The Motor Pull Thread

[d98gt]

It's always interesting to see other peoples breaks
My old sn95 went from

to stripped down after a timing chain BROKE and I slammed some valves on the pistons You'll have to excuse how bad the parts look as I didn't cover the parts after taking the heads off as I knew I was getting work done to them.

I had quite the build planned for this car at one time until I sold it to a friend. I'll have me another as a toy eventually

 

[sneaky98gt]

Yea, sucks when something breaks, but it just makes me enjoy it that much more after I get it back together. I've driven my car for less than a week in the last 2 months. I freaking can't wait to get it back on the road (hopefully this upcoming weekend).

As promised:

 

[SteedaGT9150]

saw this on fb this morning... that thing is fawked

 

[N8Dogg98]

damn Will, that's crazy.

 

[tank_567]

Hmmm I think she was running LEAN! Sorry Will, lets see some PI pics soon

 

[nickmckinney]

I bet a $3 bill if you look closely at the ends of the rings you will see the ring from the broken piston is shinier than the others. The stock ring gap is only around 0.010" and they will butt up fast under boost.

 

[sneaky98gt]

Hmmm I think she was running LEAN! Sorry Will, lets see some PI pics soon

Could have been lean, but I think it was timing. After it was tuned, I never once saw it go above 12.2, and that was with no methanol. It was usually 11.5ish with the meth.

Car will hopefully be running this weekend.

I bet a $3 bill if you look closely at the ends of the rings you will see the ring from the broken piston is shinier than the others. The stock ring gap is only around 0.010" and they will butt up fast under boost.

I'll look at that. But if you notice, about a third of the top ring on that piston is gone. So I doubt it was touching, lol.

Why would only that one piston look like that, and not all of them?

 

[nickmckinney]

You usually find the end of the ring still sitting next to the break on a piston like that. Steel rings expand when hot and when they butt up and still get hotter they will break the piston edge out of the way.

 

[sneaky98gt]

You usually find the end of the ring still sitting next to the break on a piston like that. Steel rings expand when hot and when they butt up and still get hotter they will break the piston edge out of the way.

Yup, that's exactly how it was.

Would the excessive crankcase pressure from the damaged ring/piston cause a lot of oil to get back through the PCV system? There was a good oil sheen all over everything from the throttle body forward, and I was curious how that happened. Just thought about the PCV system.

 

[nickmckinney]

Would the excessive crankcase pressure from the damaged ring/piston cause a lot of oil to get back through the PCV system?

Yup, another good test on a running motor is to pull the breather and PCV and if she is chuffing smoke like an oil coal train then a piston is broken somewhere.

 

[Mr. Rustypwnz]

yeah ring gap scares me on these things! ive got my dsm pretty wide right now. My buddies is around .012 on a teksid 2v and were hitting it with a 175 shot! we should prolly put some better rods and pistons, hopefully it shall hold!

sneaky: whats the verdict on the heads? staying npi still? trickflows?

 

[sneaky98gt]

yeah ring gap scares me on these things! ive got my dsm pretty wide right now. My buddies is around .012 on a teksid 2v and were hitting it with a 175 shot! we should prolly put some better rods and pistons, hopefully it shall hold!

sneaky: whats the verdict on the heads? staying npi still? trickflows?

Stock PIs on a PI motor. I'm curious to see what this baby will do. A few guys on the TCCoA have made 360-380 on stock PI cams, so I'm hoping it'll do around 380 since I have a set of blower cams. I suppose we will see.

 

[SRT Handz]

I still think running meth is a waste. Its just another tank you have to monitor and fill up.

Figure out some way to mount a I/C on that thing.

 

[sneaky98gt]

I still think running meth is a waste. Its just another tank you have to monitor and fill up.

Figure out some way to mount a I/C on that thing.

I don't think the methanol is a waste at all on a non-intercooled blower. If it's tuned correctly, it will be safe with or without it working, so it doesn't matter if it runs out or something breaks. And I picked up 3 mph in the 1/4 mile (untuned) with methanol.

There is no way to intercool this blower. The only way it could possibly be done is with a kit like the Tork Tech kit, but it doesn't provide the clearance needed underneath the blower. Not to mention its an extra 2 grand.


And concerning dyno numbers. I don't bench race or play dyno tag with other cars over the internet. I don't care if it says 430 rwhp or 330 rwhp, so long as it runs like I think it should at the track. On the old setup, it ran 12.5 @ 110 mph with 325 rwhp (which I recently learned was actually only about 305-310 rwhp) on the stock auto and 3.27s. There are LOTS of 400+ rwhp cars that aren't running that fast.

A guy on the TCCoA in a 3900 pound T-bird recently went 11.9 @ 117 with 'only' 375 rwhp. I think that speaks a little to the fact that these properly tuned, meth injected, SVO cars run quite a bit better at the track than the dyno numbers show.

 

[nickmckinney]

Meth is necessary on boosted 2V motors even running race gas if you want to get the max out of them.

 

[sneaky98gt]

Meth is necessary on boosted 2V motors even running race gas if you want to get the max out of them.

Yea, I just hope we can get the tune right this go round.

Also, I got the car completely back together and on the road. Have driven it about 250 miles now, and everything seems to be good.

To keep it safe, I've pulled 4 degrees of timing and added a good amount of fuel, as well as moved the shift points down to 5500ish. I'm also spraying it with a good sized meth nozzle (7 GPH) just as another degree of safety until it gets re-tuned. I haven't really 'beaten' it yet, but I've got on it some, and man does it move! Even with no tune, a lot of timing pulled out, and WAY rich, I'm relatively sure it's running stronger right now than the old motor ever did. I'm really looking forward to getting it tuned.

It's also making a tad more boost. With the old NPI motor (after the cams and 3.3 pulley), it was making 7 pounds with no meth, and 8 pounds with meth and/or cooler weather. Now, it's making 8ish pounds with no meth and close to 9 with the methanol. Not sure if it's because of the slightly higher compression ratio in the new motor, or if the old NPI motor was just worn out. It also doesn't doesn't stack boost in the upper RPM range like the old NPI heads did either.

Like I said, I'm very much looking forward to getting it retuned. Probably going to be about 2 weeks from now.

 

[SteedaGT9150]

pics?

 

[N8Dogg98]

Damn Will... didn't know you had that thing back together already. Can't wait to hear the numbers.

 

[SRT Handz]

how did you mount the NPI blower to PI heads?

 

[98COBRA281]

how did you mount the NPI blower to PI heads?

bolted them on.... and probably RTV'd the coolant ports