Any advice on how to convert a hydraulic flat tappet to a roller? I know there is something to do with feeler guages and conversion kits but I don't know whats involved. I wanna change it out because rollers are supposed to be more efficient, make better power, and get better gas mileage. I'd really appreciate somebody walking me through it kinda step by step. What has to be done, changed, and how to do it. Thanks for any advice you guys can give.

 

You need: roller cam (~$300), retrofit roller lifters (~$480), shorter pushrods (~$100), a cam button (~$10), and likely new valve springs (~$100). Solid roller cams make even better power more reliably(which is why I use one), and cost about the same too. As long as you use screw in studs for the rockers and a stud girdle, there will be no issue with adjusting lash.

 

Efficiency, power, reliability - these are easier to get with the RIGHT cam choice, and cheaper too, than just converting to a roller cam. Its the design/profile of the cam that determines these properties moreso than the lifter type.

The two main benefits of a roller-lifter setup are:

1 - You can use a cam lobe with a MUCH more aggressive ramp rate, which means the valve will open up faster and stay near max lift longer before starting to close. This will make more power than a flat tappet cam with similar duration specs. The downside, is that much stiffer valve springs are required, which can be hard on other parts.

2 - Friction. Engine oils today are just another EPA strangled product, and doesn't work as well as it used to. Especially with hi-perf flat tappet cams that use heavy valve springs. The roller wheel on the lifters pretty much eliminates this problem, which is why all the OEMs are using them. Theres also no required break-in for a roller cam (solid or hydraulic). Put it in and start it up.

 

Typing up a step-by-step would end up being really long because there are so many things that have to be removed and re-installed, depending on your body style and year.

I suggest you do a Google search and Tech Tips to see if anyone's posted a write-up. I could do it for you, but MAN what a lot of typing! It's second nature to those who've done it before, but for a first timer it would be best to have a friend who's walked that road to spend a couple of days with you while doing the job.

Now that I'm older, I break up a cam change into two days: tear down and installation of cam on day one and buttoning everythig back up on day two.

Jake

 

It's not that hard. It's obviously more difficult (time consuming) if it's being done with the engine in the car.

How large of a cam that can be run depends on what heads are being used. Feeler gauges only come into play for solid rollers. You will probably be just fine with a hyd. roller.

As for the step by step, In the TBI section, under LT1 cam digest, there's a pretty good walkthrough. I typed one up once upon a time, saved somewhere I could find. It's probably posted here, if you searched for it.

Edit: I found it. http://home.comcast.net/~stekman/Cam_swap.doc It's a word document. Read that.

 

Thanks man. I am gonna pull the engine to do the cam. I'm not gonna run a huge cam even though I got the heads for it. I want a fairly smooth idle and plenty of vacuum. I had the cam thats in it ground for the engine when it was gonna go in my vette, so the cam was ground for a stock tuned port engine, so it makes all it's power low down and according to COMP won't be stable over 5,000 RPM. I just think it could be a little better without that unusual grind. and if I'm gonna change it anyway, why not swap to an H. ROLLER while I'm at it.

 

Here are the cam specs for the cam I have now. As well as the specs on my heads as well. It might come in handy for anybody wanting to build a tuned port stroker. With this grind you don't even have to reprogram the cars ECM. And the engine makes 475HP, ( dyno proven ), at the crank. A good cam for this type of build.
Cam specs

GROSS VALVE LIFT: INTAKE-.500, EXHAUST-.494
DURATION AT .006 TAPPET LIFT: 260 INTAKE, 272 EXHAUST
THESE SPECS ARE FOR CAM INSTALLED AT 109.0 INTAKE CENTERLINE
DURATION AT .050: INTAKE 216, EXHAUST 223
LOBE LIFT: .3130 INTAKE : .3090 EXHAUST
LOBE SEPERATION 113.0

Head specs


Patriot Performance 190cc bare specs

Part # 2177 straight plug, 2176 angle plug
Aluminum 356-A
23 DEGREE VALVE ANGLE
INTAKE VOLUME: 190cc
CHAMBER VOLUME: 64cc
INTAKE VALVE SIZE: 2,02'' + .100''
EXHAUST VALVE SIZE: 1.60'' + .100''
5 ANGLE VALVE JOB
4140 STEEL RETAINER
RAISED GUIDE PLATE
VALVE GUIDES: MANGANESE BRONZE

These heads are AWESOME! my friend baught a set of edelbrocks at about the same time as I got mine. After comparing the two it was obvious the Patriots were way better. He sent his back and ordered some like mine. I'll back these heads any day.

 

I had a set of those heads and they did perform well.
That cam is smaller and less agressive than a stock 5.0 mustang cam!(maybe a small exaggeration)I am sure it will run well and you will definitley have good idle and vaccum, but the problem I see is that it is designed for factory roller lifter, which are a heavy poor design, and because of this, the lobes on the cam are just slightly more aggressive than a typical hydraulic flat tappet. And less agressive than a solid flat.
I am sure the cam would work, but if you have to pony up for all the other parts of a retrofit roller kit, then you might as well use a cam that will take advantage of the superior design of the aftermarket lifter.
I would get a cam of similar duration, but an extreme energy of the same size will: have more valve lift, produce better vaccum, idle smoother, have more tourqe, and make more horsepower, and all this out of a hydraulic roller cam!

Dont take my word for it, call comp cams cam help and compare the specs of your cam to one of there extreme energy RETROFIT cams and ask them what kind of difference there will be.
Unless this cam is ground to take advantage of the factory ecu and tpi, which now that I more carefully read your post, i see it is. So this is probably about right.

 

After reading my last post I realized that I wasn't very clear about the cam specs. Those specs are for the hydraulic flat tapit cam that is in the engine now. And it was ground specifically for a TPI althought I did install one six roller rockers. I wanna replace it with a hydraulic roller that would be more suited for the car now that it is carberated instead TPI.

 

I have a hard time beleiving that tiny little cam, which is smaller than the LT4 hotcam, made 475hp. Did you actually see the printout? Even GMs LT4 upgrade set - hotcam, springs, roller rockers, intake, and heads - only rated at 425hp, and usually only lived up to about that. And the design of the LT4 chambers is quite a bit better that those heads, and the ports are 195cc.

475hp seems awfully optimistic for that little cam. Not bashing you, just find it hard to beleive.

 

link youll need

theres all the info youll need in this thread and its sub links

 

Let me get this straight. You have an engine that was originally TPI? What year?

 

I have an 85 TPI vette. When I built the engine I was going to put it in the vette. I bought the bare block from a machine shop. I checked the numbers on the block and it was made at a mexico plant as a replacement block for factory warranty replacements. The book I got with the number info said the mexican blocks were good castings. But I don't know anything other than that about the block. I don't remember what year the block is.
Anyway, its a 4 bolt main with a two piece rear main seal. I installed an eagle rotating assymbly, then put patriot heads on it, and ordered the intire valvetrain from COMP. The cam was ground for a tuned port.
After the engine was built I stared hanging out with a guy who owned several 3rd gens and I kinda got the bug for one. He knew where an 84 Z/28H.O. with a blown engine for sale was. It was dirt cheap, I had a brand new engine sitting on the stand so I went to the parts store, got an edelbrock intake, flowtech headers, and Holley 770 street avenger, took off the tuned port, installed the new stuff, took it to be dynoed, took it back home and installed it and I was driving. And YES with the intake and carb it makes 475 on the dyno!!!! I saw the sheet. Now I will admit that I know nothing about dynoes, But I do have the sheet that says what power it makes. I don't know what it actually makes at the rear wheels. The guy was surprised it made that kinda power too. He said he had never seen a cam that small make that kinda power! I think it has something to do with the whole assymbly being put together by COMP. It must be more efficient. Or the dyno guy doesn't know what he's doing. LOL. I do know It runs extremely hard. THAT CAR WILL HAUL ***! The only thing I have tried to run and lost was too a 2007 Z06. I got my *** handed to me on that one. LOL.

 

OK, you don't believe. LOL. How much do you think its supposed to make? Honestly, I open to input. I won't try to say I know for some kind of fact it makes 475. I had it dynoed, the dyno sheet said 475, so I believed it. Especially knowing for a fact how fast the car is even with a tranny that won't shift into 4th at WOT. I've taken down a couple of C5 vettes, a 440 bigblock 73 challenger, my own C4 vette(with my friend driving it), a NISMO 350Z, every kinda Mustang including a 08 with a 100 shot of NOS. and a 4th gen SS. I give my word this thing RUNS.

 

I would be perfectly open to anybody showing me how much power they think I have and some facts to back up their claim. I would honestly like to know with 100% certainty what it makes, but there are no chassis dynoes around here and the "dyno guy" is the only engine dyno around. Madison MS is not a great place for that. There isn't anybody who could program the ECM on my vette. I had to take it to New Orleans for that! There are tons of shade tree mechanics but thats about it.

I would also LOVE to know why my cam is supposed to be unstable over 5000rpm. I have run it up to 6200rpm when racing it because of the WOT issue and it was pulling hard all the time. Am I causing damage? You seam to know more about cams than I do. I know little about them, thats why I got COMP to put a package together for me. So I couldn't screw it up. LOL
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By the way, this is the first and only engine I have ever built from the ground up.

 

If the dyno sheet (engine dyno I assume?) did say 475hp, then its hard to dispute - I never said it was impossible. Its just an extremely difficult thing to do, making that much power with a cam that small, unless you are using forced induction or nitrous. I would expect a cam/heads combo like that to be around the low 400s.... something between 375-425hp, depending on induction, cubic inches, and exhaust used.

 

I was shooting for 400, but 475 was what the sheet said. I'll dig around and see if I can find it and post it here. Somebody told me that the ''dyno guy'' wasn't reliable because of the program he used. Do you know how a dyno works? Is there a way for it to be wrong? You've got me wondering now. LOL

I am worried about my exhaust. Nobody around here would run a dual exhaust for me so I have a single 3 inch exhaust with a magnaflow and I worry that its hurting my power output. we don't have a quarter mile strip so obviously I don't know what my time is either, just what I've raced against. How much power is usually lost from engine to the ground? Say if I do have only 400 what can I expect to the ground? Is it a twenty percent loss? 30?

 

I have a non roller block I want to convert to use a roller cam block is down to the bare and I will be replacing lifters and rockers to match the new cam,what has to be done to the block its a one piece rear main non roller.

 

Even though that 475 number seems to have been taken at the crank and not the rear wheels, it still seems to be too high.

There are ways for a dyno operator to setup the dyno so it gives inaccurate results. I've never read about the specific things they can do - either deliberately or by mistake - but it's often referenced in magazine articles. The articles mention about how much care was given to properly calibrating the dyno before any pulls were made.

For example, when mags run articles on an engine they built or in when doing a cylinder head shoot-out, etc., the article makes mention that the dyno setup was verified as being correctly done. Same thing when doing back to back tests on cams or when testing to see how much difference it makes when the compression ratio is changed.

In some cases the mag will let independent persons do the dyno setup just to eliminate any cause for complaint/suspicion that the dyno was setup in such a way to favor one product or another. College students are sometimes used and even the college's dyno is the one used in the runs. All that to eliminate any bias.

So, based on the other dyno results I've seen of engines similar to yours, the 475 number is way over the top. Somethings definitely wrong.

Here's what you can do: Visit the website sites of many of the better known car magazines and search they Tech section for the engine build-ups and the dyno results they achieved. Now, once you've read a lot of them you'll begin to see the normal power different engines made with different modifications.

Some cylinder companies post the dyno results for their heads being used on their engine, but those results are suspect to me. Why? Because the head company has a vested interest in showing only the best results for their product, so the numbers could be fudged. It's about marketing and, the bottom line, SALES.

Pay special attention to any engine you find that made 475HP and see what it took to make that kind of power. Then compare what they had to do with what you have.

Of course I realize you'd like to believe that 475 number is a honest number, but those of us who follow dyno numbers find the ones given to you to be suspicious. In fact, I recently read an article where a magazine dis-believed the dyno results for an engine they'd done mods to; they said so flat out.

From time to time, a guy will post some completely outrageous power number, apparently thinking we'd not be able to know they were falsified, however I DON'T BELIEVE FOR AN INSTANT THIS APPLIES TO YOU. I believe you've been victimized by the dyno or the operator.

Keep us posted on what you find.

Jake