Do i need to wait till after the block goes to the shop for the hone and balance before i order pistons for the final diameter? Can someone tell me all the things i should have done to the block and rotating assembly to run 7000 plus rpm and know that it will hold together. My shop said they have not got a clean room for assembly so i have to put it together myself. So after all the stuff is done do i need to have them order all the bearings for me? What kind do i get? I want really good
ones. Trimetal? H series? P series? I dont know thanks. Marc

 

Bump...TTT

 

You need to do some research buddy, use the search button.

You have been told what you should be doing & that's do it once do it right.

Not quite sure what you what to hear!

 

You need to have pistons before it gets honed. Your machine shop will be able to tell you how far it needs to go to clean up. Just be prepared, if it's more than .005-.007, you're going to need a new block.

That being said, they also need pistons, rings, rods, rod bearings and wrist pins/clips before they can balance it.

 

If I were in your shoes, I would call up HKE or Tsp and look into a pre assembled short block. ONce you start adding up machining costs, and parts, you will probably break even or come out ahead with a short block from them. And all you have to do is put your top end back on and drop it in.

 

Agreed, I machined and built mine myself just because I got a great deal on the parts but if I was was in your shoes I would definitely check out buying a short block because it often does become just as expensive to machine one and build it.

 

I'm in your predicament as we speak, and I just dropped my block and heads off for machining. I had pretty bad slap on #1 and #4, but Kim Barr says that he's probably going to have to take it to 3.905, and from what I can tell, that's common. I am waiting on his phone call to let me know for sure what size. My motor is out an '01 vette with 116k. Cylinders bored, crank milled, heads worked, possibly need decking with a easy port alone was $700. Kim told me that if you're not going to change rods, don't bother with ARP bolts. He says you can never get them right, and in a 400HP setting, it doesn't matter to use the stockers. He and others have said that the rods are strong and that they are just going to check to see if they are out of round. I've extended the build time, and allocated $2000 more to the motor just to get it done right the first time. I'm doing an S-10 swap for my cousin, looking for only around 400 rwhp, so my senario may be different. I would just see what your machinist says, and follow his advice. You can get a good set of pistons for $600 {JL}, good bearings {Clevite} (cam and crank) for around $300, replace lifters with at least the new GM design that cover the rollers more ($200), springs, and some push rods ($200). It honestly depends on what you're trying to accomplish. Set your horsepower goal, and build to accomidate it. It's hard to change just a couple of things, and expect it to perform good. Imagine breaking both legs, but only getting one cast. It may work, but later on it'll bite you. Just my thoughts. My 3 month project just turned into a year, but I'm good with that, as long as it's done right.
*** $2200 for the motor, expecting $2000 in work and materials to get it right. I wish I would have just gone with the $3800 long block. I'd have a running motor by now.

 

Thanks for the info...the other option that i am looking at is getting a LQ 9 from a caddy at a wrecking yard for anywhere from 8-$1500 and go that route. And either cam it, while building the LS, or just build the LQ9. Decisions, decisions...Hmmmm? Thanks. PS. I am of the school to do it right the FIRST TIME!

 

Only issue with that is that I hear with the iron block, it tends to make the front end react different because of weight factor. Have you pulled your motor apart yet?

 

I believe the weight difference is only 65lb. Going from an LT to an LS i found no difference in the way it handles, if that is comparable. I have pulled the motor apart, and ALL lower bearings look perfect. Except for cam bearings have the copper showing through, quite a bit actually. Which i have been told on this thread is normal for fitment. The piston skirts do have scuff marks on them. But i dont really see alot on cylinder walls. Thanks. Marc

 

If there are no grooves in the walls, get it honed, and buy some pistons and moly rings from Enginetech. They have OE style replacements, I think Speed Pro or Keith Black with coated skirts for less than $300. Sounds cheap but from what I've researched, good if you're not making big ponies. <500
http://www.ebay.com/itm/97-04-Chevro...e17c7a&vxp=mtr