The Stovebolt Site Forums The Shop Area Engine Shop 1960 235 Tear Down

After an initial assessment of the the engine in our 1960 C10, I decided to tear the engine down and have a better look. I did a compression test, cylinder #2 was only producing 60 psi, cylinder #5 was about 80 psi. I added a small amount of oil to the cylinders and there was no change. I verified the valves were fully closed. I don't have any history on the engine. Removing the valve cover showed the top end to be clean, there was no sludge build up to speak of. Pulling the head revealed the engine had been rebuilt at some point, the pistons were marked 0.060. The head gasket looked intact, the valves looked good, nothing burnt, no real carbon build up. I saw nothing that would account for the loss of compression. Having the head pressure tested will hopefully shine some light on the issue. Getting the the machine shop to rework the head is a given at this point.

I pulled the rod bearing caps, the bearings were 0.010 under. there was no evident wear, nothing that would catch your finger nail. I pulled the pistons, the skirts and rings looked good. From the lack of wear it may not have had many miles on the engine since being rebuilt. There were no honing marks on the cylinder walls however. The main bearings were also 0.010 under, the crank was stamped rods 0.010, mains 0.010. The crankshaft journals showed no signs of wear. The oil pump had a cobbled together pickup screen wired over the outside.

The cam was a different story, there was significant wear on the lobes, the lifters were cupped and worn. The cam bearings showed a lot of wear. I an thinking the engine builder used the original cam and lifters and didn't replace the bearings.

At this point I'm going to mic the crank and cylinders and make a decision. I don't believe the block will need to be bored, I would hate to go any further over sized. A fresh cam, lifters and bearings are in order. A good cleaning and have the crank polished, hone the cylinders. Fresh bearings, rings and a full gasket set and I should be ready to put it back together.

A few more pictures

From the photos, that's a '54-early '55 "913" cylinder head for 235 engine. Casting date August 11 1954.

Craig, that one piston looks like something has been tap-dancing on it. That might have been the cause of the low compression in that cylinder (bent valve?)
And the cam also looks like it's pretty much done. I pulled apart a 1958 235 that had pretty much the same wear on the cam and lifters. A few lifters were pretty badly pitted.

The crank out of it was also 10 under with just a touch of wear, but suitable for reuse. I'm probably going to get that reground, or at least polished, depending on what the machine shop says.

Do you have a guesstimate of how many miles are on it?

The Melling CCS-1 camshaft is back in production, in at least a small quantity. A local parts store like Auto Zone or O'Reilly's should be able to order one instead of dealing with the resto-ripoff people. It's a slightly more radical grind than the Corvette/261 cam , which will improve torque without dropping intake vacuum or creating a rough idle. Obviously, a new cam will also require new lifters to go with it. Try my cylinder taper check, using a recycled piston ring, a feeler gauge, and a calculator. It's in a tech tip somewhere. If the taper is less than .005" go ahead with a hone and re-ring job. If you want to send me your pistons and rods, I can put a knurl on the pistons to reestablish the proper skirt clearance, and recondition the big ends of the rods for the proper bearing fit. That's what I did on John's 261 several years ago. No point in doing another rebore, unless the taper wear is excessive.
Jerry

NOS solid lifters are not terribly hard to find. Or DragSix recommends some outfit that will regrind your existing ones. Was it Schneider?

I have no idea of when the engine was rebuilt or the actual mileage. I knew the head casting numbers were off, the block is a 3769716 casting (58-62) correct for the year of the Truck.

I have a new in the box Melling CCS1, cam kit with lifters. I don't believe the pistons will require knurling, once I check the cylinders I'll know more.

As for the scaring on the piston top, that piston is #1, #2 was the one with really low compression. Who knows what this engine has been subjected to, after all did you see the pickup screen.

I couldn't even tell what that thing was until you mentioned it.

I guess I need a pickup tube, what's Jerry say " Scarcer then Hens Teeth"

Make your own- - - -it's easy with a little bit of sheet metal, a piece of perforated stainless steel, and a few pop rivets. I did it routinely on the dirt trackers when we needed a specially shaped pickup to prevent oil pressure loss in turns. Send that Rube Goldberg cobble job along with your pistons and rods, and I'll make it better than new.

Those pistons will need knurling- - - -no doubt about it with the wear they're showing. Skirt clearance needs to be .002" or so.

www.ebay.com/itm/226413393833?
Jerry

Craig - that oil pickup screen contraption looks beyond scary! Yikes!

I was thinking of just using an early BBC pickup Welded to the 235 tube. Something along those lines will work.

I think I'd braze or silver solder the BBC pickup onto the standpipe instead of welding it. Use a sweated copper pipe coupling.

Is the screen supposed to look something like this?

https://www.ebay.com/itm/405159786002

Nathan, the pick up tube is supposed to look like this.

Ah…that looks much more like any other pickup on any other engine. I suspect a merging of old plumbing and new pickup would be pretty easy.

Reminds me, I need to take a brazing lesson from someone. That would be a handy skill. I can sweat copper reasonably well.

Use flux-coated bronze rod, get the mating parts just barely red, and don't overdo it on the amount of fill rod you apply. Get the mating parts fitted pretty closely and shiny clean with a wire wheel buffer before applying the fill rod.
Jerry

That’s all there is to it?

Yes, that's all there is to it.

I do a lot of Commercial AC work, I like to use Silfaus or Silver Solder. I'm sure I can find a pick up that's close to the original design.

Hey Tuts 59, we're HVAC pipefitting brothers. I'm retired Refrigeration Pipefitter Journeyman. If you have to fabricate a new pick-up tube, I think the silver solder and corresponding flux for steel pipe would be a good choice. Or, as HRL noted, just flux coated brazing rod, Sil-Fos seems to be a little finnicky on steel.