That sounds awful. Valves hitting pistons? Pistons bouncing around in bore? Doesn't sound like rod knock.

 

Someone mentioned piston slap, due to pistons not having the right clearence. I don't understand how the car sat for 3 weeks and on first startup this happens.

 

Wow. So hold on, are you guys saying that a/m headstuds and gaskets are bad for our engines? My reason being is that I've just commited to purchasing this built motor that was built with the intention to turbo but was instead s/c'd:

The motor contains the following:
Block:
Laskey Racing Block
CP Pistons
Carrillo Rods
Darton Sleeves
ARP Headstuds
Brand New OEM Bearings
Micropolished crank

Head:
Ferrea Titanium Valves
Ferrea Titanium Dual Valve Springs
Ferrea Keepers
Ferrea Titanium Retainers
Port & Polished Head
Cometic Steel Head Gasket

 

Arp studs need to re tq, and if you look at 9/10 engines on here, it seems like its stock block is the way to go.

 

Did a compression test
Cylinder 1,2,3 all 15OPsi
Cylinder 4 125psi

Pulled the head and inspected the gasket etc. ARP's were properly torqued. HG looks fine. There are a few things I noticed.
Intake valves on #4 noticeably shinier black then others.
Block guard somewhat clogged from coolant.
Dark black/green oil.
Here's a few pics just to get any and all advice.
Improper bore size?
Broken rings?

 

Yeah compression is way too low. Should be in the 220-230 psi range.

 

Not with a 2mm HG

Blockguard and a 2mm HG? Man it could be a lot of things wrong

 

It's not exactly 2mm anymore.2 layers were removed so I'm guessing 1.40 give or take.

Any suggestions guys? I just naught telescopic gauges and a caliper gauge to measure bores up.

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lose the block guard. on my gsr turbo built i had one on and it clog up and cost me a lot of over heating. but you should check if your head or block is wrap.

 

Would this make any difference if the motor never overheated?

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