The Stovebolt Site Forums The Shop Area Engine Shop full pressure engine

hello as i am new to some of the terms used here i am wondering what full pressure or non pressure means and how you tell the difference? mine has 2 lines from the filter can that go to the block.also what is meant by babbitt bearings? i am sure to have many questions in the future as i work on this truck.thanks for now.i am still not sure weather this is a 216 or a 235? none of the casting numbers i find are in any of the charts that i can find.any foolproof way to tell?

Hy birchbark, I think some of this info could be found by using the Search or Tech Tips features. The Chevrolet six cylinder engines did not go to precision rod bearings until 1953 or 54 depending on which specifications you are reading. The precision bearinged engines were referred to as "high pressure" engines. The earlier design used babbitt as the rod bearing material, and shims at the rod cap part line for adjusting the size. The non precision bearinged crankshaft did not have oil passages drilled in it, from the main bearings out to the connecting rod throws, the rods received their oil from pressurized nozzles aimed at scoop covered holes in the rod caps. The early engines [216 and 235] are virtually identical in outward appearance, again a search will probably yield some "how to identify" photos, hope that helps.

birchbark,

3B's reference to "high-pressure" engines (some 235s and all 261) as compared to "low-pressure" engines (all 216s and some 235s) is far better than referring to "full pressure" vs "no pressure". One reason is that Chevrolet literature referred to low-pressure engines as being "full-pressure" (with respect to main and cam bearings).

The canister by-pass oil filter was an option and the same canister could be used on all 216 and 235 engines (and on 261 engines through 1957).

What casting numbers do you have and where on the engine did you find each of them? Here is some information on where to find the various codes on a low-pressure engine.

The simplest way to recognize a low-pressure /Babbit-rod engine is to look at the driver's side of the engine near the oil pan rail. If there's a roughly triangular piece of sheet metal bolted onto the block about halfway back, it's a 216 or an early-design 235, both with connecting rods that have the bearing material fused to the rod. Later-model engines have a different oiling system for the lower end of the engine, and replaceable rod bearings.
Jerry

If your engine is a Canadian engine, just do a Google search for "casting XXX" where XXX is the head or block casting number. The search will take you to a PDF file with all the casting numbers from 1917 or so to the late 70s. If you can't make this work, send me a message with your numbers and I will find them for you.

okay thanks everyone. i will look closer tonight at the numbers but had no luck finding anyone of them on a casting list. i should probably drop the oil pan and take a look at the bottom end of this engine.what should i be looking for as far as these babbitt bearings are concerned. are they easily replaceable?

You might want to first ID the engine, so that you can then look at a Shop Manual for information on how to inspect the rod and main bearings ( several Shop manuals are on-line here ).

Post the codes and people will help you with IDs. Also, follow Hotrod Lincoln's advice (above) for IDing a low-pressure vs a high-pressure engine. Once that has been done, people can give better advice regarding bearing inspection and clearances.

The low pressure, splash oil engine, oil distributor, can be seen in this PICTURE just below the exhaust pipe flange.

Replace or recondition the rods- - - -not the bearings. The Babbit metal is a soft, solder-like material about 1/8" thick that's bonded directly to the big end of the connecting rod where it rides on the crankshaft. THERE ARE NO ROD BEARINGS TO REPLACE! The rod is bored to the right size to match the diameter of the crankshaft, and as the bearing material wears, shims between the rod and the cap are removed to get the oil clearance right. If the bearing material starts co come out in chunks, or there are no more shims to remove, the rods must be replaced with reconditioned ones with new Babbit metal. Rods on a 216 engine can be replaced from the bottom side by pulling the pistons down far enough to slide the wrist pins out below the bottom of the cylinder. I believe the pistons on a 235 are too large to clear some of the webbing in the crankcase, so the piston/rod assemblies must be removed from the top side after pulling the cylinder head.
Jerry

alright gentlemen here are the numbers that i am able to find. casting on top of the head is3695451.casting on block reads 3695408. stamping on the engine just behind the distributor is x470050. the truck is a model 1100 as shown by the hood emblem and on the plate that is fastened to the cab it says its a model 1133 and the engine number x470050 is also stamped on the plate.any help is appreciated as i need to confirm what engine is in this truck so when i order parts i have the correct info.these are cool old trucks.i had a halfton model when i was a teen and can hardly wait to get this one on the road.thanks.

Here is where to find your casting number: Canadian Casting Numbers If you go down to years 1950 to 1952, you will see that the block and the head casting numbers were used for the 216 and the 235. The motor was used in cars and trucks and also used in Austrilia too. You have the same casting numbers as my truck and mine is a 216. Yours will be another example of the Canadian motor with the short side cover.