cam shaft specs

[Alss]

Hey everyone..have a question/problem. Bought the 69 Z 28..small block 302 solid lifter,all stock but it does not have the stock cam in it.I have no specs for the cam [img]<<GRAEMLIN_URL>>/frown.gif[/img]..no card, part number, make , grind etc. Sounds a little noisey, and I want to adjust them but with no cam card..what do you do? [img]<<GRAEMLIN_URL>>/dunno.gif[/img] Tried measuring the existing lashes but they are so all over the place I dont know where I would start!..plus the numbers I'm getting are what i would consider tight on my BB..avg of .010-.012 intake and .017-.020 exhaust..normal for a Small Block? I do know that it is NOT a stock Z 28 replacement and it is smaller. Previous owner wanted better drivability, and it does run well..but not like it should. I was hoping the valve lash may restore some power. I know I'll wind up putting a cam in it, just saving it for last on my option list. [img]<<GRAEMLIN_URL>>/smile.gif[/img]

thanks

[KenMaisano]

Very first thing is to make sure it is Not a Hydraulic camshaft. Put a valve at max lift and gently tap the pushrod area of the rocker arm with a rubber mallet. Then turn the crank just to close the valve and see if the rocker arm is spring loaded. If so go to .000 and a half of turn preload. If it is a Solid Cam set at .020 .020 and you will be fine. My guess is it's a Hydraulic.

[ssl78]

How long ago was the motor rebuilt some of the new profile solid cams have a much tighter valve lash than the older ones.

[Lynn]

That's a tough one. Hate working on the unknown.
When you say &quot;smaller&quot; do you mean less duration, less lift, or both?

I would start with Ken's rec, making sure it isn't hydraulic, and if it is solid, go .020 / .020 just to start.

If you are into playing averages, if it is a solid lifter cam, there is a good chance that it is a 178 cam, as that was the most popular replacement for many years. Lash on a 178 is .024 / .030.

[Verne_Frantz]

Al, Since they all had some lash, I doubt it's a hydraulic cam but there's another way to check for one. Set up a dial indicator on the valve spring retainer. With the valve closed, turn it down to zero lash then give it another 1/2 turn or so. If they're hydraulic, the valve will open first, then as the oil bleeds out of the lifter the valve will come back up and you'll see it on the indicator. IF they're solid, the indicator won't budge after you let go of the wrench.
I'm not familiar with solid lifter small blocks but if it's a solid cam, make sure the exhaust lash is at least .020&quot; if not more. It's important to let the exhaust valve stay closed a bit to let it give off some heat to the seat.

Verne [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

[Plowman]

Don't forget you could have RHOADS Lifters and are variable-duration lifter also they reduce lift at idle{very hard to check out}. Hope this helps because that is what I found on a unknown car.

[Alss]

All good points:

cam is definetly a solid lifter..no hydraulic or roades lifters.
motor was done 15 years ago or better...still 11-1 domes +.030
cam is smaller..prob less lift and duration
valves have never been adjusted to my knowledge since motor was new!
I will try the 20-20 lash on monday and see what it brings.
thanks everyone!

[Salvatore]

I think an LT-1 cam is smaller. Maybe that is the cam they used. 1970 saw the Turbo 400 trans used in the Z/28. Maybe it is an LT-1 stick.

[Alss]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: [email protected]</div><div class="ubbcode-body">I think an LT-1 cam is smaller. Maybe that is the cam they used. 1970 saw the Turbo 400 trans used in the Z/28. Maybe it is an LT-1 stick. </div></div>

thats a possibilty Sam..thanks!..I'll check it out and see what specs it calls for.

[Alss]

Not it Sammy [img]<<GRAEMLIN_URL>>/frown.gif[/img].

OK..enough fooling around. I'm putting a cam in it. [img]<<GRAEMLIN_URL>>/headbang.gif[/img]