The Stovebolt Site Forums The Shop Area The HiPo Shop 235/261 cam regrinding

The machinist I just found who does cam work has my reground cam ready- - - -about one week turn around time! He made a master cam for the Melling CCS-1 cam from a brand new one I had on hand, and now that it's in his inventory, he says he will grind good stovebolt cores for $140.00 each . (Mine cost considerably more, because he had to make a master for both intake and exhaust lobes). I "took one for the team" in this case, but I also ended up with a cam with the 216 bearing sizes and the Melling CCS-1 lobe, something that's not available anywhere else. It was also Parkerized after the regrind. I'll be picking it up tomorrow- - - -pictures to follow!
Jerry

I love Parkerized metal.

Sounds great Jerry. Can a good core be determined with just a micrometer or is it more based on cam lobe profiles? If the latter, cores would probably need to sent to the machinist for inspection 1st. Does that sound correct? Unless there is a way to inspect the lobes with a travel indicator rotating the cam between centers. If so, their must be specs available somewhere.

I've done very little automotive machining (Mostly Tool & Die and Machine Building) and find all of this to be very interesting. Especially with so many automotive machine shops shutting their doors.

John

Usually a good visual inspection will be sufficient to determine if a cam can be reground, particularly if there's not going to be a radical change in the lobe profile. I've got one really good looking core cam- - - - -on 11 lobes. The last one in line has some deep pits that probably won't be able to clean up on a regrind. Obvious lobe wear or deep rust pits are reason to reject a core, but if the lobes don't have any visible wear, the cam will probably be OK. You can also compare the base circle diameter and total lift with just a micrometer or an accurate digital caliper.

There are several good you tube videos of cam regrinding- - - -the process is extremely interesting.

www.youtube.com/watch?v=fUQnHk_LRz0

Jerry

Pictures, please! Mine will be posted later today.
Jerry

J Lucas Our local speedshop has V-blocks and tools to inspect the cam and can tell a lot about it,interesting analyses,nice big surface plate too !!

OK- - - -guess- - - -which cam is brand new, and which one is 65+ years old?

New one is on the right in the last picture

Good eye- - - -but it's hard to tell the difference. The guy does very good work! That's a mid-1950's 235 cam with the Melling CCS-1 lobe on it. The bearing journals on the used cam have been turned down to fit a 216 or spray oiler 235 engine. Once the checkbook gets a little CPR, I'm going to have him grind a set of master patterns for putting the Elgin E-293-S lobes on a regrind. Making the master pattern is a one time $150.00 setup charge.
Jerry

Old one is closer to the cardboard box.

HRL, The clue was the Parkerization you mentioned. The groove in the journal is Parkerized on the new one. It's also slightly shinier.

The bad news is that the guy who did this work is around 90 years old, and he's on chemo for some type of cancer. I didn't get nosey and press him for details. It looks like Parkerizing is a pretty simple process similar to gun bluing, and I've been doing that for over 40 years. There's a couple of cam grinding machines on Ebay- - - - - -"Hmmmmmmmm- - - - -!"

LOL!
Jerry

I've Parkerized some gun parts in the past.

Jerry, is any material added to the cam before the regrinding? If so, what method is used, spray weld, plating etc? If not, wouldn't all the specs be undersize?

Also, how does the Melling CCS-1 differ from a factory OEM specs?

I have a 36x48" surface plate, V-blocks, indicators etc. I've just never ventured much into automotive work.

P.T. Barnum would be proud that the shop took his advice to heart.

Only very radical cams such as the old Iskenderian "Hard Face Overlay" racing cams from 60 years ago got material welded onto the lobes. Those cams came with a bold face warning on the timing card- - - - "NEVER IDLE THIS CAM!" It was made to go fast for a very short time. Sane people just take a few thousandths off the base circle of the lobes and duplicate the timing and lift of the original cam, or make minor modifications to the lobes without radically changing the profile. In the late 1940's and early 50's Johnson Tappets made overlength adjustable lifters for flathead Ford engines to accommodate radical regrinds like the Iskenderian "404" cam that had lobes that looked like a rectangle grafted onto a semi-circle. It basically slapped the valve wide open, kept it there for a while, and slammed it back down onto the seat. "404" was the valve lift in thousandths, which was unheard of for a flathead V8 at the time. The lift rate was so radical that the cam required lifters with a radius on the bottom, pinned into position so they couldn't rotate. Lifter and cam lobe wear was a major concern, but those engines usually blew up long before they wore out.

Anybody with more than three brain cells to rub together doesn't attempt to put a radical lobe profile on a reground cam- - - -they buy an unturned billet and have the timing and lift ground to order. The last time I priced a billet blank from Comp Cams, it cost $3K for a solid cylinder of steel with a distributor drive gear on one end and a timing sprocket hub on the other. Then Comp would get paid an outrageous sum to whittle on the area in between to make it look like a camshaft.

The CCS-1 timing and lift is posted prominently on the Melling website for anyone with a little time and the incentive to to make a few mouse clicks and read them. Basically, it's a Corvette/261 solid lifter cam with a few degrees of duration added to the exhaust lobe to assist in scavenging of the exhaust gases, which assists in cylinder filling from overlap with the intake valve. Stock stovebolt cams have virtually no overlap, where both intake and exhaust valves are slightly open at the top of the exhaust stroke. The inertia of exhaust gases creates a slight vacuum in the cylinder as the intake begins opening, which accelerates the incoming intake charge.
Jerry

Makes sense. I always enjoy reading your posts. Thank you for your patience.

John

Glad to help- - - - -or at least to try. Us oldtime teachers have a habit of walking off and leaving our mouth running! I linked to a you tube video a while back that shows the procedures involved in making a master cam, and regrinding a cam for an antique tractor. I'm debating whether or not to try to buy a cam grinding machine that's up near Cleveland Ohio- - - -used, but brand new looking. They're asking $8K for the machine, but it's also got a "make offer" option. I wonder if I could grind enough cams at a couple of hundred dollars a pop to break even before I start looking at the brown side of the grass?
Jerry

The machine looks brand new- - - -it's very tempting to decide to get into the cam regrinding business, given the likelihood than new stovebolt cam cores may never be available again!

www.youtube.com/watch?v=AyaY1J9alfk

Jerry

Jerry, you need to be cloned for the future of stovebolt.com

I keep looking for a young apprentice, but even my own kids and grandkids aren't interested!
LOL!
Jerry

If you were closer to me I'd sign up to apprentice.

I have run a few reground cams over the years. How radical the cam can be reground depends on the cam core itself. Stock lift is in the .404 range. Typical regrinds come in at the .410-.430 range, sometimes a little higher, depending on how worn out it is. That being said, came cores are like any other part, tolerances can be close or wide. Chet Herbert reground a couple of cams for me, most were in the .450 range. The last one he did was back in 1985. That core was an exceptionally good core and he was able to regrind that core to .480 lift 280 duration. I still have the 235 motor I installed it in. Choppy idle and fun to drive, sounded great with the clifford tube headers open. But I think that cam was an exception. At any rate, 264 degrees of duration .450 lift is a pretty good street cam with pretty good street manners. The stock 261 and corvette cams are not all that great in my opinion. About the same lift as stock .405 as opposed to .404, about the same duration, the ramp events are where the changes seem to be. A much better alternative would be Langdon's bull dog cam. That cam is like .435 and is a really good choice. A little warmed up but not so much so to make the motor run choppy. Nice rumble, nice idle. I dont think Tom Langdon sells them himself any longer but Tom Lowe over at 12bolt.com sells them now and has some in stock last time I looked.

https://www.12bolt.com/store/p545/235_261_BullDog_Hydraulic_Camshaft.html

My guess is that if you wanted something similar in a mechanical lifter, any of the good cam grinders could make something up that would get you in that range.

What does a guy need for springs with that bulldog cam? The item listing says “not for use with stock springs.”

Buick Stage I springs would work. They are good to about .450 lift. But if I am a betting man, Tom Lowe probably has some suitable springs for the application.

Thanks. I have no current need for a cam. Was just curious for future reference. Seemed like a fairly mild upgrade in cam and the spring need seemed odd.

New OEM valve springs are probably adequate for any sane RPM. Over-revving a glorified tractor engine makes about as much sense as putting racing stripes on a snail. The cams that most people without a clue put into these old engines don't make good nonsense.
Jerry

Do you know what the max lift is for the stock springs? I would be more concerned with the increased lift from the cam bottoming out the stock springs than overreving it and getting float.

I don’t but the open and closed pressure for the stock springs depends on the motor. 55 and earlier mechanical cam/stick motors and different then the hydraulic motors. Keep in mind the springs were designed for cam lift in the .404 range so not likely are capable for much beyond that, which is probably why the corvette cam/261 cam can use stock springs and why the bull dog cam at .435 needs to use an upgraded spring.

Jerry and I have a friendly disagreement about cams. I love and have always loved big cams. They are not for everyone. But they are for me, lol.

Coil bind is easy to check, and anyone who chooses to go the "big cam" route needs to have enough common sense to see if a piece of paper clip wire gets pinched between the spring coils at full valve lift. "It ain't rocket surgery!"
Jerry

Thats true, but there is no point to assembling it with springs that you can verify will bind by their specs.

I could have put a big cam in my LS and checked the springs, or I could check the max lift spec for the stock spring and know ahead of time that I needed to change them. Saves a lot of hassle to not assemble it and have to change them in the engine bay.

LS springs are well defined. Maybe lift specs for the older springs are not as defined and/or consistent, but I would expect there to be a common rule of thumb for the max they are capable of.

I'm running a 0.450 lift cam with stock springs; at least that's what I told the machinist to do. Stock retainers too.

Greater lift than stock increases the open pressure by the pounds per inch spring rate times the added lift.
Yes, this may cause coil bind, or not be enough.
235 lift .316"
261 lift .396"

Just to make sure we are reading correctly: you are saying that is the stock lift for those engines, correct?

From factory literature
There is more than one 235 cam, I think the 1959-era cam is hotter but that's the only lift figure I have

Here's the valve specs for 55.2 and 59 235s. I didn't inspect them to see if there are differences between the cams on the two, but the info is there. Excerpts from the Vehicle Info Kits.
I did see that intake and exhaust valve lifts are different.

The stock cams are absolutely perfect for a stock motor. No ifs ands or buts. If I was restoring a motor (and I may in a couple of years when I have a little more time on my hands) I would not even think about using anything other then a stock cam. Long sorted out as optimal for a nice daily driver or a nice low rpm truck.

I was at the trifive nationals a couple of years ago and a guy was there with his grandmother's 55 235 powerglide station wagon, unrestored. That motor ran so whisper quiet. I forgot just how nice those motors ran in stock form. So for stock, its a stock cam for me.

But if you want to warm the motor up a little, tinker and have some fun with fenton headers and dual carbs, I just think you can do way better then the 261 cam and I think Langdon's Bull Dog cam is a good one to consider. Clifford has something similar, but Clifford's cams are pretty expensive.

Want to move up to large valves, big carbs, big gears, then you can delve into much larger cams.

Too much cam means no to Powerglide or any low stall converter.

Ok, this conversatio has run its course.

Jerry, thanks for the update on the shop that can do this work.