How to switch to roller cam?

[fussfeld]

One thing i've never been clear on is, how do switch from a flat lifter cam to a roller in a SBC that was originally equipped with a flat?

Technically, all you need is lifters with the link bars and the appropriate cam and you're good?

You don't need to drill/tap and get a special spyder tray?

 

[shiftpro]

One thing i've never been clear on is, how do switch from a flat lifter cam to a roller in a SBC that was originally equipped with a flat?

Technically, all you need is lifters with the link bars and the appropriate cam and you're good?

You don't need to drill/tap and get a special spyder tray?

Are you just curious or are you considering this switch?
Are you looking for a power enhancement?
Depending what you want and how you intend to use your truck, there may be better bang for buck routes to more power.
If this is the case (you want mo pow), can you tell us which head casting you have on your sb?

 

[shiftpro]

Basically you use retro lifters with the bar to prevent them from rotating. A cam button will need to be installed in your timing cover, The dizzy gear
on the cam has to be compatible with the gear on the cam.
If you want a cam with higher lift you will need to verify your heads can manage this. You would matched valve springs regardless. If you have crappy heads,
it doesn't matter how much lift or duration you throw at it.
If you have low compression you will be pissing in the wind regardless of cam choice.

Best bang for buck on a SB are Vortec heads from the mid 90's. Just have to verify they are actually Vortec, and not cracked.

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[75gmck25]

I just installed a Howards retrofit roller cam a couple of months ago, and can provide a parts list:

- Retrofit roller cam - it is not the same as an OEM roller cam, so don't get confused
- Retrofit roller lifters - ones with the link bars
- Cam button - keeps cam in the right place from front to back. You have to measure free play and adjust or grind the button so it provides the right amount of free play. Free play will be very small (.005?) , so its almost down to no free play. I decided to use a Cloyes cover that allows for external adjustment of the cam button free play.
- Timing cover that will keep the cam stable - cam button rides up against the timing cover, and most stock covers are not stiff enough to keep the cam stable.
- New pushrods - length will be calculated after you have the cam, lifters and rockers in place. It will be slightly different for various cams and rockers. For example, my stock 350 pushrods were about 7.75 inches, while my roller pushrods are about 7.1"

Bruce

 

[shiftpro]

I just installed a Howards retrofit roller cam a couple of months ago, and can provide a parts list:

- Retrofit roller cam - it is not the same as an OEM roller cam, so don't get confused
- Retrofit roller lifters - ones with the link bars
- Cam button - keeps cam in the right place from front to back. You have to measure free play and adjust or grind the button so it provides the right amount of free play. Free play will be very small (.005?) , so its almost down to no free play. I decided to use a Cloyes cover that allows for external adjustment of the cam button free play.
- Timing cover that will keep the cam stable - cam button rides up against the timing cover, and most stock covers are not stiff enough to keep the cam stable.
- New pushrods - length will be calculated after you have the cam, lifters and rockers in place. It will be slightly different for various cams and rockers. For example, my stock 350 pushrods were about 7.75 inches, while my roller pushrods are about 7.1"

Bruce

Thanks for your input Bruce.
Did you forget valve springs...?
And what did all this cost?
Specs?
And wondering, what heads are you running?
Is this a daily driver or Saturday night special? (I could guess probably from the specs..haha)

 

[shiftpro]

Also, I understand not all retro roller cams have a fuel pump lobe...??

 

[75gmck25]

Mine is a daily driver, and I used a Howards retrofit roller cam with 213/217 @ .050 duration. Good for my 4WD truck, but milder than many folks might use. I also installed Blueprint H8002K aluminum 64cc heads and Summit full roller rockers. Heads had the right valve springs for the new cam and with thinner gaskets it brought the crate engine's low compression up about 1.2 points. Should be running about 9.4 compression now. Cam allows use of stock fuel pump and distributor gear.

I think I ended up spending about $2300 total, when you add in all the gaskets, sealer, nuts and bolts, and other parts I replaced (i.e., I put a hole in my old radiator and had to buy a new aluminum one).

Some of the simple parts can get expensive. I bought relatively cheap Summit tall valve covers to clear the full roller rockers, but then found out that a good set of FelPro rubber, reinforced gaskets was almost as much as the covers. Covers also did not come with bolts, and the old ones were too short with the rubber gaskets. The Cloyes timing cover with external cam button adjustment was way more expensive than any other cover, and it didn't even come with bolts or gaskets.

I also had to buy a few new tools, like a Proform valve spring compressor that would work with the new dual springs. The cheap spring compressor you can borrow from the parts stores will not work on heavy dual springs. You need the spring compressor if you want to swap in lightweight springs to use when you check for pushrod length or degree the cam.

After I got done I found that my Quadrajet was running too lean for the new combination, so I called Cliff Ruggles (Cliffs High Performance) and he put together a set of new jets, rods, and spring to make a better match. The new combination works much better, but my AFR gauge shows it is still on the lean side. When you move more air you need more fuel. The Blueprint heads are drilled for dual intake patterns, so I used the Edelbrock performer intake I already had.

Bottom line - new combo starts and runs well, and runs a nice 190 degrees even with the A/C on in hot weather. Power is very good at light and moderate throttle (lots of torque), but I think more carburetor tuning will increase the power at higher RPM. It may just some tuning of the secondary spring or the APT. Engine has a slight performance sound at idle, but not enough to satisfy the rump-rump fans in the parking lot.

Bruce

 

[Daveo91Burb]

If you're swapping engines another option is to start with an 87-95 TBI SBC. The truck engines didn't have rollers (but the cars like Caprice did) but the majority if not all were prepped to accommodate rollers, i.e. the holes are drilled and tapped for the spider plate and the cam retainer. And they still have mechanical fuel pump provisions (at least all the ones I've seen do). Then you have some more, possibly cheaper, options for cam selection. Or you can do what I did and get a vortec core engine and took the cam, lifters, spider/retainers, etc. And then I sold the short block for a few bucks and almost got my money back. That option wouldn't work if you need the mech fuel pump lobe though.

 

[shiftpro]

Mine is a daily driver, and I used a Howards retrofit roller cam with 213/217 @ .050 duration. Good for my 4WD truck, but milder than many folks might use. I also installed Blueprint H8002K aluminum 64cc heads and Summit full roller rockers. Heads had the right valve springs for the new cam and with thinner gaskets it brought the crate engine's low compression up about 1.2 points. Should be running about 9.4 compression now. Cam allows use of stock fuel pump and distributor gear.

I think I ended up spending about $2300 total, when you add in all the gaskets, sealer, nuts and bolts, and other parts I replaced (i.e., I put a hole in my old radiator and had to buy a new aluminum one).

Some of the simple parts can get expensive. I bought relatively cheap Summit tall valve covers to clear the full roller rockers, but then found out that a good set of FelPro rubber, reinforced gaskets was almost as much as the covers. Covers also did not come with bolts, and the old ones were too short with the rubber gaskets. The Cloyes timing cover with external cam button adjustment was way more expensive than any other cover, and it didn't even come with bolts or gaskets.

I also had to buy a few new tools, like a Proform valve spring compressor that would work with the new dual springs. The cheap spring compressor you can borrow from the parts stores will not work on heavy dual springs. You need the spring compressor if you want to swap in lightweight springs to use when you check for pushrod length or degree the cam.

After I got done I found that my Quadrajet was running too lean for the new combination, so I called Cliff Ruggles (Cliffs High Performance) and he put together a set of new jets, rods, and spring to make a better match. The new combination works much better, but my AFR gauge shows it is still on the lean side. When you move more air you need more fuel. The Blueprint heads are drilled for dual intake patterns, so I used the Edelbrock performer intake I already had.

Bottom line - new combo starts and runs well, and runs a nice 190 degrees even with the A/C on in hot weather. Power is very good at light and moderate throttle (lots of torque), but I think more carburetor tuning will increase the power at higher RPM. It may just some tuning of the secondary spring or the APT. Engine has a slight performance sound at idle, but not enough to satisfy the rump-rump fans in the parking lot.

Bruce

Great post Bruce, thanks.
Would you agree most of the usable power your enjoying is coming from the head swap? And the additional compression...
I'm hesitant to use a retro roller for a daily driver I would hope to get 100K miles out of. So I really appreciate hearing from folks with experience running
rollers on daily drivers. These old blocks as I understand do not have the lifter bore tolerances the modern roller blocks do. Also the issue of depth of
lifer bores... at least in BBs. I haven't questioned this regarding SBs...
As I see it, the only real practical advantage performance wise is a quicker opening/closing valve allowing longer duration... but longer duration isn't what
we're looking for in a torqy daily driver. Higher lift? Well this is always nice but with the lifter bore depth/alignment accuracy in question would this not
be risky?
Bruce you chose a relatively tame cam, so I would guess you didn't go roller thinking some magical performance gain. Please expound you reasoning behind this obviously pricey upgrade. Oh and BTW, I'm not criticizing your choice by any means...
The other thing is the added weight of a hyd roller lifter... again with the intention of daily driver for 100K or more miles... hmm. Yes the rollers create less
rolling resistance but does the extra weight negate this advantage when desiring years and miles of service?
Remember there still are high mileage engines out there running today with factory flat tappet cams. The reliability of the flat tappet cam can not be disregarded.

Slightly off topic but I want to add, I would never recommend a retro roller to avoid the pains of breaking in a flat tappet cam!

 

[Rusty Nail]

*Buy a roller block ...

Lol?

 

[75gmck25]

I definitely don't have the max horsepower goal that most folks have for their 350. My truck is a 2nd/extra vehicle that I've had for the last 16 years, and I like to keep it looking good, but very functional. It looks good, and works very well as a truck whenever I need it.

My engine was originally a GM crate 350/290 HP engine ( a very mismatched compression/cam combination), and it worked well for a while. Then I swapped in a milder cam because I hoped it would improve the mixture enough to get a little better gas mileage. Mild cam was very smooth, but no real difference in mileage. I always used high ZDDP synthetic oil with the flat tappet cam

I decided I now want more performance, but to also keep the engine very usable in a truck. For performance potential, all the original GM iron heads have severe limitations, even the famed camel hump heads, so I wanted aluminum heads or Vortec iron. Even though I have 4.10 gears and stock 31" tires, the truck has a lot of mass to get moving, and I want torque to come in low so that it "feels" strong all the time. Using a cam with duration up in the high 20's or even 30-35 duration would have worked with these heads, but probably would not have improved torque in the low rpm range. I also wanted to keep stock pistons, which limited compression to about 9.4 with 64cc heads, and most high duration cams need more compression to work well. I want power/torque to come in low and stay even, and the cam I chose has those characteristics. I think this cam/head/compression combination is a good match for what I want.

The reason I spent more money than necessary on a roller cam is that its my hobby. I've looked at this stuff for years, but this was the time to try it out. I also wanted a really reliable engine, and the roller cam and full roller rockers should give me a low friction combination that holds up really well. I don't plan to rev it that high very often, so the extra valve train weight should not be an issue.

I estimate my current setup is running about 330 HP, limited by my stock exhaust manifolds and mufflers. If I swap in long tube headers and 2 1/2" pipes I should be at about 350-360 HP, and all that power will come in early and have a flat torque curve.

In retrospect, I should have looked harder at the Blueprint Vortec 350 crate with roller cam for $2,600. I could have just dropped it in, added a Vortec intake, and saved a lot of time hanging over the engine compartment working on my engine.

Bruce

 

[shiftpro]

The reason I spent more money than necessary on a roller cam is that its my hobby.

Great point... it's not always the destination, it's the journey too.
Appreciate your comments sir.

 

[73c20jim]

And please don't tell my wife. lol.

 

[shiftpro]

I used a Howards retrofit roller cam

Did Howards recommend a minimum idle speed?

 

[75gmck25]

The cam I used is the Howard's CL110235-12 - 213/217 @ .050, lift 0.485 int./0.495 exh., LSA 112, and I'm using 1.5 ratio rockers. Its power range is advertised as 1000-5000 RPM.

I have it idling at about 700 rpm in Drive, so power comes in almost right off-idle. When idling in Park at about 900 RPM I have about 18-19" of vacuum. I never asked Howard's for a recommended idle speed. I set it at 900 in Park, 700 in Drive because it still works fine if I turn on the A/C. I like to be comfortable.

Timing is 12 degrees BTDC initial, and 20 degrees more from mechanical advance, all in by 2500 rpm. I use manifold vacuum and a near-stock HEI, so vacuum advance adds about 18 degrees at idle or during cruise.

Bruce