Cam advice for more torque from 340

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BTW, the FSM's often have the WRONG torque number for the rocker shaft hold-down bolts. Take them ONLY up to about 20 ft-lbs.
 
A 262 or 268 is going to have miles of clearance unless something seriously messed up.
 
The method 1 is to put a piece of clay on top of the piston, install the head and rotate the engine CAREFULLY by hand so that the piston compresses the clay against the valves and head. You can then slice the clay and measure the thinnest spot to see how much room there is. So the way I did it was to pull the lifters for intake and exhaust on piston #1. Mine were hydraulic lifters and disassembled with a snap ring. I filled the interior with bee bee's to simulate being pumped up with oil. I then reinstalled them. I installed and torqued down the head with gasket on that side, pushrods, rocker shaft with rockers for that piston. Put a nice long bar on the crank bolt and SLOWLY turn the engine 1 rotation. If you feel any resistance, stop. After 1 rotation disassemble and measure the clay.

Another method if you have a spring compression tool and dial indicator is to remove the springs on the intake and exhaust on the #1 piston. Go to your local hardware store and get a couple light weight springs to replace them with temporarily. Then prepare and install the lifters like method 1, pushrods and heads with gaskets like normal, and set up a dial indicator on the valve stem end. As you rotate the engine you can stop periodically and depress the valve till it touches the piston and measure the distance as you go around.

You will find the tightest clearances don't happen at top dead center. As the piston comes up with the valves closing, and as the piston drops after TDC and the valves start to open will be the tightest clearances. If you decide to install the cam advanced or retarded to change the rpm power band these clearances will change and can become much more critical. It might sound complicated but its much better than having the piston kiss the valves. There are a lot of different opinions on what is minimum clearance.
 
Will I be able to see the difference between the new 268 and the old 285?

Reason I ask, these look like the same f'ing cam to me.

Everything, except the markings on the rear.

The new one says Comp and the part number. The old one just says Z016 or 2016.

I'm fuming right now.
 
Get some calipers and measure the lobes, short and long side, subtract and multiply by 1.5. That should be a close guess at lift.

If the old cam is a 285, I'd bet it's similar to the old 230-480 camshaft. Most of the aftermarket had cams in the 230-235 range and 475-485 lift. A Comp 268 has the same basic lift with a little less duration at .050 which should settle down the idle a bit.

I think you should have done other things to make what you have work using a degree wheel/dial indicator and getting more initial timing on it. You are in too deep now to go back.
 
crackedback said:
Get some calipers and measure the lobes, short and long side, subtract and multiply by 1.5. That should be a close guess at lift.

If the old cam is a 285, I'd bet it's similar to the old 230-480 camshaft. Most of the aftermarket had cams in the 230-235 range and 475-485 lift. A Comp 268 has the same basic lift with a little less duration at .050 which should settle down the idle a bit.

I think you should have done other things to make what you have work using a degree wheel/dial indicator and getting more initial timing on it. You are in too deep now to go back.
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Way too deep now to turn back.

Regarding the cam key. Am I supposed to reuse the old one or get a new one? Neither my timing set or the cam came with one.

The old one is not budging.
 
The height being the same simply says that the lift is the same; the duration can be quite different. And we don't know how you are measuring the height; the 'height' of a lobe peak versus the rough cast core has no meaning. It is the height variation of the lobe peak (toe) versus the lobe heel relative to the center axis of the cam that sets the lift. The way Crackedback explains the measurement will get you close if you are accurate and use an accurate caliper.

And I doubt you can pick up the duration differences with the eye, unless you have looked at a lot of cams! Even then it would be tough for <20* difference in duration, because the shapes of the cam lobes before and after the lobe peak (the ramps) will be quite different for different cam series'.

Why fume about it? Without taking accurate measurement data with a degree wheel and dial indicator, you can't know what the old cam is just by looking at it. At least now you KNOW what cam it has. The 'Z' sometimes shows up in Crane cam part numbers, but I have not been able to find a 'Z016' cam ID.

The cam keys usually are a tight fit (interference fit). Use a small drift or chisel from the back and tap it out of the slot in the old cam.
 
Try to tap it out with a small chisel ,then smooth the burrs with sone sort of grinder or go to the local hardware or auto parts for a new one.As far as the cam you cant tell by looking what it is , but at least you know what you have now.
 
Thanks guys.
I'm have the timing chain installed. Behind that is the cam hold down plate with the drip rail. I torqued those to 210 insh lbs, or 17.5 ft lbs. then I installed the timing chain with the o pointing toward each other for stock timing.

Then I installed the fuel pump ring and camshaft bolt. I used blue lock tight on the bolt and torqued to 35 ft lbs.

Next I am going to put in the lifters in 6 and 1 to see which one is firing to make sure my distributor gear is set correctly.
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Ok. Now on to the timing cover. Can I do the water pump separately or do I need to do these at the same time?
 
Separately is OK. Just get the right length bolts in the right holes.

Just make sure you can place a straight edge center-to-center on the crank and cams and have the dots aligned right on that edge. It is easy to get a tooth off. It looks good in the pix.... but looking at a pix is not the same as being there.

Makes sure you lube up all the cam lobes and lifter bottoms liberally with the supplied lube.

Have you read up on the proper break-in procedure? What oil are you using? That is important.
 
nm9stheham said:
Separately is OK. Just get the right length bolts in the right holes.

Just make sure you can place a straight edge center-to-center on the crank and cams and have the dots aligned right on that edge. It is easy to get a tooth off. It looks good in the pix.... but looking at a pix is not the same as being there.

Makes sure you lube up all the cam lobes and lifter bottoms liberally with the supplied lube.

Have you read up on the proper break-in procedure? What oil are you using? That is important.
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Comp says to break in the cam by fluctuating the rpm between 2300-2500 for 30 min. I'm going to use conventional oil. Either the comp cams break in oil or conventional with their additive.
 
Speaking of my timing cover. I'm wondering if I should strip it down. I plan on painting the engine corporate blue again.

I have been cleaning it trying to get the surfaces clean.

Maybe even get a repop?
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nm9stheham said:
Separately is OK. Just get the right length bolts in the right holes.

Just make sure you can place a straight edge center-to-center on the crank and cams and have the dots aligned right on that edge. It is easy to get a tooth off. It looks good in the pix.... but looking at a pix is not the same as being there.

Makes sure you lube up all the cam lobes and lifter bottoms liberally with the supplied lube.

Have you read up on the proper break-in procedure? What oil are you using? That is important.
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they are straight. However, now that I rotated the crank so #1 was firing, the cam dot is now at the top of the gear.
 
So you didn't degree the cam? Not a smart thing to do. Best to verify it's installed where it should be.
 
crackedback said:
So you didn't degree the cam? Not a smart thing to do. Best to verify it's installed where it should be.
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I thought decreeing was confirming/checking that it is what it says it is. I don't see any other method of setting it's position other than with the teeth on the timing gears. O settings are aligned right now.
 
You probably dont have to degree it but to roughly verify line up the timing marks as best to straight as possible, put in both i&e lifters put a straight edge across the top of bot lifters.The intake lifter should be around .010 to .020 higher than the exh lifter when the valves are on overlap that should be 2-4 degrees advanced.
 
WSUTARD said:
they are straight. However, now that I rotated the crank so #1 was firing, the cam dot is now at the top of the gear.
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Yes, that is right.

As for not degreeing the cam, that is done a lot. The possible issue is that the cam can be a few degrees off one way or another; sprockets and keyways can be machined in error, and cams can be manufactured in error. Degreeing the cam is a process that requires tools: a degree wheel and dial indicator.

A cam being off 3 degrees will indeed change the engine response in a measurable way. Degreeing the cam is the right and best way to do it, but it takes the tools and time and so its understandable why some don't bother. In this case (ASSUMING the old cam was indeed around 285 degrees duration), the engine change is already going to be pretty dramatic even if the cam is off 2-3 degrees.

joec said:
You probably dont have to degree it but to roughly verify line up the timing marks as best to straight as possible, put in both i&e lifters put a straight edge across the top of bot lifters.The intake lifter should be around .010 to .020 higher than the exh lifter when the valves are on overlap that should be 2-4 degrees advanced.
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This is a way to at least say that the cam chain is on the right tooth. It eliminates the chance that the cam is 15 degrees or more off, but does not show that it is 3 degrees off.
 
Your wrong, on overlap usually if the lifters are equal height it has no advance if the exh is higher its retarded if int is higher its advanced.Its not exact but close,usually about .004 thou per degree of adv., so intake higher by .016 to .020 about 4 deg adv.Most dont degree but it gives you a good rough idea.
 
Anyone know what goes between the crank end and the timing cover seal? Is that space taken up by the harmonic balancer?
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joec said:
Your wrong, on overlap usually if the lifters are equal height it has no advance if the exh is higher its retarded if int is higher its advanced.Its not exact but close,usually about .004 thou per degree of adv., so intake higher by .016 to .020 about 4 deg adv.Most dont degree but it gives you a good rough idea.
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I was generally agreeing with you....and I understand what you are saying. I am not so sure of the number of thousandths per degree as you ...... lobe ramps can vary so much, as well as the difference in durations for intake vs. exhaust will change this too.
 
WSUTARD said:
Anyone know what goes between the crank end and the timing cover seal? Is that space taken up by the harmonic balancer?
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Yes. Did you put the oil slinger on the crank before the timing cover?

It is preferred to use an installer to pull the damper onto the crank snout; some longer bolts with the right thread will work. Some guys use a rubber mallet but that gives me the willies.... that's gotta be hard on the thrust bearing.

Make sure the damper bolt has the original really thick washer under the bolt's head, and gets torqued to the 135 ft-lb spec; the clamping force from that high torque is what locks the damper to the crank and allows it transfer the crank vibrations to the damper to be damped.
 
joec said:
Your wrong, on overlap usually if the lifters are equal height it has no advance if the exh is higher its retarded if int is higher its advanced.Its not exact but close,usually about .004 thou per degree of adv., so intake higher by .016 to .020 about 4 deg adv.Most dont degree but it gives you a good rough idea.
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This is correct and very close.

If you have a question on how the cam is timed (as in straight up, advanced or retarded) you can get pretty close by looking at the valves at overlap.
 
There is a hole in the front of the block, on the drivers side, where the timing cover bolts on. This hole goes into the water jacket. It is possible to put too long a bolt in there during the cover install, and it is possible to drive that bolt right through the cylinder wall. This will allow water into the oilpan and really spoil your day when you find out.
BE CAREFUL!
 
AJ/FormS said:
There is a hole in the front of the block, on the drivers side, where the timing cover bolts on. This hole goes into the water jacket. It is possible to put too long a bolt in there during the cover install, and it is possible to drive that bolt right through the cylinder wall. This will allow water into the oilpan and really spoil your day when you find out.
BE CAREFUL!
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Good to know. I used all the original bolts so I should be good. However, I will pull all the lower ones and place some thread seal on them. I didn't know hey went into the jacket.

I have the timing cover, water pump and oil pan on. I just hope nothing leaks.

Right now I'm working on assembling the rockers on my heads. The machine shop took them off when they were cleaning and checking everything out.
 
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