Recommend a Vortec overhaul kit?

[NatersXJ6]

Hey all,

Long story short, I needed a really cheap SUV to send to family back east. I found a 99 suburban 5.7 for $500 with a blown head gasket but otherwise looking recoverable.

The 5.7 Vortec was overheated when a hose broke, causing the engine overheat and blown gasket. Oil is pure cream at this point.

I can google parts as well as the next guy, but I plan to tear it down and rebuild with a basic kit, bearings, timing, gaskets, oil pump, valve job, maybe not pistons, but possibly rings.

Does anyone have actual experience with one of the budget overhaul kits and a recommendation to buy or avoid?

I’m doing this shadetree style, and if the thing manages to run 75k more miles I’ll call it success.

Thanks,
Nate

 

[DailyExpedition]

How many miles does it have? Also is it the old body style 99’ or the new body style with the LS engine? I would not go cheap on the rebuild kit, if you’re taking the time to do it, might as well do it right. However if it’s only the head gaskets you could save money by just doing those. When you pull the heads you can check to see how much lip or scarring you have on the cylinder walls. Also if it’s the old body style vortec then you can upgrade the spider injectors since they are prone to going bad, if they haven’t been changed before And flush the engine a few times to get the water out.
I blew the head gaskets on mine, I have the old body style vortec and it ended up cracking the heads, which is fairly common cost me $300 for a new set of heads. Luckily no oil in the water and since putting the heads and gaskets I’ve put well over 100,000 miles on it.


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[lilkia]

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Ive rebuilt several 5.7s with the basic summit kit. But you really need to mic your journals and make sure theres no oversized bearings or at least check for damage. If the engines never been opened and theres no damage the above should be everything you need.

 

[Smileyshaun]

those summit kits are great , done a couple motors with then . take the heads in and have them checked and get the block hot tanked it won't cost much and can save you a ton of headache .

Also look around at some local engine builders you may find some good deals on a rebuilt motor. There's a local shop around here that I can pickup a rebuilt vortec 350 for 1600$ and it has a lifetime warranty that they fully stand behind it.

 

[lilkia]

And for whatever its worth. I rebuilt a pre-vortec '92 5.7 with blown head gaskets using a similar summit kit many years ago broke ass shadetree style. In other words jstraightedging the heads cleaning it up and slapping it back together. It lasted me another 40k before I sold it to a buddy as junk hauler/plow truck. 15 years later and a bunch of pop riveted rust repair hes still running it on the same engine. As long as you cover the basics those 5.7s are pretty damn bullet proof.

 

[rayra]

I'd suggest comparison shopping at rockauto.com
https://www.rockauto.com/en/catalog/chevrolet,1999,k1500+suburban,5.7l+v8,1353327,engine
And maybe just start with a gasket kit until you break it all down and see what it really needs.

And if you intend to leave the crank and pistols etc alone you might consider a higher-volume oil pump or replacement oil pump regardless.
You might want to hone and re-ring, but if you're doing that you might as well change all the crank bearings too.

Hydraulic lifters. #1 and #3 sets seem to be first to stick and fail.

And I recall something about an updated fuel injector spider for this series.


I've done a lot of 'shade tree' work on earlier SBCs and later-series Vortecs, but I've managed to skip the OP's generation, so I can't really say specifically what to look for, other than general wear / age issues.

 

[vintageracer]

You can buy a complete NEW L31 5.7 Vortec 350 crate engine from GM with a 3 year 100K mile warranty for less than $1800 all day with a little bit of shopping.

Why would you even consider rebuilding an unknown overheated block and heads when $1800 buys a complete NEW engine with a killer warranty?

Something to consider IF your truck is nice and you intend to keep it.

 

[NatersXJ6]

This is great, I appreciate the feedback. 167k miles, history unknown other than overheated and “runs badly now”. There was 8” of foam and no oil on the dipstick, so I told the guy I didn’t even want him to start it. Why make it worse?

My goal is to be below $1000 for repairs and upgrades. I plan to tow this thing home Saturday, and immediately pull the engine and strip it to bare block. I can straightedge the heads and block, clean it, hone it, and mic everything here. It is the all Iron engine, maybe they call it L31? Not the LS, I know that for sure. I figure that a good inspection, master rebuild kit, probably pistons, rings, rod, cams and mains, timing set, water pump, oil pump, and valve job gets it moving again.

Any special places to watch for cracks?

Does anyone know if this uses torque to yield head bolts?

Thanks for the help!

 

[vintageracer]

Any special places to watch for cracks?

Does anyone know if this uses torque to yield head bolts?

Cracks? YES! Expect to have to replace the heads due to cracking from the overheating of the engine. This happens a lot on overheated L31 engines.

Torque to Yield head bolts? Yes

Also expect to replace the FI "Spider" for reliability if that upgrade has not been previously completed.

Add to the above everything else you mentioned replacing in your post above.

 

[DailyExpedition]

This is great, I appreciate the feedback. 167k miles, history unknown other than overheated and “runs badly now”. There was 8” of foam and no oil on the dipstick, so I told the guy I didn’t even want him to start it. Why make it worse?

My goal is to be below $1000 for repairs and upgrades. I plan to tow this thing home Saturday, and immediately pull the engine and strip it to bare block. I can straightedge the heads and block, clean it, hone it, and mic everything here. It is the all Iron engine, maybe they call it L31? Not the LS, I know that for sure. I figure that a good inspection, master rebuild kit, probably pistons, rings, rod, cams and mains, timing set, water pump, oil pump, and valve job gets it moving again.

Any special places to watch for cracks?

Does anyone know if this uses torque to yield head bolts?

Thanks for the help!

Cracks are usually between the valves and the valves and the spark plug. Definitely get new head bolts and the spider injectors. Since the miles are that low you may not need to do anything to the lower end, but if they drove it and blew the head gaskets they way they did who knows. I hope it doesn’t need much to be road worthy, sounds like you know the ins and outs of what you’re doing Good Luck!


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[Pacific Northwest yetti]

Im still going strong at 250k on my 6.0, but following.

 

[NatersXJ6]

Ha ha! 1 horrible crack on the same cylinder that had the blown gasket.

Thank you Fresno junkyards! $115 netted a pair of Vortec heads in decent shape. The best part was that someone else had torn the engine down, apparently for the pushrods! Even the hood was off. All I had to do was unbolt the heads and walk away.

 

[rayra]

There was a problem in the GMT800s with Castech heads having manufacturing defects resulting in hairline fissures thru them in a couple places near their rockers. Coolant would seep from the head water pathways out into the valve / rocker space and down the oil return holes to the pan to get mixed in. Small seeps would lower coolant levels without much trace other than come condensation inside the oil fill cap on a cool morning. Bigger seeps give you the same chocolate milkshake as a head gasket failure.

GMT400s might have had a similar problem, you should search for such issues in the 5.7 series motors.

But if it's already 'running badly' and already has signs of coolant in the oil, I'd seriously expect to need to replace all the engine bearings and probably expect to do more than just a surface hone of the cylinders. And being a hi mileage motor anyway, the oil pump and timing chain too, anyway. Even without the contaminated oil.

Unless you can do almost all the work yourself and know a good value place to get head and cylinder work done, you're going to spend just as much as a replacement long block, anyway. If you are really on a shoestring budget, it isn't hard to do the work, you might save ~$500 when all is said and done. You really aren't going to know for sure until you pull the heads and get a look at your cylinder bores. And get the crank surfaces uncovered. Basically take it and apart to really determine any lasting damage and repair costs, before you go buying anything.

 

[DailyExpedition]

Ha ha! 1 horrible crack on the same cylinder that had the blown gasket.

Thank you Fresno junkyards! $115 netted a pair of Vortec heads in decent shape. The best part was that someone else had torn the engine down, apparently for the pushrods! Even the hood was off. All I had to do was unbolt the heads and walk away.

That’s a steal! I would take them and get them checked and leveled, won’t cost much and it’ll keep you from having to find out that they’re no good


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[NatersXJ6]

I tore them down and cleaned them. They are in an electrolysis bath right now for derusting, inside the coolant passages was pretty ugly. Unfortunately, it is taking longer than I want because my newer “smart” battery chargers aren’t recognizing the bath as a battery, so they won’t push power. I’m limited to the 10A of my old school charger.