(Engine Trashed?) Thread of Unfortunate Events

Thanks - I’m no FI expert but was the boost level proven out by pro charger or whoever put the kit and tune together? As an engineer I’d thing there would be some level of testing to show the engine can handle those boost levels for X miles.

 

From research I've seen stock internals can handle 6-8psi of boost. The stock springs I dont think can handle over 7k rpms though and pretty sure I was able to get up to 7500ish (which would explain the thrown rocker arm on cyl 4). I know for a fact that there are many maggy and pro charged 2gr fks' with stock internals and have had no issues. The real issue in my case was the tune. I was an early tester for Yotawerx procharger tune that eventually caused engine failure. Unless someone can actually confirm another reason for the ring landing to pop like that. I'm going to make sure on the next tune that we have a conservative rev limit in place to protect the engine.

I also had a trusted performance shop (the shop that's building my corvette motor) confirm that a poor tune would have caused my failure.

 

Ooo, what's the corvette motor specs?

418lsx? fast 102 intake? afr heads? lumpy cam?

 

The mightiest of cams.

 

Rip. Worth a shot, but they are blaming the valve job. The shop did. (Ran the vehicle for maybe 10 minutes) after the valve job. Every "mechanical" thing we tackled was evolved around the cylinder 6 imbalance code.

 

If they admitted fault that would ruin yotawerks.

 

Eh, yotawerx has been ruined for nearly 2 years now, I don’t think it matters anymore. They couldn’t do anything to help with this even if they wanted to.

Regardless, I think that answer is complete crap. A poorly sealing valve isn’t going to destroy the cylinder, and for whatever it’s worth, there is nothing to “adjust” in the valve train on this motor. That is why we have hydraulic lifters. The tune is likely what caused the trouble, and ain’t no way yotawerx will do anything to help with it. That’s why you sign your life away on the piece of paper when you buy their tune packs, so they have no fault if things go south. With yotawerx, they’ve fallen so far that even if that wanted to help, they can’t. The guy who started it and built everything isn’t even there anymore, how much tuning assistance can they really even offer? Just an embarrassment.

 

Good news is OTT is going to work with me after the engine is fixed. So, probably won't have any tuning issues this next go around.

 

If a shop did your "valve job" & they didnt sublet it to an actual machine shop who specializes, ide also question the valve job also but didnt cause this....
Leaking valves would just decrease combustion pressures & help relieve the stress you put on the pistons from the SC....

Heres a question, how much boost are you running?
Be honest......

While you figuring things out & chewing on your plan of attack, something to check inregards to the valve job,
Check if theres any leakage,
Install all 6 spark plugs
Turn heads over & stabilize them so the combustion chambers are facing up,
Fill each chamber with water, acetone would be better but water works...
Ten with an air compressor air nozzle / blow gun...
Shove it right up against the back side of the valve through the exhaust ALL the intake & exhaust ports,
Cover the port with a rag so you really pressurize the port & blast it with as much air pressure as you can,
Your using the rag to trap the air from just coming right back out the port opening & doing nothing, pressurize the intake & exhaust ports,
With the nozzle shoved right up against the back of the valve.
Move the nozzle around all over in the port, trying to induce air bubbles in the water...
We do this with our commercial high pressure compressors at the shop,

UNDER NO CIRCUMSTANCE should air bubbles be forming...
Those valves under just spring pressure should be 200% fully sealed.

Regardless if you just had a valve job done or not, I would triple check this to verify youre good...
Way too much work to just assume cuz it was just done..

 

Thank you for this, I have 120psi and acetone at work. I'll take my heads in and perform this test. The mom and pop shop just removed the heads and sent it to an engine builder. That engine builder (Bruce Performance) replaced the exhaust valves with factory. Removed the intake valve and sent them somewhere to have "upgraded" valves machined. I don't know out of what material but they are definitely machined valves. Bruce then reassembled the heads - which doesn't look like a whole lot of work and sent the heads back to the mom and pop shop to assemble back onto the motor. This whole process took 7 months. When I drove the truck hone I still got the imbalance cylinder 6 code. That's when I parked it and planned in removing the engine a year later....

Bruce built the 5.3 V8 engine I installed into my 97 jeep wrangler 12 years ago and it's still going strong.

 

The imbalance codes are pretty much always burnt exhaust valves to no longer seal to the seat. If they simply replaced the valves, it is not surprising at all that it still leaked, because the seat corresponding to the bad valve is pretty much always ruined from the leakage.

You are going to need to address that as well. The dealer fix is just to supply a new head and new valves. So if your bank 1 head is fine, I’d add a bank 2 head to the list of parts and I’d probably add all the valves to the cart too. Otherwise you are probably dealing with very iffy valve work that will likely show up again if you don’t refresh it all with new.

 

Well the cylinder 6 is the cylinder that the piston was broke in. The valve was a bad diagnosis.

But I'll perform the test and see if they leak. I saw somewhere that the Lexus Ti valves are cheap and direct fit for these heads. I might just swap them anyway, idk how much I can trust what these machined valves are made out of.

@Jowett
Ti intake 13711-38050
Ti exhaust 13715-38090

 

Upgrading the clutch while I'm in there. Hopefully this is a good one.

 

My advice regarding the clutch/flywheel is to pick something that's the same weight as stock. We're only going up 70hp or so. Heavier flywheels and different clutch materials can make for a miserable driving experience.

As far as the corvette motor I was expecting something from the ls3 c6 era. GM lost me when they switched to the LT1/LT2 motors.

 

Seems like most like the heavier flywheel. I didn't go with one on mine because I was going with super low gearing at the time. What would make it miserable? Seems like it maybe would be slower to rev up, but ultimately smoother down low with more inertia at low speed stuff.

I'd be curious to try one on mine. Not interested in a clutch different from stock though.

 

Slower to rev, lost hp, rev matching can be more of a challenge.

For drag racing, sure a little heavier can be good. For road racing and everyday driving, don't recommend.

 

I would start with just water first....
If they dont blow bubbles with water, think youre good....
Pretty much shouldn't leak at all, should be sealed shut like a bank vault.....

Ive done this test on new heads, just to educate myself, & nothing....

Learned this when diagnosing leaking valves on the 3.0 ranger, valve seats & valves would get hammered & start leaking but visually they look ok....
Really bad ones would have hammered valve seats & tulliped valves.
Cold start cranking relative compression will be a little low on the bad cylinders.
For the most part would run fine but trucks would come in with misfire codes...

 

I too have 5.29 Gears.

 

How much boost are we talking, just curious....
I have no idea quality of factory toyota clutches on Tacomas since its really not a performance vehicle...

I ran a factory motorcraft oem clutch on my 95 5.0 mustang as pretty much the best option, there was no need to go centerforce in my application.
Was a long time ago, if I remember correctly got dyno'd at 600'ish hp at rear wheels...
14lb vortex S trim SC
cam
aluminum heads
fuel system upgrade to the hill.
amongst all sorts of other goodies I wont bore you with

 

I had 5.29 gears and then swapped in the RC60F transmission. I was thinking the low end would be annoying to wait for rev hang rpm to fall in the low gears with the transmission and 5.29 combo. Then I swapped the gears back to stock, so I am only on the transmission now, and feel like a heavy flywheel might feel nice on the current setup. But I'm also happy how it is too. Just seems like the heavy flywheel would help the anemic slow speed stuff.