midman

Rebuiding a 1931 90 Series Engine

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Well ladies and gents I am going to start to reassemble my engine over the next month or so. Going to go slow and clean. It will take a little longer because I want to scrub the newly machined block down and the weather is not cooperating out here in Pennsylvania.

I will post pics as I go along with what I'm doing and what I'm running into since I did not find much information when I was struggling with this motor (though I did find lots of help here when I posted questions).

Anyway I bought the Buick 4 or 5 years ago, running and rust free but showing its age. It ran OK, but had weak compression and overheated regularly. After a cosmetic restoration I started to drive the car and it had less and less power and overheated no matter what I did, flushed the block, re-cored the radiator, pulled the water jacket cover and cleaned it out etc. Worse it started making noise. I dropped the pan and pulled a main cap and discovered the babbit was starting to spall. I made the decision to get the block checked, machined and re-babitted.

Using suggestions from this forum I had Reeves Enterprise do the machine and babbit work (very nice people). I decided to do the assembly. I like to learn new things and this will be my first prewar engine.

First I pulled the head and found the cooling passages almost completely blocked with loose scale. Then I pulled the engine and tranny together. Heavy but doable. Hint- I suggest you pull the steering box and shaft if you are going to pull the engine. Then off to Reeves it went. He found two small cracks in the block which were repaired and some old repairs to the head so I hope this thing holds together. I had to have new pistons made, and decided to have the connecting rods machined to accept inserts.

I have the newly machined babbitted, and balanced engine back so as soon as I get it cleaned and start assembly I'll post pics and what I did.

Wish me luck.

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Newly machined and babbitted block. Lots of oil passages to clean out before the thorough block washing.

 

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I tagged along with midman to get his engine. The one they are working on for my 1925 is still underway.

 Here he is with Patrick Reeve . He may be thinking...    "What have I gotten myself into"?

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Freshly machined and balanced crankshaft. Much heavier than the head I helped carry.

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Well the cold weather that hit here set me back since I wanted to get the block outside and wash it down thoroughly before beginning assembly.......Still waiting for it to be warm enough.

In the meantime I assembled the pistons and connecting rods and installed the piston rings. Reeves machined the rods to take inserts. Hopefully not something I will have to deal with again in my lifetime but done all the same.

 

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Wow, talk about a loooooong stroke! Those connecting rods look like they're more than a foot long! I have never had a 344 engine apart like this. They are monsters to lift--done that before but don't want to do it again anytime soon. You hope and you pray and hope that your engine hoist won't tip over!

Pete Phillips, BCA #7338

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Well, It got warm enough to get the engine thoroughly washed down!! Finally.

I decided to put the motor together on a heavy duty table I made because this thing is just too darn big for my engine stand. It lays on its side cam on the high side. We picked up the crank with the engine lift and swung it "gently in. Worked well.

I installed the pistons and pushed them through first since the big end of the connecting rods are bigger then the engine bore and I did not want to deal with taking apart the harmonic balancer and screwing around with installing them from underneath after installing the crank. It worked great. Pushed them through, installed the crank then pushed the pistons back through as I assembled the connecting rods to the crank.

Installed the cam no problem.

Next step will be installing the cam gear and bellhousing and flywheel (that's why the rear main is still off. I need to get to the crank flange bolts when installing the flywheel and bellhousing. Then the cam followers and oil pump and oil lines and buttoning up the bottom end.

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Concerning your engine cleaning, this is required after the block is returned from the machine shop to make sure there is no tramp oil, metal particles or grinding debris remaining anywhere inside. But I would have thought that both the oil passages and coolant jackets would have been cleaned thoroughly before the machine work was done. The last thing I'd want would be for any residual sludge being blasted out of the oil galleries and onto a bearing surface or a nicely honed cylinder bore.

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Don't you just love the counterweights on the crankshaft!!!

 

There are very few oil galleries in the block.  there is a passageway from each main bearing up to the cam bearings,  two ports at the oil pump to and return from the oil cooler, and a fitting through the block  at the rear right side for oil to filter and cyulinderhead.  Oil distribution from the pump to the mains is by way of a copper tubing manifold.  

 

Bob Engle

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The pistons were made by Ross. I could not find original pistons standard or oversize anywhere. I did find a couple sets of oversize piston pins. Ross will need the pins along with the specs to machine the pistons. Not cheap though. Over $100 each

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Carl,

We did discuss compression. Originally I was looking at putting an overdrive unit in and bumping the compression to make the car more tour friendly, but after some thought I kept coming back to the shortcomings of mechanical brakes and decided to keep the car a back road tourer, so I kept the pistons at the standard profile. 

I do have the overdrive unit if I change my mind once I start driving more.

Chuck

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Well the front gears, cam roller assemblies and oil pump are installed. Next will be the oil distribution manifold (This manifold uses copper sandwiched gaskets that I could not find so I'm using the old ones), bellhousing and flywheel and front cover as well as the oil pan. I am going to install the engine without the head to help with the weight, hopefully next week it will be back in the car.

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On 12/04/2018 at 11:19 PM, midman said:

the shortcomings of mechanical brakes

Can you enlighten us on these shortcomings please? Henry Ford was adamant they were as good as hydraulic and continued with them well past when others had gone hydraulic. They must be in good adjustment though.

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https://www.wikihow.com/Lock-Wire-Drilled-Head-Bolts  I would assume this is the proper way to wire any pair of bolts/capscrews, not like the third picture of post #15.

 

I do not believe there are any shortcomings with mechanical brakes.  When set up correctly you can park the vehicle for any period of time and they are ready to work correctly when needed.  From 50MPh I can lock all four of my wheels with half a pedal.  Without locking the wheels I can stop from 50mph in the length of my head light beams.  I adjust my shoes every 20,000 miles ( 2 years ish) or so and usually get 70,000 to 85,000 miles on a set of linings.  The only limitation I see is the number of square inches of rubber to the road which has nothing to do with actuation of the brakes either hydraulic or mechanical.  One thing for sure with mechanical brakes you will never burst a hose and the chances of breaking a cable, clevis or rod is very low and at the worst you would only lose braking on one wheel.

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1 hour ago, Tinindian said:

I would assume this is the proper way to wire any pair of bolts/capscrews, not like the third picture of post #15.

 

YES! As it is at the moment, the left bolt will undo the right bolt if it comes undone and the right hand bolt will pull on the LH bolt if it comes undone and make it more likely to undo.

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Now you see one of the reasons I post this stuff. Thanks for the helpful feedback. 

When I tore the engine down that is how the bolts were wired. In fact the oil manifold in the pan was wired like that too. I know this engine was repaired in the past though so it can certainly be incorrect.

I’ll do some more research and rewire the cam follower housings if that is the correct procedure.

 

As far as the mechanical brakes go, you are probably correct in that the surface contact size of the tire is minimal compared to today’s cars, being the biggest issue to better braking, but the fact remains that I decided I am not going to drive 70 miles an hour on the interstate with this car so I did not bump up the compression. In my opinion hydraulic brakes are better, but that is more because they are easier to maintain and more consistently apply equal pressure to each wheel without lots of adjustments.

 

 

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OK Ladies and Gents,

Here is how I rewired them per Tinindians helpful link.

 

 

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I also want to throw a question out there. The cam gear retaining bolt had some damaged threads. I cleaned up both the male and female but I am concerned about putting too much torque on it. I tightened it to 20 ft pounds with red thread lock but I’m not sure that will do it. Any thoughts.

 

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Edited by midman
Spelling (see edit history)

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1 hour ago, Spinneyhill said:

They didn't have torque wrenches in 1931. A good mechanic would tighten it until it felt right.

 

All the old timers I knew used to tell me they tightened things "goodentight".

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Sorry this is a late note, but I thought about using inserts instead of babitted connecting rods.  On the connecting rods, the original design is babitted main end caps and  the wrist pin is bolted tight to the connecting rod.  There is babbiting on the sides of the big end of the connecting rods.  This keeps the wrist pin from working it's way to the edge of the piston and into the cylinder wall.  On a modern engine, they use c clips in the end of the wrist pin bore to keep the wrist pin away from the cylinder walls.  The insert bearings are narrower than the connecting rod.  Did they do something to prevent the wrist pin from floating into the cylinder wall when they installed the inserts?   Did they put the insert into the babbitt and leave the babbitt on the sides?  

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Here is a bolt torque chart.  I am not sure what size your cam gear bolt is.  Hardware may not even be grade 2, so maybe look at these as maximum specs.     

I also wanted to share this head bolt tightening sequence in the second image.  It seems like a strange one to me.  I am used to starting on the inside and working outward.  Wondering what your plan is.  I also think that they are a little aggressive on the torque specs in the second posting.  Hugh

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Edited by Hubert_25-25 (see edit history)
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