sickbananas

Hi guys,

I’m after some opinions on how to best tackle my problem.

Ultimately I’ve told my engine builder to give his opinion on what to do, as he has to fix it. Having said that I want to educate myself in the process and get your opinions which can hopefully conclude a general consensus.

My engine is a built LS with a 2.9L Whipple, which I will summarise below using my stock GM E38 ecu.

The car was previously NA, so the initial start up was done at my tuner, where he changed the settings in HP tuners to allow for the new larger injectors, new map sensor etc etc Essentially making it safe to start.

We started the engine up, adjusted some more parameters letting the engine warm up, all vitals were good, getting up to operating temperature with a healthy 4 bar of oil pressure. (The engine was oil primed properly prior to start up)

Once we reached this point, we started to increase the rpm to 2000-2500. This is when we started to hear what I think sounds like a lifter noise, it was a loud horrible mechanical clacking noise. When dropping down to idle it disappeared and then came back but not immediately on higher rpm, meaning it was not consistent. We stopped and switched off at this time as we did not want to cause any potential damage.

The engine had been running for less than 5mins for its first time ever.

As said it’s my builder responsibility, but I would like to know how best one should look at this to fix it. I want to take the zero risk path as I have too much money in this build and can’t afford for failures.

All input/feedback will be appreciated! Thanks in advance!

Here is a summary of the build:
ALL PARTS ARE NEW

-LQ4 block bored to 4.030
-Stock L77 crank
-Summit forged connecting rods
-Summit forged -12cc dished pistons
-Summit matched rings
-Clevite bearings
-ARP studs used
-0.051” Cometic head gaskets
-Melling high flow/pressure oil pump
-OE lifter buckets
-Delphi LS7 lifters
-OE rockers with trunnion upgrade
-Tick performance pushrods
-BTR dual valve springs
-BTR PDS cam
-821 casting ported heads
Calculated compression ratio 9.3:1

jayyyw

Sounds like a failed lifter out of the box. Definitely don't run it anymore. You should be able to narrow it down to which one(s) are causing the noise. Let the car sit overnight. pull the valve covers off and check to see if any rockers have excessive lash/movement. It's not an uncommon failure, although it does suck. I recommend going with Morel drop-in lifters.

Old Buzzard

And.... Cut the filter open.

Jimbo1367

I agree with the previous recommendations. You could also remove the intake and valley cover tray. When they rebuild the motor, did they use GM trays? Anything other than GM trays are a crapshoot.

sickbananas

Thanks for the replies so far. Yes genuine new GM lifter buckets were used.

Once we start to open things up, I will post what we find/what the outcome is.

grinder11

iTrader: (1)

The fact that it stopped, then came back, makes me think it may be a broken valvespring. This sounds exactly like my first 427, a Darton back in 2005. Valvespring broke at approx 2,500rpm, as I left a stop sign for work @5:00 A.M.. 300 miles on engine. Not saying that is what it is, but what it could be. I heard it immediately. All of a sudden, a loud WHACK WHACK WHACK!! Then nothing. Then another WHACK WHACK. Hope this helps, and best of luck to you. Like old McDonald..... Here a whack there a whack, everywhere a WHACK WHACK!!!!

Jimbo1367

At least he’s trying to get it resolved vs. continuing to drive it.