Post Motor Rebuild Issues

[Cablefed]

First off I have spent countless hours searching archives and have gone through most of the possible issues and remedies. So I have done my homework on this issue, I'm just looking for something I may have missed.

I have a 98 GS-T that has 22K original miles. I rebuilt the motor to handle more HP and boost. I got the motor back in the car and am having idle issues. When I press the clutch and rev the car past 3K and let the RPM's fall the car stalls and dies. I also get the same effect on the road. When I press the clutch in to stop at a sign or stop light it dies. When the car is in Neautral I don't get the stalling. I can rev. the motor to what ever I want and it comes back down like it should. The stall only occurs with the clutch pressed in and revs go past 3Kand back down again.

I know for a fact its not the ISC, TPS, and or BISS, trust me I've checked and rechecked these components. I ran this issue through my local guys and one guy says it maybe bad thrust bearings. since RPM's drop a bit at idle when I press the clutch in. They don't drop enough to kill the motor but enough to see the RPM's change by 100 or so when I press the clutch in. I wanted to run this by a bigger audience Here is a list of items I have upgraded on the bottom end.

Eagle Rods
Wiseco Pistons
ARP Main studs
Concept racing dowels on main skirt
New Rod bearings
ACT 2600 Clutch
RRE lightened flywheel
All items have been balanced by a machine shop

On the intake side I have the following:

2G Throttle Body
16G Killer (IHI ball bearing T-bo)
APEX FMIC (All the clamps triple checked for tightness)
Stock Injectors (for now)
S-AFC (set to 0 across the board)
Extrude Honed 2G intake manifold
HKS 264 Intake / 272 Exhaust CAMS
K&N Filter
Aeromotive FPR set at 43 PSI
Greddy BOV (Not venting to the atmosphere)

Tuning Tools include:

All gauges (EGT / Jumptronix/ you name it!)
Pocket Logger


Any help you guys can throw my way would be greatly appreciated.

Marc

 

[onegee]

the idle drops from the vaccum...if u push both the clutch and the brake while decelerating it should almost die..why? because mine used to do the same thing......clean out ur maf plug in...mine had white gum like material...that should, i dont know exactly how but it does...

http://www.dsmtuners.com/forums/showthread.php?s=&postid=181574#post181574

try reading that too...thats where i got the info to solve mine..pz


its worth a shot and if doesn't work, at least u know ur maf plug is clean..

 

[germain101]

check the end play on the crank...

 

[MikeL]

Amazing you spent all that time and money to build a 7 bolt which is known for cranwalk problems, and with only a 16g your stock engine would have EASILY handled the power. Pull the oil pan right away and check the thrust bearing surface, it's most likely scored.

 

[Cablefed]

Mike not to knock it or get pissy, but why do people look down on those who build up a 7 bolt? There are tons of 7 bolts out there with good miles on them. I built the bottom end up to handle more boost and to eliviate ever throwing a stock rod and trashing my block. I plan on checking the the thrust bearings by doing what you said. The pain will be to fish them out of the crank. I'm almost tempted just to pull the motor and put it on a stand and do it that way.

All the other advice will also be checked. Thanks guys.

Marc

 

[germain101]

it's very easy to change the thrust bearing while the motor is still in the car...just as long as the crank hasn't made contact with the block, you should be fine...

 

[Cablefed]

I bet that is a good ol time doing that upside down. I assume you have done this before. How do you get to the bearing while the crank is still in there. I know you have to remove the main cap and bearings but how do you fish the bearings out and get the new ones in? Definatly worth a shot. It beats having to pull the motor again.

 

[germain101]

just push it right around the journal...if it's seated pretty good, you can break it loose with a flat head screw driver (carefully) and then just push it around...take the new one, slop on some assembly lube, and slide it right right back in the way the other came out...

 

[MikeL]

When a 6 bolt block with a good crank can be found as little as $300 why spend 2k+ building a block that has like a 20% success rate. Just my opinion. My 99 block has over 100k now and is actually doing well, but I'm putting a 6 bolt in it anyway just because it's so much more proven.

 

[Cablefed]

It turned out to be a bad alternator. For the guy that wanted to lecture me on building a 7 bolt they need to a have a section for you for when you and others feel like telling people what they should do. I asked for help with a problem and all you gave me was unneeded input. Thanks anyways though.

 

[Cablefed]

Well its not the alternator like I thought. Back the drawing board and trying to figure out whats wrong. Is there any kind of leak test that can be done to trace a vacuum leak?

 

[MikeL]

The answer was already given to you, you just didn't bother to check for it.. RPMs should not drop when you press the clutch in.

 

[C. Black]

Originally posted by Cablefed
It turned out to be a bad alternator. For the guy that wanted to lecture me on building a 7 bolt they need to a have a section for you for when you and others feel like telling people what they should do. I asked for help with a problem and all you gave me was unneeded input. Thanks anyways though.

Yo, his "unneeded" input was something you should have heeded. Sometimes when people are telling you what you don't want to hear it gets upsetting, and it can seem like they are harassing you over your 7-bolt build. But, its done from experience bro, no one means to get you all chapped up. But......
You've more than likely got crankwalk, plain and simple.
Have you missed the thousands (if not tens of thousands) of posts that have been made not only in DSMtuners, but EVERY DSM forum about this EXACT issue??? Your car should not die when you push the clutch in, PERIOD. THERE IS A REASON WHY PEOPLE ARE TELLING YOU THIS, ITS BECAUSE THEY KNOW. Listen.
If I am way off, someone enlighten me please. And I sincerely wish you the best with your car bud, I hope we are all wrong and you make us look stupid.

 

[Cablefed]

There is no doubt in my mind that it is the thrust bearings at this point. I was just trying to make sure it was'nt something simple I was missing. I had a few other things such as the lights dimming without the clutch disengauged that puzzled me to think something was carrying a load outside of the motor. Before the car goes closed loop, cold motor, the car works fine. I can press the clutch in and out all day long and it does not phase the motor idle or RPM wise. After the car has had few to warm up and the O2 sensors start feeding the computer info and goes closed loop the car starts acting up. That explains my reason for steering away from the thurst bearings and more towards a possible vacuum leak, bad alternator, and so fourth. Again, thats just me covering my bases before I leap for something that should not be failing with a motor that only has 6 miles on it.

When I pulled the motor there was no issues and did not have crankwalk based on how the thrust bearings looked. The whole purpose of me even pulling the motor was to beef it up a bit and not have the dreaded 2G rods go on me. Yeah I should have left it stock and blown the motor and gotten a 6 bolt. I'm not one to sit there and mess with could haves and should haves I move forward and deal with the issue at hand.

I don't mind facing the fact that I have to pull the motor again and replace the main and thrust bearings as well as the pressure plate, I think the 2600 is to heavy for this car, esp. a fresh motor. What I don't get is when I'm trying to work with what I have and get some logical help and people are trying to tell me to do otherwise its hard to get help when you have someone telling you you could have or should have done, yes I am aware of 7 bolts getting CW, yes I know 6 bolts are the way to go, but the fact is there is nothing wrong with my 7 bolt. I'm not gonna trash a perfectly good 7 bolt motor just because something is known to have issues, nothing is bullet proof even 6 bolts.

Now if the crank had or has, which I doubt, eaten into the block then yes time for a new block. I'm not trying to be a smart ass or jump on anyones back, sorry MikeL, I was just trying to take steps to trouble shoot the issue before I really had to get down and dirty by pulling the motor again. What I meant by un-needed input was simply telling me that 7 bolts are a waste of time to build up. Anyhow, sorry if I pissed anyone off I was just looking for productive input.

FYI...The motor and tranny will be coming out for new bearings as well as new lighter PP. Anyhow tomorrow is another day, I'm out!

 

[98TsiAWD]

Well do yourself a favor and pull your 7bolt shortblock out, sell the pistons/rods before crankwalk damages them.
Then buy a 6 bolt block/crank.