z0stix

So my forged 383, with a D1sc procharger making a little over 800hp took a ****...its smoking bad, misfiring, sounds like a messed up Subaru...I was at a local street event and in 3rd gear, (still no traction) oil shot out the breather and dipstick...like everywhere, the whole engine was covered in oil....oil pressure is still strong, but I've lost vacuum on the boost gauge, and just sounds broken...I'm sure a piston/ring or 2 is done....I had no knock, a/f was around 11.4, with a dual nozzle alky control meth spraying and keeping the intake temps down...speed density tune if that matters....

can I use my current rotating assembly in say a 6.0 iron block and just get appropriate pistons for the bigger bore??

Should I keep it aluminum?? Can I bore an iron 5.3 to a 383 safely??

Any input is greatly appreciated

Turpid porpoise

The 5.3 has the exact dimensions of the 5.7 so I don't see any reason why you couldn't turn it into a 383. I'd just do an iron 6.0 if I were in your position.

neutron82

need to tear it apart first to see what is salvageable and go from there

FourG63 97GST

dont know what you do with the car, but adding the weight to the front is the worst place to add weight, sounds like you have a street car, you'll over power the chassis and heads, before you outgrow an aluminum block, but ideally this comes down to budget

Rkreigh

at much over 800 I like the small bore iron block engines

you can bore a good block to the 3.89 stock bore but I would leave the meat in the block as the displacement isn't critical

if you want an alum block, think about the 5.3 alum truck blocks with the small bore size

the 6.0 iron block has the advantage of supporting better heads with the larger bore size

the blower will make all the power you need IMHO so the extra displacement just gets you there faster

I like the durability of the short stroke small bore engines for FI applications as they take quite a bit of punishment.

Rkreigh

I'd pull the engine and as described above and see what you have to work with. Since you still have oil pressure you might just get away with some new pistons

if the bores are hurt and you have the $, you can sleeve the block and go with bigger displacements with great reliability


do you all know anyone that does the 6 bolt conversions on stock blocks? superdeck no longer does.

_zebra

E.r.l.?

Turpid porpoise

I believe ERL is out of the motor game.

_zebra

aww

Rkreigh

ERL Superdeck 6 bolt conversions are indeed out of biz hard to find as the conversion on the stock block is expensive

I'd like to find someone with enough experience to weld the 6 bolt tabs on a block for me

or maybe even a bolt on girdle that I've been looking at designing that would work for iron blocks too

z0stix

I finally had time to mess with the car, i took out all plugs and they all seem decent except for cylinder 4, the tip broke off....so I then did a compression test, starting with that cylinder and it came out to 200, so I did the rest and all were about 190 to 200 except for piston 1 (front driver side) it showed 0 compression, nothing, pressure gauge wouldnt even move...., so removed valve cover but dont see anything wrong on cylinder 1s valves springs so I'm proceeding to remove the head, but i forgot I left my good tools in my ctsv trunk which is in the body shop getting hail damage repaired ....anyways...

so maybe bent/broken valve?? maybe it made hard contact with piston and broke ringland? since it was smoking out the exhaust, I'm sure it's a piston failure....but what would cause that on piston 1, I'd expect that from number 7 or 8 though

mcantuaria23

I was at the same position when my 383 TT blew so I decided to go with 408ci Lq9 iron block wirh 235 AFR heads 1100rwhp. So much torque than 383, it only add 80# of weight.

z0stix

I'm looking to get an lq4 block, but 402, any noticable difference in ride with the iron block weight, I dont track/take hard turns, and I have lg coilovers if that matters...thanks

stevieturbo

Any cylinder can fail. No4 plug has not "broken"....it has been damaged via detonation.

But yes, 0 compression if the test has been done correctly is odd and would suggest valve issues. However dumping oil out all the breathers would not suggest valve issues....but fucked pistons.

New alloy blocks arent that expensive really. I'd always choose alloy over iron, unless for whatever reason iron was deemed absolutely essential. And as for going from a 5.7 or 6.0 etc to a smaller 4.8 or 5.3, no thanks. Even more so for a daily, you will miss the extra torque etc of the larger motor.

mcantuaria23

No difference at all.

z0stix

finally got the head off, and to no surprise....

**** happens, oh well, the wall doesnt even look that bad, its smooth except for the area where the piston broke is kinda rubbed off on there..anyways I'm still gonna go with the iron block

neutron82

looks like it detonated

stevieturbo

Too lean, improper tuning, detonation...whatever. It's fucked lol.

Although at a push if it is a stock bore, a 5 thou hone might clean it up to be quite usable. Not perfect..but perfectly usable on a budget.

z0stix

I highly doubt it was the tune, my tuner is very good...it's on a speed density tune and same weather conditions as when dynoed, the meth was spraying because the intake temps went from 120 to about 75....the only thing I can think of is that it spun so much the rpm stayed at redline for maybe a little too long in 1st and 2nd gear

stevieturbo

Mmmmm ok. Whatever you think.