racing cam = no more power !?

[hydroli]

Hi everybody,

I purchased a racing cam from Lunati (278 dur, 112 deg) and I'm very unsatisfied. In fact, I can't see any difference after I changed it except that I have lost my low end power !? What am I missing? Should I do porting or something else before expecting a power gain...? I run an automatic transmission what doesn't help me, but I'm planning to build a racing thm200 with a 2300rpm stall. My final setup will receive a turbo, what explain the choice of a 112 degree cam. That's the project, but right now I can't see why I don't see any difference with the new cam.

Does anyone can help me a little?

[Preston32]

is this a dirt car or drag car?

[DOCTOR FIELDS]

Alot of factors can cause a loss of power when installing a racing cam.

1. Is your valve train / cam geometry right?
2. Did you degree the cam in?
3. If so, please explain in detail the process you used to degree it in. Do you have it set at 112*?
4. What kind of compression do you have?
5. What is your ignition timing set at?
6. Have you checked your spark plugs? Rich / Lean condition?

I've seen so many people incorrectly install a camshaft and lose power. This is one of the most critical steps in building a racing engine.

Let us know what you got and we can help you further.
Stephen Fields

[hydroli]

This is a street car. I checked if the cam was properly instaled with a dial indicator ar Top Dead Center. I turned the cam and the valve completely closed after 2 degrees like the cam card says. Ignition timing is set at 12/14 degrees. I dont have a timing light but the numbers I'm telling you are right. I tried many carbs and if the HO carb helped a little, the car never pasted over 65mph on a flat road ! Tonight I removed the head to see if it's something wrong... I'll replace it by a low mile head (45000 miles). Maybe will it help. I'd like to try the racing cam again but I don't want to have as much problem as I had. I need a good runing car for everyday use and I want it to be the last time I open this engine before winter.

The cam seems perfect and the carb is in shape. The head only have 45'000 miles...

Would you try the cam again if you were me?

[rad15E]

i have a 278 lunati just like the one you have,this is not the best of cams for an all out race motor unless your running on a small ,tight track,the 278 duration should be strong on the bottom and give up at high rpm-don't no where the 112 came from but degree this cam in at 102 from .050 center-also if your running hyd. lifters it might calm it down even more----also check all the things doc. fields said

[hydroli]

112 is the lobe separation. What is wrong with my cam and what should've been good for me?

[rad15E]

just read that its a street car which this cam would be great for the street, you have something wrong but it sounds to me it might be something simple,make sure your not 1 tooth out on your belt its real easy to do,check all the stuf you might look over

[hydroli]

Thanks for your help rad15e but I already double checked at it, plus I tried to run it a tooth before and after the right one just for fun, but again it's at the right place. I'll try it again tomorrow and post here the results of my rebuilt head engine.

I think I'll try the racing cam again... if you think I should go stock, please let me know.

A last question for you rad15e. What would be the power band of my new cam? and what is the range of a stock cam? And while I'm at it, what kind of cams and power band are you running in your track engines? I dont want to ask for secrets, just want to compare my grind with what you call serious cams.

[DOCTOR FIELDS]

Here's some info that may help.


Step 3: Attach the pointer to the block. Many people will make a pointer out of some sort of rigid, yet
manageable wire. A stiff coat hanger wire works well.
Step 4: Attach the degree wheel to the balancer and install the assembly on the crankshaft. There are
several ways to attach the degree wheel to the crankshaft. The crank may be rotated from either the
front or from the flywheel end. Obviously, if the engine is in the car, you must rotate from the front.
Remember, the greater the leverage, the smoother the crank rotation, thus more accuracy. Note: Never
use the starter to turn the engine while degreeing a cam.
Step 5: Before installing the piston stop, rotate the crankshaft to get the #1 piston in approximate TDC
position with both the intake and exhaust valves closed. This can be a rough guess, but it can save you
from making a mistake later. Adjust you pointer to zero or TDC on the degree wheel.
Step 6: Turn the crankshaft opposite the engine rotation approximately 15-20 degrees. This will lower
the position enough to allow the TDC stop to be installed in the spark plug hole. Screw in the piston
stop until it touches the piston. Continue to turn the engine in the same direction until the piston comes
back up and touches the piston stop. Mark the degree wheel with a pen or pencil on the number the
pointer is on. Turn the engine in the other direction, same as engine rotation, until the piston comes
back up and touches the piston stop. Make a mark on the number the pointer is on.
Step 7: Remove the piston stop after marking the two points on you degree wheel. Rotate the
crankshaft to the midpoint of the two marks. This point is TDC for cylinder #1. Without rotating the
crankshaft, adjust the degree wheel to read 0 degrees at the pointer. You are now ready to locate the
intake lobe centerline relative to TDC. If you are not absolutely sure that your 0 degree mark is set at
TDC, repeat this procedure. This step by step is critical to proper cam alignment.
Step 8: Attach the dial indicator to the dial indicator mount. Position the dial indicator mount so the
tip will contact the retainer of the intake valve. It is important that the indicator plunger be parallel to
the valve stem. Any variance in the angle of the indicator will introduce geometric errors into the lift
readings.
Step 9: Rotate the engine in the normal direction of rotation until you reach maximum lift. The dial
indicator will change direction at the point of maximum lift. At this point, set the dial to zero.
10
Step 10: Back the engine up (opposite normal rotation) until the indicator reads .100.” Next, turn the
engine forward in the normal direction of rotation until the dial indicator reads .050” before maximum
lift. Record the degree wheel reading.
Step 11: Continue to rotate the engine over in its normal direction of rotation until the indicator goes
past zero to .050” on the closing side of maximum lift. Again, record the degree wheel reading.
Step 12: Add the 2 numbers together and dived by 2. That number will be the location of maximum
lift of the intake lobe in relation to the crank and piston. This is the intake centerline. For example:
The first degree wheel reading was 96 degrees. The second reading was 116 degrees. These two
numbers (96 + 116) added together will be 212. 212 divided by 2 will equal 106. Your actual intake
centerline is 106 degrees. Reference back to your cam spec card and see what the recommended intake
centerline is.
In the event that your camshaft did not degree in as per manufacturers’ specs, it will be necessary to
either advance (move the cam ahead) or retard (move the cam back) the cam to meet the suggested
intake centerline. Depending on the engine application, there are several different ways for advancing
or retarding the camshaft. A second method is to use offset
bushings that fit on the cam pin and in the cam gear. The offset will advance or retard the cam
depending on how the bushing is placed on the cam pin. A more elaborate system uses an adjustable timing gear. Contact COMP
Cams® for the method best suited to your application.
Note: When degreeing a cam, remember to look at the degree wheel as a full 360 degrees no matter
how the degree wheel you are using is marked. Many degree wheels are marked in 90 or 180 degree
increments. On wheels that are marked in 90 degree increments, keep in mind that you must
continue to count the number of degrees on past 90 degrees. Be sure all readings are taken from
Top Dead Center.
Keep in mind that to advance the cam, you must lower the intake centerline. For example, if our cam
has a lobe separation of 110 degrees. Moving the centerline to 106 degrees advances the cam 4
degrees. If we change the centerline to 112 degrees, this would be 2 degrees retarded.

[rad15E]

the lunati cam i have has a range from 2500-6000 its also on a 110 centerline not a 112,the lazer 290 cams run 3500-7500,bullitt 308 's are rated up to 8100rpm, i run the lazer 290 in my race motor--------------the cam you have should be a direct replacement if your block or head hasn't been shaved,put your timing marks on the crank at top dead center make shure your roto button is pointed to # 1, line up the 2 holes on the cam pulley and shield and it should run

[hydroli]

Thanks alot! You both helped me a lot with my little problem. I'll finish to change the head, since it's the only solution I found that will fix any possible problem, then try the cam again and give feedbacks of the new tests soon.

[hydroli]

I tried the engine with the new head and the racing cam. It was really better than it was... but again, the lifters were making noise!!! I can't figure the reason of it since that in the other engine it was very quiet. About an hour of highway from home, after desperately trying any rpm variation to help it take the lash, I tried to rev the engine higher... very high... I don't have rpm but if I refer to the sound the crank started to do after I rev it, I guess it probably went to 8000 rpm... I really am bored of al the time I passed tryin to fix this engine. It's midnght and I just dont have any idea of what I'll do tomorrow about this.
How long is it to replace the complete trans/engine assembly? Do you remove the crossmember assembly to make the procedure easier?

[Racer 33]

the noise the lifters are makin is where u have a bigger cam, my car has been doin it for a year or so,.. usually it takes us 25-50min to pull a motor and trans, and we never took the cross member off the trans when we pulled motors unless we was goin to reuse it on a different trans

[hydroli]

Ok for the cross member, but I was talking about the part that will attach the two front wheels to the frame. I'll know for the trans. cross member, thanks. For the cam noise, does using mechanical lifters will help for this? I'm planning to replace them for mechanical.

For the rest, I'm near to put my other old engine in the car. The worn out with the lunati cam is out. I won't put the cam in the car before I have finished my turbo setup with all the mods done to the engine (high pressure oil pump, mechanical lifters, lunati cam, turbo, modified carb...). I'll go stock for a while.

By the way, does anyone have a thm200 that will fit a 1.6?

[rad15E]

get rid of that auto trans, every mod you do to the motor will be eaten up in it ,get a 4 or 5 speed and change it over