gator's 99TA

iTrader: (2)

well guys, got a 95 LT1 383 Canfield headed cam motion cam lunatti/SRP bottom end fully forged combo. Vortech S trim turning about 13 psi aftercooled. all the boltons (LT Headers, open cutout, etc, etc). made a few baselines last week and it ran horrid. Ed Wright tune. made only 440 rwhp and 450 rwtq (4L60e with Yank 3200 PYE). the graph went to trash at 5600 rpms (where it peaked) and only made 430 rwhp at 6200 rpms. found out it still had a LT1 knock module in it. so we replaced it with an LT4 knock module hoping it would give it some timing instead of picking up false knock. all of the sudden the car began idling worse (ever so slight, like a miss maybe). gonna have it dyno tuned by our local programer. made some test runs to record on his laptop. first run from 60 mph to 130 mph (test track guys ) everything seemed fine except the temp went to about 200 degrees. this run was only for a few seconds. the car pulls excellent now since the new LT4 knock module! made another run to log about the same mph but we had to shut down because the temp was pegged at 230 something degrees (according to the laptop program). also i noticed in third gear the convertor seemed to lock, as rpms dropped about a thousand rpms. i THINK this is normal as this type of convertor has posi lock up clutches. i got off of the throttle and then the car stalled as we slowed down and the aweful smell of burnt coolant was everywhere. havent had time to pull the heads off yet, but it looks like BOTH heads lifted as coolant was puddled on both sides of the motor and under the hood! also just as disturbing, as we pushed it on the trailor, we noticed a small puddle of oil on the ground! ok, now i am PISSED!!!

looking at the program, it looks like there was as much as 33 degrees of timing in the original program. we run 93 octane. before the LT4 knock module, it has made easily 100 WOT runs playing around with no problems. i know this is probably/definately too much timing with the long stroke and octane but it has never been a problem before the new module. also, only at the convertor flash and downshift was there any spike in timing retard according to the log. so i dont belive there was much detonation.

any ideas on what are the possible problems with this combo? i dont want to replace gaskets only to have this happen again. with teh aftercooler, it is a **** to get to the heads and intake. could it be that now the motor is getting full spark, it was too much to take?

gator's 99TA

iTrader: (2)

oh yea and the car wont start after we pulled it to the side of the road and it stalled.

BizZzatch350

iTrader: (33)

Chances are the water pump puked and dumped coolant all over the opti, i.e the reason why it wont start. Find the reason why it was leaking coolant, for me it was a bad hose that caused the water pump to puke. Chances are its been leaking cooling.

Vendetta

Honestly, I'd keep the LT1km and just get her dyno tuned. I would much rather be picking up false knock, then not picking up real knock with an F/I setup, especially on 13 psi...

PS- what pulley size is on the S-Trim to huff 13psi? Are you on stock heads still?

gator's 99TA

iTrader: (2)

it has never leaked coolant. under the motor looks more like a mirror with all the chroming. this car gets MAYBE 50 miles a month on it. unless we go to a car event somewhere. car has never had the heads off since we rebuilt it forged.

bowtie9696

Is the block o-ringed with head studs. If not, you probably lifted the heads off the block running that kind of boost.

Vendetta

Makes sense, but that's usually an LS1 problem... LT1 and classic SBCs have an extra bolt in the heads than LS1s do. There are a decent amount of LS1s boosting 13psi without lifting the heads, also. 13 psi is moderate boost, really. There are a lot of LT1 guys with the YS-trim Vortech blower boosting around 17 psi without head lift problems.

gator's 99TA

iTrader: (2)

not o-ringed. and they are just ARP head bolts, not studs. didnt think it would be needed with "only 13 psi" on pump gas. this is LT1 world where guys have turned big numbers on YS trim for years. maybe the tune was just too aggresive? is 13 psi and pump gas on 8.9/1 compression just a lot to ask for?

bowtie9696

Maybe I'd just rather play on the safe side, but if I were to run a true 13psi to the intake and spend all the money on a forged bottom end, I'd go ahead and o-ring and stud the motor. Just my .02

gator's 99TA

iTrader: (2)

as described in the first post, this is a fully balanced and forged bottom end. srp/je pistons, H beam rods, and Lunatti forged 3.75" crankshaft.

96SCTA

Have you found the problem yet. ??? I went through 2 sets of head gaskets casue i though i was "lifting the heads" So i studed them and same thing happend. Finnaly found out that my stage 2 gtp heads were ported to far and hit a coolant passage. Must have been a small crack at first but finaly it gave out. I finaly realized this when i saw coolant comming from my header