well first off if its stock it shuld be a hydrolic lifter motor... i belive that the 70 lt1 was the last of the solid lifter motors..

WARNING: DRIVER HAS ATLEAST $50 WORTH OF AMUNITION!

-83 'yoda (soon to have a 4.3v6) 5.29, dual arb's, dual stock tcase, wagoneer springs, 35" sx's

 

Make sure which lifters you have - mechanical or hydraulic - all stock 350's after '71 should be hydraulic. The only accurate way to set valve lash is the exhaust just opening-set intake, intake just closing-set exhaust method. No other way is accurate because no other way gets the lifter face directly on center of the heel of the base circle of the lobe being set. Never set the valves with the engine running, besides destroying your feeler gauges its messy and not accurate. Its more work than other methods, but you only have to do it once.

 

I didn't know there was a solid cam motor in '73. Anyway you need to find out the lash, probably from the dealer. I think it's .030".
If you set lash on the cylinder when it's on TDC be sure it's on the firing stroke, if not it will be really loose.
I've never heard of the "exhaust just opening, intake just closing" method, but it sounds good.
Yes they are loud, and will always make noise. If you want it quieter you can get a tight lash cam with .010 to .014" lash. Or like I do, run an agressive hydraulic cam with .008-.010" lash.

The valves are E-I-I-E-E-I-I-E.


Chevota

 

Thanks, I hope this does not sound too stupid, but how do I know if it is for sure solid or hydro, and if it is hydro, then my lash is .000, correct?

 

actualy, you take it to 0 lash, then preload the lifter aprox .040 ( about 1/2 to 3/4 of a turn)

WARNING: DRIVER HAS ATLEAST $50 WORTH OF AMUNITION!

-83 'yoda (soon to have a 4.3v6) 5.29, dual arb's, dual stock tcase, wagoneer springs, 35" sx's

 

Well, my firt question is, what made you think it was solid to begin with? You can tell the difference by looking at the rockers when the engine is off. If all the valves are closed, it's hyd. If there are some valves held open, it's solid. The hyd lifter will bleed out the oil and collapse from the spring pressure, the solid is of course, solid.
If you've run lash on a hyd lifter you have probably damaged the wire retainer that holds the lifter together. Eye-ball them thru the push rod holes in the head.

Chevota

 

Chevota, I know I'm about to step on your toes. But I have to express my opinion here. I do not believe the valves will close on a hydrolic lifter engine due to spring pressure and lifters bleeding down. I have many an engine with the covers off and the valves were not closed. Plus it sure would suck to start one up if you had to wait for oil pressure and the lifters to pump up enough to open the valves.
It is hard to tell a hydrolic from a mech even when you have them both in your hands. They look the same from the outside.
But like everyone said,a 73 engine won't have mech unless someone put it in there. And if this is the case, remove that mechanical and install a hydrolic. Unless you plan on turning that engine over 7000 a mechanical is just a pain in the buttski.
And just wondering why, since I'm already on your foot chevota, why would you run lash in your hyd lifters?

 

RolngThun:
Don't worry, I wear steel-toes! If you don't believe me that hyd lifters bleed down then try this, tighten one of your rocker nuts down and watch that the valve won't stay open.
If you do this with a solid cam the valve will open and say open. If the lifters didn't bleed down, then everyone who adjusted to zero lash plus a half turn (or whatever), the valves would all be held open.
And hyd usually start to cause power loss at 6K, but that depends on the cam, springs and brand lifters. Solid cams are the hot ticket in my book, but I prefer "tight lash" cams that use much less lash, maybe .012". You can also run solid lifters on a hyd cam, but the lash should be .008-.010". Any more is too hard on the valvetrain. By doing this you reduce overlap and duration, and get the bennies of smoother idle, more low-end power, better mileage, and no lifter problems at higher rpm. The loss of duration is quite a bit at "advertised" .006", but very little at .050 and on. The slow opening and closing speeds at .000 lash make unnecessary duration, and only contribute to poor low-end performance. The open/closing speeds with lash are much more agressive and help maintain a better air/fuel mixture at low R's.
The only Hyd lifters I will run are Rhoads. They will reduce the overlap and duration at low R's even further. But they do not work good above 7K. I have a 236/246 agressive lobed Hyd cam in my motor now with Rhoads lifters, and .010" lash. I will be changing it out for another Hyd grind of around 250/260 duration soon. I will also run solid lifters this time.
The performance advantage of running lash far exceeds any trouble of adjusting.
P.S. Don't run lash with a Hyd lifter that has the wire retainer clip, only use the hardened clip like Rhoads or solid lifters have.

Chevota

 

Well, being the "novice" that I am, I erroneously assumed that something that old had solid and not hydro lifters, should have done the research. Well I started it up and loosened the rocker until I heard tapping and then tightened it down until it stopped, I then tightened 3/4 of a turn but that brought the engine idle down and it stumbled, so I tightened them all approx 1/4 after the tapping stopped. The drive to work this morning seemed to be fine, 60 miles one way, so maybe I got it right this time. The reason I am concerned is that one rocker already broke while driving down the highway, I replaced it, changed oil, and got all the broken bits out. I do not want that to happen again. Thanks for setting me straight, and why would a rocker break, is this common?

 

Im really interested in all this... But i have a few questions what is the difference in a solid and hyd lifters and cams? and what the heck is lash???

/wwwthreads_images/icons/wink.gif"Your driveway doesn't count as Off-Road"/wwwthreads_images/icons/wink.gif

 

Chevota, I only have two engines laying around with hydr lifters, a 350 that I removed from a dump truck for the steel crank and a tall block with 4.25 stroke that I built several years ago. Neither engine has run in a few years, but all the valves are closed. So at this point, I have to agree with your method and idea. Basically I stand corrected.

 

RolngThun:
It's cool.. Tell me about this 4.25 stroke motor. I love modified stuff like that.


Chevota

 

That engine is really not all that special. It is a marine tall block, Callies crank, Ross pistons, oval port heads, stock intake, and I don't remember the cam specs anymore.
I built it for a rich guys motor home a few years back. He wanted more power in his RV. One trip to Florida and back and his wife gave him a choice, different engine or she never rides with him again. Seems this guy turned into Richard Petty on the highway in a RV. So he had me rebuild his original 454 to stock specs, and had me keep the tall block.
I was holding onto it with plans to build a crew cab, dually with 38's to pull my mud racer and for camping and such. But I have been happy enough with my stock 98 2500 not to bother with it.
Now dad just bought a RV with a 454, so I can imagine where it will go next. He has been eyeballing it alot.
My real pride and joy engines don't have any non stock strokes, or flat tappet cams.

 

Badbowtie3:
Sheeeze, this is a big post!
The best way to explain would be with pictures & arrows, but that won't work here.
I'll explain this assuming you know what a cam does, and the basics of a valvetrain.
A hyd lifter has a hollow center that holds oil it receives from the oil pump. The cam lobe is touching the outside, or "body" of the lifter, but the pushrod is touching the "plunger" on top of the lifter. The plunger can be pushed down into the body of the lifter, but with oil pressure fed into the hollow lifter from the side of the body, the plunger pushes up. When you adjust a hyd lifter you tighten the nut on the rocker arm 'till the rocker arm is just barley snug, then tighten another 1/2 turn or so. This extra turn forces the plunger onto the lifter a little bit. Now with constant oil pressure you will have a lifter that will maintain a "tight" (zero play) valvetrain, but not enough to effect the valve springs. Now a hyd cam w/ a hyd lifter rides in contact with the cam lobe all the way around. When the cam lobe comes along and pushes the lifter, it's really pushing the lifter body, the body is pushing the oil, and the oil is pushing the plunger. The oil does leak out of the lifter at a controlled rate, but the cam opens/closes the lifter too fast to let much oil out. The oil pump replenishes what little oil escapes before the next cycle. The plunger can go up and down to compensate for wear on the valve seats or wherever and still maintain a tight valvetrain. In fact, that’s the whole point.
Make sense so far????
A major problem in hyd lifters is at higher rpm the lifters can “pump-up”. This happens if there is play in the system from an unstable drivetrain, usually from weak springs. Like “seat bounce” when the valve bounces off the seat after closing, or maybe catching a little air off a lobe. What happens is while the valvetrain is loose for this split second, the lifter fills with oil in an attempt to fill the gap. The problem with this is when the valve is supposed to be closed now, it isn’t. It’s got that extra oil in there holding the valve open a few thousandths. There goes your power.

A solid cam uses a solid lifter, as in it does not move at all. It is basically the same as the hyd lifter, except the thing is plugged up inside with a steel insert, or machined so the plunger can't move down. With this set-up you will need some play in the valvetrain to compensate for wear and thermal expansion. This is done by simply making the whole valvetrain loose. This is done by adjusting the rocker nut down to snug, but you use a feeler gauge between the tip of the rocker arm and the top of the valve when you do this. This clearance left after adjustment is called “lash”. A common lash (determined by the cam manufacturer) is .022”, which was made by….. you guessed it, a .022” feeler gauge.
The typical solid cam itself is different because of the shape of the lobes that were ground on it. The very beginning and ending of the lobes start out very slowly in comparison to the hyd cam lobes. This is to slowly take up the slack “lash” in the valvetrain to avoid a violent collision that will damage components. And the closing ramp eases the valve down on the seat to avoid pounding the seat and valve bounce. “Tight lash” cams work on the same principle except the lash is much less, maybe .012”. But you have to keep closer tabs on your lash because when you wear down to zero it will hold the valves open, there goes the power again. Also a tight lash cam is less prone to poor performance if the lash is not exact. If you have say .015” on a .022” cam, then the valve will open slowly at the beginning of the ramp and give you the same problem a hyd cam has. If the lash is right where it’s supposed to be the cam will take up the slack, start flexing the valvetrain just about ready to open the valve, then it should hit the aggressive part of the lobe.
Running a hyd cam with solid lifters is the ticket in my book. You need to have lash .010” or less to avoid valvetrain damage. It is quieter and does not have the transition ramp for lash so you never have worry about losing power. You just have to keep an even closer eye on lash to avoid getting near zero. I’ve been running lash for 8? years now, and I have yet to find it out of adjustment. I usually don’t go more than 5K miles, but the lash is always where I left it.
I sometimes run Rhoads lifters on my cams (both solid and hyd) those are the lifters that bleed out so much oil that while it’s holding the valve open, the plunger is pushed down a noticeable amount. It’s designed to do this to reduce overlap and duration at lower rpms. This bleed-down function all but gone at high rpms because it doesn’t have time to bleed out.
Between running lash and Rhoads lifters, you can have a big cam that is very tame at idle.

Whew! my fingies r tired. Let me know if anything doesn’t make sense, or you have any questions.

And get this book! It can explain all this and much more!

Here's the book, typed as it appeared on the cover.
Motorsports International
Powerpro Series
How To Build & Modify
Chevrolet
Small Block V-8
Camshafts &
Valvetrains

By David Vizard 1992

Amazon.com. carries this book.


Chevota