Chevy 8.1 Vortec Rebuild

[skyhightree1]

If it needs a valve stem seal you can replace that without pulling a head.

Thanks Kingfisher, I thinks he's going to look into that for the short term.

There is alot of places the oil can be leaking from that isn't very hard or expensive to fix unless its something like a main seal. The other side to the coin is you can rebuild and or swap and have issues most rebuilds aren't warrantied atleast here atleast. If you find your problems and they are fixable atleast you know what you have. I try to make the most of my farm/business trucks and understand what you are saying but when I do a motor its cause it suffered a major breakdown

 

[highgrit]

Good luck with it, I would buy a new truck. If the engine is wore out so is the rest of the truck. You may have more time than money, but once you open the can up worms go eveywhere. The chances of you finding someone to do the job right is slim to none. Most all mechanics are parts changers, the labor cost will eat your lunch. Now if you knew a good mechanic or could fix it yourself, a factory GM crate engine might be the way to go.
Time is money, and I don't know about you but, I'm to old to walk.

 

[CottageFarm]

Thank you for the feedback, but a new truck isn't in the cards right now.
And if we're going to go with a used truck, I would rather stick with the one we have and know well.
It's perfect for us other than the high miles and we know what's been done to it, by whom, and how well.

 

[Nesikep]

How much a rebuild will cost will depend largely on how the engine looks inside... If the cylinder is worn, it'll need new pistons, as well as rings, if the crank journals are worn, they'll need regrinding, The heads should be machined and new valves and seats put in regardless... There are also things replaced as a matter of course, oil pumps, water pumps, and any seals... In a worst case scenario, I could see the block machining costing about $800, as $100 per bore seems to be a pretty common price, $800 for pistons and rings, about $500 for a crank grind including bearings, and probably about $700 in gaskets, oil pump, etc. While its apart, I would seriously consider putting a mild cam in it, it will need some research, but with the right one, you can get better mileage and power... Including lifters, that would be about $600... You should be able to get rebuilt heads for $800... So the parts and machining comes to about $4000, and probably will be less... If you have a drag strip around there, you can find some people who are good at that kind of work, and get a whole meal deal from them... Unless they're RICH, most guys there are kept broke by their hobby, and will be happy to do some work for you

 

[CottageFarm]

Thanks Nesi, that gives me a good starting point.

 

[saltbranch]

I realize that it's current problems don't necessarily warrant a rebuild at this point. The plug fouling issue has been going on for about the last 30k miles, it's also starting to leak some oil in the past week, and as I mentioned it's at 238k. That's a lot of miles on a big motor, so this is something that will likely need to happen in the next 30-50k miles no matter what. Most people seem to figure 200k on a big block is really good, and I figure by the time this happens we'll be at 250k.
While I don't want to spend any money that I don't have to, I also want this to be a planned inconvenience, rather than have the truck die at the worst possible time. We all know that Mr. Murphy would prefer the latter option.

I am of the opinion that 238k is not a lot of miles for a gas motor these days. Twenty-thirty years ago...yes. The 8.1's are pretty sweet motors if maintained right. Only you can determine the need. For what you are describing, I would fix the current problem and run that truck into the ground. Then rebuild it if you want another 200k down the road. Compression test first, then decide. 238k is nothing for the 8.1, JMHO.

 

[chevytaHOE5674]

Agreed if its been maintained well then you shouldn't need a rebuild at 238k. We had an 8.1L in a woods truck at the sawmill that had about 500k on it before we sent it to the crusher because everything was simply worn out, and it spent its whole life running back and forth from the sawmill to logging jobs getting abused.

You need to figure out why it is fouling the plug, and then go from there. Some year 8.1L motors had TSB's for replacing the intake bolts and gaskets, they also had some PCV valve changes along the way.

As far as oil leaks, figure out where they are coming from and go from there.

If the motor has good compression and good oil pressure then there's no reason to rebuild.

 

[Nesikep]

I would agree with chevyTahoe as well, a compression test is the first thing it needs, you can do it yourself pretty easily with a guage available at any auto supply store... Cylinders should not deviate more than 10% of each other, and should be somewhere in the 120-180 psi range, dependent on engine design, and your altitude and temperature as well. If some or all seem low, squirt a little oil in each one and retest, if the readings are much better, that points to the rings being worn and it will need a rebuild, if it doesn't improve much, it's either a head gasket or bad valves. At that point, you can decide if you want to have someone take the heads off with the engine in the truck, which isn't too hard to do, and then you can see the condition of the cylinders and decide if the complete rebuild is worth to do then.

Does the truck smoke? If it smokes when it starts, then clears up, that is probably valve seals, if it smokes under deceleration, that's more likely to be rings.

From what I understand, you could just get a 'top end' job done on it.. rings and heads, unless it rattles and clunks the bottom end is probably fine...

 

[10-e-c-dirtfarmer]

http://www.crateenginedepot.com/81-Ltr- ... 8C720.aspx

 

[CottageFarm]

Thank you all, it's very helpful.

Nesi, no it never smokes. Not sure if that tells you anything, but I figure that's a good thing. He is planning to do a compression test.
The truck has always been well maintained, and has performed beyond expectations, which is the reason we don't want to replace it with an unknown and would prefer to fix it.

 

[Nesikep]

I would doubt you need a complete rebuild, and I'd certainly take the heads off with the engine in the truck and check it out before I look for another engine at this point

 

[Ouachita]

I'm going out on limb here and agree your bottom end is fine. And that's all I got to say.

 

[robb]

If it was me I'd buy another truck.

I sold an '03 2500 for $9500 last year and it took six weeks to find a buyer.
It was an 8100 ext cab long bed 4x4 hard loaded leather seats and all the options with 95k miles and it was a flawless 2 owner truck.

Sell yours by the piece or whole for parts and buy another 8.1 or even a newer 6.0 gas with lower miles they really do run good for a gasser.
The gas trucks are just in very low demand. They don't bring anything compared to a diesel and you'll be way ahead of paying someone to put a motor in the old truck.

 

[CottageFarm]

I'm going out on limb here and agree your bottom end is fine. And that's all I got to say.

:lol: :lol:

 

[CottageFarm]

If it was me I'd buy another truck.

I sold an '03 2500 for $9500 last year and it took six weeks to find a buyer.
It was an 8100 ext cab long bed 4x4 hard loaded leather seats and all the options with 95k miles and it was a flawless 2 owner truck.

Sell yours by the piece or whole for parts and buy another 8.1 or even a newer 6.0 gas with lower miles they really do run good for a gasser.
The gas trucks are just in very low demand. They don't bring anything compared to a diesel and you'll be way ahead of paying someone to put a motor in the old truck.

Thank you for the feedback. Can't have a diesel because I'm allergic to the fumes. Gives me a migraine in about 30 seconds.
6.0 don't have the power we're looking for. Don't really need to get a different truck at this point, just want to fix what's needed on this one.
For now we'll probably just get something else for him to kick around in to keep some miles off the dually.

 

[Carpenter2n]

I like gassers too. I want a truck with a starter
Keep it and fix what needs fixin'

 

[saltbranch]

Thank you all, it's very helpful.

Nesi, no it never smokes. Not sure if that tells you anything, but I figure that's a good thing. He is planning to do a compression test.
The truck has always been well maintained, and has performed beyond expectations, which is the reason we don't want to replace it with an unknown and would prefer to fix it.

Can you post a pic of the plug that has to be replaced? How often do you have to replace this plug? What brand of plugs are you putting in the truck? If its not smoking, it don't get why the plug has to be replaced. Not sure what brand you put in it, but I would put AC delcos at least. Don't cheap out on the plugs. Post the compression results too. When was the last full tune up was done? Need lots more info before anyone can suggest pulling the heads or suggesting a rebuild IMO.

 

[Brute 23]

This is just an opinion... If I were in your shoes... I would try to address the issue and run it in to the dirt. You have between now and then to make plans for another truck.

Engine swaps can be done... but... if you don't have right mechanic its a nightmare and you will be money ahead getting a "new to you" truck with lower miles. The only way I would consider a new motor is if I bought a crate motor from GM and had that same dealer install it (which I did). You do an engine swap and start throwing a bunch of codes on these new trucks and you will want to drive it off a cliff just to make the pain stop.

Just my .02 :tiphat:

 

[CottageFarm]

Just to update.
We'll try to get the current issues diagnosed and repaired when we have the time. We'll see how many more miles we can get out of it before something significant needs to be done with it. Husband is also of the opinion to keep driving it till it won't go no more.

In the mean time we bought a low mileage '00 Durango this weekend that will allow him to tow the smaller trailer, keep some miles off the dually, and it gets better mileage than the truck, and gives us the 3rd vehicle in case (when?) my Rover finally gives out.