Hello!

I have a 1984 300zx with a SBC and g-force 101a that I have installed an s480 turbo. I run an MSD 7 programmable ignition box and a 750 Holley HP. No intercooler on pump E85. I only want to run max of 10psi. I have a goal of 850rwhp. My chassis/class prohibits anymore; Too fast for my safety gear. The car weighs 3500 with me in it. I have listed more details below and will include some photos of the setup and the carnage.

Unfortunately, I failed miserably with getting a tune in this car or even making boost! The few hits on the street were extremely impressive. Nice throttle response, 2-4 psi on the gauge. Lambda at 0.82 to 0.80 under load. The performance at the track was much less than desirable. First pass was 1/2 throttle shakedown. Nothing to note. The second pass was when I lifted both heads and fried the rings. All of them… not joking. I crisped too and second rings.

I thought I was safe pulling 12 degrees of total timing(locked at 22 degrees) and running rich. My AFR and Boost Controller gave me a false sense of security. I only pulled 3rd gear WOT that run. I didn’t launch or load 1 or 2nd. It ran like a bay out of hell… briefly lol

Both runs my aem boost controller was set at 6lbs. During the second run I never saw more than 2psi boost and my wideband started at 0.76 then 0.72 before I let the smoke out of the engine lol.

Obviously my tune is garbage. I suspect I was way way too rich and I had too much timing. I don’t think the wastegates even opened. The engine coolant was slightly elevated at 190 degrees. Great oil pressure, but ran very poorly on the way back to the trailer. The plugs don’t show excessively rich; however I can see where the electrodes melted. Look at pictures below.

I am looking for some advice and thoughts of what I did wrong and how I should proceed.

I am rebuilding my engine right now from due to the mistakes I made. Furthermore, I am hesitant to put the turbo on my backup engine. The Backup engine is a Weaker build with an eagle forged rotating assembly, less desirable heads/valvetrain(Victor with Harland sharps), less compression(10.5:1) and a smaller solid roller camshaft.

Build Specs:
12.5 to 1 compression
Manley forged rotating assembly(1000 HP)
Block is Filled
ARP studs, windage tray, oil restrictors and etc;
675 lift 280 ish duration 3/4 swap 108 lobe separation solid roller cam
Jesel valve train
AFR 227/235 heads
Two Tial 38mm wastegate 10 lbs springs
Tial 50mm BOV
AEM x-series boost controller
Magnafuel pro star pump with -10 main line and -8 feeding the carb
Magma Fuel fuel Pressure regulator 1:1 boost referenced
E85 Pump gas that I test ethanol amount; it is E85
Holley 750 double pumper boost modified
MSD 7al, pro billet dizzy, NGK plugs gapped at .028; 1 heat range colder

Questions:
What the heck happened?
How do I ensure I don’t smoke another engine?
I am Considering changing over to EFI for data log and tuning. I am familiar with Holley Terminator X; should I do that?

Front by Ethnbert posted Mar 25, 2024 at 12:48 AM

Passenger Side by Ethnbert posted Mar 25, 2024 at 12:48 AM

Driver Side by Ethnbert posted Mar 25, 2024 at 12:48 AM

Driver Side Plugs by Ethnbert posted Mar 25, 2024 at 12:48 AM

Passenger Side Plugs by Ethnbert posted Mar 25, 2024 at 12:48 AM

Head Pass Cyl 7 by Ethnbert posted Mar 25, 2024 at 12:55 AM

Headgasket(Pass) by Ethnbert posted Mar 25, 2024 at 12:55 AM

 

That sucks man. You lifted the head, that’s the problem… why a head lifts is mechanical fastener failure, what causes it to occur is the answer to the problem. But I mean you have solid evidence of a melted plug but I mean you still lifted the head so… I cant really offer advice because I’m not familiar with or use e85.

 

depending on who modified the carb for blow thru, often they will be lean a part throttle.
So unless you have confirmed part throttle safe afr, that may be the issue.

At that bitty amount of boost, 32 deg. timing shouldnt be an issue.
Not sure why its not making boost.

what heads. Never seen an aluminum aftermarket head with short reach spark plugs.

 

At a quick pic glance (maybe I can't really see what is going on...) the plugs look like they have more timing in them than you want, did you verify the timing mark on the damper is syncronized with the rotating assembly?

 

and also that the timing out the msd follows programming.

also why the heat range 4 plugs?

 

AFR Heads 227/235 Part Number AFR-1121
This is a drag race only car. Very little part throttle usage. I modified the carb for blow through. The AFR gauge showed I am rich at idle, part throttle, and extremely rich under load.
I chose to use the colder short plugs to clear the dome on the piston. The extended plugs would strike the top of the piston.

I suspect my boost controller is not reading boost properly.

 

I just looked at the plugs and realized I have the wrong spark plugs.... they are supposed to be UR5 not UR4

 

I dont think thats a good thing. That plug is way too short for that head. UR is .460 reach. The plug that is supposed to be in it is .750.
If the autolites recommended by afr are hitting the heads , I would try a non extended tip plug.
NGK r5671a-8 is the plug I would be using. If they still hit, since you have it apart, cut clearance in the top of the piston to clear the plug.

If you are anywhere near .74-.80 lambda , your safe. Even if it went a bit below .70 it would at worst misfire .

 

I realized your timing here. Thought you pulled down to 22 which is already way low for e85.
With your base timing, even if it made 10 psi , 10 deg.total is unsafe.

36-38 locked pulling 1 deg per pound would be a safe starting point.