Cam Timing advise

[Linear Six]

I just finised building my engine and find the power less then expected. I firmly believe I have a timing \ Cam issue.
This is what I have, 200cid with 79 head milled to give 10.2:1 compression, flat top pistons, crane electronic ignition with the stock dizzy (points removed and subbed with photo transistor) Clifford Dual headers, 2" pipes with pacemaker exhaust, Webber 2 barrel dgv progressive carb, Clifford 272 cam and valve train to match with 1.75 and 1.5 valves, Yella Terra full Roller rockker assy, fully ported and polished head, dual roller timing chain and a port divider.
I would like to have good low end torque and moderate top end. What are some suggestions for Cam timig, how much or little cam advance should I degree my cam at. What would be a good starting point for dizzy timing setting.Can some one help me??

 

[xctasy]

Please be really carefull. If it has a rope seal, it will be very latharic for quite a few miles. There are also some basic running in teathing problems like exhast leaks or carby vaccumm leaks which can drive people nuts before they push on through. Once it's run-in, then you can start looking at the cam and ignition.

Steve Knott, a race builder of great touring cars in Australia, found that newly dynoed 430 hp 5 liter V8 engines would be producing up to 10 HP more after a 621 mile race than when tested before. All because of clearances and the need for components to 'get it on'.

If its had 1000 to 2000 miles, then check this:-

The conversion from non-electronic to electronic causes an intial timing retardation for some reason. The ignition advance must grow savagely from a low level of initial advance to about 32 degrees, no more. I'd keep vaccum advance, don't go to full mechanical. The dissy needs to be retuned on a Sun machine. The very best way is to first lock the ignition, and dyno tune it. Then degree the cam. It may need to be advanced or dialed back at the cam.

I'd personally never replace a cam until the donky work on dyno tuning the ignition, and then the cam. There is a litmus test is cranking psi. It should be no more than 180 psi, and no less than 130.

It is very expensive to just change cams if you consider that this means front cover, balancer and and still not getting any joy. If you do it right, and just do the ignition first then you may hit pay-dirt! If not, then you'll find that advancing the cam may help.

If all the stuff is there, then look at other avenues. The valve pockets, if inserted, could be very rough. If the cam is mechanical, changing valve lash will help.

 

[MustangSix]

Cam timing should be set to match the cam card.

Production machining variations in the block will naturally cause the relationship between the cam and crank to vary. The main idea behind adjustble cam gears is to be able to match the cam spec to the crank position.

As a first step, I would get a degree wheel and a dial indicator and figure out how your current setup compares to the cam manufacturers spec. You may be spot on or you may be way off.

Knowing that, you then have a starting point to make adjustments. But if you try to proceed without that, you will have a harder time of it.

 

[Linear Six]

Well I have roughly 1000 miles on it now. The dissy is from a 1968 200 with both Mechanical and vaccum advance. The cam and valvetrain is all hydraulic. The car idles well, and starts excellent. When I received my cam from cliffy, the data did not match what I had measured using the degree wheel, I had a buddy of mine check timing on the cam and he too had the same results (had the timing gears set at zero). I found it to have as much as 12 degrees of advance. While the paper work indicates 6 degrees.

 

[gotta61comet]

I thought I read in the FSPH, that timing sets varied through the years. Your cam timing can vary depending on the year the timing set was designed for. I think the later six cylender cam gear was degreed differently to accomodate tougher emmission standards.

I could be WAY off the mark here. Feel free to correct me if I'm wrong (my wife is an expert at it)

Jim

 

[80broncoman]

Did you measure the degrees of duration at .050 tappet lift to make sure the spec card and cam are the same grind?
I think this is a good idea to make sure it was not marked wrong or misboxed.
You probibly already know most all spec cards are in crank degrees.