Open chat thread for Buick 350 Camshafts

Tell me more about the engine and car it'll be going into.

Key elements: compression ratio, heads (ported? larger valves?) intake (stock? TA?) exhaust (manifolds? ported? headers? primary size?) exhaust style (crossover pipes? (H or X), mandrel bent?) weight of car, transmission used, stall converter, gear ratio, etc.


Gary

 

Ok here is what I'm working on given the heads surface.... If not ah porting we go! engine close to 9:5 comp idk about the valves in a street engine ( Anyone want to comment on this? Bigger valves on a street ride...) Modded Qjet! May go headers 1-5/8, 200 4r Trans, 3.08 gears don't really care bit roasting tires, stock intake (unless heads and [stage 2 scoop ] are produced) car is a full weight lark. Wheels undecided. stall only if idle calls for. Car will be a cruiser. That will get a dyno after a/f mixture is final.

---------- Post added at 10:44 PM ---------- Previous post was at 10:42 PM ----------

Might have an h pipe

 

I've calculated a build with a 3.23:1 gear and the 200-4R trans, and with first gear it will have the same ratio as a TH350 using a 3.51:1 gear, while overdrive will be like using a 2.16:1 gear. At 70 MPH it would be at 1900 RPM, and at 55 MPH it would be at 1500 RPM. My combination will be pretty mild though, capitalizing on the Buick 350's innate high torque, low-mid range RPM strengths.

I'd say anything numerically less than 3.23 with the 200-4R trans and you'd need a much milder cam than the one you've suggested.

Where do you want to keep the RPMs of the engine most of the time?

We can come up with a camshaft that will ideally suit your combination if you like. Find out where your compression actually is, whether or not you'll have any port work done to heads, etc.

Another thing I've learned about the big valves:

They flow more at lower lifts as well, so would (believe it or not) do well for a low-end grunt motor. The reason is keeping the velocity high with a low lift cam permits more flow with larger valves without sacrificing velocity.

In fact, if one were to port the heads removing very little material and mostly just contouring for a better velocity-type flow, used the "Stage1" valves, and kept the lift low @ max lift, would serve as a dynamite combination with a mild cam...

What this would do is improve on the flow ratios on the heads, permitting them to flow a little better in the runners while widening up the CSA enough to match the flow @ valve curtain lift, all while maintaining an excellent velocity to VE ratio at lower lifts where the heads will be flowing.

This would permit a camshaft around the size of the Crower level 2 or 3 to really turn on.

Gary

 

Hi Guys. I've been off this Thread for awhile. Gary, I made a mistake about the Cam I told you I was using. It's a Crower Level 4 Cam. The numbers I wrote down are for that cam. I just picked up an Aluminum Intake for my 350. I Will be porting it out. I plan on having the heads planed just a bit to flatten them out if they're warped. I have them ported out quite a bit. When Poston was still in business I purchased a set of V6 Pistons advertised at 10:1. Who knows what they really are. I use 93 pump gas that's available around here. I plan on taking a bit more cast iron out of the Heads when I get them back. I just have to find the will to do it. I just bought a '65 GS and went over to the big block dark side. I'll be working on a 425 this Winter also. But the 350 is First on the list. Take care guys. I'll be submerging soon. :TU:

PONCH

 

Gary I'm really liking the rpm at the mph you listed. Comp is going to be set at 9:5 and mild port work you suggested will be done working the runners getting the curves transition better. nothing drastic just enough to keep velocity high and more cfm. I may just get the bigger valves just depends on my builder.
These things will come after rebuild the Trans and I paint my c10 this spring. What are you thinking cam wise?

 

Nothing etched in stone cam wise, but there are a few guidelines to follow, the main one being to match the intake valve closing point @.006 with your compression ratio to get an optimal dynamic compression.

Generally speaking, LSA's of 110 or 112 are usually best suited for street cams. I prefer less lift on intake than exhaust, but only because it better matches the typical head flow parameters. Putting lifts further into the flow plateau is always good, and it usually ends up as the exhaust being higher lift. These are just 'rules of thumb' here and can change based on your specific combination.

Many here like to build an engine with a nice lopey idle and higher RPM usage, and that's cool too. My philosophy is to work with the engine's strengths and build it within reasonable guidelines so as to not venture too far off the path. To do so costs a lot of money and creates an engine that behaves more like a chevy.

If your goal is a cruiser that gets good gas mileage and still has enough get up and go to make people wonder if it's a big block, then you won't be disappointed with a Buick 350 built within these parameters.

This isn't to say that you can't have a nice lope when you put it in gear. The idle doesn't have to be super smooth in order to achieve these things.

Based on what I know thus far, I think a cam that has a .050 intake opening event of 3* before top dead center, with an exhaust closing even around that time will suit you. Much like the cam that other guy recommended.

You can go with a cam that opens after top dead center for more intake vacuum and less reversion, but the idle will tend to be a bit smoother. Having the exhaust close around this time, while creating a similar overlap, would cause the engine to become more dependent on scavenging and higher RPM usage to make its power.

Or you can go in-between, which is opening before TDC for intake and after TDC for exhaust, though the more it shifts toward ATDC (after top dead center), the more the scavenging and higher RPM is needed.

There's a lot of variables and it all revolves around how your engine's going to be used, and which parts other than stock parts will be used on it, such as intake and headers or manifolds, port work on heads, etc.

Using headers and an X pipe or H pipe I'd say you'd want exhaust closing 3-5*ATDC with intake around 3-5* BTDC for use with a street engine that still has enough vacuum to operate power brakes.

Intake closing event needs to fall somewhere between 30-35* ABDC @.050, while exhaust opening event should be around 40-49* (BBDC), depending on where the intake sits.

Once we get these numbers sorted (which will be the RPM range where your engine will behave) we can figure out the .006 events which will determine DCR, vacuum, and idle quality as well as lobe intensities.

LSA and centerlines are just happenstance really. Wherever the events fall, the rest is calculated. I've seen ideal cams falling within the 111 LSA and 3* advance areas, which is 1* off in either direction where you wouldn't expect them to be. More on that later...

We can sort this all out once more is known about your final combination.


Gary

 

Gary thanks your Awefrikinsome!

 

If we used your cam example and added enough duration @.006 for good vacuum and idle, the numbers would look like this:

This is 272*/276* I/E @.006 for 58*/56* I/E lobe intensities, at 108* LSA and 4* advance (104* ICL)

IVO is 32.0 BTDC ( - indicates ATDC)
IVC is 60.0 ABDC
EVO is 70.0 BBDC
EVC is 26.0 ATDC ( - indicates BTDC)
Overlap is 58

With 9.5:1 SCR and 60* IVC ABDC @.006, you end up with 7.87:1 DCR:

Static compression ratio of 9.5:1.
Effective stroke is 3.11 inches.
Your dynamic compression ratio is 7.87:1 .
Your dynamic cranking pressure is 155.63 PSI.

Which is good. You could use premium pump gas with proper ignition timing and have no detonation, although you may need to adjust the ignition timing a bit, and/or use an octane boost depending on where you wanted it to sit.

If you wanted, we could increase the intake duration @.006 for an IVC point of 61-63 to lower the DCR for safer use with pump premium, depending on where the actual SCR ends up (lower or higher than 9.5:1).

This way, the camshaft can be adjusted to match your engine for optimal performance and efficiency.

Your lope will be slight, but idled down low enough and under load (in gear) you will hear it better.

One of the downsides to this style of cam is the tight LSA will give good power, but within a stricter RPM range, and with the intake lobe at 214*@.050, the 108 LSA and 4* ICL will help to offset the higher duration, bringing the power band down so you could get away with not having to use a stall higher than stock.

Power would be strong between 2000-4500, with peaks probably more within the 3000-4000 zone, and an overrev potential to probably not much higher than 5000.

Total power band from weak to weak would be ~1800 to ~5200. This means from idle to 2000 or so it'll feel pretty wimpy until it comes into its power band. While you wouldn't NEED a higher stall, it would be advised to have one. Power would begin to trail off pretty quick after about 4800 RPM or so probably.

Ultimately this cam isn't one I would recommend personally. It's ok if you want to hear some lope, but you're suffering a bit with a narrower power band. For the gear ratio you're talking about, this cam wouldn't be optimal below 2000 RPM operating range for cruising.

As always, remember I'm not a pro and I could be off in my description, but it should be pretty close.

Generally, cams with IVC points happening sooner are reserved for cams with later closing points and matching exhaust events to compensate for it, so this cam would be specialized to focus on mid-range power while offering a non-stock sound. Your gas mileage wouldn't be as good.

If this sounds like something you'd like, cool. If not, I can offer another route to consider.


Gary

 

Gary now I think about it. I don't need a lope if it cost me a awesome street cruiser... What tire size WA that to which would give me those low RPMs you speak of? I do like having a wide power band(big time). That power band is a Lil out of a dd use. Until you step on it... how bout we bring the comp down to run 91 with no issues (tuning and detonation). I'm thinking I don't want to have issues with my valve train failing or tq. If like to do burn outs longer than my c10 with a built 355. Or just as long. 15 foot no braking...

 

The Erson 214 .050" duration lobe has a ADV duration of 292* and a 0.299 "lobe lift.
The 220 .050" duration lobe has an ADV duration of 284* and a .315" lobe lift.

Looks like he spec'd the lift at 1.55 rocker ratio for the exhaust and not sure about the intake.

Paul

 

Thanks Paul. This is the same cam I sent you a pm about a while back

 

I calculated it with 26" tires, or about the size I'd be running on a G-body Regal using 235/60r15's.

Anything from stock to mild (up to about 210 intake duration), I think the 3.23:1 ratio with the 200-4R trans would be fine. Much higher than this and I'd be looking at either using a numerically higher gear (3.42:1 or 3.73:1) or a milder cam.

Another thing to consider is that with Bowtie Overdrives (the one I was going to use was their level 2 version which can handle 'up to 450 ft. lbs') they have 2 choices for lower-RPM converters, an 1800 and a 2200, both of which cost the same. I figure with a locking converter, might as well get the 2200 unless you were going for a towing application.

They have converters higher than this of course, but they cost more money. The next grade up, the 2400, costs about 100 bucks more, but still isn't too bad on price, and they say it has 'special sator modifications' for a harder launch. This is the only converter that carries this statement for some reason.

Anyway, what I'm getting at is you could feasibly use that '214' cam with this setup, as long as you got a 3.23:1 gear (like I plan on using) or numerically higher, and don't use the overdrive or lockup unless you're on the interstate or something.

It's personal preference, but to me that'd be too much gearing for that cam.

Cruising at 1500 RPM @ 55 MPH is pretty low RPM, and the cam would need to be within its power band at that point in order to efficiently pull up hills, etc. during normal driving conditions. This means stock up to not much higher than the Crower level 2.

I figure it if gets too bad I'll just drop it out of overdrive and cruise around 1:1 in normal driving conditions, since lockup on converter will be engagable in 3rd or 4th gear.

So putting around in the "D" instead of the "OD" when you know you'll not see speeds in excess of 55-60 and letting the converter lock up in 3rd should be sufficient for optimal cruising. Then if you get on the interstate and move up to 65-75 engage the OD and let'er cruise.

That's my plan anyways.


Gary

 

I'll prob be using a 28 to 30 inch tire. What do you think hear wise

 

Well just calculate it in your mind. Find your finished result in your mind, what you'd think would be the ideal scenario you would want, then shoot for that.

Taller tires and I'd have to say 3.42:1 with that 214 cam with a 2200-2400 stall. Sweet thing about those 200-4R transmissions is you can run pretty much any stall you need with it having the locking feature.

OR a milder cam and the 3.23:1 and 2200 stall even with larger tires would still be ok.

 

What gear do you have in the car now?

 

Keep in mind also that the lockup will lower RPM by another couple hundred or so...

Even with a Crower level 2 cam that's advertised to begin its power band by 1500 RPM, the 3.23:1 gear, 26" tires, and 200-4R trans will be pushing it at 55 MPH in overdrive with the lockup engaged.

I'd say 3.42:1 for much more cam than that (which wouldn't take much lol).

Most people say 3.73:1 or 3.42:1 for that trans anyway, which is about right for most lopey type cams.

If that cam was ground on a wider LSA it wouldn't have much of a lope at all, and as it is it may not have much of one even with a 108 LSA.


Use TA's 212-350 cam as a reference point. Properly set up, it will have a mild lope @ ~750 RPM, and it has 118* intake duration @.050 and a 110 LSA and power starts to come on for it around 2300-2500 RPM.

It seems to be the cam that other cams are measured from, so it's a good reference. Take other cams you may be familiar with and compare them to it, then you can build your mental image of how cams will behave in a Buick 350 relative to your reference points.

Crower level 3 with 210* @.050 and 112 LSA has a smooth idle. Other factors come into play that determine idle and vacuum, etc. but these guidelines will give you an idea.

I've heard the Poston GS 114 cam idle, and it has a 114 LSA with I think it was -.5* overlap @.050 which is less than the 'Erson 214' (or whatever it's called), and you can barely tell it has any lope at all, especially when the engine goes much over idle.

Here's the overlaps @.050 for the aforementioned cams:

TA 212-350 = 4*
Crower level 3 = -9*
Poston GS 114= -.5*
Erson 214 = 1*

Idle wise, it'll be closer to the Poston GS 114 than the rest, which means you're not going to have a lot of lope. Idled down and in gear you would hear it probably.

I understand the attraction a nice rhythmic horse-galloping idle has. I prefer to remain in the shadows myself, with 100% stealth. Besides, I like the rhythmic sound of a nice low RPM steady booming super smooth idle.

Best sounding idle I have ever heard in my life was my 1969 Electra with the stock 430. Idled at 500 RPM with a sweet smooth hypnotic resonance through those dual turbo mufflers.

All this is preference though.

Get the ideal sound and feel you want, then build the car around that. Don't settle for something. Get what you want. Once it's all built and done, you're living with it, so make it good.

I gotta get outa here. Spending too much time on this site! lol

Peace bro


Gary

 

2:73

---------- Post added at 08:46 PM ---------- Previous post was at 08:41 PM ----------

Thanks allot for your time.

 

Cool good to know,with Gary's info you can run a 700R4 with similar results. Instead of changing the gear you can shorten the drive shaft and run an adapter plate for the trans,that would be less expensive than changing the gear?(depending on how you source everything to swap?)

So if you're interested on learning a little bit more about gearing,shoot me a PM and I'll try to teach you.


Derek

 

I have been thinking of running a 700R4, seeing how they are plentiful down here at prices of 700- 1000 bucks with a high performance build. (monster in a box) can't find anyone to even touch a 200-4r for that.

 

Here's a link to Federal Mogul's site showing OEM camshafts and other stuff camshaft relevant:

http://aftermarket.federalmogul.com/en-us/technical/pages/bulletins-engine.aspx

The Buick 350's 'stock' camshaft is the one listed as CS647:

http://aftermarket.federalmogul.com/en-US/Technical/Documents/Camshaft - CS647.pdf

Sealed Power is the purveyor I presume.

Gary

---------- Post added at 07:43 PM ---------- Previous post was at 07:37 PM ----------
For $188.97, one could procure a camshaft, lifters, and timing gear/chain set all synchronized together to be properly timed and setup.

http://www.northernautoparts.com/part/tg-kct647

Just a thought for those who think they have to bump the lift up to cam-chewing parameters in order to get any power out of their Buick 350.

Would go well with any restoration job or towing application/street build, or for someone who doesn't want all the hassle.

Gary

---------- Post added at 08:54 PM ---------- Previous post was at 07:43 PM ----------

More prattle in case anyone is interested:


Here's a little short story about my personal experience with a 1968 Buick 350-4v:

Advertised at 10.25:1, it had more like 9.67:1 actual.

When I bought the car, it was using 89 octane regular leaded gasoline and ran fine off of that.

I advanced the distributor and put in the (newly introduced) 93 octane super unleaded from Ammoco or whatever its name was.

I did this also with my '68 Skylark with the 350-2v advertised at 9:1 and I could advance the ignition so far that it simply wouldn't start because the firing was happening so far before TDC it prevented the engine from turning over fast enough to start up.

I couldn't advance the timing quite so far on my 350-4v higher compression engine without it spark knocking a little, though I could still tell ignition was happening before TDC pretty far down since it would slow down every time the spark plug fired when turning it over.

Both of these engines ran very well this way, and were far from anything that I would consider a weak engine. I'll spare you the boring details about me burning rubber and beating the 'hotrods' of the day with similar CID engines, but rest assured they did.

So let's see. To summarize, 9.67:1 compression ran fine off premium pump fuel (93 octane @ a few hundred feet elevation) when ignition was advanced with a stock cam. Speed Pro makes a stock cam that's supposed to be pretty close to what those cars were using in that day (maybe even a little bigger). Engine ran fine off 89 leaded octane when ignition was set to 'normal' range, though didn't have quite the power.

The stock cam's 8:1 DCR rating was sitting at 10.2:1 SCR, so I had way less than 8:1 DCR.

It was more like 7.60:1. This could be off of course since the camshaft may not have been spot on exact as the Speed Pro's version, though I bet you it's pretty darned close.

Something to chew on.

Gary


EDIT: After rechecking some things, stock cam's installation point is different (it's complicated) which threw me off about .75* for centerlines, so technically the 8:1 DCR @ SCR is 10.56:1, even higher. I guess they wanted to ensure there'd be no spark knocking, which they did a good job. This puts my old engine's DCR at 7.35:1 which explains why I could advance it like I did. This also begs the question of at which point does it become in danger of detonation...

I suppose it depends on a few things, but the safe zone would certainly be around 7.5:1.

Just FYI stuff in case anyone cares.

(The 10.2:1 SCR @ 8:1 DCR came from the 67* IVC point, which would be cam specs @ 4* advance. With the stock timing gear set, I'm not sure if it would be installed straight up, or advanced or what. IF the cam is installed @ specs, it's 71* IVC point. There's 3.25* advance @.050, and 1.5* retard @.006 built into the cam. All funktified, there's more distance between .006 and .050 on closing sides of lobes than intake sides, and it's different still between the intake lobes and exhaust lobes)

Which means if it IS installed at 4* for the stock timing gear, the 109.5*/116* I/E centerlines would then be 105.5*/120 I/E @.050...

Which puts the .006 figures of 116*/112.5* @4* advance to 112*/116.5* I/E (67* IVC @.006 gibt es fr 10.2:1 SCR @ 8:1 DCR as opposed to 71* IVC @.006 gibt es fr 10.56:1 SCR @ 8:1 DCR)