I got a timing light and got the initial timing set at 12. The idle rpms are around 1100 which seem high and vacuum is now hovering around 18-19.

The break in went fine and when I changed the oil I saw no metal in it so I don't think I sheered anything. When I was just testing it, it now seems to hickup or like a light popping when I'm around 1800 rpm which does not sound right.

I got the cam cause everything I read said it had good low end since I rarely go over 3500 rpm. When I'm cruising with it now around 1200 and hit the gas you can barely tell which I find very disappointing.

Thanks everyone for all your help.

Tim

 

I did a little more tweaking and got rid of the poping. One thing I noticed is that it appears the car is pulling a lot better over 3300rpm. This is almost the opposite of what I wanted as I want the most power between 1200-2600.

Tim

 

ok, what did you do to get rid of the popping?

that cam is next to the smallest xe sereies cam comp makes and it is tiny . . if you want more bottom end that that, you can try the smaller cam . . there is no such thing as a cam that only revs to 3500 or 4000 rpm . . you could install numerically lower gears which will increase the acceleration rate.

 

When I set the carb back up I didn't put the vacumm advance line on the right port on the carb. I moved it to the ported carb and it went away. I am now set at timing on 12 and total of 34 and vacumm of around 18.

From 1200-3000 the car has almost no pull but when I break 3000rpm she really begins to pull. I was really hoping to increase down low power since Im normal cruising around town. Is the lack of power due to setup problem or did I chose the wrong cam.

Tim

 

cams are incredibly complicated, but in general, more lift increases torque if the heads are capable of handling it, which with this cam, any head will, however, the additional duration on the intake side will cause it to rev farther which could cause it to be defined as being "bigger", because in general, the more rpm an engine spins, the more hp it makes and if it makes more hp with one cam than it does with another, people tend to refer to the one that makes more hp as a bigger cam.

 

this cam is smaller and will do what you want . . i am a comp cam dealer and engine builder and have never heard anyone complain bout the cam you have being to big.

http://www.compcams.com/Company/CC/c...?csid=797&sb=0


plug your vacuum advance and leave it plugged forever or until further notice, then tell us what the timing is at idle and at tell us what rpm it reaches total timing at.

next, advance the timing 4 degrees while it is idling and see if the rpm increases.

next retard the timing back down 4 degrees.

next hold the throttle 1/3rd open and advance the timing 4 degrees and see if the rpm increases.

if the rpm increases in both cases, leave the timing there and go 20 mph in second gear for a few seconds then floor it up to 35 and listen for a slight pinging sound.

do a compression test on one cylinder if you have a gauge . . if it is less than around 135, you will get more power everywhere by increasing it but if you increase it enough, you need to run high octane/premium gas.

post the results . . i will be here all day.
.

 

So I did the test and at idle the rpms did not really change, maybe went from an average of 850- 870. When I increased the throttle 1\3 it was too hard to see if the rpms move a lot. They did not sound like they did. I did not hear pinging while driving.

I don't have a compression guage to check that.

Thanks

Tim

 

ok, it sounds like you have a low compression engine and unless you noticed and improvement in power, i would retard it at least two degrees which will leave it with 2 ore degrees than you had when you started.

if the engine turns over more slowly when it is warmed up, retard it 2 more so it will be back to its orig setting.

it looks like if you want more bottom end, you need to increase compression and/or install a smaller cam and/or install numerically higher gears.

 

So will some engines just have lower compression? I didn't do anything to the car to effect compression. What would be the optimal compression I would want to get the low end power from the cam? I guess I'm just confused if I did not change anything with compression why going from the old cam to the new one that is supposed to have better low end that I lost power.

Thanks

Tim

 

okay hold on...what transmission do you have and what rear end gear are you running?

I would expect that with that amount of duration that a cam like that would not make good power until 3000 rpm

Was your total timing above 50 or 60 before you got a light on it?

if you are running a t5 with 2.75 gears that would be an issue

-Gun

PS do you have the actual grind number for that cam so i can look at the cam card?