Wide open throttle on an old 5.7 vortec? Good or bad?

[redfishsc]

Hey guys, is it generally good, or detrimental, to do some intentional WOT on these old Vortecs? I have a 99 Suburban, 210K miles, and the only "performance" mod I've done is swapping the rear gears to 4.10's. Oil is Penz Platinum 5W30, trans fluid and filter is fairly new (Valv max life), tires are 31X10.5. 2WD, C1500. Oil stays clean for a very long time, really never turns black even after 7K miles. Coolant is brand new, well flushed, green stuff.

Back story.

I used to have an 03 Deville with the Northstar. Utterly different motor than the 5.7 Vortec obviously, but that motor absolutely demanded some WOT treatment or it would burn oil like crazy and smoke a little (blue). If only my wife drove it (mild foot), it smoked. If I drove it for a week, it didn't, because I'd give it plenty of WOT. In fact, the guys over Cadillacforums.com pointed me out to a good WOT treatment (2nd gear, WOT going from 55mph to redline allowing the engine to slow it back down to 55, repeat 3 to 5 times).

With all seriousness, doing that was the best thing for that Northstar. When it was totaled by a guy that pulled out in front of me last year, it had 173K miles on it and it ran like a brand new car. It had more power at 173K than it did when I first got it at 90K (was not driven hard at all, used a lot of oil, sticky rings).


I know the 5.7 Vortec has very little similarities with the Northstar, other than being a GM V8. But is it beneficial on these Vortecs to do some WOT once or twice a week, intentionally, or am I asking for a blown head gasket at this late in the game at 210K miles?

 

[90halfton]

I'm sure it'll be fine. Don't know about once or twice a week being necessary though. My stock 90 350 TBI gets a wot run on occasion. I'm a firm believer in "knocking the cob webs out" like old folks used to say.

 

[redfishsc]

I've had 2 1990's. One was a 4.3 manual, the other was a stock 350TBI with a 4sp auto.

The one with the 350 I got about 5 years ago, from family that had let it sit. Piston 1 had a leaky valve guide that fouled up #1 spark plug a lot, but I still gave that truck some WOT. The plug fouled a lot more if I did that (maybe it was a stuck ring instead of leaky valve guide, I dunno). Either way, love those early 90's trucks. People poo-poo the TBI's but this truck still ran strong and was drop-dead simple to work on.

I love the Vortecs but they are a lot more complicated and finicky.

 

[2 Sweet]

You'll be fine. Going WOT every once in a while won't hurt anything, IMO. I typically do it at least once a week in every car I've owned, and I've never popped a gasket. Hell, I went wide open in my '92 Camaro pretty much every single time I drove it. When the subframe finally rotted out and the car was no longer road worthy, that old 305 TBI was still running strong at over 250k.

 

[SAATR]

338k miles here, and have been taking her to redline a couple times a day, every day, since I got her at around 240k. I've run 0W40, 5W30, 10W30, 10W40, and finally settled on Rotella 5W40. Uses about a quart every 5k miles.

Piston during her last surgery at around 330k. Had a small head gasket leak causing overpressurization of the cooling system. Pistons are damned clean for the mileage, though do show some signs of light oil burning.

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I'd love to think that putting the engine through her paces on a regular basis helps keep the rings free and knocks some of the carbon off the pistons, ie the old "Italian tuneup". I say give it hell.

 

[laidbackbigun]

When you say small head gasket that over pressurized your cooling system can you explain more on that. Not trying to thread jack sorry op

338k miles here, and have been taking her to redline a couple times a day, every day, since I got her at around 240k. I've run 0W40, 5W30, 10W30, 10W40, and finally settled on Rotella 5W40. Uses about a quart every 5k miles.

Piston during her last surgery at around 330k. Had a small head gasket leak causing overpressurization of the cooling system. Pistons are damned clean for the mileage, though do show some signs of light oil burning.

You must be registered for see images attach

I'd love to think that putting the engine through her paces on a regular basis helps keep the rings free and knocks some of the carbon off the pistons, ie the old "Italian tuneup". I say give it hell.

 

[SAATR]

When you say small head gasket that over pressurized your cooling system can you explain more on that. Not trying to thread jack sorry op

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There was a small split developing in the fire ring of the head gasket on cylinder #7, and you can see the faintest traces of separation where combustion gases were being pushed past the fire ring circled in red above. It was small enough that only combustion pressure was pushed into the cooling system, but no coolant was being pushed into the cylinder, causing the system to pressurize quickly when still cold and stay pressurized long after the engine was shut down and cold again. It caused some minor bubbling in the radiator when running. Never enough to overheat, but enough to push air and coolant into the overflow tank after several minutes of highway driving. I attribute it to age and the fact that the rear cylinders have a tendency to run hotter than the front in most V8's.

Sent from my XT1585 using Tapatalk

 

[Colonel Sanders]

Just picked up a '99 with the 5.7 and 231k miles, when I first test drove it it was smoking a little but bought it planning on rebuilding the engine. I had a friend follow me back home and gave it a couple WOT runs to try to determine what was causing the smoke, first time could barely see behind the truck but each time got better and after driving it home it now no longer smokes at all. After doing some research it seems like the smoke was caused by carbon buildup in the engine/exhaust and the WOT runs cleaned it out, so while you don't need to redline it all the time it might be good to get it going on the on ramp or when passing every so often as the extra fuel and combustion can help clean out the engine.

 

[laidbackbigun]

So still thread jacking. thats like the best scenario you can have for a cracked head gasket i assume. i mean besides swelling upper radiator hoses and losing possible coolant out of overflow right.

My dad always told me to crack her open every once in awhile and blow the carbon out. he also said if there is any underlying timing issues it may be the only time you feel it.

 

[biggbiker]

My 96 5.7L with 218K has seen several redlines with no damage.