Cam install troubles.

J

jerrad

Member
Joined
Aug 21, 2004
Guys,
I installed a roller cam a while back and the car ran like crap and popped under load. I pulled the pushrods out and they were 8.050. I called the person I got the cam from and they said I should have 8.200's in there. I bought the 8.200's and installed them about 30 minutes ago and now the car wont start. It sounds like the valves are staying open 100% of the time.

When I crank the car it spins very fast and thats it. Does it seem like my pushrods are now too long and not letting the valves close fully?
Thanks for any help.
 
Did you use a adj pushrod on initial setup for proper valve tip geom and lifter preload to get the proper size pushrod?

Every car is different due to machining, gaskets, gasket squish, decking ,etc.
 
jerrad said:
Guys,
I installed a roller cam a while back and the car ran like crap and popped under load. I pulled the pushrods out and they were 8.050. I called the person I got the cam from and they said I should have 8.200's in there. I bought the 8.200's and installed them about 30 minutes ago and now the car wont start. It sounds like the valves are staying open 100% of the time.

When I crank the car it spins very fast and thats it. Does it seem like my pushrods are now too long and not letting the valves close fully?
Thanks for any help.
Click to expand...

Why would you buy anything without checking to get the correct length?
 
jerrad said:
Guys,
I installed a roller cam a while back and the car ran like crap and popped under load. I pulled the pushrods out and they were 8.050. I called the person I got the cam from and they said I should have 8.200's in there. I bought the 8.200's and installed them about 30 minutes ago and now the car wont start. It sounds like the valves are staying open 100% of the time.

When I crank the car it spins very fast and thats it. Does it seem like my pushrods are now too long and not letting the valves close fully?
Thanks for any help.
Click to expand...

You can answer your own question if you like and do a leakdown test. But like the other members said you should definitely check for proper geometry with an adjustable pushrod tool. It does sound kind of like things are hanging open. I would be careful this is one thing you want to avoid as piston to valve contact can be troublesome.

Good luck
 
Mad_Trbo said:
You can answer your own question if you like and do a leakdown test. But like the other members said you should definitely check for proper geometry with an adjustable pushrod tool. It does sound kind of like things are hanging open. I would be careful this is one thing you want to avoid as piston to valve contact can be troublesome.

Good luck
Click to expand...

Using a pushrod checker will not correct a geometry problem. If the geomety is off he will need to raise or lower the rocker arms.
 
jerrad said:
Guys,
I installed a roller cam a while back and the car ran like crap and popped under load. I pulled the pushrods out and they were 8.050. I called the person I got the cam from and they said I should have 8.200's in there. I bought the 8.200's and installed them about 30 minutes ago and now the car wont start. It sounds like the valves are staying open 100% of the time.

When I crank the car it spins very fast and thats it. Does it seem like my pushrods are now too long and not letting the valves close fully?
Thanks for any help.
Click to expand...

make sure your degree the cam.If the cam is 180* out it will pop under load and run like crap..and valves won't open and close properly.you won't have compression in some of the cylinders and that's what it will sound like..
 
87buickracer said:
make sure your degree the cam.If the cam is 180* out it will pop under load and run like crap..and valves won't open and close properly.you won't have compression in some of the cylinders and that's what it will sound like..
Click to expand...

Lol. It will fire through the intake:eek:
 
Thanks for all the help guys. Looks like I'll get a checker and figure out the proper length. Does the motor need to be a tdc when I do this or can it be anywhere?
Thanks
 
Checking pushrod length is a time consuming proposition.

When ever I build a customers engine, I always measure every intake and exhaust. It ensures that you get the proper preload on all lifters.

I recommend doing the intake and exhaust on all cylinders.
 
87buickracer said:
make sure your degree the cam.If the cam is 180* out it will pop under load and run like crap..and valves won't open and close properly.you won't have compression in some of the cylinders and that's what it will sound like..
Click to expand...


how do you put a cam 180 deg out?
 
I assume you don't have an adjustable valvetrain...

Adjustable roller rockers are worth their weight in gold. :cool:
 
I'd like to get some but I don't want to throw money at it and it not fix anything.

Does anyone know if having the wrong length pushrod would cause the popping?
 
jerrad said:
I'd like to get some but I don't want to throw money at it and it not fix anything.

Does anyone know if having the wrong length pushrod would cause the popping?
Click to expand...

yes
 
I'm about to measure the pushrod length and have a quick question. Does intake/exhaust valve need to be in any particular spot before I measure or does it matter?
Thanks
 
How do you get there? I turned the motor until the intake valve just started to open and measured at that point.

Also, the pushrods that I installed first have about 15 miles on them and the ends are already bare metal. Does that sound like they're too long?
 
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