47-55.1 Eliminate draft tube options

[dsraven]

when buffing the piston tops make sure to have the pistons at the top of their stroke so the cylinder walls don't take a beating.
eventually you will likely need/want to take the pistons out for machining work to be completed. the pistons could be cleaned up then. I usually put them in a tray of aluminum compatible solvent to soak and soften up all the carbon etc. for the gasket surfaces i use a long board with sandpaper. for the combustion chambers I use a stiff knotted wire wheel on a die grinder with the valves in place at first, then, after the valves are out, the same brush works well down inside the ports and bowls where the vales seat but be very careful not to go too deep or the steel body of the brush touches the valve seats and thats not a good thing. when the head is completely dissassembled you could use oven cleaner on it and then wash it all with hot water. then use compressed air to dry and when it is drying look for any traces of spots where the water doesn't dry uniformly as those spots may be holding water in a crack. the old heads had a habit of cracking in the combustion chambers. ensure to keep all the valves in order of where they came from if you take the head apart.

[dsraven]

if taking the head apart for cleaning its a great time to replace the valve seals, check the valve springs and their retainers and the keeper grooves in the valve stems, valve stems for wear limits, stem to guide clearances, check the gaskets surfaces for warpage, etc. clean the head up well, check for any cracks, lube the valve stems with some assembly lube or molyslip grease (my personal choice for valves) and slip it all back together. then clean and check the rockers and the rest of the valve train, lube and assemble as much as you can, in modules, so when assembly time comes those parts are easy to unbag and you know they are good to go.

[TX3100Guy]

Originally Posted by dsraven

if taking the head apart for cleaning its a great time to replace the valve seals, check the valve springs and their retainers and the keeper grooves in the valve stems, valve stems for wear limits, stem to guide clearances, check the gaskets surfaces for warpage, etc. clean the head up well, check for any cracks, lube the valve stems with some assembly lube or molyslip grease (my personal choice for valves) and slip it all back together. then clean and check the rockers and the rest of the valve train, lube and assemble as much as you can, in modules, so when assembly time comes those parts are easy to unbag and you know they are good to go.

These are all tasks that I'm hoping to assist my engine builder buddy with. He's done this as a business for 60 years and now in semi-retirement (he's in his 80's) he's interested in passing "lessons" along and I'm a willing student.

I had already mentioned to him that when he was working on the end cap/line bore that I'd like to observe/assist/learn. He seemed to think that was a good idea.

[TX3100Guy]

Are the crankshaft bearing caps the same on the 235 Chevy as the 261?

I may have located an entire set of 235 end caps.

[leegreen]

maybe. Sealed power 960M main bearings show as fitting both 235 and 261

[TX3100Guy]

Originally Posted by leegreen

maybe. Sealed power 960M main bearings show as fitting both 235 and 261

Well, I may have wasted $40 if they aren't the same, however that isn't the most amount of money that I've wasted on this truck so far.....LOL

I found a used set on eBay and purchased them just in case they were a correct fit. I guess when they show up I'll have a better idea if the front end cap measures the same.

[leegreen]

If it fits.....
I'd be tempted to plastigauge it to check how uniform the bearing clearance is with the new cap and then consider if it could go back together without line boring.

[TX3100Guy]

Originally Posted by leegreen

If it fits.....
I'd be tempted to plastigauge it to check how uniform the bearing clearance is with the new cap and then consider if it could go back together without line boring.

It could happen.......

[dsraven]

as a guy who worked in an engine shop waaay back outta high school, i would say that there isn't a snowball's chance in......it's gonna be a direct fit. but, you could install it and torque it up with no crank in there, just the bare bore, and then use an inside micrometer on it to see if it is round or not and it it is round through the whole fore to aft length. otherwise the engine guy you know will surely be able to fix you up for cheaper because he will already have a good front bearing cap to work with.
too late now anyway since you already hit "pay the guy" on ebay, lol.
you can always make a cool lamp out of the stuff it it doesn't fit. lol.

[TX3100Guy]

Originally Posted by dsraven

as a guy who worked in an engine shop waaay back outta high school, i would say that there isn't a snowball's chance in......it's gonna be a direct fit. but, you could install it and torque it up with no crank in there, just the bare bore, and then use an inside micrometer on it to see if it is round or not and it it is round through the whole fore to aft length. otherwise the engine guy you know will surely be able to fix you up for cheaper because he will already have a good front bearing cap to work with.
too late now anyway since you already hit "pay the guy" on ebay, lol.
you can always make a cool lamp out of the stuff it it doesn't fit. lol.

Lamp???? With all the stuff I've bought and not used I could make a huge lawn ornament and have the HOA throw me out of the neighborhood.

I have a call into my engine buddy to see what he thinks. He's the one who told me that this route might be my best shot time and money wise.

[TX3100Guy]

Look what $40 on eBay got me.

[TX3100Guy]

My engine builder buddy suggested I take the new bearing cap and the old bearing shell and smear a fingers worth of clean engine oil on the shell and the crank. Then mount the cap and in increments of 10 ft/lbs test how easy the crank turns by hand. I started by torquing the bolts to 30 ft/lbs and the crank turned just as easily as it had without the bearing cap. I continued in increments of 10 ft/lbs up to 90 ft/lbs and the crank was just s easily turned as it was without the bearing cap. I didn't want to press my luck at 100 ft/lbs, but will do that tomorrow. My engine buddy called me the luckiest guy in Dallas. More to come, but in the end the crank will still come out.

[dsraven]

if you wanna see how tight the tolerances are all the way around the crank, clean the bearings and the crank with a clean lint free cloth so no oil to speak of is on the bearings or the crank journal, then put some plastigage the full length of the bearing cap 1/2 of the bearing, then put the cap back on and torque it up being careful not to turn the crank while doing this. then remove the bearing cap and see what you have for clearance on the plastigage. if you don't know what plastigage is, it is a plastic thread that comes in different colors for different clearances, you likely need the green stuff that will show up to a couple of thousands clearance. when you put that on the bearing and then torque it up it will get squeezed and flatten out some depending on the clearance there is left between the two parts. then when you take the thing apart and look you will see the thread has flattened out. the little paper package that the plastigage come in has markings on it to compare the width of the flattened out plastic thread. really flat means not nuch clearance. of course the opposite for a thread that didn't get flattened out much. when you put the thread around the whole half circle of the bearing cap bearing shell and torque it down when you look at the plastigage after you can see if there are parts that show a more flattened out thread that other parts are showing. this can help you see if the bearing cap you bought is a close match to being bored on the same center line as your old cap. it's one in a million but there is a chance it is close enough to run it that way without doing any machine work. if thats the case then you need to buy your engine buddy, LG, me and yourself a lottery ticket. haha.

[leegreen]

could also plastigauge the clearance with old and new caps to see how they compare

[dsraven]

yeah, good point LG.
you think of everything. inside and outside the box.

[TX3100Guy]

Ok, so today I inserted a piece of Green plastigauge on the newly acquired bearing cap (with the original bearing shell) and torqued the two bolts down to 100 ft/lbs and here is the result.





When I did the same thing on the old bearing cap (the cracked one) the result was even less thick than with the new bearing cap. It was clearly compressed by not by as much as the new bearing cap.

Did I hit the bearing cap lottery?

[dsraven]

that actually looks pretty good. maybe have your engine buddy look at it and see what he thinks, or send him the pics.
buy a ticket, lol.

[TX3100Guy]

Originally Posted by dsraven

that actually looks pretty good. maybe have your engine buddy look at it and see what he thinks, or send him the pics.
buy a ticket, lol.

I posted here first and then sent him the same photos.

[1project2many]

Originally Posted by TX3100Guy

Did I hit the bearing cap lottery?

Maybe. One of the potential issues is that the bearing bore in the cap does not align with the bore in the block. If you are careful you could lay plastigage across the bearing surface as close to the cap parting line as possible to get a reading. If the plastigage is narrower at one end after compressing this may indicate the need for alignhone / alignbore.

[TX3100Guy]

Originally Posted by 1project2many

Maybe. One of the potential issues is that the bearing bore in the cap does not align with the bore in the block. If you are careful you could lay plastigage across the bearing surface as close to the cap parting line as possible to get a reading. If the plastigage is narrower at one end after compressing this may indicate the need for alignhone / alignbore.

That seems to align with the comments from my new engine builder buddy. He was hung up from showing up to take the block yesterday but promises to show up today (he's semi-retired). I'm getting a bit impatient to get this issue addressed, line bored if necessary, and get back to assembling the engine.

My best friend who sold me the truck has been sending me links to small block Chevy engines saying that Summit could delver one to my house in two days....... I really want this engine with the McCulloch supercharger given how unique it will be, but I have admit the small block is getting more tempting as every week rolls by without a solution completed.

[1project2many]

My best friend who sold me the truck has been sending me links to small block Chevy engines saying that Summit could delver one to my house in two days....... I really want this engine with the McCulloch supercharger given how unique it will be, but I have admit the small block is getting more tempting as every week rolls by without a solution completed.

The story of getting this truck going is definitely worth retelling. No one will blame you if you choose the smallblock and it would get you out on the road in a hurry. But hearing the 261 sputter to life, listening to the whine of the supercharger, pulling the truck out for it's first drive? Those moments will make this journey epic.

[TX3100Guy]

Originally Posted by 1project2many

The story of getting this truck going is definitely worth retelling. No one will blame you if you choose the smallblock and it would get you out on the road in a hurry. But hearing the 261 sputter to life, listening to the whine of the supercharger, pulling the truck out for it's first drive? Those moments will make this journey epic.

My 80+ year old engine builder buddy showed up today and was impressed with the condition of the block and head. He's going to allow me to work with him on it, learning what I can. He wants to use a dial gauge on the head to ensure that it both straight and flat. He also suggested sonic testing the cylinders given that the cylinders were previously over bored.

Other that we discussed us doing a few others things "while we are at it" such as line boring the block, dipping the block and head, replacing all the freeze plugs, boring a hole in the head that gets tapped, and rattle can painting of the block and head. Seems these engine had a historical problem with over heating due to air in the back of the block/head. By tapping this hole, the engine can be "burped" to get all the air out.

By early next week he's going to give me an estimate of cost and timing, given his other semi-retired projects.....He agreed with me that a small block would be fun and faster to get done (Summit could have one here on Monday), but he also said that my setup with the supercharger and magneto would be too cool to pass up.

His only comment to me was that if the block should fail any of his tests, he'd rather not have me spend a silly amount of money to make it work, when a small block is an option.

[dsraven]

measure at it's fattest point and see what you get but it looks pretty good.

[TX3100Guy]

Originally Posted by dsraven

measure at it's fattest point and see what you get but it looks pretty good.

Where I have the paper plastigauge measuring guide (.002) was the widest part of the thread.

[dsraven]

hopefully thats not a nick on the journal there. gotta be careful moving things around etc. I usually put an oil moistened rag around my journals and use tape to keep them on there until ready to do something with the crank. you are already working with it but just a thought for when you store it until the engine guy has a chance for a peek or whatever your plan is.