i need help w/duster engine

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Bill that is the best way to check but those BTDC and ATDC numbers I gave earlier are where the least amount of clearance is going to be measured so no need to check all around. Minimum valve to piston clearance doesn't happen at full lift.
 
I realize that what you said is true (about where to check for clearance) and I also am sure you're right about the maximum valve-lift position not being, necessarily, where the least clearance would occur.

Thanks for that information!!! Maybe I didn't to too bad.... beginner's luck????? :read2:
 
Bill Dedman said:
I don't want to hijack this thread, but as a novice engine builder, I made the mistake of bolting on my heads before I checked the valve-to-piston clearance, and had them torqued and didn't want to take them off, if I could find a way to check the clearance in some other way.

Here's what I did. I'd like to know if this is a viable way to do this...

I bought some very weak (VERY weak) "checking" valve springs and installed them on both valves, for one cylinder. I had already degreed the cam, so I positioned a dial indicator on a magnetic stand, over the retainer/rocker arm, and put a long breaker bar on the socket in the center of the crank, and turned the engine over VERY slowly, and when the crank position was getting close to where valve-to-piston interference might possibly occur, I set the dial indicator to zero, and used physical pressure (it didn't take much; the springs were very weak, as I said) to push the valve further down until it touched the top of the piston, noting the distance beyond where the cam had positioned it. Then, keeping minimal pressure on the valve, holding it gently downward, against the piston, I had someone else very slowly, turn the crank, and watched the dial indicator closely, to ascertain the minimum amount of valve clearance I'd have at ANY crankshaft position, on both sides of the cam lobe, and on both valves.

As it turned out, it had beaucoup clearance on both valves (dished pistons and a cam that only lifted .525"), but is there any reason why Melissa couldn't use this method, if she gets all her other problems ironed out?

I am asking... I am advocating nothing... just here to learn from others' experience. I have NO experience with this, beyond what I just told you, so any comments and advice will be welcome.

Thanks for listening.:read2:
Click to expand...

I did that on my 5.0 Ford. Worked for me. I would be careful on a motor w/ domes. As Bill said, SLOWLY turn it. The edge of a valve could just nick a dome and, OUCH it.
 
Melissa,
the only way to get an accurrate distance is to do what's called claying the piston. You remove the head and take regular modeling clay and flatten some out so it is about 1/8" thick and goes accross the valve pockets and a little of the dome (flat surface). Then you remove the heavy valve springs from that cylinder's head and replace with light weight checking springs. The replace the head. rotate the engine slowly by hand and the valves will open and close with the cam as if the engine were running, making marks in the clay. After both valves have openned and closed, pull the head and measure the clay thickness and THAT is the true piston to valve clearance. I agree with the above posts. A roller cam is NOT a drop in regardless of what you read or want. It needs to be carefully done or you'll need a completely new engine when the parts come apart. Also, the new member here OU812 has the best drop in lifter for small block mopars.
 
i am not sure what to say about some comments..:munky2:

i havent read all of them...yet...just reponding to a few.for now.
this is a complete running engine..its still in my duster..
I want to change the cam....Right? already said this....lol
there is no way i can pull the motor...My father isnt even thrilled that
i want to change it... but he's not here right now...
So if i can do my home work..and get the parts all ready..
then he wont be able to say..no...
even if he did..as long as i can do it...then thats all that matters..
Now i need some help ..
Can someone explain to me why i have to take the engine apart..?
i guess if i have to ....then i have to?
is there no way i can figure this out with the engine the way i have it now?
it was running ..until i pulled the intake off....
I will go back and read more of the post's now....
Mel....
 
I know what claying is...we did it to our.Whaley terminator outlaw engine.
ok a couple of things......
i am not sure...what i read so far...
i cant put a roller cam in this because i have stock length valves..?
and i wont be able to run enough spring pressures.?
what if i dont go .600" lift...like chepstreet duster said..?
Am i just stuck with this..?
Again maybe i am missing something..but why cant i get the data in need
by measuring the valves with the head still on?
i can do a measurement at 25* before and after if i need to..some one mention'd that?
aarrrrGGG....?
Mel...
 
Originally Posted by Bill Dedman
I don't want to hijack this thread, but as a novice engine builder, I made the mistake of bolting on my heads before I checked the valve-to-piston clearance, and had them torqued and didn't want to take them off, if I could find a way to check the clearance in some other way.

Here's what I did. I'd like to know if this is a viable way to do this...

I bought some very weak (VERY weak) "checking" valve springs and installed them on both valves, for one cylinder. I had already degreed the cam, so I positioned a dial indicator on a magnetic stand, over the retainer/rocker arm, and put a long breaker bar on the socket in the center of the crank, and turned the engine over VERY slowly, and when the crank position was getting close to where valve-to-piston interference might possibly occur, I set the dial indicator to zero, and used physical pressure (it didn't take much; the springs were very weak, as I said) to push the valve further down until it touched the top of the piston, noting the distance beyond where the cam had positioned it. Then, keeping minimal pressure on the valve, holding it gently downward, against the piston, I had someone else very slowly, turn the crank, and watched the dial indicator closely, to ascertain the minimum amount of valve clearance I'd have at ANY crankshaft position, on both sides of the cam lobe, and on both valves.

As it turned out, it had beaucoup clearance on both valves (dished pistons and a cam that only lifted .525"), but is there any reason why Melissa couldn't use this method, if she gets all her other problems ironed out?

I am asking... I am advocating nothing... just here to learn from others' experience. I have NO experience with this, beyond what I just told you, so any comments and advice will be welcome.

Thanks for listening.
Click to expand...

I did that on my 5.0 Ford. Worked for me. I would be careful on a motor w/ domes. As Bill said, SLOWLY turn it. The edge of a valve could just nick a dome and, OUCH it.
Click to expand...

Ok ...i sorta did this...only i set the piston at 10* before...then i open'd the valve from the seat all the way open till it hit the piston...and i wrote down the measurement.....thats where my numbers come from.
INTAKE VALVE (standard lenght 2.02 mopar)
.323" @ 10* btdc
.305" @ 10* atdc
.645" max lift to coil bind (with piston out of the way)
exhaust valve (standard length mopar)
.395 @ 10* btdc
.360 @ 10*atdc
.665 max lift to coil bind (with piston out of the way).


Mel...
 
Bill Dedman said:
I don't want to hijack this thread, but as a novice engine builder, I made the mistake of bolting on my heads before I checked the valve-to-piston clearance, and had them torqued and didn't want to take them off, if I could find a way to check the clearance in some other way.

Here's what I did. I'd like to know if this is a viable way to do this...

I bought some very weak (VERY weak) "checking" valve springs and installed them on both valves, for one cylinder. I had already degreed the cam, so I positioned a dial indicator on a magnetic stand, over the retainer/rocker arm, and put a long breaker bar on the socket in the center of the crank, and turned the engine over VERY slowly, and when the crank position was getting close to where valve-to-piston interference might possibly occur, I set the dial indicator to zero, and used physical pressure (it didn't take much; the springs were very weak, as I said) to push the valve further down until it touched the top of the piston, noting the distance beyond where the cam had positioned it. Then, keeping minimal pressure on the valve, holding it gently downward, against the piston, I had someone else very slowly, turn the crank, and watched the dial indicator closely, to ascertain the minimum amount of valve clearance I'd have at ANY crankshaft position, on both sides of the cam lobe, and on both valves.

As it turned out, it had beaucoup clearance on both valves (dished pistons and a cam that only lifted .525"), but is there any reason why Melissa couldn't use this method, if she gets all her other problems ironed out?

I am asking... I am advocating nothing... just here to learn from others' experience. I have NO experience with this, beyond what I just told you, so any comments and advice will be welcome.

Thanks for listening.:read2:
Click to expand...

I did my "Brand-X" motor the exact same way. It's been 5,000 miles and no problems. Oh, and quite a few passes at the track.
 
mopar melissa said:
I know what claying is...we did it to our.Whaley terminator outlaw engine.
ok a couple of things......
i am not sure...what i read so far...
i cant put a roller cam in this because i have stock length valves..?
and i wont be able to run enough spring pressures.?
what if i dont go .600" lift...like chepstreet duster said..?
Am i just stuck with this..?
Again maybe i am missing something..but why cant i get the data in need
by measuring the valves with the head still on?
i can do a measurement at 25* before and after if i need to..some one mention'd that?
aarrrrGGG....?
Mel...
Click to expand...
You can use stock valves ona roller cam.
You could get the data by using checking springs and leaving the heads on. Check piston to valve every 2° from about 100 crank ° before TDC on the exh stroke to about 100° past TDC on the intake stroke. Somewhere in there is the closest point. Or just pull the head and turn it over once with clay... In any case, roller cams are not simply drop in in most cases. Your impatience and youth is really showing right now. That's a good way to hurt parts.
 
I think she is doing well,wish I had her patience.A lot of replies are pretty far removed from her question,I still don't see why her idea won't work.
 
i have all the patience i need...the racing season is over for me..
the car is in the garage just setting....\
I know my dad....he is busy running a business and dealing with my brother.
if i wait for them to get around to it....it will be summer and my car will still be setting right where it is right now.
The rep from Doug Herbert said these lifters will drop in with no machining..
should i not believe this....?
My lifter bores are indexed and bushed....but they are not oil restricted...
that should take care of it....if not..i need to do more home work.
(which by the way i got a ton of already....plus volleyball practice)
i am gonna order the checking springs..but my brother will have to pull them as i he's got more muscles...
i only need to do #1 piston hole right...?
just pull/keep the pushrods out on the rest...?
Mel..
 
green1 said:
Yeah, clay it while the heads are off, valves hitting pistons is expensive.
Click to expand...

arggg...I am not taking the heads off...i am taking the springs off..

I swear..you guys are just like the guys at the track...they tell me to put
a ford engine in it or a chevrolet engine in it... Pa-LEASE?





mel.
 
Melissa I could be way off here but it seems to me that if you bring your cam to max lift then that is where the piston will be at max lift,then check your clearance with the dial ind.that will be the clearance for that cam,knowing this you should be able to stack measurements and arrive close to a # for the other set-up.I don't think the motor knows or cares if you use clay or not after it will be the same measurement.
 
Don't take the heads off, clay is NOT an accurate measurement. Checking springs and a dial indicator are the only truely accurate method but 100*? Not necessary use my numbers they came from Engle cams and I have a much more radical cam than the roller you are looking at.

The long valves are because the stock A valve installed height is only 1.65". This is not enough to allow for the stiff valve springs (think thicker coils and triple springs) that are needed for the roller cam to function properly. Any spring strong enough to handle the roller will be coil bound at .600 lift if it's installed at 1.65". This is basic physics, two pieces of matter can not occupy the same space at the same time.

If you want to improve the ET of your car I can recommend several things to do, the first would be better heads, and by that I don't mean Edelbrocks. Indy's, W5's, B1BA brodix, W2's, large port Commandos, etc., there are a bunch out there before you get into exotics like the W8 or W9.

Head flow is where the horsepower is. The more air and fuel you can pump through the motor the more power it will make. That's why larger cubic inch engines make more power, they can pump more.
 
bigdemo1 said:
Melissa I could be way off here but it seems to me that if you bring your cam to max lift then that is where the piston will be at max lift,then check your clearance with the dial ind.that will be the clearance for that cam,knowing this you should be able to stack measurements and arrive close to a # for the other set-up.I don't think the motor knows or cares if you use clay or not after it will be the same measurement.
Click to expand...


This is dangerous advice my friend, minimum valve to piston clearance does NOT happen at max valve lift. In fact it happens on the intake as the piston is going down and the valve is opening. On the exhaust side (this is why they recommend more clearance on the exhaust valve) the piston is coming up as the valve is opening but minimum clearance is still not at max lift because the valve is already closing as the piston approaches.
 
what am i missing? what event in a motor can put the piston closer than top dead center? if the valve is opened till it hits there and measured from seat and clearance is added how can it ever hit? Maybe you could run more lift due to event timing, but tdc clearance cannot be less right?
 
bigdemo1 said:
Melissa I could be way off here but it seems to me that if you bring your cam to max lift then that is where the piston will be at max lift,then check your clearance with the dial ind.that will be the clearance for that cam,knowing this you should be able to stack measurements and arrive close to a # for the other set-up.I don't think the motor knows or cares if you use clay or not after it will be the same measurement.
Click to expand...
The valve is closed at TDC. The intake hits because it is still not closed, before TDC. The exhaust hits for basically the same reason- overlap, and it is still closing; 114, etc.
 
I think this wouldnt work because at tdc your valve could barely open without hitting and the lift you,d calculate would be way under actual lift capacity.
 
daredevil said:
what am i missing? what event in a motor can put the piston closer than top dead center? if the valve is opened till it hits there and measured from seat and clearance is added how can it ever hit? Maybe you could run more lift due to event timing, but tdc clearance cannot be less right?
Click to expand...

You can't possibly put valve reliefs deep enough in a piston for .600+ lift with the piston at TDC. The top ring groove would end up 1/2" down in the cylinder and the tops of the pistons would have to be more than 1/2" thick.
 
daredevil said:
what am i missing? what event in a motor can put the piston closer than top dead center? if the valve is opened till it hits there and measured from seat and clearance is added how can it ever hit? Maybe you could run more lift due to event timing, but tdc clearance cannot be less right?
Click to expand...

because the intake valve starts to open as the piston leaves tdc..
if the cam profile opens the valve faster than the piston is pulling away
it will strike the cam..on intake stroke.
on compression stroke the intake valve may stay open after bdc..
its prolly more critical on the exhaust stroke as it keeps the valve open to the very last minute as the piston comes up.. the exhaust valve closes..
i dont want broken parts..thats why i am asking the question...

I was hoping someone had used these pistons before and already did this...?

as far as heads..i have W-5's but my brother say's they are his... i also have commando heads..but no one knows anything about these..
My grandfather ported these..but he isnt doing it anymore..his neck and back and hands cant take it..
he said I could do it....but my hands get froze...besides..i just dont like doing it..
my heads flow 266 cfm up to .500" and some more after that..My dad ( i just spoke to him on the phone) said he will find the sheet..
or my grandfather might have them..
Mel
 
the whole thing that started this. is..
if the heads potential at 266 cfm..(this part confuses me, is it 266 CFM?)
or is it supposed to be 2.66?
anyway..
if i do the math..266cfm head flow should give me 547hp ...pontentially..
i am only seeing 496 hp...sooo.. I think that if i get the cam correct i can get 547 hp...(rwhp)
Right..? I mean its technically there...
Mel.
 
I still don't get this ,if the valve is open all the way then how could it be open anymore regardless of where the piston is,your clearance is your clearance the cam and crank will come to a point where both will be at max stroke/lift in relation to each other,but not necessarily at the same time just because you have .508 lift doesn't mean you have it at TDC if the valve is opening then the piston is moving the valve only hangs open for a few degrees of crank this is why it gets checked.I still say that if you bring your assembly around to max.lift then check how much you can drop or push the valve into the cyl.that is your clearance at max.lift only,now with the dial on the stem rotate the crank +/- degrees you will know how much room you actually have.
 
BTW the question was piston to valve clearance not what type of valves/springs/lifters should I buy.
 
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