SSilverSS

Ugh well after many months of terrible piston slap at startup and burning oil(and glitter in the oil recently) I have decided to rebuild. I just need some guidance for gathering all the parts I need please. Disregard my signature as that setup is long gone.

Current setup
M62 on 2.7 pulley
60s
dual pass
longtube catless dp
zzp H/E
OTTP PCM
ARP Head studs
ZZP forged and coated pistons
Head resurfaced and fresh valves 2 yrs ago
Timing set replaced 2 yrs ago
Unsure if rods are aftermarket as I bought after rebuild by previous owner

I plan to have the the bottom end rebuilt, new clutch, axles, brakes maybe wheels if any pop up on the classifieds.

I have all new girdle bolts rod/main bearings and gaskets, upgrade clutch from CED, axles from zzp. What else might I need for the engine?

Will I be able to re use the forged pistons even though they were slapping?
I am unsure if this engine was bored when it was rebuilt, is there a chance the block will be trash due to the scoring from the slap?

Also would you folks recommend stock pistons/rods for my setup if they need replacement?
I'd really like to re use the pistons and rods if possible, but i'm not an engine builder so this is new to me.

Any input you have will be much appreciated. I plan on staying in the 230-250hp range daily driven.

PS I don't have 5k to drop on this more like 2k. My builder will be taking this apart next week, but id like to be prepared if I might need anything else.

I also must consider the ZZP gen3 short block, as it is a much easier option. Any suggestions?

Thanks!

jdbaugh1

iTrader: (1)

Honestly I think the complete short block will be your best option. If your pistons are slapping and burning oil because the cylinders are worn out your sleeves may be too far gone. If it turns out the cylinders can be corrected with a minimal hone of around .002" then you can go that route, re-use your old rods but you will have to get custom .002" overbore pistons. They have .02" overbore pistons available but it is typically recommended to not bore your sleeves out that far as they are already very thin. The other option to re-use your block would be to have new sleeves installed after the old sleeves are removed but unless you know someone with the sleeve removal/install tool this can be cost prohibitive. You would be better off sourcing a decent condition used gen 3 block and going with a slight .002" overbore and custom pistons.

If you go with your old block or a used block you need new girdle bolts rod/main bearings., head studs and gaskets like you said you got. I would also replace the water pump, water pump/balance shaft chain, timing chain and timing chain components. Also a good idea to throw in a new main seal.

Henry3959

What was the condition of the cylinders when the pistons were put in?
How many miles did they last?

SSilverSS

Ok so. Builder tore engine down with me and there were wiseco pistons in there not zzp im not sure why I said that sorry. Cylinder walls are toast. Pieces of metal in the pan roughly 5-6 mm look like they might be ring or bearing pieces

HGT they have 70k if that and two qm passes on them. This engine i believe had too much ptw clearance to begin with, or I fried the rings in it somehow. Not sure

jdbaugh1 you are correct for the price of sleeves and install a new motor is the best option.

ZZP LSJ Gen3 shortblock arrives tomorrow! along with a gasket set stage 1 axles and gm upgrade clutch. Hoping this setup will hold up at roughly 250hp daily driven. Timing components look good but gonna replace anyway due to the amount of shavings ran through this engine.

Cams look decent and the head got new valves and seals 30k ago so im gonna take my chances with it. . .

Shout out to zzp. They had a gen3 block ready to go and shipped it the same day.

Does anyone know of any modifications besides the oil cooler line and oil pressure switch that are necessary??
Looked at a couple other build threads with this gen3 block but that seems to be it.

Thanks

jdbaugh1

iTrader: (1)

Awesome man getting things moving along. The gen3 short block from ZZP will safely take a beating at 250 hp all day as well as the clutch. Should be fairly bulletproof setup. What rods and pistons did you get in the short block?

Does the gen3 block use a different oil cooler or why do you have to change oil cooler lines? Is the oil pressure switch that sensor that is threaded into the oil cooler on LSJ? I have an LSJ block in my L61 Cobalt and wondered what that sensor was for since I don't use it in my application. Got me wondering if that would be a good place to install an oil pressure sending unit for an oil pressure gauge.

SSilverSS

Got the standard DI rods/pistons as I don't plan on pushing it too hard anyways. Just beat on it on the hwy every now and then. . .

Actually I was confused about the oil cooler line issue. The zzp block comes with a new oil cooler that "should work fine". On the stock lsj block i believe the pressure switch is located below the oil filter housing at an angle. However both of these locations would probably work for an oil sending unit

Builder is going to swap the head and everything over today/tomorrow and we should have it in the car by tuesday I will post some pics soon and notify of any issues we run into.

Viperoni

You put the DI (LNF) pistons into a PI (Port Injection / LSJ) engine?

SSilverSS

ZZP says they will work fine ad shouldn't affect the burn/overall performance. . . . .

Sharkey

iTrader: (1)

there has been much discussion on this topic, no real evidence of anything good or bad happening from running the di pistons with port injection. the only noteable thing is a decrease in compression with a stock gen 3 bottom end with an lsj head.

Johnny Bliss

damn how did your engine get so fucked up so fast. did the original guy who put it together not do his due dilligence