zwede

A roller cam can slide in or out. Out is controlled by the cam button. In is controlled by the cam gear contacting the block.

The torrington bearing goes between the cam gear and block.

However, I have never used a torrington bearing, and no one I know who retrofitted a roller has either. I've had no problems without the torrington and I've run a roller cam in my 454 since the late 90's.

If you think about it, a flat tappet cam has the same issue. It is constantly pulled into the block by the angled lobes. Yet a flat tapped motor does not use a torrignton bearing either.

cooper9811

I agree - 63Mako is giving good guidance.

On the torrington bearing issue - Like Zweded, have heard of people going both ways, as well as drilling a tiny (maybe 1/8") hole into the oil gallery passage in the block above the camshaft. If my memory serves - and it might not - The hole is a really good idea w/out the bearing, and less important with a bearing. Others can weigh in here, but I agree with Zwede on this one.

scottyp99

Sorry, this is the one I meant to post:

http://www.summitracing.com/parts/CCA-CL12-407-8/

It's even smaller! And costs over 700 bucks. I don't think I'll be going with Comp Cams for the retro roller. Howard's has good prices for retro roller kits, and they seem to have an excellent reputation. Maybe something like this?

http://www.summitracing.com/parts/HRS-CL110235-12/

It's operating range is 1000-5000 rpm, I think I want to optimize power in the 1500-4500 rpm range, so that sounds like it matches up well. I have the 3.07 diff gear, and I'm installing a 700r4 transmission, so that will bring my final drive in first gear from 7.74:1 with the th350 to 9.39:1 with the 700r4, that's within spitting distance of the "10:1 in first gear" rule of thumb, so I'm pretty happy about that, but I figure the wide gear spacing on the 700r4 means I need a nice, wide, flat torque curve, and so I'm concerned about that, too. Also, I would like to run a stall converter of no more than 2000 rpm stall speed, so I figure I need the power to come on early. (I think what I really want is a big block!!)

The plan, for now, includes the 72cc combustion chamber, 180cc intake port, Dart SHP heads. They are available with small and large diameter valve springs, for flat-tappet and roller tappet, respectively, and I will order accordingly for whatever I decide to do, tappet-wise. The plan also includes flat-top, -5cc pistons, which, by my math, assuming a .025" deck height and a .015" head gasket, will result in a 9.39:1 static compression ratio, and using the Howard's cam in the above link, with a 4 degree advance (I am not sure if it's ground in or not, but I'll be degreeing the cam, so it'll end up that way, either way.) a 7.73:1 dynamic compression ratio. Could stand to be a little higher, but a move to 64cc heads brings that to 10.26:1 SCR, and 8.42:1 DCR, which I think may be cutting it a little close. Although, the SHP heads are aluminum, and have a very nice looking combustion chamber shape, very similar to the Vortec combustion chamber shape, and assuming a .025" deck height, the .015" gasket gives me a .040" quench across the entire face of the flat-top piston. I wonder if I could get away with it? If I install the cam straight up, the numbers add up to a 8.18:1 DCR, which sounds a lot more manageable.

There!!! How's that? I crunched the numbers, and they seem to work out well, any questions, comments, or concerns?

I would like to say once again how much I appreciate everybody's help and patience while I wade through all this roller cam stuff. It can be kinda confusing if you are new to it. But it seems that once you get past a few technical details, it's still just a camshaft. But, like they say, the devil is in the details!


Keep the shiny side up!
Scott

scottyp99

I crunched the numbers on the cam in your link, and, installed straight up, the DCR comes out exactly the same as the one I posted a link to! Must be the LSA (112 as opposed to 110). The power range is close, (1300-5500 as opposed to 1000-5000 on my pick) it should still work well with a 2000 rpm converter, right? Decisions, decisions! Well, at least I'm narrowing it down.


Keep the shiny side up!
Scott

scottyp99

Is this what you're talking about? (third picture down)

http://www.aaroncake.net/RX-7/damage.htm

I gotta tell ya, I would be really nervous about all those itsy-bitsy, teeny-weeny pieces rattling around inside the timing cover if it let go! I have seen 2-stroke engines with roller crank bearing let a bearing go, and all that crap rattling around inside the engine can cause a lot of damage! Apples and oranges, I know, but still, I have seen the apples go wrong, and it makes me suspicious of the oranges, if you can follow along with the metaphor.

I don't know much about torrington bearings, except that they remind me of roller bearings, anybody have any experience with them in this context?


Keep the shiny side up!
Scott

lionelhutz

I would agree that your first cam links were a little too mild for what you stated as the application. They'd work but would likely leave you wanting more fairly quickly.

The Howard cam suggested looks pretty good. I'd even consider going to the next larger cam but then it might be a little too much. Keep the intake duration below around 220 degrees basically as a rough guideline to put you into the power range you're looking for. I'd also suggest looking at a higher ratio rocker to get the lift up. Check to see what the lift vs flow of the Dart heads is and give them more lift if it will make a significant difference.

Stick a V6 S-10 converter into the trans if you want to get a higher stall on the cheap. The nice thing about a lock-up converter is that you can give it more stall for accelerating yet still lock it for better cruising and highway driving.

The torrinton bearing is like you posted. I agree with the others and I would not run one either. It just is not necessary.

iokepakai

Did my cam swap with this timing gear set from Jegs.http://www.jegs.com/i/JEGS+Performan...20411/10002/-1
It uses a bronze thrust washer instead of the roller bearings.Almost went retro roller but the cost was just to much.Installed a solid cam with EDM lifters and ss roller rockers.Really like how quick the engine revs with those solid lifters! Good luck with your build....

63mako

Torrington bearing not needed. The cam tunnel has a plug at the back to limit rear movement. The flat tappet cam pushes back hard due to the angle of the lobes. This is why a cam button is not needed with one. The roller has flat lobes looking at it horizontally and loads the rear plug less. The only worry is forward movement with a roller.
Your numbers look good. With a 700 R4 I would be tempted to go with the 64 CC heads and the next bigger cam as well. This one has nice lift and duration, Your new gearing and a 2000-2200 stall convertor it will all work fine and not pull past the rpm capabilities of your bottom end. The 700R4 and convertor will allow you to build more motor and still get what your looking for performancewise.
http://www.summitracing.com/parts/HRS-CL110245-10
This is available with a 112 LSA the kift is less and RPM range moves up but torque curve is flatter. More LSA raises the curve at both ends and drops it in the middle. Your DCR will look a little too small but better cylinder filling from the duration and lift will make up for that some, Might be able to run midgrade or regular fuel too. 4 degrees advance is ground in so install straight up.

scottyp99

Can I clarify one thing here? The LSA and centerline thing can be a little confusing. When I say straight up, I don't mean line up the timing marks, because that would mean the ground in advance would be in effect. I guess what I am saying is to install retarded to get rid of the ground in advance? So the LSA and centerline are equal? I know that changing the LSA/centerline relationship can have a big effect on DCR, and I want to optimize DCR, which means cutting it close, so no room here for misunderstandings, know what I mean? So, when I say "straight up" I mean LSA and centerline equal, so for a cam with 4 degrees of advance ground in, that would mean install 4 degrees retarded to cancel out the advance. Am I using the term incorrectly? Or am I misunderstanding the whole LSA/centerline relationship? Sorry if I seem a little dense about it, but I want to make sure I am understanding correctly, and that we are all using the same terms to mean the same thing. The music sounds better if we are all on the same sheet of music, right?


Keep the shiny side up!
Scott

scottyp99

Another thing is that I am using an old version of desktop dyno (DD2000), and when I tell it to use seat-to-seat valve timing, and .050" timing, I get very, very different looking curves for the same camshafts. Which should I be paying more attention to? I understand that these programs are not the most accurate way of predicting actual torque and horsepower, but I figure it's at least good for comparing cams to each other.





Keep the shiny side up!

Scott

63mako

DCR is not the end all, just a tool. You won't want to cancel the advance. Install timing marks lined up. Retarding moves the RPM range up and reduces DCR. The ground in advance is a good thing in your application. I would go with the 110 LSA cam I last recommended, better cylinder pressure and lower RPM torque. It won't be quite as stong at the top RPM but good for your needs. Run the numbers, you seem to like that. Good heads with higher lift and duration will fill the cylinder better and offset a little lower DCR by increasing volumetric efficiency. Look here and you will see where I am coming from:
http://www.cpgnation.com/forum/effec...tion-2630.html
This is actually a pretty mild cam with a little lope. Not radical at all. Your Desk top dyno is pretty generic. I think the newer models have inputs at seat to seat, .050 and .200,. way more accurate results. If it is set up for Roller cam go seat to seat.

63mako

http://www.compcams.com/Base/MultiMe...XR275HR-12.wav
Similar to this sound. A little lope and smooths out right off idle. Plenty of vacuum.

scottyp99

http://www.summitracing.com/parts/HRS-CL110245-10

Whew!! Mama mia, that's a spicy meatball!!

OK, according to my DCR calculator, this cam, installed "straight up" (which I am taking to mean installed with the timing dots lined up, as Howard intended, with the 4 degrees of advance that is ground in, giving a 106 centerline), with a 64cc combustion chamber head, will give a 8.18:1 DCR. With a 72 cc chamber, 7.50:1 DCR.

I gotta tell ya, this cam kinda scares me! It's big! The advertisement says 2500+ stall converter. And that idle recording you posted a link to sounds like a little more than I want. I know, I know, I'm a big wimp. Maybe we could split the difference. What do you think about this choice?

http://www.summitracing.com/parts/HRS-CL113215-10/

I get 7.73:1 DCR for this cam with 72 cc chambers, and the advertisement says stock converter OK. That makes me feel a little better about it.


Keep the shiny side up!
Scott

63mako

Look at the operating range of both, not a lot of difference. I like the 8.2 to 1 DCR and 10.25 compression setup myself. A 278 cam with a 1600 to 5400 operating range and a 700R4 don't need a 2500 stall convertor. A 2000 - 2200 will work perfect because of your lower final 1st gear ratio. I can see a 2500 convertor with a TH350 and 3.08 gears but you would be fine.
You could drop compression and go smaller, it is your build, but I think your leaving noticable power on the table in the power range you will use that will cost you nothing extra. I don't know what you really want out of it.
Look at my profile, Im a more power guy, if you got the gearing for it build it..
I would put it like this:
If you had your stock trans and gears I would recommend the smaller 270 cam and 72 CC heads to anyone posting.
With the 700R4 and a 2200 convertor I would recommend the 64CC heads and 278 cam. Better match. Free power. Either will work.

scottyp99

Alright, then, I guess that just about narrows it down enough were it's up to me now. When the money and time become available, I will be able to make informed choices. Or maybe I'll change my mind completely, and buy a Honda! Who knows?

One thing I do know, is that I really appreciate all the help everybody has given me on this thread, especially 63mako. Thanks to you guys, I am now confidant that I know what is involved in a retrofit roller cam upgrade, and I have some good choices to choose from. I really learned a lot, and I am sure there were plenty of others who were along for the ride who learned a lot, too.

Mako, I'm not making any promises, but when I get ready to start this project, I will try to grab my you-know-whats and go with the big cam and the 2200 rpm converter! Peace!!


Keep the shiny side up!
Scott

gingerbreadman1977

Thats some bad damage there Cooper. I really cringe when reading about those kind of things going wrong but its worth the read to learn from them and not make the same mistakes.It actually sounds like that enging builder took very little care with anything so hopefully he is out of business now I was however very glad to read it wasnt a torrington bearing failure but an installer issue as YES i have one in the Corvette of all cars. I did alot of research on them before i installed mine and its been going well for 5, maybe 6 years now. I do however agreee with Scottys sentiments of small bearings and eliminating things that can go wrong and im all for that for sure !! .... on the flip side there was a time when roller rockers,roller tipped fuel rods,roller lifters etc appeared and they are all common trusted parts now and I have never yet heard of a torrington failing so im quietly confident they are worth it when looking for as much free spinning parts as possible.

I just wanted to put it out there that its important should anyone decide to use one that they do follow the instructions of at least scribing the channel from the oil gallery hole in the front cam bushing as well as drilling the 1/8th hole in the back of the thrust surface (if the motor is not assembled.) Its just my opinion but i wouldnt use anything else on a big block as i have seen a fair few blocks with pretty bad wear on that machined thust surface and with the torrington there is absolutely no wear.

cooper9811

What damage? I agreed with Zwede (and others) the bearing is not required. I also clearly stated my memory may not be 100% accurate relative to block preparation. But I'm having no issues with my engine.

cooper9811

I should add that if I was unclear and anyone felt mislead - my apologies. And Gingerbreadman, I do appreciate the intent of your post.

lionelhutz

I have the LT4 Hot Cam in the LT1 in my 65 Impala. It's still pretty tame with that cam. The 2k rpm stall and lockup works great with it. I honestly would want more if it wasn't a top down cruiser.

I'm running a 4L60E and I probably put 30 tunes into the computer just adjusting the lockup and shift points when I first got the swap done. Honestly, if you don't have the trans yet, spend the extra and run a 4L60E with a stand-alone computer which monitors both road speed and engine load (or throttle position). You will not regret it.

63mako

The specs on that cam would be real close to the 270 duration cam linked earlier. That was my thought, that it would leave the op wanting more.