After reading many posts about failed LIM, coolant in oil posts ETC, the gearheads here often advise replacing the motor. I wondered why no one recommends a rebuild? IS this purely from a cost/time standpoint to just drop in another engine and go? Or is it all the involved critical work dealing with clearances, boring etc?

Now the next 64k question, are these engines that will take a durable rebuild when time/money/enjoyment is there?

FYI, around here a JY 3800 runs around $300. Stopped at a yard about 100 miles away while on lunch break and he offered me a stripped LN3, lying on its side in the dirt for 100. I passed on that "sweet deal"

IIRC, the bearings are usually destroyed.

I think clm2112 rebuilt a failed L36 into a L67

Rebuilding is usually way more money and even a 3800 with 100k on it is usually still a strong motor. Thats why a JY motor is often recommended over a rebuild.

Yes, it'* usually cheaper to swap an engine than rebuild one. But the 3800 is completely capable of being rebuilt.

Definitely. Extremely rebuildable. I think most the reason people just go with a replacement is the lack of hassle and time savings. Plus unless you really know what you're doing, you can screw it up pretty quickly. And its hard to know who is really going to do a quality job if you have it rebuilt. The only replacement engines you can really trust are remanufactured engines such as Jasper engines with a great warranty or a new crate engine. So that would be my view on most peoples reasoning.

The downside I can see to a JY motor is getting one that only lasts a short time. Or like the LN3 I was looking at in the dirt, don't know how it was stored right there in the JY.

I followed Curts thread with great interest, no expense was spared on that engine and he wont be too worried about its prior history at least.

Definitely. JY engines are fine as long as they have a GOOD warranty on them. I'd like something like 90 days. Otherwise go with reman if you don't have the skills/tools/time/space to rebuild your own. But the 3800 is probably one of the most rebuildable...i mean, its all iron! best kind to rebuild.

Define "rebuild"


if you're rebuilding a motor due to a failed low end, and forget to include everything, you may have problems again. "Everything" is a broad word and depends on what the issue is and what exactly happened. However if the rebuild is not done properly or not in depth enough you may see a repeat failure.


The 3800 is considered easier to rebuild than most other modern engines if that is what your asking. The reason for reccomendations for the JY engine is because an L67 is $400-$700 with low miles and a non supercharged motor is usually $300-$500 in perfect running order. In addition compared to other FWD V6 Cars the bonnevilles are much easier to work on.

To me, if I were faced with an engine that needed a rebuild.

Heads go to machine shop for magnafluxing, valve job and seals.

Block gets tanked, magnafluxed and checked for round cylinders, straight mains and cam bearing install.

Rods and pistons get checked for weight balance and excessive wear.

lifters cleaned/replaced as needed.

Reuse cam if it was running OK before.

Reassemble with new bearings,rings timing gears and chain.

New oil pump (not taking chances here)

All new gaskets and new water pump

This is what I would consider to be a good rebuild that I wouldnt have any regrets over. I did this to my 88 Royale back in 96, except I didnt handle the short block, I dropped it off at a rebuilder in OKC and they supposedly did all this. It was burning oil 20k miles later. It did last thru the 12/12000 warranty though. Always ran well if sparkplugs were changed about every 10-15k. I always wonder if I had the skill and time to do it myself back then if I would have had the same outcome.

Costs back then start to finish was around 900.00. I had opted for the rebuild as opposed to a JY motor because I wasnt interested in a short life.

That, coupled with the GH advice to replace with a JY motor, led to my questiions

Anyone want the gearhead information?

The 3800 is a very fussy rebuild engine. Frequently those rebulding them (not professionals) find they don't last long after the rebuild. Even this morning I read something on ConnGP where a member (dealership mechanic) mentioned how these are a fussy motor on a rebuild.

The costs are also a determining factor. To get a known good motor it cost me $600 (after a bad one) and then labor.

Sending the heads out
Tanking the block
Buying a crank kit, lifters, etc etc..gaskets..
Would be well over $600 w/o any labor to assemble it.