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Was this 1940 248 engine as advertised?


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So it's been a while since I last reported on my 1940 56S. I had just gotten it up on the ramps by taking a running start (see here). I spent the next 3 weeks working on the garage and first thought you might want to see the results:





With TR-3 back inside


Lotsa work but worth it. I also got a much better air compressor out of the deal.

So while the car was on the ramps I did a bit of wiring repair and decided to get the oil out of the engine. I still hadn't changed it since I got the car last summer. So first thing, it took great force to remove the plug. Bad sign #1. Then, as it was coming loose, about 2 oz of water leaked out. Bad sign #2. I removed the plug and the black goo that exuded from the oil pan orifice was a sight to behold. After a while it started to chug, almost like the engine was vomiting it out. Bad signs #3, 4, and 5. Put in good oil and all is well although idling oil pressure is lower (measured it with a good gauge at 12 lbs idle, almost 40 lbs running).

Now, keep in mind that I was told that the engine was "rebuilt" and in fact I found an old email today from the seller stating this. But with the state of the oil and the appearance of the pan exterior it's hard to see how the pan could be removed and replaced while keeping all of the garm totally intact. I also stuck my finger thru the oil drain hole and I could feel a lot of sludge on the bottom of the pan.

So, remember here that I did a compression test with less than satisfactory results. I tried to replicate the results but the numbers were way too low; determined that the Shraders had failed in my 25 year old gauge so I got a new one along with a leak down tester. Pressures were no more than 75 lbs and again adding oil didn't seem to help. So I did a leak down test and the only noise was from the dipstick hole (indicating rings). The percentages are only relative but all were 40 to 60%, or "moderate" leakage.

Next, I got a video scope and took a look inside the cylinders. Here are some intake valves, looking so-so:


Here are some exhaust valves, generally looking good:


Here are a couple of cylinder walls at the top (you can see what I think is the ridge and the area above the head gasket)


So, the bottom line: do you all think this engine was overhauled? Could unset rings leak this badly? Maybe they required oversize pistons but he was too cheap? Maybe he did valve work only? Or maybe "rebuilding" an engine is just stopping the obvious oil leaks? Thoughts?

At this point I am thinking complete engine teardown next Spring. Sigh.

Cheers, Dave












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Really nice job on the garage! You can clean up mine anytime you are in the area!

Sorry about the disappointing engine.

Since the seller told you in writing that it was overhauled, it appears you were lied to and the vehicle is not what it was proported to be.

Rebuilding the engine would be a major expense. I am usually very nonconfrontative, but in this case, I would feel justified in attempting to get the cost of the rebuild from the seller.

Even if the seller stated "as is" or "no warrantees," Fraud is fraud.

Good luck,


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That engine definitely does not appear to have been overhauled anytime recently. I feel you already know this, hence you even asking. I hate to assume you were lied to intentionally. Like you allude to, maybe the seller thought doing some other sort of tune up work on the engine to make it run better meant he was "overhauling" it? Different terms can mean different things to different people???

The garage looks fantastic!!!

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Dwight, Billy,

Thanks on the garage! It was a *lot* of work but it was worth it. The only thing left to do is to put in a small workbench.

This is from the seller's email:

>>>> David, Underside pictures of the 1940 Buick. I just had the motor rebuilt and it sounds like a sewing machine[very quiet].Restored in the 90's.Chrome and stainless are like new, but the paint is showing it's age.<<<<

He was basically right on the chrome, stainless, and paint, but very wrong on the motor. Sewing machine? Maybe an angry sewing machine...


Camera link, got it on Amazon:

Autel scope

Cheers, Dave

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At the very least, I would give the seller an opportunity to explain himself:

"I opened the drain plug, I looked inside the cylinders....You emailed me saying the motor was just rebuilt. How can this be? Did someone cheat you?"

You may get an honest mistake answer or maybe he had it "rebuilt" and someone cheated him.

He may offer to reimburse you.

You may be surprised by his answer!

I had my coffee now.


Edited by Dwight Romberger (see edit history)
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Wayne: LOL, but unfortunately the TR has no top so it has to stay dry. BTW, it's my next project; paint and interior are fabulous but needs mechanical help. Too bad I can't fit in it!

Dwight and Grant, I am writing the seller tomorrow. Will let you all know his response.

BTW, am taking it off the ramps and out for a spin tomorrow. Will have AAA on speed dial...

Cheers, Dave

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  • 2 months later...

So, to catch up, I was able to take the car out a few times but the oil on the clutch is pretty debilitating. Then we were away for 3 weeks and then I finished up adding lights and power in the carport. I then tackled the gas gauge and fuel tank issues which is covered here. I am also going to swap out/in clutch and trans over the winter.

I did contact the seller and he put me in touch with the mechanic who worked on the car. The guy swore up and down that he took of the head and had it "serviced," what that means, although he did say 4 exhaust valves were replaced. He also said he replaced the rings, but said they were not oversized, and apparently did not check to see if that was needed. So that could be the compression trouble right there.

So, finally getting back on the engine once more before car hibernation. I had mentioned the plug fouling. I also noticed a lot of gunk coming out of the exhaust, to the point that it leaves a smear on the pavement. I had been assuming that it was all oil related due to the low compression, but on looking into it further - it's not oil. The inside of the tailpipe has lots of black deposit, but it's not oily. A closer look at the plugs reveals the same. And the black smudge on the pavement is not oily, either.

Any ideas on where to look for the apparent rich running? I am going to pull the carb in the next few weeks and recheck the float level. Any other things to check? Fuel pump pressure is very good - I put an inline pressure gauge prior to the carb so I can monitor it real time, and it's never above 5.5 lbs. Air cleaner is clear. Choke is currently manual, and in fact I hardly use it, the engine seems to start better without it. Any other ideas?

Cheers, Dave

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Good morning,

First, the black watery gunk coming out the tailpipe, is fairly common in these old cars, as my '39 does the same. Seems to be condensation blowing out, taking some carbon with it. Too rich? Possibly, although mine runs well even with the 10% ethanol we are forced to use. Second, when I bought my '39, the compression was only 70 lbs., give or take a few pounds. The previous owner stated that the engine had been out and sent to a shop for rebuild. He re-installed the engine, but never completed the restoration, and I bought it that way. All evidence points to a complete rebuild. Why the low compression? Two likely causes are rings that are too hard ( some used to be chrome plated), and take forever to seat. Second is that possibility that the cyl. walls were honed after boring and were actually too smooth for the rings to seat. Anyway, 14 years (and 32000 miles) later, the compression is up to 100 -105 per cyl., with little variation between them.

Just thought I would pass along my experience with the 248 engine.


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Guest Grant Magrath

All good stuff Gary. The cylinder walls could be oval as well, not allowing the new rings to do their job. Maybe do a leak down test?



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Thanks Grant and Gary!

I did do a leakdown test and it sure points to rings, although it could be they are not seating like Gary said. But I think the next major step is to take off the head for a peeky-poo as they say down South. I think that will tell the tale. Meanwhile I will take another look at the carb.

See attached pic for a look at my 'tailpipe smear.'

Cheers, Dave


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When you remove the head, check the bore diameter at the top and bottom. Many times the bores have more wear at the bottom from the piston skirt rubbing against the walls. If you have oil fouling of the plugs, the engine will then appear to be running rich from plugs not firing properly to burn the mixture. you may also want to check the amount of oil getting to the rocker arm area. excess oil will be sucked into the engine from worn valve guides. Buick restricted the oil flow to rocker arms and the restrictions were frequently removed by mechanics not understanding the consequences. I would also be concerned about the oil pump condition with all the gunk you found in the pan. Sorry no good news to offer you.

Bob Engle

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Just a thought on the oil line restrictor in the head under the valve cover. I checked mine several years ago, and I was lucky to find that was correct with a 1/16in. hole. The fitting is identified by a small grove in the hex portion. Of course, with the age of these cars it is very possible that someone years ago drilled it out because of "valve problems", and wanted more oil on top. Check the hole with a 1/16in. drill bit.


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