rotary1307cc

iTrader: (5)

I will give u my old forged pistons for dirty cheap if u want. 4.03 bore

Phish806

iTrader: (5)

PM'd about the pistons. I am unsure of the extent of the damage. Hopefully the block did not see any issues.

Forcefed86

iTrader: (4)

I’m no world class tuner, but the LS motors seem a little sloppy with timing sync from the factory. The 4-5 motors I’ve played with were all over the board. I had to sync the timing with my setups since I was using an aftermarket ECU and one of my engines was almost 5* off. The others were all off at least 2*. To check the timing sync you have to find TDC and mark the balancer/ timing cover after it’s pressed on. Then use an adjustable timing light to verify the ECU and engine are reporting the same timing values. Given there is a lot of room for slop and error so some of that could be my fault.

I’m with you though. You wouldn’t think 18* would hurt anything at those boost levels. But if that 18* is really 23* it could be an issue.

IMO starting out at a highish timing level and adding boost isn’t the best way to tune. I’d start out with something silly low like 11*. Then dial in the AFR and dial up the boost to your desired level. Lastly I’d bump timing up a degree at a time until you stopped seeing big gains. (I believe denmah said 25whp per degree was pretty common on the LS motors) but it should be pretty obvious what to expect after the first degree is added. Would be better IMO if there were no timing numbers to go by. Turn it all the way down to start, then slowly turn it up till it stops making big jumps in power and stop. Too many people blow things up shooting for “X” timing at “Y” boost.

Maybe Toss a bone stock $200 4.8 in there and get the tune sorted? Should still be able to run 9’s pretty easily. I went 9.1 @ 151 with my spare 4.8 this year at 19lbs. The $ to fun ratio was pretty high! Good luck

Phish806

iTrader: (5)

well i got the motor pulled and the head off. This is what i found:

oscs

iTrader: (19)

Damn you can burn through some motors. Sucks man

Phish806

iTrader: (5)

After talking to some friends of mine, were leaning twords a fueling issue, or a backpressure issue. I know that guys have had issues with the 80/79 and backpressure in the past.

Forcefed86

iTrader: (4)

Looks like the typical crunched out ringland to me... Did the plug have any detonation spotting?

Phish806

iTrader: (5)

i couldn't really get much from the plug. it was somewhat destroyed by getting hit multiple times by the debris.

Phish806

iTrader: (5)

First things first - I am a complete moron. I have had the steam ports in the rear blocked off the entire time my car has had a turbo setup on it. They were blocked when i was running the bottle, and i never gave it a thought when i swapped out the spray to the turbo setup. I am pretty positive this is why i have been melting down the pistons in the rear of the motor. I cant blame anyone but myself I guess so live and learn and move on.


That being said, Number 5 had melted down quite well and number 7 showed signs of melting as well. The pistons came out, i cleaned up the block and installed some LQ9 pistons that i picked up from a somewhat local guy. The ls3 heads were able to be saved once again, but had to be cleaned up with a .010 mill off of them. While the motor was out, i went ahead and swapped in a am that was specd for my setup. The new cam is a 223/231 .617 .598 115+5. (old cam was a 232/234 .595 .598 112). Also the stock 98 ecu has been pulled off the car and sold. Now a MS3Pro will be going on the car along with onboard air for the boost control. The MS3Pro should be a nice change from having nothing to having more control then i could have imagined. I am also lucky to have Scott Clark within a couple hours so he has been giving me some info on the MS setup and will be doing the tune as well.

I also pulled the stock 90 Rx7 suspension off of the car. I fabricated some Lakewood 90/10 shocks for the front out of camaro, rx7, and mustang parts and got them installed out front. I also have purchased some rear adjustable shocks and springs that will go in the rear and help me stiffen it up some. All of this combined, should help me 60' a little better.

As far as actual progress, I just finished the assembling the motor last night. Next step is to drill and tap the water pump for the new steam crossover setup that i am going to fab up for it. Once that's all done, it can get dropped back in the car and I can start focusing on the upgrades more instead of the "repairs". I will try to post some pics up later on of progress and the things that are changing.

Forcefed86

iTrader: (4)

I think the MS3 will help you with your piston melting issues. I really like mine. I'd guess it was a cam overlap/high backpressure/tune combination that did those pistons in. Not steam ports.

There is nothing wrong with blocking the aft steam ports. All the new gen3/gen4 engines are setup this way as well as many of the race team engines. This should not cause you to melt anything. I have changed to front only... no ill effects I can tell. There's a few write-up's as to why "forward only" stem ports are better if you search. Some big names still prefer 4 corner. I have an OEM ls1 4 corner vent setup if you need one, PM me.

Those the ones I sent you? Interested to see how they turned out. My FC turned into a wheelie machine as soon as I put loose shocks up front. Made a HUGE difference, I think you'll like it

oscs

iTrader: (19)

Can you post a link to the info about the blocked rears being better? I'd like to see the logic behind it.

Phish806

iTrader: (5)

edited... In for info on rear ports as well. I read that the rear ports are not an issue until you go FI and or start making big power.


Yes, the shocks are the ones that you sent me. I did an entire step by step write up on Norotors on how i did the modificatinos. here are some pics:







Here is the link to the thread that i did the how to article on. Some better pics in their: http://www.norotors.com/index.php?topic=21067.0

Forcefed86

iTrader: (4)

Link also goes into why the water pump isn't a a good steam vent return. Steam vent outlet needs to be at the highest point in the cooling system.

Here ya go.. think around post #17 talks about blocking the aft ports.

https://ls1tech.com/forums/conversio...-vent-q-s.html

Phish806

iTrader: (5)

My waterpump is the highest point on the cooling system....

I believe i am still gonig to open mine up. I have had a few guys tell me this is my issue and a few others tell me it has nothign to do with it and that its a tuning/back pressure/uneven air flow to cylinder issue.

Either way, the exhaust will get more free flowing mufflers, and a cutout added to help with the back pressure. i am also thinking about adding some ports to test the BP when on the dyno. I dont think that BP was my issue with this though. I think the MS3Pro and a decent tune with really help the situation as a whole and keep the motor together ... hopefully.

Did you take a look at that thread on the front suspension?

RedRocketZ28

iTrader: (19)

You know my stance on it, open them up. You've just had some shitty luck man. The tune in my car was a little more aggressive than yours, I ran quite a bit more boost through the motor, and it's still hanging in there after three years.

I'm anxious to see what your car does this year. Should be extremely quick.

Phish806

iTrader: (5)

I still plan on opening them up and having them tap into the pump. It has seemed to work well for alot of the guys. You, Josey, Jason... I actually have already bought four of the ports that plug into the heads and convert it to -4 an fittings. i will most likely use hardline to connect it all. I have a bunch left over from when i bent up the nitrous lines.

thanks for the confidence Andy, Its been a clusterfuck of blown motors, disappearing pistons, and scored bearings to get to this point. Now i am hoping for a nice smooth ride to the mid 9's with this setup and calling it a day.

Forcefed86

iTrader: (4)

I should say the highest low pressure point in the system. Where are you planning on putting the steam vent return? The system is designed to use a swirl tank. Without one, It really doesn't work as it should...regardless of what "worked" on someone else's DIY build. It's not like the guys that "successfully" used the water pump as a steam return have done any sort of testing with or without a "proper" swirl pot design. If the WP return was ideal, you'd see race teams and GM using that location. For the system to work it's best the WP is a poor choice for a steam return. Again this isn't a super critical item and isn't going to melt you engine either way IMO.

I know Kurt Urban and a few other big names still prefer a 4 point vent system. I installed an LS6 intake and to continue running my OEM 4 point I would have had to grind the bottom of the intake. So I just blocked it. 30+lbs of boost and my OEM pistons look nothing like yours! So I really don't think that is a critical item either.

That engine detonated...hard! I don't so much think it’s a post turbo back pressure issue. (though that can add up as well) Your old cam had 9* of overlap. I'd guess that cam mixed with preturbo back pressure introduced a lot of exh into your intake air charge. That mixed in with 17-18* of timing caused detonation, killing it. I like a neg. overlap cams for street setups running a healthy amount of back pressure. Big cams are for big turbos with very little back pressure. Usually paired with high rpm race engines. I think your new cam will work very well.

I did check out that the susp. Thread. Very slick!

Phish806

iTrader: (5)

I plan on putting the return in the top of the water pump right next to where the cable attaches to the TB. You can see in the pic, that the steam port has always returned into the coolant pipe coming from the top of the Radiator. Its the black braided line "T"'d into the black coolant hardline in the pic.




Thanks for the compliments on the front shocks. They were a bit more work then i thought, but really were not that bad. Just took some time is all. I want to get the motor in the car so i can get it on the ground and see how it all works out for ride height and spring height and all that good stuff. I cant wait to see the effect they have on the car and how it leaves. Hopefully it will have a better 60ft and leave quite a bit harder. Was your FC a solid axle or an IRS car?

Forcefed86

iTrader: (4)

IRS originally, then solid. I ran the AGX adjustable all around form the start though. Was a big mistake. OEM up front work well. I’d imagine 90/10 like you have would work great if you can stiffen up the IRS enough.

Phish806

iTrader: (5)

I am hoping the AGX out back on full stiff with the 12" 200# springs will be enough to stiffen the IRS. I don't think I will be the "wheelie machine" that yours was though. The IRS will keep that from happening I believe