Rebuild or Replace

[Wahugg]

Hey all,

I've had a small knock for a while now that always went away after a minute or so while warming up. However it now seems to take even longer to go away, and it's become more pronounced.

Would you guys rebuild the lower end or just throw in a used one?

Thanks
-Wahugg

[Aries]

Hey all,

I've had a small knock for a while now that always went away after a minute or so while warming up. However it now seems to take even longer to go away, and it's become more pronounced.

Would you guys rebuild the lower end or just throw in a used one?

I have the same! My 02 TB has had it for as long as my GF has owned it. I just never noticed it as much until it became my DD. Rebuild is not an option for us and a used 4200 Vortec is gonna run 2K.

Here's some posts that go back to 2005 http://forums.trailvoy.com/showthread.php?t=427

I don't see where my ZIN: 1GNET16S726123328 falls in with the below info:
Year: 2002
Division: Chevrolet
Model: TrailBlazer
From: 22100007
Through: 22358861

[v7guy]

It depends on the price/mileage you can find a used motor with.

It also depends on how comfortable/willing you are to do the work.

It's kinda hard to make recommendations here.

[bartonmd]

Word from the tech guys at GM, third hand, is that the similar thing with the small blocks is a ring of carbon deposit at the top of the piston travel. When everything is cold, the rings tap on this ring of carbon, and make some noise. This goes away as it warms up and everything expands. They will last 300k like that. The trucks do.

Now, if you want to try and get rid of it, you could try a seafoam treatment where you suck it in a vac port until the engine dies, then let it AIT 20 min before starting again.

When the early north star v8s did this, the cure was, I shit you not, for the tech to drive the piss out of the car for 45 minutes, and burn the carbon out of the cylinders.

Mike

[HARDTRAILZ]

I just looked at used motors due to a GMT thread and they run about 500 not 2000. I know different prices in different areas, but you may want to do some research.

I would drive it til it died if it is just noise and not performance being affected.

[Wahugg]

Thanks for the advice.

Mike,

This could be my problem since the knock goes away completely once the motor has warmed up.

Kyle,

Thanks for the tip on price. Most of the ones around me tend to be ~650 depending on millage. I would just drive in till it blows, but 90% of my driving is over long distances to Michigan or Texas, and that would be a dreadful time for the motor to kick the bucket.

-Wahugg

Edit: I should mention that the knock is only present while under load while it's cold. If I just turned on the motor and left in Park, then there would be no knock. But the second I drop it into drive, it starts to make the knock noise that's dependent on rpm.

[Aries]

Most of the ones around me tend to be ~650 depending on millage. I would just drive in till it blows,

A quick search in my area brings up a 2004/150,000ml/$600 an a 2006/53,000ml/$1250 they are both out of a TB. These engines were used in a number of other models too. Once I get my build to where I want it I will start an engine fund for the future. I see where the street rod guys are buying the 4200 Vortec and bolting on turbochargers for their builds.

From Wikipedia

The Vortec 4200, or Atlas LL8, is a 4.2 L straight-6 in the GM Atlas engine family. It has four valves per cylinder, utilizes dual-overhead cams (DOHC) design, and features Variable Valve Timing on the exhaust cam, a first for GM Inline engines. Introduced in 2002 for the Chevrolet TrailBlazer, GMC Envoy, and Oldsmobile Bravada, the engine is also in use in the Buick Rainier, Saab 9-7, and the Isuzu Ascender. The engine was rated at 270 hp (201 kW) and 275 lb·ft (373 N·m) in 2002 then 275 hp (205 kW) and 275 lb·ft (373 N·m) in 2003–2005. In the 2006 model year the GMT360 platform received an increase to 291 hp (217 kW) and 277 lb·ft (376 N·m) . The Vortec I6 engine was on the Ward's 10 Best Engines list every year since its introduction in 2002 through 2005.

Applications:

2002 270 hp (201 kW), 275 lb·ft (373 N·m)
2003–2005 275 hp (205 kW), 275 lb·ft (373 N·m)
2006–2009 291 hp (217 kW), 277 lb·ft (376 N·m) (can vary slightly through the years due to the new SAE rating procedures)

[dvanbramer88]

I found this for you

"Problem : engine sounds like midget with hammer inside it .

Problem solved by : Mike

Solution : Took hammer away from midget."

[RyansTBLS]

I love it!

[mikekey]

Put a 350 in it an win points for originality. Only been done once so far, and that show queen hasn't been seen in a few years.

[HARDTRAILZ]

Put a 350 in it an win points for originality. Only been done once so far, and that show queen hasn't been seen in a few years.

Its seen every year. Just saw it back at All Pro shop getting some nice fender work done. Keep hoping it will sell and the new owner will take it straight out and wheel the piss out of.

[Aries]

Put a 350 in it an win points for originality. Only been done once so far, and that show queen hasn't been seen in a few years.

Way ahead of you, I have one sitting in my shop.

SBC350/TH700R4/Dana300/Dana 44 Front/Ford 9" Rear


If we put on our thinking caps we could make it happen,

[TBYODA]

If we put on our thinking caps we could make it happen,

Daily trivia question. Who other that I and Aries know which film this is from? HaHa

[bartonmd]

A quick search in my area brings up a 2004/150,000ml/$600 an a 2006/53,000ml/$1250 they are both out of a TB. These engines were used in a number of other models too.

Out of curiosity, which number of other models did this engine come in?

Mike

[ErikSS]

I know that movie.

[mikekey]

A quick search in my area brings up a 2004/150,000ml/$600 an a 2006/53,000ml/$1250 they are both out of a TB. These engines were used in a number of other models too.

Out of curiosity, which number of other models did this engine come in?

Mike

Um, none that weren't GMT-360 platform unless there is some global variant we are all unaware of (or he means Bravada, etc), but since they were all built in Ohio, I'd say no.

[bartonmd]

A quick search in my area brings up a 2004/150,000ml/$600 an a 2006/53,000ml/$1250 they are both out of a TB. These engines were used in a number of other models too.

Out of curiosity, which number of other models did this engine come in?

Mike

Um, none that weren't GMT-360 platform unless there is some global variant we are all unaware of (or he means Bravada, etc), but since they were all built in Ohio, I'd say no.

That's what I was thinking. I haven't seen it used outside of the GMT-360/370 platform.

Mike

[Wahugg]

After driving 700 miles through Michigan, the nock has become slightly audible even when the engine is fully warm. Looks like this may become a winter break project versus a summer project.

Right now my plans are to pick up another used 04 engine and slap it in there but.....

..... Depending on financials and how fast I can get this done, I've been thinking about taking out the 4l60E and putting in a 5 speed AR5 from a Colorado. I can source a custom fly wheel from a guy over at the Vortec4200 forums, and a H3 bell housing will allow me to bolt it up. The only issue I've run into is trying to figure out if our T case will bolt up.

-Wahugg

[Regulator1175]

Wallace, if you need an experienced hand, and are willing to drive here for a weekend, I will be glad to help you with this swap. I imagine that I can get Hatchet, AJ, and Erik to come over for the weekend as well. The four of us did a motor swap on Hatchets truck recently, starting Friday night and had it fired up before lunch on Sunday.

[Diacom]

If we put on our thinking caps we could make it happen,

Daily trivia question. Who other that I and Aries know which film this is from? HaHa

Gotta love Kelly LeBrock in it, no doubt.