Big Block Chevy Rocker Adjustment Help: Ok so we are putting my dads BBC back together it is a 13 to 1, 460 inch motor with a big Crower Solid Roller. I don't have the exact specs with me at work but it is like .688 lift. I hear that due to ramp design of a solid roller that the cam should be adjusted valve by valve and not a pair of valves on any given cylinder. What is the best way to start? I believe number 6 should be ready to adjust as the cam and crank gear are set up correctly with the two dots lined up correctly. I really appreciate a step by step on how people here have adjusted their solid rollers. ie adjust number 6 exhaust, then use timing marks and rotate the motor 45 degrees then adjust such and such cylinder's intake and or exhaust. feel free to post or message me here or even better email me a step by step at SFABOSTON (at symbol) HOTMAIL.COM thanks in advance, has been awhile since we had the motor apart and want to make sure all is done correctly. Here are pics showing that it appears number 6 is ready to adjust with cam and crank gear set up.

[img]Big Block Chevy Rocker Adjustment Help: Ok so we are putting my dads BBC back together it is a 13 to 1, 460 inch motor with a big Crower Solid Roller. I don't have the exact specs with me at work but it is like .688 lift. I hear that due to ramp design of a solid roller that the cam should be adjusted valve by valve and not a pair of valves on any given cylinder. What is the best way to start? I believe number 6 should be ready to adjust as the cam and crank gear are set up correctly with the two dots lined up correctly. I really appreciate a step by step on how people here have adjusted their solid rollers. ie adjust number 6 exhaust, then use timing marks and rotate the motor 45 degrees then adjust such and such cylinder's intake and or exhaust. feel free to post or message me here or even better email me a step by step at SFABOSTON (at symbol) HOTMAIL.COM thanks in advance, has been awhile since we had the motor apart and want to make sure all is done correctly. Here are pics showing that it appears number 6 is ready to adjust with cam and crank gear set up.[/img]

 

deleted dumbass comment . Is Cylinder #1 at TDC?

There is a paper out there on how to do it...
Essentially you want to adjust each cylinder while the cam is off the ramps....
So when both valves are closed on the compression stroke.

When the exhaust valve closes you should be good. Then follow the firing order and do each cylinder in order. Im sure someone else will have more detailed expalnation.

 

I'd go with adjusting the intake as the exhaust opens and exhaust as the intake closes. (I think that's right- I get it backwards so often I have a decal on the firewall). Takes a lot of turns of the engine to get it done, but it's worked for me.

 

On a fair size solid i do them one valve at a time also the other method never once worked right for me . Suppose it depends on the cam who knows
It really doesnt take much time.

When youre done, spin the motor over a few times then double check your lash youl be 100% positive of where youre at wiht things. Then put the cover back on

 

SBC and BBC are the same firing order. This will work. Use the lash your cam requires. Big cams require this sequence since they have big overlap. This puts the 2 vaves your adjusting on the center of the base circle opposite the lobe center.

http://www.lbfun.com/warehouse/tech_...n/SBvlvadj.pdf

Probably really just need this:
http://www.lbfun.com/warehouse/tech_...adjustment.pdf

 

Use the EOIC method.
When the exhaust valve starts to open, adjust intake. When the intake valve is closing, adjust exhaust. This is the most accurate method when adjusting valves.

 

I agree, correct information up there,

Or, ICE {as intake closes adjust the exhaust}

.....EOI {as the exhaust opens adjust the intake}

And, dots together its firing on 6....the valves on 1 will be on overlap slightly off the seat

 

^^This. By far the best way.

 

I made myself a little sheet with the target lash, accurate position of each valve in conjunction with piston location, and firing order.

Sheet in hand, I was able to work my way around the engine in under 30 mins. Took longer to remove/replace fan for ratchet on crank bolt than actual adjustment.

And I ended up with a cheat sheet for exact lash so I could compare it to the next time I adjusted. Any changes quickly point to a deteriorating component in the valvetrain.

 

thanks, I have been reading about different methods.....

So what if I bring up each piston on TDC, can I adjust the intake and exhaust valve then rotate and bring another piston up?

 

The cam is not on it's base circle for both intake and exhaust at TDC. The EOIC method is really easy. With the valve cover off, just bump the starter while watching the rockers move.

 

Can we Keep It Simple Stupid....KISS? It is perfectly fine to adjust valve lash while the piston is at TDC on the firing stroke......mark the harmonic balancer......cut the top off an old distributor cap if your worried about mistakes and let the ignition rotor tell you where to adjust the valves. I'm an old fart I guess but, I have owned a series of factory solid lifter Chevys ( starting with a Z/28 302 ) since the 70s. In fact I guarantee you won't screw up the lash adjustment going by the cut distributor cap and rotor indexing method alone. There isn't a cam design on any normally aspirated motor that keeps an intake valve open very long after the piston hits Bottom Dead Center at the beginning of the compression stroke and keeps that exhaust valve closed until pretty much BDC of the power stroke, that's 180 degrees of crank rotation to find where the valves are seated to adjust lash. The other methods are just too confusing and easy to SCREW UP!

 

You poster need to really go and study the operation sequence of an Otto cycle engine......the cam is definitely on the base circle at TDC on the firing stroke.....IN FACT! It is on the base circle from pretty much 90 degrees of crank rotation BEFORE and AFTER TDC of the power stroke. If the valves weren't seated you would get back firing either on the intake side or exhaust side when the fuel mixture was ignited

 

YES! Absolutely you will be able to adjust your valves with the piston at TDC on the firing stroke.....remember the piston goes to TDC 2 times on a 4 stroke ( Otto cycle ) motor.....if it is not on TDC the intake AND exhaust valves are slightly opened.....the exhaust valve is almost seated.....the intake is just starting to open....this is the overlap event that gives big duration cams their lopey idle sound.

Pull a valve cover and rotate the motor.....watch the valve action, you will see what is taking place. Lash them at TDC on the firing event.....TDC on the firing event can be checked by pulling a spark plug and plugging the hole with your finger, it will build pressure because both valves are seated and ON the base circle.....at TDC adjust the lash. I can adjust valve lash in less than an hour start to finish on my motors.

 

On the firing stroke yes. But why make this so difficult? The EOIC method works, is foolproof, and is MUCH simpler to remember. You can have your opinion and I have mine.

OP, since there's more than one way to do this, everyone will form their own preference. Here is a good article on the different methods:

http://www.hotrod.com/how-to/engine/ccrp-0702-camshaft/

 

X2

The EOIC method is easier to remember and you really cant screw it up. You can bump the starter to get the engine into the correct position, but I prefer to remove the spark plugs and turn the engine over by hand using a breaker bar on the crank.