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Since it looks like I will get the old 836 to roll again, I have turned my attention to the engine. After carefully measuring the cam journals with a mic and the block bores with a bore gauge, I have determined that my cam bearings/shells are missing as the clearance is .100″. I asked the counter guy at NAPA if he had any and you can guess how that went.
Some of my old Triumph cams ran in the block, steel on iron. I have heard that some diesel engines use bronze/brass bushes. A 2″ nom sch 40 brass pipe has enough OD and ID to machine the 6 bushings out of if I could calculate how much interference I need in the block.
Does anyone have any other suggestions?
You can use babbit or bronze. You need a good line bore set up to do them correctly. The modern set ups used at the engine builders today WILL NOT WORK. The cam bearing is where most engines drop oil pressure. It’s common to see a car with a rebuilt engine and poor oil pressure due to the fact that no one wanted to deal with the cam bearings. It takes a lot of time to do them correctly. Babbit shells must be spun, installed, and then cut to the correct measurments. Bronze is the same, I installed them in my 36 V12 and set them up tight. I have lots of oil pressure even on a 90 degree day agter hours of driving. Use a Kwick-Way bar if you can find one. Good luck, Ed
Hi Bill, please check your measurements. And your block. you should have more than .100″ if your inserts are missing, And a lot less if they are ‘merely’ worn.
You should be able to see the bearing insert, in the block due to the different color of the metal, and the edge of the insert..
Greg
I answered my own interference fit question. The “Engineers Edge” says for bushings 3″ OD and less, the tolerance is .002-.003″ over the nominal size, then chilled prior to installation.
I also found bushing material at bronzebushings.com. Less than $70.
All I need now is a lathe.
Bill, come on up to the frozen north !! It was ‘only’ -11*f last night.. You can use my lathe in the 55* shop!
LOL…
Greg Long.
I was able to find a 2′ piece of bearing bronze. It is 2.5″OD x 2″ ID. All the bearings can be machined out of this size. Joe Knowles has offered to help. This isn’t like one of his Delta jets, but should be a satisfying project. I need to freeze the bearings to install them, so Greg’s offer was considered as I could just place them outside, but I am afraid spring has come.
I need to clean the block first. Most shops can’t handle anything over 36″ ( block is about 48″). I talked with Greg Long and we discussed electrolosys, molasses, etc. but they all take a tank you can fit a block in. The block was cleaned about 50 years ago, when the shops had the good chemicals, hot tanked everything and the EPA was just letters, so all I have is surface rust to remove, but it is everywhere.
Any suggestions?
Bill, if you’re goal is to remove surface rust from the block, an inexpensive but effective way is to buy a $25 suction feed sand blaster as found at Tractor Supply and use sandbox play sand from Lowes or similar supply house. Last time I bought 50lbs it was $3.
You may use 150lbs, but it works fine outdoors. Might want to but a sandblast hood from Eastwood too. Follow it up with self etching paint on the exterior or WB40/SAE30 inside the crankcase.
Best of Luck-John
Sorry John, but your advice is bad in two very important ways. First, silica sand should never be used on internal surfaces of any machinery. Sand particles remain after cleaning and make their way into the lubrication where they will destroy bearings. Second, silica sand should not be used as a blasting agent due to extreme health hazards. Google silicosis! There is a variety of safe media available; glass beads, garnet, steel slag, etc. I buy several different materials from a local supplier to save the shipping cost from folks like TP and Eastwood.
Bob
Bob, my approach to dealing with the engine rust is sound.
You would advise using another media for the blasting exercise. I’m certain Bill appreciates both of our feedback.
John
John and Bob,
Thanks for both of your inputs. That is what I was looking for. What I am most worried about is the oil galleries/lines and the rust inside of them. That is the problem when you hot tank an engine then sit it aside for 50 or so years. 2 key things I worry about are silica dust and the isocyanides in paints.
John, your comment on self etching paint and WD 40 answers another question I had on what to do when it was clean. Thanks.
Good helpful points.
Bill
Thanks again. I will let you know what I come up with.
To clean the oil galleries just remove the plugs and run a brush through them. I have no issues sand blasting a block as long as you spend the ten hours to clean it correctly. It’s hard work.