Engine and Transmission Tech

Any input on the max lift a stock Olds 215 can take considering its a flat top piston at .025 deck clearance?

I wish I had a complete motor to measure things, but I have about 75% of a motor and no stock pistons to play with.

Better question is will 0.481 gross lift be ok with a flat top piston at .010in deck clearance? I'm thinking it should be fine when you add in another .020in of head gasket thickness. My set up would have a total of .030in from deck of head to top of piston while stock is .045in. I will absolutely be double checking the clearance during the assembly and blueprinting but I need some ballpark knowledge to work with on paper. I'm dialing in my compression and shooting for the stock 10.75 to a max of 11:1 and I may need a small dome or exh valve relief, things may get tight.

Richard,

Chad McNeely posted a compression spreadsheet that you could modify to work things out. Here's the link to it: [www.dropbox.com]

Thanks Airwreckc, I will check it out.

I have been using these calculators for over a decade to play with combinations.

[uempistons.com]

Yep Carl, my spreadsheet isn’t anything new. What I found was that I liked being able to save results, and have multiple copies as I tried various combos. It gave me a great place to store the specs of last week’s combo, in case this week I found something a little better, maybe. And, I think my version puts all the parameters I was interested in on one page. Some folks aren’t into spreadsheets though, and a paper notebook and the internet calculators, or hand calculators - it’s all easy arithmetic - work just fine.

To the original post on this thread, I don’t think it will help with valve clearance questions. I don’t know of an easy way to calc that out from published numbers, without the heads and pistons in hand. There’s a reason it’s one of the things most builders verify by putty impressions, once the parts are first being fit.

Clay on the piston. Have at least .100 clearance. Advancing the cam puts it closer on the intake valve. Retarding the cam puts it closer to the exhaust valve.



Edited 1 time(s). Last edit at 12/03/2022 11:26AM by mgb260.

"It gave me a great place to store the specs of last week’s combo, in case this week I found something a little better, maybe."

Yes, I like that. Big improvement. I printed out a bunch of pages of combinations & shuffled back & forth thru them.

I really was hoping to hear about how other people's high lift builds worked out for them clearance wise. Being there is no real way to check short of clay in the cylinder I was just wondering if folks had an opinion as to what is safe. I am assuming I should be safe around .480 but I have decided to zero deck the piston to raise the compression a tad so I lost a bit of space from last weeks thoughts.

Reverse osmosis/ or ? In other words, Adj. int./exh. push rods. Crank to top of lobe, checking spring only, adjust push rod to desired
piston/valve clearance. Crank back to "heel", check clearance. Got good notch ?
Onward, Art.

When I ran an Olds 215 in my 'B' some years ago, I had a Crower 50232 cam with stock valvetrain, heads and pistons. (AFAIK, close to stock 10.25 ratio)
Advertised lift specs for the cam are 0.488 on the intake and 0.490" on the exhaust. I experienced no valvetrain clearance issues at all!
At the time of the engine build, I consulted with Dan Lagrou at D&D in Almont, Mi. - maybe a call to Mark at D&D might clarify component compatibility for you.



Edited 1 time(s). Last edit at 12/08/2022 11:31AM by ex-tyke.

"When I ran an Olds 215 in my 'B' some years ago, I had a Crower 50232 cam..."

What kind of gas mileage did you get with that big of a cam in a 215, Graham? Was the idle lumpy? I don't remember.

Carl,
Not lumpy at all - in fact it's pretty well the equivalent of the infamous 'B' cam I have in my Ford 302 now.
IIRC, mileage was in the 23-24mpg (US) at highway speeds with a 500cfm Edelbrock , the original MG axle (3.91 RA), a T5 with a 0.63 OD and 24" dia tires.

The Mighty "B" cam?! ;)

I ask because I have four different cams in my Camaro. Always bigger to the point of maybe this cam is a bit extreme for the street.

I made list of Crower cams for the 215. The 50229 is purported to be a close equivalent to the stock cam for my 215 hi comp engine. There are two more cams between that one & the 50232.

I am talking about going from a 258/260 .430/.445 to 276/281 .488/.488. Pretty good jump in duration that I would think would hurt gas mileage. Might not give much gains without a bit of porting.

I like that 50231 (270/276 .450/.477) aids the exhaust more than the intake, which the heads seem to need.

With the price of gas, maybe a milder cam might be a better choice.



Edited 1 time(s). Last edit at 03/28/2024 11:01AM by MGBV8.

Carl,

I'm curious as to your thought. With the late Rover heads, which I think have smaller intake but larger exhaust than the 300 heads, which way would you lean on the camshaft?

The same cam will seem smaller in a larger engine. You could use the same cam (50233) as Mike Moor's 300 with home bowl porting & gasket matching, or the 50232.

It really depends how well the heads flow. No point in using a larger cam if the heads can't take advantage of it.

Thanks Carl, agreed on matching the flow.

Been a bit of topic drift and from what I've seen any BOPR/SBB engine should be able to handle a cam with 1/2" of lift. There may be a case where that isn't true but so far I haven't seen it.

I've kinda come to the conclusion that pretty much all of these OEM heads were limited by the small valve sizes. It's not uncommon to see cams for the Buick engines that have 3/4" of lift and I think it's mostly for that reason, although even with seriously reworked and aftermarket heads big lift is used. Seriously, have a look at the cam grinds in the TAPerformance catalog. I think you can get any of those grinds on the blank of your choice. There's a lot of variety. For my first build I ran a CC 268H in a Buick 215 and I don't think you can even get that grind anymore. The idle was a little high but I really liked that engine. The most popular TA grind for street engines seems to be the TA-212. It might be edifying to look up it's specs. Off hand I don't remember what they were.

If the valves were larger I think the grinds would need to be milder, or in other words The smaller valves need more aggressive cam grinds. It's a working theory. Does anyone feel like they have overcammed one of these engines? I could see that in terms of duration but on the lift I'm not so sure, other than ramp angles getting too steep. In 1955 the 265 SBC had a 1.720" intake valve and by 1965 it had increased to 2.020 in the 327 with a 1.5" exhaust. So in terms of valve sizes even the TA heads with the largest valves that can be fitted are in terms of valve size roughly comparable to a STOCK SBC. This means that comparing lift and possibly also duration numbers between the two engine families is a mistake and because most cam grinders seem to base their descriptions on a generic Chevy grind, their description for a Buick grind has the potential to be highly inaccurate. Just something to keep in mind. Since TA's business is Buick only and their grinds are in-house designs the descriptions should be more accurate but even so the wording tends to be a bit nebulous. Much better by far to get the feedback from actual use such as on the V8Buick forum. That is where the 212 grind has consistently gotten favorable reviews.

Jim

Jim,

Here's a snapshot of some of the camshaft grinds from the TA catalog, including the 212 you mentioned. It's worth noting that TA has quite a bit of technical information on their grinds in their catalog, as well.

And here's a snapshot of descriptions of those cams. Of note, the performance gains they mentioned are based on the 455, so the SBB or Rovers would likely be less.




Edited 1 time(s). Last edit at 12/09/2022 10:41AM by Airwreckc.