broke a rod?!

[Joseph Upson]

Were you boosting without an air fuel ratio gauge for the first motor and did you assemble the engine without checking bearing clearance on the second to miss a problem with rod fit? From the brief description given it would appear that the first and second engine failures were easily preventable.

[kwhauck]

I bent a rod on 15psi after two years.........but three trannies before that.....

[Jbrogan]

i was running an a/f ratio gauge on all motors. yea they were preventable i made some mistakes i shlda checked the rods and used a mic on em on the second motor but i didnt cuz i thought theyd be right lol... but anyway i pulled the engine this mornin theres a hole in the oil pan behind the starter and theres a very nice chunk of piston u can see laying on the bottom. the rod doesnt look broke actually i may have just blew the piston to pieces. i will tear into it and post pics as soon as i do. im thinkin it was just runnin too hot and lean. the turbo i just put on flows a lot more air than my old one so im guessing 8-9 psi on that turbo requires bigger fuel injectors than i got to keep it a little richer. i do need a good tune on it i have a half ass one now so a good tune would prolly help. i need to get ahold of an hp tuners or dhp...

[85erbirdie]

if ur having issues running to hot with boost or detination check out this site it a water alchol injection system this system works so well that you can even get rid or the intercooler check it out man you like you like i say http://www.alcoholinjectionsystems.com/

[1988GTU]

You may need to fatten the tune and take out some timing OR run 110+ if you wish to run higher timing tables, but it only bandaids it for so long and if you are running incorrect plugs with an improper gap, the fuel will not make much difference and running it rich will just return poor driveability conditions.

I have ran over 18psi countless times with a 3100 flat tappet motor and over 22 psi with my 3.1/2.8's. All lasted fine until I started upping the rpm's and cupping lifters. With a roller 3x00, it should last longer and be able to rev higher.

[3400-95-Modified]

exploded piston definately points toward a bad tune, or even a bad injector that caused a cylinder to go way lean.

I thought nitrous killed motors I have yet to blow a piston or break a rod... damn knock on wood!

[robert 1980]

Sucks what happend this is why i worry so much about tuning myself.Hope you get things figured out.

[bob442]

Tuning with boost is harder and more particular than a n/a, it's apples to oranges

[robert 1980]

Tuning with boost is harder and more particular than a n/a, it's apples to oranges

I never said that it wasn't.But then again i had a really bad tune i spent 3 hundred dollars on.lol And it was completly stock besides headers.

[pocket-rocket]

Sucks what happend this is why i worry so much about tuning myself.Hope you get things figured out.

This is also why you keep an eye on vital signs of the engine. Things like fuel pressure, coolant temp., A/F ratio, knock count, ect.

[Jbrogan]

so i didnt break the rod it did bend a little but yea the piston is no more.... im goin to put a 3400 in the beretta and leave it n/a and maybe sell it all my parts that are still good r for sale. cam, pushrods, valve springs, rocker arms, lifters with upgrade springs, lower intake manifold, turbo crossover pipe, and more if anyone needs anything. im going to try a new project with a different car.

[bob442]

some brake clean, new piston and rod, good to go lol.

So no more beretta

[Joseph Upson]

exploded piston definately points toward a bad tune, or even a bad injector that caused a cylinder to go way lean.

I thought nitrous killed motors I have yet to blow a piston or break a rod... damn knock on wood!

That's a tough call, coincidently it's piston #5 one of the two most troubled pistons in some of these engines, the other being #6. This should provoke the question as to why GM only installed oil squiters on those two pistons in the 3500. My turbo 3100 was very near this fate when it was removed. The skirts on pistons 5 & 6 were on the verge of failing and there was about .040 clearance between the piston and the bore.

[Jbrogan]

yea the same piston went in my first engine it only melted the side down tho. and bob442 i cant put a new rod and piston in lol the cylinder is all torn to hell would need bored and the head is trashed as well lol. but yea no more turbo beretta just gunna put a 3400 in her and see if i can get some money outta it. i wont sell it if i cant get 3000 outta it tho ill keep it and drive it. i have a new project im gunna try out 4g63t built swapped into 93 eagle summit (same as mirage or colt) they run 12.9s on on stock 4g63 swap imma put a built one in so its gunna be scary fast...

[pocket-rocket]

Just be sure to check the check valves in the piston squirters in the 4g63 before you drop it in. I've read where they opened too early at low oil pressure bleeding the pressure off the main bearings eating the bearings in the process.