[Tom Vaught]

Sun Tuned, there was a good friend on the Turbo Forums (named Dave) that went by dave2 on the board. Well, Dave was running a twin turbo "sequential boosted" BB Chebby in a Chebby S-10 type chassis. "sequential boosted" means the boost from one turbo goes into the inlet of the second turbo so if the first turbo is making 5 psi the second turbo will be kicking out 4 times the boost and making 20 psi. So not image 15 on the first turbo and 60 psi going to the engine.

The point being if you run 60 psi on a BB Chebby you better know what the alcohol percentage is in the fuel. So Dave posted on the forum how to make a E-85 Tester so he could measure the percentage of that fuel to alcohol just like your boat guy did with the Pump gas stuff.

The info is there on how to take a GM Flex Fuel sensor and make a stand alone fuel tester that you can take to the different gas stations to test your fuel.

So your buddy Woody has his act together testing the fuel.

So some of the gas out there could easily kill Ross455 carb power valve in a short period of time. (And cause engine damage).

Tom V.

[Ross455]

It's an 830 Annular. We did swap the baseplate out a while back and I can't remember if we put a 1-3/4" or the stock 1-11/16 back on it. I never opened up the PVCRS. I just jetted up. The power valve is a 2.5. I am running 80 primary and 90 secondary. It does cause me to cruise at 11:1 though. All air bleeds are untouched. I have only had the wide band a short time and intended to open the PVCRs up so I could lean the cruise out.
The front of the engine has always been the safe end. It has always hurt 5-8 (though it did get #4 this time). I have the standard Procharger bonnet (not the low profile). It's clocked at about 5'oclock.
Interesting about the fuel. I know I need to replace most of my braided. It's older than 10 years and probably deteriorated.

[Tom Vaught]

The 830 carb is basically a 850 main body with a 800 base plate (1-11/16" blades) on it.
850 has 1-12/16" blades (1-3/4"). The base plate is modded by Holley to allow either base to be run on the mainbody. No real worries there.

With the primary PVCRs being stock and not adding any extra fuel under boost in the primary side and the primary jetting being 80s (exactly the same as a stock 850 cfm carb) all of your fuel enrichment was happening on the secondary side of the carb which could make some difference (even at 10 psi of boost).

I have tried to set up the Primary PVCRs so that the extra fuel needed under boost was shared by the Primary system (Jets and PVCR) and the Secondary system (jets only) EQUALLY.

Tom V.

[Half-Inch Stud]

Originally Posted by Ross455

I did have a pic on my phone of one of the pistons still in the block.

The JE2618 Slug looks like the ROSS slugs I have. Sounds like another case of being "Lean & Retarded" is better than Phat & Advanced".
Where in AL? Near Monte Sano?

[Ross455]

I live in Greenbow, AL

[v869tr6]

I have watched a friends old world record holding turbo car throw so much black out the back you could hardy see it a 1/4 mile away.
He claimed it wasn't really fat but I know melting pistons wasn't a problem for him.
My guess is if the tips of the plugs are still there it was lean that melted the pistons.

[Ross455]

I thought that Greenbow comment would have got some reaction. Especially from someone who lives in Bluebell, AL!

I opened up the Carburator and didn't find any issues. PV was still good. I think my lesson learned is be more diligent in watching my tune up, especially on pump gas. I had gotten a little too comfortable. I used to be real careful and limit WOT time unless I had race gas in the tank.

Thanks for everyone's input. I plan to start a new thread for the IA2/F1R build I am beginning for the 62 Tempest. Would appreciate input from others with experience.

Thanks

[Tom Vaught]

Richard Guido has a similar engine package running currently with a aftermarket block and a F1R supercharger (using Luhn Performance Engineering Brackets) so he could help on the basic install stuff and Luhn (LPE) could help on the camshaft/heads/overall engine package. Nice to hear about another Centrifugal Supercharged project.

Tom V.

[Ross455]

I was asked for pics of the car.
I'll be running an n/a 455 for a while now that I hurt my engine.
Should be good for 10.80s or so.
This was my 1st car. My grandmother bought it for me in 1989 about 6 months before I turned 16.

[guidos]

Beautiful cars, love the tempest...if I didn't have my GTO I would have a tempest like yours. The one thing I didn't hear mentioned was the design of your piston. I basically had the same Ross pistons that were good till above 14lbs of boost then a few of my pistons looked like yours. Mark from LPI told me that the design with no dish on the one side of the piston (basically the quench area) can cause the piston to sorta cock side ways in the bore and lift the ring and break the piston, he mentioned Steve Morris had simular experience. From what I read you might have increased the boost with the higher Rev's?

I have a MR1A 4.27 bore and 4" stroke, Edelbrock heads 8.2 to 1 compression. I have a F1C procharger. Just got off the Dyno recently. Only tested two of my pulleys but made 16.4PSI with my biggest pulley, middle one made 18.5PSI and depending on the hat. I will post some pictures of my new pistons they have a full dish and some pics of the pulleys with numbers!

[guidos]

Here is some picts, we didn't tune to the nth degree, my goal was 800HP for the 4.5 pulley, 900Hp for the 4.25 pulley and 1000HP for the 3.85 (which we didn't get to try) but I am sure we could of made it.

[guidos]

Coated piston and my GTO

[Ross455]

It does seem reasonable that the initial hit to the piston would be one sided with the D shaped dish. They definitely fail in a consistent way when things go bad.
Your GTO is very impressive. I've read several posts about it with both the big cube engine and the Procharged one.
How much tire and gear are you running? I would love to do drag week one day. That has got to be a blast.
One thing for sure is boost is a lot of fun, so I'll keep learning and trying.
Watch for my new build thread and let me know what you think.

[guidos]

Definitely Ross, love your car. Because it's a stick car, I run 28x10.5 slick. FYI I stayed with a smaller bore just to help the head gasket, give it a better chance with boost. Just a thought with your new motor. Drag week is a blast, make a ton of good lifelong friends going through that chaos together.

[Engo]

Originally Posted by Ross455

I have hurt my engine 3 different times over the last 10 years or so. Each time the top ring lands were lifted on 3 to 5 Pistons. It was cylinders 5-8 each time, and each piston was lifted at the intake valve relief.
I have read lean was the cause and rich was the cause. I have a Fast AFR meter but was not logging when I hurt it this last time. Honestly I hadn't had an issue in so long I wasn't concerned. AFR is stable around 11 at WOT.
Blow thru carb. Annular boosters. 428 with home ported Edelbrocks and Victor.
Pump gas with 8.5 CR. MSD BTM pulling out 2 degrees per pound starting with 34-36 total. Around 10 lbs boost. No burned plugs.
I must admit to being foolish and laying on the rev limiter for about a full second doing a burn out on the street when this last episode occurred. Made a pass right after and finished off 3 Pistons. I really think it may have been hurt during burn out though.
Car runs 6.30s at around 110. 1969 Firebird at 3600 race weight.
Any thoughts would be appreciated. Other threads I have read it seems like the people with the answers don't want to give advice.

Excessive heat burns up pistons. Heat is generated when fuel/air mixture is burning. Excessive heat is usually the result of a fuel rich mixture in combination with a lot of ignition advance. Your problem with burning of number 5-8 pistons is likely a intake manifold distribution problem, giving uneven fuel mixture to each cylinder. Get rid of that MSD box as it is most probable the cause of your problems. Also get a better intake or go modern and EFI your stuff.

[Half-Inch Stud]

Originally Posted by Ross455

I thought that Greenbow comment would have got some reaction. Especially from someone who lives in Bluebell, AL!......Thanks

4-days later a reaction. Ahhhhhhhhh i get it. Neither are on the map.

[Ross455]

I feel better now. I thought I had wasted that clever response!
I actually live in Dothan.

[Ross455]

Agree that engine was probably on the rich side and timing was likely what got it. Intake and carb are probably OK given that I had the equivalent of about 1000 passes on it over 10 yrs. Wouldn't mind going efi, but must say the worst engine damage I have seen (on something I was associated with) was a tuned aftermarket efi on my brothers Mustang that destroyed a piston when an injector had an issue. This was all top notch new stuff from pump to filters to injectors.
I do agree though that efi is more tunable and precise. The problem with the Tempest I'm putting together now would be making room for an intercooler (almost impossible) which is not as necessary with the carb. Would love to do the e85, but it's just not practical for a street car when there are about 10 stations in the entire state. Maybe efi with a meth/water injection, but then more things can go wrong.