351 C no start ..... help

[woodsnake]

This cam?

http://www.summitracing.com/parts/SUM-K5201/

.509/.509 is a fairly healthy cam, did you change the valve springs, and check for proper pushrod length while you were at all this? How big of a Holley did you put on? A 650~ish? Did you also change the torque converter and rear gears to go with? I would think a 3.25 would be good for that cam...I would think, that 10 degree's initial is a bit retarded for what you are working with.

 

[shellbuyer]

This cam?

http://www.summitracing.com/parts/SUM-K5201/

.509/.509 is a fairly healthy cam, did you change the valve springs, and check for proper pushrod length while you were at all this? How big of a Holley did you put on? A 650~ish? Did you also change the torque converter and rear gears to go with? I would think a 3.25 would be good for that cam...I would think, that 10 degree's initial is a bit retarded for what you are working with.

Yes this is the cam, I put a 600 cfm Holley on it, yes I checked pushrod length, and no I did not change valve springs and no I did not change rear end gears yet, nor did I change torque convertor. Would the timing of 10 degrees cause the engine to act like this upon acceleration? I will go out to garage and turn dizzy a bit to see if it will help? Would I turn it clockwise or counterclockwise? I dont think the torque convertor or rear gears would?? How would the car act if I have the wrong gears? I am sorry if I am being a pain, I just dont quite understand which of the comments you made might better my situation. Once again thanks guys.

 

[woodsnake]

The info on summit's page recommends at least a 2K stall speed torque converter, and "gears"....Did you get a cam card with the camshaft? It should have had a list of other recommendations..

I think in this case, if you were to advance the initial timing to around 12 degree's, you would have some better bottom end performance. However, with out the gears and torque converter to match, you will not realize the full performance gains of your new cam. Do you have a tachometer, and a vacum guage? Two critical tools, for working on an engine with a carburetor.

Also, did you install a new timing gear set, when you changed out the cam? From here, I would think that you want the car to idle at about 750-850 rpm, in park, with your initial timing at least 12 degree's.(when setting your initial timing, be sure to DISconnect the vac advance from the distributor)

There are two small screws, on the "bottom, outside" of the metering block on the holley. After you get your timing and idle speed set, with the engine running, screw one side in, until the motor starts to idle rough, and then back out 1/2 turn. Do the same thing on the other side of the carb. The idea at this point, is to get the engine to idle with as much vacuum as possible. I.E., 18 inches, instead of 10. SBFTech.com has a real good animated vacuum diagnostic aid, to help determine how your engine is running.

The info on summit's page recommends at least a 2K stall speed torque converter, and "gears"....Did you get a cam card with the camshaft? It should have had a list of other recommendations..

I think in this case, if you were to advance the initial timing to around 12 degree's, you would have some better bottom end performance. However, with out the gears and torque converter to match, you will not realize the full performance gains of your new cam. Do you have a tachometer, and a vacum guage? Two critical tools, for working on an engine with a carburetor.

Also, did you install a new timing gear set, when you changed out the cam? From here, I would think that you want the car to idle at about 750-850 rpm, in park, with your initial timing at least 12 degree's.(when setting your initial timing, be sure to DISconnect the vac advance from the distributor)

There are two small screws, on the "bottom, outside" of the metering block on the holley. After you get your timing and idle speed set, with the engine running, screw one side in, until the motor starts to idle rough, and then back out 1/2 turn. Do the same thing on the other side of the carb. The idea at this point, is to get the engine to idle with as much vacuum as possible. I.E., 18 inches, instead of 10. SBFTech.com has a real good animated vacuum diagnostic aid, to help determine how your engine is running.

http://sbftech.com/index.php/topic,3020.0.html

If you aren't familiar with SBFtech, those guys LIVE for shaving a tenth of a second, their focus is on going fast. Also Jay Allen cams.

 

[guys72Mach1]

I hate to be the barer of bad news my brother, but that Holley 600 is too small for your engine and you are getting a lean stumble under load.

Are you running a 1850 or a 4777? If an 1850, those come from the factory with 66 jets in the primary. Generally you want to change jets in 2-3 step increments, but since you are pretty under carbed, I'd jump up to 72's and see how it runs. If it improves, then try 74's. If it improves again try 75's or 76's. I think that will be as high as you can go and I have a feeling the 74 will probably be the sweet spot, but that would get you a little improvement. all that will probably run you about $20-30 if you have to buy the jets.

Once you get there, you may try bumping your primary nozzle up to a 28 or maybe even a 31.

If it's a 4777, I may have the specs for that one to get you close, but there will be a lot of changes and if you don;t have a good stock of jets and nozzles, it's gonna cost you some more $$$.

If it was me, I'd C-list that bad boy and pick up a 700 or 750cfm Holley, which is where you should be. I know that hurts, but your options are a lot of part changes to try and fix something that you could do quickly with he right cfm carb.

 

[shellbuyer]

I have no problem trying a 750 on there as I have one in the garage, I was very scared of over carburating as the car I had previous was way too much (twin 750 s). Do you think it would do any good advancing timing a few degrees? Or do you think it is strictly a fuel issue? I suspect it is fuel beacuse my car acts just like the last car I had which was over carburated. Thanks for the help. Not sure if I mentioned but the carb is a brand new 4160 Holley, not sure what size jets are in it but I did buy it from Summit.

 

[marks73]

With what you are descibing. You may want to consider changing the valve springs to match your cam. With the weaker springs and the lift you have it may be the valves are going wide open prematurely and closing late. There should have been a spring recommendation with your cam. You can replace them in the car just be ready to cuss trying to get the air adapter in some of the plug holes to hold the valves up. :s

 

[shellbuyer]

Problem solved! I set the timing to 14 degrees and adjusted the fuel-air mixture screws on the Holley and wham! the car works like a top. It idles good, starts good and seems to work well on the road. It seems to have lots of power even with the 2V heads. I may sell these Cobra Jet heads and cam I have from 351 CJ. Anyway, once again thank you guys for all your help and input through this.

Ted B

 

[will e]

I am glad it is working out for ya.

Where you might run into some problem is the stock valve springs and stock valves. Avoid the temptation to take it over 5K. When you get into cams that support higher RPM's it is necessary for the valve springs to be a little stronger so the valve can close fast enough.

The stock valves will not handle a lot of torture. Keep the RPMS down...

 

[shellbuyer]

Thank you, yes the cam does make it want to go into higher rpms so easily! I will replace springs and valves before too long, all I wanted to see was if the stock 2V heads would work well for me, as there are many opinions on that subject. I didnt want to spend a lot of money or time on the stock heads if I was going to have to use my CJ heads, because those will need a full rebuild as they have been sitting for 30 or more years. Thanks for now and will post vid of engine, I just like going to garage to start it up... LOL!!! I love the sound... I have a little tidying up around the engine to do yet before the first car show in May. Thanks again.

Thank you, yes the cam does make it want to go into higher rpms so easily! I will replace springs and valves before too long, all I wanted to see was if the stock 2V heads would work well for me, as there are many opinions on that subject. I didnt want to spend a lot of money or time on the stock heads if I was going to have to use my CJ heads, because those will need a full rebuild as they have been sitting for 30 or more years. Thanks for now and will post vid of engine, I just like going to garage to start it up... LOL!!! I love the sound... I have a little tidying up around the engine to do yet before the first car show in May. Thanks again.