i just put the cam in and buttoned everything up its backfiring and will start for a sec and dies. I think we messed the timing up i need a second opinion and if you think it is the timing how do i set the timing we tryed to set it but we didnt pull the oil pump and is there a dot on the front of the crank gear? do we need to pull the oil pump off or what anykind of help will be greatly appreciated

 

you can see without taking the oil pump off...kinda hard though it has to be absolutely perfect dot dot....it sounds like your a tooth off or so....are you sure your wires etc. are hooked up well? i wouls check all that stuff before going back in the motor

 

You need to put the dot on the crank sprocket at the very top, and the dot on the cam gear at the very bottom, so they point at each other.

You may have bent valves, take it apart and try again. May also do a compression test.

You dont need to do anything with the oil pump. Not related.

Good luck

 

whoa whoa... you put it all back together and have been running it and you don't know if there's a dot on the crank sprocket? I would suggest the following...

1) do NOT start that thing back up
2) pray you didn't F anything up
3) Yes, there definitely is a dot on the crank gear. Tear it back down and line up the dots (crank gear dot at 12, cam gear dot at 6).

Should have used this tutorial... http://www.ls1howto.com/index.php?article=23 . However, it's not too late to start now!!

 

Agree 100% with this. Did you line up the cam dot to the bottom on the old cam before you took it out, then put the new cam in this way? If so, you may be OK and you may have just not got a coil pack plugged back in good. However, if you didn't know there was a dot on the crank gear and just put in the cam, then I'm betting you bent some valves. If you are just a tooth off one way or the other, the car will run fine, it just won't make as much power. If it won't run, then you most likely smacked some valves or bent some push rods.

 

Agree 100% with this. Did you line up the cam dot to the bottom on the old cam before you took it out, then put the new cam in this way? If so, you may be OK and you may have just not got a coil pack plugged back in good. However, if you didn't know there was a dot on the crank gear and just put in the cam, then I'm betting you bent some valves. If you are just a tooth off one way or the other, the car will run fine, it just won't make as much power. If it won't run, then you most likely smacked some valves or bent some push rods.

 

another thing to remember. If it is backfiring through the exhaust then its a wiring problem. If it is backfiring through the carb, t/b ect...then it is mechanicle. Hence not dot to dot and so fourth. These rules are always good to follow.

 

 

What we did was before we pulled the stock cam, we got the cam gear dot at the bottom. I didnt see a dot on the crank gear. so we just marked the crank gear with some white out. I didnt hear any knock when we turned it over, and it does start for about 2 secs, then it dies.

 

You are probably pretty close then. That's really good to hear. I bet it's electrical, but it wouldn't hurt to take the water pump and front cover off again just for piece of mind. Also, you may want to check your rockers and make sure they are tight. Did you use loctite on the rocker bolts? What about the springs? What springs did you go with? How much lift does your cam have? What length pushrods did you use?

 

The prob was they had a ground wire behind the driver side head. It fired right up after that. The cam is HPE S Cam. 605 lift crome push rods. Springs were Rev Double Springs, Dont' know what kind of length.

Thanks For All The Help

*Always remember to check your grounds before you pull the timing chain.

 

Glad you solved it, there for a while it sounded BAD. How did this ground become disconnectd for just a cam swap? Or did you swap or pull heads as well?

 

I'm wondering the same. Camshaft timing is the most important timing there is! This is especially true while running a bumpstick the size of the S cam. I was about to congratulate you on destroying your first LS1!

Are you positive you diddnt rotate the crankshaft after you pulled the cam sprocket off? I sure hope you diddnt screw the goat on this one.

 

Bumpstick?? I call it a boogystick!

He's right though! If I were yousI'd check that gearing again just to be 100% safe!

 

That first post was pretty scary.

 

if it was me, i'd be pulling the timing cover worried sh**less.

 

I was also going to ask if he rotated the crank, but he did mark it, so that is just as good as dot to dot.

 

We did pull the timing cover off and checked the timing again. The dot was just kinda hard to see. Its was right on though. That ground was on the back of the drivers side head and it bolted on the e.g.r. We took it off to get the valve cover off and didnt put it back in becouse it was too hard to get to and at the time we didnt know there was a ground wire there. It was turning the fuel pump on and off for some odd reason. But once we regrounded it, the car fired right up.

 

Yeah, that dot is hard to see, you have to wipe any oil off first, then you can see it pretty well. Glad you got it worked out.

 

When doing my camswap and having to line up those dots, it never really struck me untill I was doing it.

"Hey if this is wrong, the worst thing that can happen is it destroys the whole shabangabang" -

I had like 6 people look at it to make sure it was correct. I rotated the crank 360 and checked top to top, rotated it backwards, rotated it more and rechecked, had someone else do it and check it themselves.... I was a bit nervous.