The 280 magnum is on a 110 L/C and not that great for a turbo. Im sure it would do alright but not the best. It sounds like maybe your motor popped because of too low octane for 25 degrees lead. Every motors different but i cant run over 12 lbs booat on 92 octane WITH an intercooler and around 25 degrees timing. I wonder if your back cylinders are running lean?

Sometimes a piston melts and everybody blames it on being lean. In reality, what can melt down a hole with a good tune is simply losing ring seal. How does a piston cool itself? Thru the ring pack. When the seal gets real bad, the piston head can hit critical temps and burn down but it also means the tune had no safety in it and was borderline to start with.

 

hmmmm this makes the story that youre grenade engine survived because of the blowby a little harder to believe
if wat you say is treu the grenade would have knocked the edges of the top of the pistons by now unless you kept it running kindah rich

 

I always had oil leaks and alot of blowby....Ring seal was shit from day one of this build. No intercooler and I used to always run 20 degree's with 93 octane and had no issues. carb had a few lean spots but not bad.

 

The Granade had piss poor oil rings but pretty good comp rings and i think for a motor to melt down a hole with a good tune, it first had to be detonated or fried enough to cause the upper ring land to get messed up to the point the ring is pinched in ther groove, broken ring etc. Once the top ring goes dead, the 2nd ring has to fight to hold all the compression and fire. Once they both go, the piston has no choice but melt down.

I honestly dont know how the Grenade hung on at such lean A/F ratios without croaking. Id have to guess the accuracy of EFI vs. a carb setup keeping every cylinder the same A/F ratio.

 

naysayers coming in three years after you parked it

 

Back when this thread was just a baby, there was a reason i documented the hell out of the engine with lots of detailed pix after it had already made a lot of fast runs, head gasket changes, etc. Just so everyone knew it wasnt a fake. About the only thing i didnt do is have a dated drag video followed by a pix of the current days newspaper. LOL

 

This has be my favorite thread ever. It makes me feel better about my plans to push my 4.3 v6 ( 350 missing 2 cylinders) to 400hp.

 

Hell yeah. I kinda miss running the piss out of a junk engine to see what happens. Its exciting to know it might blow into orbit every time you hit the throttle! Hey how come so many people claim the pistons are weak in the 4.3's? Why are they much different than what the GRENADE has in it? Shouldnt it last with a good tune?

 

maibe different harmonic vibrations compared to the one with 2 cylinders extra

 

I've seen 9s run on a stock crank in a 4.3L but ultimately that is the weakness that is hard to get rid of without some very expensive parts. The pistons are pretty much standard 350 slugs of the era. Rods are bigger on the big end, and the crank is a split journal style crank rather than 2 rods per throw like an SBC.

 

How much horsepower do you think that 4.3 was putting out?

 

i think you wold be able to reverse calculate that with some trackprogram (heared theres a little book that does guess the minimum horsepower needed for weight wheelsize and endgear to drive the quarter mile in a certan time )

 

I have my own grenade story going now! 89 Chevy Silverado, I got my motor out of a suburban with 280,000. I put my sportman2 heads on it, and it will probably get a cam here shortly! I just about got my megasquirt2 installed. Within the next 3 to 6 months will be getting a tv7512 that I picked up off Ebay for 80 bucks. I have no clue what the mileage was on that motor but it has ran for the last year with little problems. I have a link to my build check it out and let me know what you think....

https://www.theturboforums.com/smf/index.php?topic=147579.msg1480807#msg1480807

 

TV7512 for $80? Envious to the exteme. Should be a hell of a lot of fun. Wow I can't believe this thread went for weeks without a re:. It looks as if I may have scored another 305 to throw in the "hot spare" pile. I am about to the point of trying to find a hot hydro roller to stick in in it too, and ditching the TPI for a single plane setup.

 

Dude the guy has a ton of them, when I got mine I asked him if he had anymore and he said yep how many you want. I have watched all his auctions and the all go for 80 bucks. PM me if you want more info.

 

this man speaks the truth
just dont bid on the one im bidding on im about to grab one for 81 bucks

 

Its crazy and I dont know why they are so cheap! If I wasnt half broke I would buy like 4 of them!

 

shhh i thought the same dam thing, i just got the motorcycle sold so i have 1000 bucks sitting nexto me lmao

 

Easy on me craig , I finally found one of his turbos and got a bid in.
If I know my money I wont win, come on guys gimmy 2 days..... LOL :clem:

 

lmao so ur bidding on the same turbo i am