just rebuilt runs bad

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I'm having trouble grasping this. Gonna take some time I think. It's not a matter of accepting or not accepting what you guys are posting, I just want to to be able understand. Thanks.
 
kman521 said:
Maybe this info will help.
http://www.cranecams.com/uploads/instructions/803.pdf

Or this one
http://www.compcams.com/technical/instructions/files/145.pdf
Click to expand...

I was able to follow the article. Thank you.

My set up presents everything bass ackwards. If I convert, the intake has just closed at tdc, it started to open at 10 BBDC, and therefore has a duration of 190, all in very rough terms. Which is still totally wacky. Now with a better understanding, I'll have to try again....


Intake:
At TDC compression stroke the intake is closed, stays closed a full revolution (360 crank degrees) then starts to open at TDC, full open 95 degrees, full closed 190 degrees, goes past TDC then begins open 360 degrees later at TDC, full open 95 full closed 195, goes past TDC then begins to open 360 degrees later at TDC, full open 95, closed 190, etc…..

 
Time to step back for a couple of days to regroup and enjoy the holiday season.
:D

Green1 had a good point about having the dial indicator on the shoulder of the lifter because after turning the engine over manually for quite a while the hydraulic lifter can bleed off pressure so having the dial gauge on the tip of the rocker you might not be seeing when the cam is actually starting to lift.

Cheers,
 
I'm guessing you might be a little sketchy on the anacronyms. This might help even tho it is a little general:
In regard to the cam card degrees...
The engine has 360° of intake valve cycle that spans two strokes. The intake opens After Top Dead Center on the exhaust stroke and closes After Bottom Dead Center on the intake stroke. Bottom Dead Center (either BBDC - Before Bottom Dead Center or After Bottom Bead Center) means the piston is down at the bottom of it's travel, and is the 180° mark on your tape lining up with the timing cover "0" mark. The intake valve closes After Bottom Dead Center at the beginning of the compression stroke. As before, Bottom Dead Center is going to be the 180° lining up with the zero mark.
The exhaust valve cycle also has 360° that spans two strokes. It opens After Bottom Dead Center of the power stroke and closes After Top Dead Center on the exhaust stroke.
You have to keep the four cycles in mind when you read the cam card and track the number of degrees as you turn the crank and count.
 
Here is my take on it. Don't try and add up the numbers to compare total duration, focus on the opening and closing events. When you do the math see how many degrees before or after the 0 and 180 marks the valve opens or closes. From your number I get this.
Int open at 0' BTDC should be 34' BTDC off by 34.
Int close at 10' ABDC should be 66' ABDC off by 56.
Exh open at 25' BBDC should be 78' BBDC off by 53.
Exh close at 25' BTDC should be 30 ATDC off by 55.
I assumed the 135 number you wrote should be 335 to make it closed just before TDC. Even though your method is not machine shop perfect it is very good to show a consistent difference that indicates that other than that exhaust closing number, they show the cam is retarded 34-56 degrees.
If you try again, try the dial indicator on the retainer not the roller.
 
Thanks guys. Christmas and family are in full swing now. So like someone suggested, I'll probably set this aside for a day or two.

Looks like there is good info that was left today for me to absorb (if I can sneak away every now and then) :)

Merry Christmas!

Duff
 
Uh, why are we checking the cam timing at the valve and not at the lifter? Are not the timing opening and closing events, as listed on the cam card, referenced at .006" lift at the lifter?
 
IQ52 said:
Uh, why are we checking the cam timing at the valve and not at the lifter? Are not the timing opening and closing events, as listed on the cam card, referenced at .006" lift at the lifter?
Click to expand...

Understand what you're saying. Thanks. Just going for "ball park" readings, trying not to disturb anything the machinist assembled. He's suppose to be coming out to take a look soon.
 
Great info on post #207,208, and 209. I followed it, but for me I'll have to read read it another dozen times (and I will) before it starts to click (no pun intended).
 
If I'm understanding correctly, I only need to go as far as the intake valve starting to open at TDC instead of 34 BTDC to know that something is not right. All the other readings simply confirm it.
 
6tfo said:
If I'm understanding correctly, I only need to go as far as the intake valve starting to open at TDC instead of 34 BTDC to know that something is not right. All the other readings simply confirm it.
Click to expand...

That's correct, as long as you are on the shoulder of the lifter with the dial indicator so you eliminate any hydraulic lifter leakdown it will be close enough.
You know for sure you are seeing the cam lift when you are on the lifter shoulder because the lifter is resting right on the cam lobe.
 
Thanks 67Dart, that might have been me. I tried to post it here but it needed review as I am a new member. It is the best one I have found and shows exactly the events around TDC and BDC that I believe are the problem here.
 
My machinist came out today and agreed that the #1 intake valve was not opening where it is suppose to.

We pulled the motor and laid it in the back of his truck. He'll take it back to his shop and go through it thoroughly. He apologized and said he would make it right. When complete, he'll bring it back and help put it back in the car and hang around until it's running the way it should.

Life happens. I can only hope things go smoothly from here. I really appreciate everyones support on this.

One thing I didn't tell you. The very first time I found TDC I used a #2 pencil. After finding TDC I removed the pencil but the eraser and aluminum casing stayed behind in the cylinder. It took us two weeks to get it out and I ended up having to buy a borescope to find it. It was stuck to the bottom of the head.

Again, life happens.
 
its good to hear that they are taking care of you.let us know how that new motor runs when you get it back in the car.
 
Good to hear you have made positive progress. All the way through this thread I kept thinking "no good builder would make a timing mistake like that" but it appears that is exactly what happened.
 
That's good news! :cheers:

I don't think it's too often that an engine builder would make that mistake if they degreed the cam. I'm willing to bet the original timing set would have worked too.
I guess another positive is you learned something along the way.

Let us know how it runs once it's back in the car.
 
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