New cam install ?'s "Help"

[Dark_5.0]

I got rid of the 90LX in favor of the cleanest 90 coupe you have ever seen.

I got my engine sitting in the garage floor and have decided to try and go with a Lunati .536 lift single pattern cam.

Since the heads are already bolted on how do I check for piston to valve clearance?

I was thinking about intsalling the cam and bolting down a few rockers and then gently turning it over by hand.

Is this an acceptable method. BTW speed density is long gone. I now have mass air

Thanks,

[Jeff Chambers]

With the heads bolted on, the only way to do it is to pop the springs off an intake and exhaust valve and replace them with weak checking springs. Then bring the piston to TDC on that cylinder and measure the available valve movement using a dial indicator. One of the bad things about this is that it doesn't show you where its contacting or how close the valve may be to the eyebrow, etc.

Doing it at you say by rolling it over gently won't do as you'll collapse the lifter an get a false sense of security. When you fire it up and the lifters pump up, you could have serious P-V issues.

[Dark_5.0]

Originally posted by Jeff Chambers
With the heads bolted on, the only way to do it is to pop the springs off an intake and exhaust valve and replace them with weak checking springs. Then bring the piston to TDC on that cylinder and measure the available valve movement using a dial indicator. One of the bad things about this is that it doesn't show you where its contacting or how close the valve may be to the eyebrow, etc.

Doing it at you say by rolling it over gently won't do as you'll collapse the lifter an get a false sense of security. When you fire it up and the lifters pump up, you could have serious P-V issues.

Thanks, thats what I get for listening to stupid people.
It turns out the guy that told me to check it like that has a solid roller cam I didnt even think about the fact that my lifters are hydraulic

I just ordered a B-303 cam at .480 lift it should be fine

[andy669]

Sorry Jeff, but the place to check P to V is not TDC. You'll have all kinds of clearance there since the valves are closed.

I use a lifter that I have 'blocked up' to make it act like a solid.

Assemble the rocker arms and pushrods, set the lifters at zero lash. With a dial indicator on the exhaust retainer rotate the crank until you see the the dial reach close to 1/2 of max lift. Push down on the retainer until you feel the valve touch the piston and record the distance traveled off of the indicator.

Different cam profiles are going to have different results so its impossible to say that you shoud check at .xxx lift. Its a good idea to check every 50 thou up until max lift.

With the cams I have checked this way, the closest point on the exhaust side was around .400, and it was around .200 on the intake.

I have a modified pair of big channel lock pliers that I use to hook on to the rocker arm and push down on the retainer, but I check at full spring pressure and take in to account some pushrod deflection. Checker springs work fine and are alot easier.

Andy

[WADS56]

Originally posted by andy669
Sorry Jeff, but the place to check P to V is not TDC. You'll have all kinds of clearance there since the valves are closed.

I use a lifter that I have 'blocked up' to make it act like a solid.

Assemble the rocker arms and pushrods, set the lifters at zero lash. With a dial indicator on the exhaust retainer rotate the crank until you see the the dial reach close to 1/2 of max lift. Push down on the retainer until you feel the valve touch the piston and record the distance traveled off of the indicator.

Different cam profiles are going to have different results so its impossible to say that you shoud check at .xxx lift. Its a good idea to check every 50 thou up until max lift.

With the cams I have checked this way, the closest point on the exhaust side was around .400, and it was around .200 on the intake.

I have a modified pair of big channel lock pliers that I use to hook on to the rocker arm and push down on the retainer, but I check at full spring pressure and take in to account some pushrod deflection. Checker springs work fine and are alot easier.

Andy

I check it allmost the same way. I replace valve springs with check springs, use a solid lifter, set it a zero lash, and I turn the engine over by hand very slow checking clearence with a feeler gauge. This way I know how much i have throughout the entire stroke.

[302 LX Eric]

Dark - why not just unbolt one of the heads and use the clay method? I used this method and it works very well.

E

[Jeff Chambers]

Sorry Jeff, but the place to check P to V is not TDC.

Absolutely right Andy. That's what I get for answering posts at 7:00am before that first cup of coffee.

I've never even attempted it with the heads on....too much of a chicken. I've always done it by claying the pistons with converted lifters just so that I can section the clay and see where the real problem exists. 'Course mine have always been set up pretty tight since we're trying to get the maximum compression out of the heads. Often times, I end up sacrificing two or three degrees of cam timing just to pick up a much needed 0.030" of PV clearance. I always try to maintain at least .100" on the intake and .125" on the exhaust.

[andy669]

Originally posted by Jeff Chambers
That's what I get for answering posts at 7:00am before that first cup of coffee.

ROFL..... I figured it was something like that. I read your reply 3 times before I replied. I know you know more than that... heheh

The only time I have tried clay I ended up putting way too much on the top of the piston and locked the motor up solid when it came up to TDC. Took me more than an hour to clean that mess up.

Andy

[fiveohpatrol]

The only time I have tried clay I ended up putting way too much on the top of the piston and locked the motor up solid when it came up to TDC. Took me more than an hour to clean that mess up.

LMAO, sorry andy, I just thought that was funny.

mainly because I can see myself doing the exact same thing

[289]

Question
I'm putting in a steeda #19 Cam with a .480 lift and putin 1.72 SVO roller rockers on that. Which I'm told that the lift will be .510 I'm putting Crane valve springs on. I was wondering is my lift going to be ok with piston to valve clearence.
Thanks

[Dark_5.0]

What heads. pistons etc... are you running.

[302 LX Eric]

Originally posted by 289
Question
I'm putting in a steeda #19 Cam with a .480 lift and putin 1.72 SVO roller rockers on that. Which I'm told that the lift will be .510 I'm putting Crane valve springs on. I was wondering is my lift going to be ok with piston to valve clearence.
Thanks

Your total lift will be .516, not .510.

Calculated as follows:

.480 / 1.6 = .300

.300 x 1.72 = .516

Lift would be .510 with a 1.7 rr.

E

[289]

i'M running stock heads and stock pistons