Compression & Ignition Question

Robert

0.078" Valve clearance is not enough which could mean the cam is advanced too far.
The cam is actually ground 4 degrees advanced with the timing gear at 0*.


However you cannot assume correct timing simply by installing it according to the timing gear.
It is very important that you check the timing using a degree wheel.

The following thread shows a detailed procedure for degreeing your cam.

http://www.v8buick.com/showthread.php?t=220945

Sorry for the confusion. When we said to install the cam 4* advanced, what we meant was install
the timing gear at 0* and check to see if the cam is 4* advanced.

Thanks for posting you progress.

Paul

 

Sorry paul but now im very confused...

I tell u what i did.

1. I put the cam in
2. i put the crank in
3. With an indiactor set up, I use it to find the uppermost travel of the piston.
4. Than i put the 9 Keyways rollermaster timing gear on the crank on +4 Advance position.
5. Than i put the chain over the camgear and mounted on the cam like on the picture.

How i can mount the cam gear on the cam with 0 degrees but with +4 advanced? Or u mean with timinggear only the gear on the crank?
But the gear on the cam i can only make change with the teeth right?

thanks

Robert

 

Robert try to degree it where it is at. With the crank gear 4* advanced. Here's why.
Most cams are ground so if you install it staight up (0) the intake lobe will degree to the recommended centerline (usually 4* advanced).
However when using a Rolmaster timing gear set 4* advanced is what (0) is on other brand double roller timing gear sets.
Confused? This is why you should degree a cam. There are many machining steps that may cause an error. By degreeing the cam you will know where the cam is.
With your 118 LSA if you want it 4* advanced you will want the intake lobe centerline 114*.
Ray

 

I would like to know who was using the desktop dyno program? That system is way off, There is a program that is much better then Desktop dyno, http://www.jegs.com/i/Comp-Cams/249/181501/10002/-1?parentProductId=1200813 This is within 10 ponies and 10 ft lbs of trq. There is alot more primeters to be fofulled in this one to get very close to your goal. I use this one when I get time to.

 

Robert

Do just what you did except put the 9 Keyways rollermaster timing gear on the crank on the 0*position.

The cam is ground so that it is 4* advanced when you install the timing gear on the crank at 0*.

Do you have a degree wheel?

Like Ray said you must check the intake lobe center to make sure it is at 114* ATDC.
Then check to see if the exhaust lobe center is at 122* BTDC.

Do this exact procedure using your cam specifications:

http://www.v8buick.com/showthread.php?t=220945

Let us know if you still need help. This has to be right for the project to work as planned.

Paul

 

Ray & Paul thanks for your advice. Now im in the military and i'm only at the weekends at home. I try to work this weekend.
First what i will do is degree the cam. Is intake ATDC not 114* i will set the timing back to 0* and measure again.

Thanks for your support Ray and Paul, i need really ur help!

Robert

 

*Update*

The timing gear was set on +4* on crank. So i put a dregee wheel on the crankshaft and locate the highest point of the piston and set the degree wheel to 0*. Now i turn the crank to the point where the cam has fully open the intake valvle. I mark this with zero on a special tool, wich i stick in the same hole like the hydros. Yet i turn the cam slightly to 0.1 and than i read the degree. Next stop is the same ramp but 0.1 bevor the zero. Read the degree again. Now i dont know wich degree exactly it was, there are many tries... But i can tell u what i calculate. Dregree higher - degree lower / 2 . This number + the lower number is the 118* ATDC. So i hope u understand me what i mean.

So now i will 114* Intake....

:error:hmm i read the gear card again... Oh ou: ratio is 2:1 .
Now i installed the timing gear on +8* and than i measured an ATDC at 114*.
I guess the cam is now right installed and so i put some gum on piston 1. Heads and valvletrain assembled with new gasket. I turn the crank several times. Same thing with the exhaust lobe.
You can see the result in the pictures. Next week i will assemble the engine together and measure again intake and exhaust ATDC's.

regards

Robert

 

Robert if you are sure the #1 piston is exactly 0* on the degree wheel when at TDC and you took a reading on the degree wheel at the same height on the way up and down the intake lobe, added the two readings and divided by two to get 114 you did it correctly. If the intake reads 114 the exhaust should lobe should be on a 122 centerline because the cam is now 4* advanced.
You do not want to turn the crank alot as you do not want to run the bearings dry of lube. If you are sure of the intake lobe just be sure of the exhaust lobe and assemble.
Ray

 

Robert

I didn't see any pictures in your last post.

What was the piston to intake valve clearance?

Paul

 

Im sorry....

 

Robert, the close spot on those type pistons is on the outer rim area on the side toward the dish. You had the area covered in your first picture and then cut that piece away. Also at the very top of the valve would be another close area.

Something doesn't look right because, without going back over your thread, the outer clay area should have been compressed to around at least .090" if the block wasn't decked at all(.050" deck & .040" gasket). Your clay doesn't look flattened at all on the outer rim.

You did use a solid type lifter or a "jammed" up hydraulic lifter to measure the piston clearance? A typical valve spring will collapse a hydraulic lifter unless you use a very light checking spring.

 

NoLift, the clay was compressed on the outer rim. I used a loaded hydro wich doesent get smaller under load. I have checked id serveral times to be sure...

Today i have cleaned the engine and put the mainbearings with the bowls on (fastened with 150nm). After i read jims post, i guess for bearing 1-4 is 0.0020 good and for the 5 0.0025?

Here are a picture, the quality is bad (dusted iphone 3GS)

 

Robert

I just want to be sure everything is OK.

Having the timing gear set at + 8 degrees seems like a lot to get the cam timing correct.

How did you zero the degree wheel?

Jim brings the piston to the top and sets the dial indicator to zero.
Then he rotates the crank clockwise till the dial indicator reads .050
The degree wheel should be around 11.5 degrees. Record the reading.
Then rotate the crank counterclockwise passed TDC till the dial indicator reads .050
The wheel should again read near 11.5. Record the reading.
Adjust the degree wheel until it reads the same in both directions.

I always take the time to double or triple check myself.

Paul

 

I wouldn't worry about having the cam on the +8 spot. That is typical for the Rollmaster timing set plus a TA cam that is probably ground straight up like they like to do these days for some unknown reason. They usually recommend installing any cam +4 anyway so not building it in doesn't make any sense. Check your timing card to see if it has 0 or +4 advance built in.

I usually check it a few times just to make sure. Never hurts to check the exhaust and that will confirm what is going on.

 

I take a photo of the cam card. I remember on the card (right corner up) was write: with +4 Advance is Intake center line 114*

 

The crank / mainbearings have a clearance from 0.0019". I increase the clearance to 0.0025" with polishing the crank. All holes in the crank are light sunked to improve the oilfilm. I hope this modification keep the bearing heathly

regards

Robert

 

Robert

According to the cam card, the cam is ground without any offset as Mike "No Lift" expected. BTW Mike thanks for your input.

However in order for the intake duration to be 230 degrees and the lobe center at 118 degrees as specified by the card,
the intake would have to close at 53 degrees ABDC not 58 degrees as shown on the card.

The 58 has to be a misprint but you better check both intake and exhaust just to be sure.
The intake lobe center needs to be at 114 degrees ATDC and the exhaust lobe center needs to be at 122 degrees BTDC for the cam to be right.
The intake lobe timing is the most important and the exhaust lobe timing is to verify that the lobe separation angle is correct.

If it were me, next chance I had to put the degree wheel back on, I would record both intake and exhaust valve opening and closing times both at .050 and .006 LIFTER LIFT
so I knew exactly what the cam spec are.
That would be a total of 8 readings and will give you the actual .050 duration and the .006 advertised duration as well as the lobe timing.

The .006 intake lobe closing will tell you what the DCR is.

Paul

 

*update*

- Crank polished to 0.0025" clearance
- Cam installed
- Crank installed
- Alls Piston with rings installed
- Timing set to 114* Intake maximum lift (122* exhaust)
- Timingcover mounted

I have a TA Timingcover and their 500hp fuelpump, is there a incompatibility acquainted?

 

Should be no problem. The TA cover design adds timing chain clearance to the fuel pump arm, so the stock timing cover modifications are not required.

Devon

 

Robert

Thanks for the update.

Looks Great

Paul