It is a matter of economy. Rebuilding properly is very expensive. It is much less expensive to replace a bad engine with a good one from a salvage yard, than any other option.

These engines are not hard to remove and replace.

For the L-36, prudence would dictate that the "new" engine gets aluminum LIM gaskets, a sleeved UIM and a small stovepipe, prior to installation.

Captain Anal, reporting for duty!

I rebuilt mine after spinning the #3 rod bearing. Yeah, I could have gone the junkyard route but I didn't like the idea of not knowing what the replacement engine had suffered through. To me it was worth the added cost to know what I had under the hood. I hate not knowing what I'm getting into. A proper rebuild will certainly be more expensive than a junkyard motor.

I suppose one could "freshen" his engine rather inexpensively by installing new rings, bearings, oil pump, water pump, etc., and leave the heads, cam, crank, etc. alone.

Anyway, MY preference is to rebuild.

Now for my input


If you come to the decision of junkyard motor, be very cautious when looking. Even cars with low miles showing may belie problems. Most of the time, cars that have been rearended are your best bets. *Maybe* a low-impact frontal damaged car. No damage to the car at all.....I would pass on. Because either the engine went bad, or the trans did.

L67 motors I would NEVER trust from a junkyard unless they can provide the mileage of the car when it came to them. Most L67 powered vehicles came with cars that had digital odometers, which makes verifying mileage impossible to do.

As for the rebuild route, I can personally vouch that it does cost some green. Ebay helped out quite a bit, and doing most of the labor outside of a shop also helped alot. A crank kit alone cost around 300.00, gaskets another 250.00, and then oil pump, lifters, cost of fluids, motor mounts (if needed), and all the other little things...it all adds up.

I've rebuilt ALL my motors. Out of 30+ motors I've lost 3-4. Even the motors I get from JY get a full rebuild.
However I will only refresh a motor 2times before I consider it junk. I rebuild my "race" motors every winter-normally just because.
My other motors that I build for costumers have easily seen 50k+ and still counting. No costumer failures-YET!

You can reuse 90%+ of the parts from a "blown" motor (spun bearing, popped piston,ect), you just have to know what to look for, and how to clean the parts.

Taking the parts to a machine shop does nothing except cost you money for the most part. The hot tank does clean things as thurough as doing it by hand, the tank DOES make it look better tho. Only customer motors and my race motor get tanked.

If you don't know what your doing you WILL loose another motor! These motors aren't like the SBC motors most have grown up with.

I wouldn't rush to discount machinists though. Not everyone has the ability/facility to do any type of machine work. Sure I can Plastigage to determine clearance, but then what do I need to do with the info? Machine work may be required

If you are capable of doing machine work, then great, but for the casual rebuilder (someone like me) I would more likely than not find a good one I can trust.

Edited to add, this reply was to 13secGTP. I got all panicked when approaching the thought of rebuilding a 3800 without a machinist LOL.

Rebuilds (non-cataclysmicly destroyed cores that is) can be done w/o machine work. "Freshening up" is what it is usually called. However, after looking at the heads and intakes of both L67s and L27s, you would do good to machine out some of the casting inconsistancies. I've seen more casting flash than I care to comment about, and none of it is good.

3800 blocks are typically good. At 175k, my motor still had its crosshatching in the cylinder walls. Heads typically don't need work either, though it has been proven that they CAN warp. Only things that really need rework are cranks and rods, unless you want an overbore.

Of course, freshening up, includes cam bearings, correct?

Is there any benefit or reason to worry about the mains not being straight? This would be another major thing I would want a machinist to check. If the motor was running ok when taken down, maybe just burning some oil or low pressure, is this even an issue?

My $0.02 on rebuilding the 3800...

Yes, they can be rebuilt. No, they are not mainstream enough to be rebuilt cheaply (unlike the Chevy and Ford V8 small blocks) They seem to outlive a lot of the sheetmetal they are wrapped in. For example, I bet I'm the only other guy in North East Florida to rebuild a 3800. When asking around machine shops, only one came back that he had worked on a 3800 for another customer...no surprise, this shop got the crank to rebalance for mine.

You can rebuild one yourself, up to a point. There are some things that require expensive tools that you will not have and couldn't afford unless you are going into the rebuild business (boring machines, balancing equipment, big lathes.) Having a shop do it can be trouble too..sometimes they don't even have the tools to do it (as I found out when trying to get a balance job done on the 3800 crank.)

For a stock replacement, you are amost as well served by buying a commercial rebuilt short block and trade your old motor in as a core.

However, if you want something better than stock, you will be looking for either a custom rebuilt motor from one of the speed shops, or doing it yourself (with help from real machinists.)

From my perspective, the 3800 had some surprises inside it (like the oil pump arrangement) but nothing that couldn't be addressed in a rebuild.