michal@

hi.
I bought, Z303 cam.
I Degreeing and Cam (wheel test) and the intake valve to piston clearance is very small. .002"

specification shaft;

intake opening; 7 * BDTC
closing intake; 41 * ABDC
exhaust opening; 51 * BBDC
exhaust closing; 3 * BTDC

I degree stock position cam 1 tooth left, and the result;

intake opening; 9 * ABDC
closing intake; 57 * ABDC
exhaust opening, 35 * BBDC
exhaust closing; 12 * BTDC

clearance cam 1 tooth left .090"

Will there be any loss of power in my engine? or more problems?
Please help

sn95_331_GT_ yellow

so whats the question?

yes, a Z cam with stock pistons will cause PTV issues

1 tooth back is a REALLY stupid idea, the proper way to do it is to get an adjustable keyway set, retard by 4*, and install a set of 1.7 rockers if you want to use the stock cam...

hope this helps, but still have no idea what the question was...

mjr46

what heads are you using?? also an adjustable timing set will be needed to advance or retard when ptv issues occur

michal@

I use AFR 185cc heads 2.020 intake and 1.60 exhaust valve.
I'm sorry but my English is not the best.

I have a Ford Racing adjustable timing, I want to move the camshaft in order to have a break pistons PTV, but I do not know how to set the timing marks on such timing;

http://www.summitracing.com/parts/FM...B302/?rtype=10

mjr46

if you have stock pistons , you'd be wise to notch the pistons or else if you retard or advance the cam timing to avoid ptv then performance could suffer if the valve events are not at the optimal setting.

michal@

I LX 1988 engine with forged pistons
OK, I advance the cam timing 2 *
PTV is 0.2 "

later
advance the cam timing one tooth is PTV ,090 "can not be a tooth back?

sn95_331_GT_ yellow,
why a tooth back is a REALLY stupid idea?

sn95_331_GT_ yellow

1 tooth back will be alot more than 4* which is probably about what you need, thats all.

it would just completely mess up the valve timing events and run REALLY bad...

michal@

I'm sorry, but I do not understand

whether it is associated with the balancer marks and ignition. ?
or how I go back one tooth, it will be bad camshaft position of the crankshaft?

.boB

Advancing and retarding the cam has been used to fine tune an engine for many years. That's why so many gear sets have differant slots for the key way.

Advancing the cam will move the power band down a little. And retarding the cam will move the power band up a little. Usually about 300-400 rpm's; so it won't make a huge differance. You might see a small gain or loss in total power, but it's so small that you'de need a dyno to see it.

You should use a crank gear with multiple slots for accuracy. If you simply slip the chain one tooth on the crank gear, you could get a variable amount of timing change. By looking at the numbers you posted, you advanced your timing by 2*. That's not a problem, and it seemed to work out for you. Since it measures out well, I would not change it. Run it as is and it will be fine.

AdderMk2

im pretty sure you have the cam timing mixed up .bob

isnt it retard the cam to increase the power band rpm range?