The Stovebolt Site Forums The Shop Area Engine Shop Canadian 'Poncho' Rebuild

Look at the advertised exhaust duration on the CCS-1. It's considerably longer that the Melling cam, and particularly if that's combined with a split exhaust manifold and a bigger exhaust valve (small block V8 1.6" diameter stainless steel valve and some pocket porting) there should be much better exhaust acavenging. It would take some serious dyno work to find the torque sweet spot by using an offset Woodruff kay on the cam gear, but I believe I could make a pretty impressive gain in torque with the right combination of exhaust system and cam timing. The Mrlling cam has an advertised intake durtation 4 degrees less than the Elgin, but the intake port shape is so terrible on a stovebolt that intake tuning is pretty much a lost cause.
Jerry

Thanks, Jerry. I see that, and exhaust scavenging is certainly key.

I was taught way back in the '60s that the duration at 0.050" lift was what to look at, not advertised duration. On that basis, the Elgin cam seems to be the longer exhaust duration cam, regardless the high advertised duration number on the Melling cam. You don't go by the 0.050" lift duration as the better apples-to-apples comparison point? Not trying to be argumentative... trying to understand.

Thanks, again.

Doug

.050" lift specs are mainly for convenience in degreeing a cam, as there can be a lot of error in total duration on some cam grinders' products. A really well-made cam will be very accurate at low-lift points, in addition to the .050" lift specificattion. I've used Comp Cams for many years, and there's a huge difference in the uniformity of the lobes between their cams and a few of the other major brands. The Elgin cam I checked when we built John's engine was right on the money, even at very low lift and clearance ramp points. I've got a new Melling cam stashed away, but I'm not ready to do a degree check on it yet. Comparing them for lobe accuracy will be interesting.
Jerry

Thanks, Jerry. It will be interesting to see how the Melling cam degrees. I expect their specs to be "good" since they are known for quality.

Having said that, I worry more these days about accuracy of actual product conformance to specs, as more and more manufacturing moves offshore. QC seems to be suffering pretty much across the board with that. Most, but not all, of the Melling plants are still in the US, at least. Thanks again.

Doug

As I mentioned in another thread, I believe the problems that recent-manufacture hydraulic lifters for stovebolt engines have with losing prime, rattling, etc. might have to do with poor quality control and inconsistent leakdown rates. All hydraulic lifters leak a little, and they must be replenished by engine oil pressure while the lifter is on the base circle of the cam lobe at minimum load. Since NOS hydraulic lifters don't have anywhere near the problems that new ones do, I believe the difference must be in where, and how they're being made.
Jerry

If you're installing any cam, do yourself a favor and buy a degree wheel and check the cam against specs. I have degreed several stovebolt cams over the years from factory to Crower to Howard's and the only ones close to its spec are the original factory cams, not the stock repops. Back in the day McGurk ran dyno tests on a 261 with various mods and determined that more exhaust duration improved things with no other changes. Of course his McGurk 3/4 race cam was the best all-around compromise but the factory 261 cam, which he said in the same Hot Rod Magazine article, was the same part number as the Corvette cam came in a close second to his cam.

What I ended up with in my 235 is a Crower with more lift and duration than is probably optimum at 0.450 lift and 215 deg @0.050 lift. Same profile intake and exhaust. None of these is what the spec sheet showed. I advanced it 4 deg with a key which was as much as I dared due to intake valve/piston interference. I checked it with modeling clay then double-checked with a dial indicator after final assembly. I got the recommended 0.050 minimum.

My starting point for TDC was to use a strap and a bolt across #1 cyl to stop the piston, go back the other way to stop and divide the degree wheel readings by two. TDC found this way was not what the UC mark on the flywheel indicated. The flywheel was not original to the engine. UC mark is off by about 4 degrees IIRC.

Cutting to the chase the engine pulls hard at 2800-3000RPM but you better think about shifting down if it drags below about 2500. The fire sort of goes out. That said it will pull down to about 1400 and recover smoothly. FWIW this is a hotter cam than I would want if running a straight 4-speed SM420. I can run the engine between 2500 and 2900 right up through the gears. It works well with a 3-speed brownie or perhaps with a 2-speed axle. I never pull it over about 3300 and only then to make the next gear on a pull, so all that capacity above there is for naught. Not enough carburettor anyway.

Machine shop called and the head is ready to go. Next I will be dropping off the block. I'm making notes for the shop, as I've never been through this before and just want to make sure they have all the details they need. Here's what I have so far:

Salvaging from the 216:
- 6v starter, bellhousing, flywheel, clutch, waterpump, pulley, fan, crank pulley, generator

To do list:(other than the internals)
- Cam - swap out fiber gear for metal (likely new cam)
- Waterpump repositioning plate (Got one from Deve, need extra holes drilled/tapped)
- Front Engine mount (swap for front plate with front mount)

Anything I'm missing here? Again, other than the usual rebuild activities that they will be doing.

Went by the machine shop today to have a look and drop off some cash. Head is done and block is getting ready for rebore:

[img]https://www.stovebolt.com/ubbthread...umber/27117/filename/20210128_101346.jpg[/img]
[img]https://www.stovebolt.com/ubbthread...umber/27118/filename/20210128_101412.jpg[/img]

I've changed my mind and decided to do what I can to make this engine look like the original, including the top-nut valve cover. The one on the original 216 leaks bad. I've reworked the edges and changed the gasket and it still always leaks in the back. I would like to use it though on the 261. Has anyone tried drilling out the four bolt perimeter pattern on a 216 cover? I'm just curious if I do that if it will help seal it better (there will be 6 bolts/nuts in total)

Thanks

Ok, another update, the machine shop is having a hard time finding a supplier for 261 pistons .060 or larger. Any favorite distributors I should check with?

I would ask
Egge Machine Company
8403 Allport Ave., Santa Fe Springs, CA 90670

Expensive tho, make sure you are sitting down
Perhaps laying on a fainting couch best.
-s

There is a set of new .040s, and set of used .060s and a set of new .080s on ebay right now. the new .080s are 300 with the pins. egge has .080 pistons for like 325. I dont think that is terrible.

Dropped off some paint to the machine shop yesterday. I was having a problem sourcing the original green that Pontiac put on this engine, so I decided to make a sleeper I'm going to go with the grey and put the studs in so that I can keep the valve cover off the 216. With that and the original air cleaner, most people likely wouldn't know the difference. I didn't get a pic, but she's really coming along. Not sure when I'll get around to even installing it, as I'd like to pull the doghouse off, cleanup the frame and the bottom of the cab and put new seals in the transmission. I may enjoy it as is this summer and then really rip into it next fall.

That is interesting that you mention the paint. I have been kicking the bushes to find some reference to that color. I was really hoping to find a Canadian restorer who had some recommendation but thus far, nada.

The other thing I have been trying to source is the Pontiac decal for the valve cover. The Pontiac 261 valve covers are the same as the Chevrolet 235/261 valve covers but blank where the Chevrolet would otherwise be. Pontiac used a decal and man is that one hard to come by. I have a 261 Pontiac valve cover that I would like to restore one say if for no other reason then to make it a conversation piece in my garage.

Hey Dragsix you could look for a Canadian gmc that has a 235 as they are blank also ,I have one on my 54 9300

Goach 2 Your cylinders got rainwater froze and burst ,look for other freeze damage. It is pretty far gone but maybe could sleeve it.Better study the head surface to see if it will clean-up. Straight edge it.

That was the first block. I scrapped it and found myself another.

John and Jerry. I'm fairly new guy here and am curious about what backgrounds you guys have that you know so much about these trucks.
I think others may also be interested if you and some of the other experts posted bio's somewhere on the site.

Well, I'm sneaking up on 65 years in the automotive trade, and I'm the middle of 5 generations of mechanics, from my grandfather to my grandson. The first things I got paid to fix were a bunch of peanut vending machines my grandfather bought when I was 12. He bought about a hundred dirty, rusty ones and paid me a dollar apiece to get them working. That was in 1958, and I've been fixing things ever since. Growing up around the best independent auto shop in Nashville Tennessee and soaking up knowledge from a bunch of oldtimers who had been working on cars since the 1920's helped also. I topped that experience off with 30+ years of teaching auto mechanics, auto body, machining, and welding in the public education system. I "retired" in 2011. Now I'm trying to pass on as much knowledge as I can to younger folks, as a tribute to those who shared their wisdom with me.
Jerry

Up until about 10-11 years ago I was pretty good at taking stuff apart. After 10-11 years reading nearly every word written on this site, I am getting better at putting stuff back together...

Engine's ready for pickup. Will post some new pics this week.

Well, hard to see in the daylight, I'll have to get some better ones after dark, under the lights:

[img]https://www.stovebolt.com/ubbthread...umber/28421/filename/20210224_120517.jpg[/img]
[img]https://www.stovebolt.com/ubbthread...umber/28422/filename/20210224_120535.jpg[/img]

So, this isn't going to be a quick swap, I have a few items to take care of while I have the 216 out. One of those things is all new seals in the transmission. I actually have a spare 4-speed on the shelf from a later 56ish truck. Is there any benefit to going through this one instead, other than the fact that I can do it now, without pulling mine out of the truck?

Any tips on what to look for to judge if the spare is in good shape?

Going to move the trans conversation to here:

https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1398898.html#Post1398898

Cleaning up the distributor, have it all apart, except for the pin/shaft. Now that I'm ready to start putting it back together, what do i use to grease the bits inside, under the cap. Also, should I be packing the hole before I put the spring and grease bowl back on?

Well, didn't get any feedback on this, so this is what I did:

Engine oil inside the distributor, for the actions under the points plate, bearing/chassis lube in the hole that the bowl threads into. Not 'stuffed' but filled so that when the grease cup is turned, it will push grease in (no air space). I'm assuming this will be better than the dry cracked stuff that was there for years.

So the little cap on the side is moved in a bit every so often to push the grease in. Inside there should be a little Bakelite disc held in by a spring.

I have the four speed in my 51 1 Ton. When parked it dribbles small amounts of tranny lube onto the clutch and this can cause chattering. Some years later they put a bearing in the front that had a seal to stop that from happening.

So, I just wanted to add this info to the collective. I know I've seen a lot of articles on the full bypass filters on the 261s, with the little pin that you push in or it sits out. Here's what my Canadian Pontiac 261 has:
[img]https://www.stovebolt.com/ubbthread...umber/28896/filename/20210308_182348.jpg[/img]

No options! Anyone know a good place to pick up these lines to the remote filter?