TurboZ28408

iTrader: (18)

i have a motor I just slapped in the car and fired it up the 1st time today


I had an LS1 built before but developed rod knock after racing. the piston slightly hit the head but did not bend any valves or anything.


I had an LQ4 built at a machine shop and had them install new rods, pistons, bearings, balance, torque plate, bore etcc as well as refurbish my head and install new guides etc.


During this time, I'd also have them install new lifters into the motor with my old ls1 turbo cam approx a 230/232 .594 lift with 114 LSA I believe.

I reuse my old push rods. and upon starting the car, i get great oil pressure about 80 psi or so but I get a pretty bad knocking noise.


While researching youtube for similar sounds. its not rod knock .. cuz rod knock is just horribly loud.

I'd imagine its the push rods or the lifters ? ( brand new lifters remember)

how likely is it that the chromoly push rods had bent when I spun the bearings in the previous motor ? How can I check ? I also think it could be a lifter issue but changing out pushrods rather than lifters is a much easier job. Possible I have air in the lifters ? I'm sure the machine shop would've soaked them in motor oil. and when putting the heads on i had put assembly lube on top of the push rods and lifters.

Now that I think back, I wish i would've checked the push rods to make sure they were straight.


any tips or pointers or things i could try ?

lmt0705

iTrader: (7)

roll the pushrods on something flat and see if they wobble, did you check pushrod length? check for a cracked spring?

TurboZ28408

iTrader: (18)

using this ...

Here it is again in a nutshell:1. Using the EO/IC method, get the lifter to the base circle of the cam.
2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn wtih a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...




i fall right in 1.75 turns so thats " technically" the .050 preload

cowboysfan

roll the rods on flat glass. hows ur oil pressure on start up?

TurboZ28408

iTrader: (18)

oil pressure is good. The valvetrain noise is registering from the driverside bank of cylinders 1-3-5-7

I've used the method above and all my PR's are within spec EXCEPT #3. rolled on a flat surface none of the PR's are bent. I did find some fine metal shavings on cylinder 1 rockers and thats right next to #3. no other cylinders share the same shavings.


cylinders 1-5-7 all reg about 1.25-1.5 " turns" until 22 ft lbs

However# 3 only registers .75-1 turn


all PR's are 7.400

is it possible just 1 PR out of the bunch is off ?!?!

getusumws6

iTrader: (9)

your rocker might not be seated correctly on the pushrod.

TurboZ28408

iTrader: (18)

well .. i put it all back together and no noises now =) now to find some CEL gremlins and tie up loose ends

Soul TKR

iTrader: (4)

interesting fix/result