Low Mileage SBC Minor Rebuild: What to do?

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strokersix
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by strokersix »

Adam,

Only you can decide what is the right way to proceed with your project. Everyone else has a different perspective. It's fine to ask, but you have to decide.

If you want to cheap out, great. Odds are you will be fine. If you want someone else to tell you that cheaping out is the right way, forget it. You need to evaluate your risk tolerance yourself.

My opinion. I've built questionable assemblies lots of times and had good luck but I won't recommend it to someone else.

I agree with the above comments about saving the original assembly for future. Buy another block. SBC are cheap.
68post
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by 68post »

novadude wrote: Wed Oct 17, 2018 1:18 pm With that kind of low mileage, I wouldn't touch the bottom end at all. Swap heads/cam/intake and call it good. I can's see replacing good rings, bearings and rod bolts for no good reason. I've done ghetto top end swaps on short blocks with more mileage that ran well, and continued to run well for a long time. Knock out the freeze plugs and flush the water jackets with a high pressure hose and leave the bottom end in one piece.

The comments about factory cranks, rods, and pistons not being that good is kinda funny. L82s had "the good stuff", and those parts would have been coveted up until the 1990s when all the cheap aftermarket stuff started coming on the scene. Even the garden variety cast stuff in L48s will last forever in a 350-400 hp engine at < 6000 rpm. Not every street engine needs fancy parts to keep from exploding in the first 100 miles.

Just my opinion.
I agree wholeheartedly with the above statement and have also done the same. You can use CLR in the block and rinse it out to remove ; calcium, lime, and rust ! (I've been gaining experience since 1974).
tresi
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by tresi »

I never meant to suggest your parts were unsuitable for 450 hp or 6000 rpm. But just a few things to consider, If you get new rod bolts they need resized. By the time you buy new bolts and pay to resize them you almost spent enough for a new rod made from better metal. If you judge the condition of your bores eye and odometer but it's really has taper and out of round you will have more blow by than before you tore it apart. A stock forged crank will handle those power levels but so will cast crank and the cast crank will out last it. Your crank is likely going to need tuned or at least polished. You want studs in you block and it sounds like you would prefer to have it squared up but you want the factory stampings So you're going to have to spring for a prepped block or be happy with what you have.
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by rebelrouser »

NewbVetteGuy wrote: Tue Oct 16, 2018 2:36 pm
rebelrouser wrote: Thu Oct 11, 2018 8:50 am Adam, I teach engine rebuilding, this is what I tell my students, locate the specifications for the engine, measure and inspect each component, after you compare your measurements with the specifications for each piece of the engine, you decide to use the component as it is, have it repaired or rebuilt, or you replace it with a new one. All the things you mentioned in your post can be measured and compared to specifications. Many shops replace things like rings and bearing, oil pumps, with every rebuild. Some states have laws about what a shop to replace to sell the job as a rebuild. If you are doing the work yourself it is your decision.
I appreciate the feedback; it seems like good, generic advice for a generic rebuild, but does everything on a such a low mileage motor actually need replaced?

What does NOT need to be replaced on a very low mileage, 40 year old engine? -That's the crux fo the question.


Adam
That is the point I am trying to make. Most replace an oil pump with every rebuild. Take the pump apart, clean and measure, if it measures good reuse it. If the main bearings look good have no scratches, measure bearing clearance and reuse them. If the timing chain has no stretch, reuse it. If the piston ring lands have proper clearance, and piston to wall is in specs reuse them. Rebuilding any engine is all about proper measurements and comparing those measurements to specifications. It is just easier to buy an engine kit and replace with all new parts for common wear items.
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by novadude »

tresi wrote: Wed Oct 17, 2018 11:11 pm I never meant to suggest your parts were unsuitable for 450 hp or 6000 rpm. But just a few things to consider, If you get new rod bolts they need resized. By the time you buy new bolts and pay to resize them you almost spent enough for a new rod made from better metal.
My opinion is that there is no reason to consider replacing rod bolts on this engine if it has so few miles. I don't believe rod bolts need changed every time the engine is disassembled. Same with lots of other parts (as mentioned above).
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by tresi »

It all depends on the bolt and how hard it was used. I had a truck with well over 400,000 on it when I sold it all with the same rod bolts
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by barnym17 »

Just to give you some info on how tough stock stuff is Chevrolet in its durability testing would put their engines on a dyno and cycle the rpm from peak tourque to peak horsepower under load for 24 hours.
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by NewbVetteGuy »

rebelrouser wrote: Thu Oct 18, 2018 8:50 am
NewbVetteGuy wrote: Tue Oct 16, 2018 2:36 pm
rebelrouser wrote: Thu Oct 11, 2018 8:50 am Adam, I teach engine rebuilding, this is what I tell my students, locate the specifications for the engine, measure and inspect each component, after you compare your measurements with the specifications for each piece of the engine, you decide to use the component as it is, have it repaired or rebuilt, or you replace it with a new one. All the things you mentioned in your post can be measured and compared to specifications. Many shops replace things like rings and bearing, oil pumps, with every rebuild. Some states have laws about what a shop to replace to sell the job as a rebuild. If you are doing the work yourself it is your decision.
I appreciate the feedback; it seems like good, generic advice for a generic rebuild, but does everything on a such a low mileage motor actually need replaced?

What does NOT need to be replaced on a very low mileage, 40 year old engine? -That's the crux fo the question.


Adam
That is the point I am trying to make. Most replace an oil pump with every rebuild. Take the pump apart, clean and measure, if it measures good reuse it. If the main bearings look good have no scratches, measure bearing clearance and reuse them. If the timing chain has no stretch, reuse it. If the piston ring lands have proper clearance, and piston to wall is in specs reuse them. Rebuilding any engine is all about proper measurements and comparing those measurements to specifications. It is just easier to buy an engine kit and replace with all new parts for common wear items.

I bought a Melling "Select" Shark Tooth Standard Pressure, Standard Volume pump; I think it technically has a 10% increase in flow and pressure over stock just because of the shark tooth design.

The main bearing under the RMS had some copper showing; all the bearings are being replaced.
Timing chain had nylon gears and I've got a double roller.

I talked to Dale Green Machine in Auburn, Washington yesterday. They're going to inspect the block, crank, rods, and pistons; then if it checks out ok hot tank it (they actually still have a Hot Tank), paint it, take the old cam bearings out for me and put in my new cam bearings, and "Power Hone" it at a minimum. (They said torque plate honing is pointless as the block wasn't bored with a torque plate on.) I was quoted $300 for everything assuming that nothing else needs to be done; very happy with that, not actually knowing what it SHOULD cost. (Labor around Seattle is insane for everything.)

It'll get new bearings everywhere except the small side rod bearings and new Total Seal rings.
They said there's a chance that the mains alignment isn't within spec given that only my rear mains bearing shows wear, but they'll check it out.
I put fuel line hose over all the rod bolt threads before pounding the pistons out but it looks like 3 of the rod smacked into 3 of the bores and left small marks when I was removing the pistons this weekend. Hoping / expecting a quick hone takes care of them.
I've also got some wear on the bottom of the skirts of most / all the pistons.

I appreciate all the advice and I'm hoping everything checks out ok; but if not I'm sure I'll be posting back here second guessing everything..


Adam
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by F-BIRD'88 »

I would have just sold this motor to someone who has a L-82 Vette or Z/28 and needs this motor.
And build a basic cast crank kit 10:1 383 .
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by NewbVetteGuy »

F-BIRD'88 wrote: Tue Oct 23, 2018 3:59 pm I would have just sold this motor to someone who has a L-82 Vette or Z/28 and needs this motor.
And build a basic cast crank kit 10:1 383 .
I'm strongly considering that. Getting this very basic machining done on the block, and bolt all the original L82 parts back on it and essentially selling a newly refreshed fully assembled L82 long block. The stock cam would have to go; it's awful, IMHO.

I'm not sure there's much of a market for it; especially when someone can buy a BluePrint crate motor with a warranty for $3,000; why would they pay $2,000 for a no-warrantee motor with 882 heads?



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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by F-BIRD'88 »

The 882 heads do suck. :-)
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Re: Low Mileage SBC Minor Rebuild: What to do?

Post by F-BIRD'88 »

On the stock L46 L82 hyd cam if yoy want a bit more torque out of it you can advance it a bit to a 107/in c/l. Its normal centers are 115/113. I hear ya.

I am ?hinkin you really want to have the higher torque and power of a 383 stroker sbc.
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