1970 442 with 45 degree 425 +.030 Mahle 4.155, Comp. ratio: 9.9 1970 "E" heads / Edelbrock Performer 2151
Turbo 400 with a B&M 20404 2,300-2,500 stall.
Rear gear ratio: 3.23

Cam installed on 107 ICL. Note - The crank timing gear ended up being set at 6 degrees retarded when it was in at 107.
Car performance is ok'ish, but doesn't feel like it's running as good as it should. Low end seems off.

Cranking compression with cam in on 107 ICL
1 - 170PSI, 3 - 165, 5 - 165, 7 - 175

10 PSI of hot idle vacuum

At a minimum, I think I should re-index to a 110 ICL and possible advance another 3 degrees. Which would basically put the timing gear on 0.

Cam card is below and specifies 110 + 3. Does that mean the cam has 3 degrees of advance built into it?
Anyone have thoughts on how I should adjust the cam?

 

+3, the cam is ground +3 in relationship to the dowl pin.

First off what method did you use to time it. Lobe center line or opening and closing events. With modern hydraulic rollers you don't use the centerline method. The lobe might not be symmetric. Check to make sure that at .050 lift your at 7 degrees.

 

I used ICL. Measured at .050 and .020 and both came in at 107.
At .050 intake lift I am at a 5.5 degrees.

 

When you measured it did you use the ramps ore the nose? If your at 107 your events at 50 should match up.

 

What was your intake closing at .050 ? do a compression test on the right bank

 

Are you using a lifter or one of the cam tools that sits in the lifter bore ? I would start from scratch and check all of the opening and closing spots for both intake and exhaust. I have seen a few cams in the recent past that where nowhere close to what the cam card said. Like duh said, if your icl is right then the opening and closing points should be too.

 

Motor's still in the car so I am using lifter/pushrod to measure lobe lift.

Intake closing @ .050 looks about 137/43
Cranking compression 2 - 180PSI, 4 - 185, 6 - 145, 8 - didn't check

Not sure what's happening with #6 in terms of cranking compression. Something else to check out.
I can check exhaust @.050 tomorrow.

 

your int c/l is 109. the reason I asked for your right bank comp numbers is because if you had to retard it 6 degree to get those number on #1, is because it’s acting like a 39deg bank angle cam in a 45 block.

which your comp numbers on the right show..being much higher. the right bank will be 6 adv and the left bank 6 retarded (reason for #1 having to be 6 deg ret to be close)

spin it over to find what the int closing is on any of the right bank cylinders. if it’s around 37, that’ll tell you it’s for a 39

 

How do I set the degree wheel when checking the .050 closing on cylinder #4? Do I leave the degree wheel set to 0 on TDC of #1 or re-index the wheel so it's at 0 on TDC for #4?

 

just do #6 without resetting the wheel….roll it over as is. you can do the others using the 90deg positions but 6 is easier to understand

move the dial indicator to #6 intake lifter

 

Cool - got it. Use the cylinder pairs. Thanks!

 

#6 Intake @ .050 closing.

 

Moved dial indicator back to cylinder #1 and reran the .050 intake closing.

 

now your int c/l is 110 and your int closing on each bank is the same so my theory is out the window.

it’s still doesn’t explain why your right bank is averaging 14 psi more?

something is going on with your right bank…maybe that head was cut more or has some smaller stock chambers?
i was going to say adv it 4 to a 106 int c/l but that may shoot your right bank close to 200 crank psi. Maybe try adv it 4 and see what you get on each side again.

 

Before adjusting the timing/ICL I decided to baseline the compression check again. I wasn't able to thread the gauge into #8. All plugs out, throttle wired open, all passes done as found with no oil added to the cylinders.. I did two passes today.



Why am I seeing some 20 lb swings in compression? The only thing I think that's changing is that the lifters are pumping up.

 

I personally do not think that is accurate enough. Mainly because of the pushrod being able to move around. Also there is the chance that the lifter is not pumped up all the way. You need to be right on the lifter body itself. They make long extensions for the dial indicator so you dont have to pull the intake.

Also it might be the camera angle but is your pointer rubbing on the degree wheel ? I prefer it short of the wheel myself. I would cut an inch off of yours if I was doing it. Personal preference

 

No oil? you have to have oil pressure

 

Thanks for the laugh. Go back and re-read.

My reading comprehension is fairly good, as I have been in this country for a long distance now. He said, he didn't add any oil. As in, no extra oil in the cylinders for the test..

 

That's not bad thinking. As for your timing issue try dialing just the open event. Then check the closing. This should be done at 50. If the closing is ok with the intake dialed in then measure you centerline using the ramps at 50. It should be dead on. If not check for something loose or moving like your degree wheel.

 

How did you adjust the valves? Zero lash+3/4 turn? EVERY time I have used that, the valves were too tight and not closing properly. Try zero lash+1/4 turn! Even adjusting with the engine running this makes a huge difference!

 

ah ok, so no extra oil in the cylinders? Why would there be oil in the cylinders when that was never mentioned before? I was referring more to cranking the engine enough to have good oil pressure on the gauge so the lifters are pumped up to running height, that’s why I said pressure . if they aren’t, the readings will be erratic

the engine has been apart for a while by the looks of it and he’s been turning it over by hand, which will bleed down all the lifters. it’ll take some good cranking to pump all of them up before getting a correct comp test…especially with stiff springs.

 

Thanks everyone! I was aiming for .040 preload which on my setup as measured above the push rod is a little more than 1/2 a turn.
I like the idea of trying a 1/4 turn and will probably give that a go.
The motor runs like it's bleeding compression off somewhere and I am trying to figure out if it's the cam or perhaps the lifters.

My plan at this point is:

• Pick up an dial indicator extension to get a more accurate lift reading off the lifter.
• Check the cam for the umpteenth time to see where it sits in regards to the 107 cam card ICL.
• Figure out if I want to try advancing the cam 2 - 4 degrees based on above measurements.
• Try a different preload.

Appreciate everyone's feedback, I know remote debugging is a PITA..
Thanks again!

 

Here's an update on this thread as to where I am now.

Checked cam timing multiple times and the ICL keeps coming in @ 107. Valve timings @ .050 also matched cam card.

Decided to advanced the cam 4 degrees. So now cam is at 103 ICL.
Did a compression check after moving to 103 ICL and the numbers looked reasonable.


So, I put everything back together and ran it.
Vacuum at idle is up 4-5 lbs to the 14-15 range which helps with the power brakes.
So some overall improvement but still going to try some more things.

 

Thanks for the feedback @Dave65-442 , however if you read my initial post you'll see that I am running a 45 degree 425 in my 442.
Also, Supercars Unlimited is out of business.

 

Well that actually made me laugh.

 

What makes me laugh is posters who are so misinformed they don’t even know why I am laughing at their posts, as well as idjits that don’t think others are multi-lingual.