1951 Meadowbrook Rebuild

[51_Meadowbrook]

So my compression has finally gotten too bad and I think it’s time to rebuild the engine in my ‘51 Meadowbrook. The cylinders are between 89 and 94. I’m using a lot of oil too. So how in depth does this rebuild have to be? Can I just replace the rings and the gaskets and call it a day? Everything runs very well and I see no metal in the oil changes. The oil pressure stays in the correct pressure. These engines seem to be tanks, you can’t stop them. 

[rhelm1953]

Back in the day I refreshed the engine or more than one old beater with just rings and bearings using a hone and plastigage.  You won't know until you pull the head, if the ring ridge at the top of the cylinder is minor then you can probably reuse the old pistons, hone the cylinders and drop in new rings.  It won't be the same as a rebuild but can get you another 20,000 to 30,000 miles.  On a lightly used hobby car that might be enough.  If you have broken pistons and the cylinders are rough shape then you are in for more work.  Pull the head, take a look and decide what you want from the car/engine and proceed accordingly.

[knuckleharley]

Depends on your intended usage and the condition of the cylinders. If you plan on driving cross country to Mopar meets as well as everyday transportation,do it right and be done with it. Which means overbore and new pistons if needed,as well as turning the crank and buying new bearings if necessary.

 

If your use is more casual,you can almost always get away with new rings and bearings. I have even taken oversized rings and filed the end gaps so they would fit into the worn cylinders with the proper clearance,and gotten away with that. No real problem on a typical 50's low-compression/low RPM engine.

 

In either case,do yourself a favor and figure in a new oil pump,timing chain,and valve lap as a part of the process. Your rings aren't the only things that have X-Amount of miles and hours on them.

[51_Meadowbrook]

The excessive oil consumption is what is concerning me the most. When I decelerate I get a soft cloud of smoke and I have used 4 quarts of oil in about 150 miles. Now this week is a little unusual in terms of traveling because I took it on a freeway and drove about 55 miles for 20-30 minutes. I also went with a lower viscosity in this last oil change. I was adding 15-40 at my oil changes because when I dropped the pan I cleaned it and made it so that it could handle detergent oil, according to how the guys on these forums said to do it. This oil change they didn’t have that oil so I had to go with 10-30. Could the rings be just worn enough that that viscosity change would make them leak? I also found that my valve covers appear to be leaking. It hard to see the back one because it’s under the manifold but I put my phone down there and blindly took this picture. Does high speeds create a pressure under those covers that would create a bigger leak at 50mph over 30mph?

[JerseyHarold]

FWIW, if the draft tube and oil cap are clogged, you can get pressure build-up in the crankcase that leads to blow-by.

Edited June 21, 2018 by JerseyHarold

[Don Coatney]

7 minutes ago, JerseyHarold said:

FWIW, if the draft tube and oil cap are clogged, you can get pressure build-up in the crankcase that leads to blow-by.

 

Where does that pressure come from? Blow-by is an indication of defective piston rings. Not pressure due to clogged draft tube nor crankcase breather. 

[JerseyHarold]

2 hours ago, Don Coatney said:

 

Where does that pressure come from? Blow-by is an indication of defective piston rings. Not pressure due to clogged draft tube nor crankcase breather. 

I thought about it afterwards and realized I got it backwards.

[Jerry Roberts]

20 hours ago, 51_Meadowbrook said:

So my compression has finally gotten too bad and I think it’s time to rebuild the engine in my ‘51 Meadowbrook. The cylinders are between 89 and 94.

 I don't think that compression is too bad . No one has mentioned valve guides , if they are bad you will be burning oil , although you are using a LOT of oil . And yes a thicker oil might help a little .  I live in a warm climate and run 20-50 year around . 

Edited June 22, 2018 by Jerry Roberts

[51_Meadowbrook]

I’m in New England so during the summer it’s 80-90 degrees. Would a 50 weight oil be ok in this environment? This engine has never been rebuilt to my knowledge and I don’t want to make the oil so thick it doesn’t lubricate properly. I’ve always noticed I lose more oil when traveling at highway speeds. And whenever I stop I get a puddle. I just cleaned the breather tube, which was not clogged, just dirty. I tried to tighten the wing bolts on the side pans but they are pretty tight and didn’t move. If it was easier to get to I’d love to open them up and look in there and then put new gaskets on it, just to ensure that they aren’t leaking most of my oil. 

[Jerry Roberts]

Well 20-50 is a lot thinner than 50 . Check your owners manual for the correct weight of oil . You can run thicker oil in warmer temperatures . On your bolts for the valve covers can you tap the heads and then try to loosen ?

[51_Meadowbrook]

It says 30 straight throughout the year. 

 

If you look at the picture in post 4 the covers are under the intake and exhaust manifolds and there isn’t much room to get at them. If anyone has suggestions as to how to get to them without taking the manifolds off i would love to know. My cousin doesn’t want me parking in his driveway because the oil stains make his “pretty” truck look bad. 

[tom'sB2B]

Stick a fresh piece of cardboard under it and see where the major leaks are coming from..rear main seal, timing cover gasket, etc. the valve covers can be reached without removing the manifold, though you may have to remove the tire and lower inner fender to get at them.

[51_Meadowbrook]

Tom, I see that you just rebuilt you 47. If I was to rebuild my engine, do you have any advice or information that would help me? Especially anything that you wouldn’t expect when rebuilding it. 

[tom'sB2B]

I’m still in the process.

Finding a machinist that still knows these engines and will work with you regarding  buying parts, proper machining and pressing in valve guides. Ect.

Utilize this forum and your service manuals. You will find everything you need to know from this forum. Including some great and knowledgeable build threads.

The prep work... bagging and tagging everything and then properly cleaning everything. Makes the rebuilding portion so much easier and enjoyable.

i like to make lists, which helps me prepare knowledge wise for what I need to do next and if I can tick off one or two things a week, I feel like I’m making progress. 

Honestly. I’m the last person you should ask. This is my first rebuild..and I ain’t close to being done.

Hopefully some more knowledgeable people can chime in.

[51_Meadowbrook]

Sometimes it’s best to ask the newest person. They are less afraid of things because they don’t know of the possible different outcomes. I rebuilt a Cadillac V-8 just by looking at things and saying hmm that looks right. And it’s still running today with no problems. I didn’t know about all the different variances and tolerances in everything. Now I’m reading about your clearances and the difference between machine gauging and plastigauging and it’s making me nervous about things not being exact and screwing it up. My 51 Meadowbrook has a 230 in it and it’s a tank. The thought of destroying it is scary. That’s why I started this thread, to see if I could do a minimal about to the engine to get it to be good with oil and not leave puddles everywhere. 

[squirebill]

Your comment about a "soft cloud of smoke" on deceleration caught my eye.  Back in the mid '70s I had  a '65  283 Malibu.  Classic sign of worn valve guide seals was a puff of smoke after deceleration and then accelerating again.  In my case it showed up after coasting down a hill then accelerating to go up the next hill.  Also  the valve covers leaked at the rear of the engine. Just like your symptoms.   Seems this was all because the oil return galleys in the heads were clogged with sludge or the like. I seem to remember they were about 1/4 inch diameter once I found them under the sludge.  So the oil would be pumped  and build up in the head with no return or slow return through the clogged galleys then would seep past the valve guide seals and into the combustion chamber.  Also would leak past the valve cover gasket.  So cleaning the return galleys was the remedy.  While you were there it was recommended to also do the valve stem seals and valve cover gasket.  I used a long brush, something like a rifle bore brush, on the galleys.  Even heard of others opening up diameter of the galleys to like 3/8 ". I figured once mine were cleaned they were good to go.  Anyhow, would make sure your oil return galleys are clear as a maintenance item now or during your overhaul and maybe the puffs of smoke and oil consumption will be reduced.  

[51_Meadowbrook]

Squirebill, are you suggesting that the rings might not be the problem? Instead it may just be clogged oil reservoirs?

[knuckleharley]

51 minutes ago, squirebill said:

Your comment about a "soft cloud of smoke" on deceleration caught my eye.  Back in the mid '70s I had  a '65  283 Malibu.  Classic sign of worn valve guide seals was a puff of smoke after deceleration and then accelerating again.  In my case it showed up after coasting down a hill then accelerating to go up the next hill.  Also  the valve covers leaked at the rear of the engine. Just like your symptoms.   Seems this was all because the oil return galleys in the heads were clogged with sludge or the like. I seem to remember they were about 1/4 inch diameter once I found them under the sludge.  So the oil would be pumped  and build up in the head with no return or slow return through the clogged galleys then would seep past the valve guide seals and into the combustion chamber.  Also would leak past the valve cover gasket.  So cleaning the return galleys was the remedy.  While you were there it was recommended to also do the valve stem seals and valve cover gasket.  I used a long brush, something like a rifle bore brush, on the galleys.  Even heard of others opening up diameter of the galleys to like 3/8 ". I figured once mine were cleaned they were good to go.  Anyhow, would make sure your oil return galleys are clear as a maintenance item now or during your overhaul and maybe the puffs of smoke and oil consumption will be reduced.  

I remember working in gas stations and garages in the 60's,and sometimes pulling a valve cover off of a Chevy V-8 ro fix a tapping valve and seeing it so gummed up under the valve cover that I could barely see the rocker arms. The cars were invariably owned by old people who still used Quaker State Oil "because it is the best oil".

 

I have no idea how the bearings got enough oil to not seize because damn little was being drained back down to the oil pan.

 

This didn't really seem to be a problem with any cars other than the ones with SBC engines,though. Don't remember seeing the problem with BBC engines,or other GM engines.

[squirebill]

As I said, the puff of smoke during or after deceleration is what caught my eye and jogged my memory.  Although clogged return galleys may contribute to oil burning and leakage, they may not be the only problem.  Taking a look at them first may be worth the effort as a maintenance item (before you get into a ring job)to see if your oil consumption and puff of smoke goes away.  In my brain, bad rings would result in oil burning all the time, not just during deceleration.  A compression test with 5 psi delta between all cylinders seems good to me.  Did you do a wet and dry compression test?  Better/higher readings with the wet test would indicate you have ring leakage.

[51_Meadowbrook]

The test was a dry test. I need to change the oil because it’s black, it’s always black. But I’m going to put in my normal 15w-40 and see if it still smokes. I know I have to figure out how to stop the leaks at the side covers. The engine leaks when it is running. It doesn’t leak when it is off. Not sure if that helps with any further thoughts or if that sounded like a dumb statement..

Edited June 26, 2018 by 51_Meadowbrook

[Don Coatney]

This might or might not help.

 

 

 

[Don Coatney]

On 6/22/2018 at 12:18 AM, 51_Meadowbrook said:

My cousin doesn’t want me parking in his driveway because the oil stains make his “pretty” truck look bad. 

 

 

Try a different cousin?

[tom'sB2B]

Felpro valve cover gasket set : VS4253C

 

[knuckleharley]

2 hours ago, 51_Meadowbrook said:

The test was a dry test. I need to change the oil because it’s black, it’s always black. But I’m going to put in my normal 15w-40 and see if it still smokes. I know I have to figure out how to stop the leaks at the side covers. The engine leaks when it is running. It doesn’t leak when it is off. Not sure if that helps with any further thoughts or if that sounded like a dumb statement..

If you start running high detergent oil in it,you are really going to see some leaks. Be prepared to change oil and filter every day or every other day for several days if you drive it all the time because the HD oil will flush all the sludge loose in the engine.

 

Pay CAREFUL attention to the oil pressure gauge while driving,too.

[knuckleharley]

1 hour ago, Don Coatney said:

 

 

Try a different cousin?

Or drop by to visit his wife or children when he isn't home.

 

Make sure you park in his place when you do.