Starting to understand why building engines may be best left to the professional

[scott foxwell]

"Zero degrees" as in "straight up"? Dot to dot? That isn't going to cut it. You need to degree the cam per the cam card. Either to the intake centerline, or the intake opening event @ .050" (which is what I recommend). You could be off by a mile per where the cam is supposed to be installed. Until you know where the cam is installed, you're chasing your tail. As far as cranking compression...you have plenty of time on the engine for the cranking compression to be accurate, especially if you have moly rings.
JMO

[My427stang]

We installed it as the cam instructions called - zero degrees. On the question of cranking pressure vs static compression one of my buddies told me to calm down and get it broken in. I still have less than 200 miles on it.


 BTW with vacuum at 6 inches the stock powervalve was probably open at idle.

I think you may have a cam timing issue, either the cam isn't what you think it is, or it is late, your cranking compression and vacuum is really really low.

Also, just to be clear, your thoughts on powervalves are not correct.  It cannot flow fuel at idle if the carb is adjusted properly.  Sure it could be open, but the PV does not contribute fuel to the main well until the throttles are open.  The route for the fuel just does not get energized until there is flow by the boosters.  Additionally, you likely never get to 3.5 with your setup, my hunch is cruising vacuum is higher.

If it were mine, I'd degree the cam to include the cam profile, and then tune the carb correctly after getting vacuum where it should be.

What are the cam specs?  I cannot imagine you went too big in a truck, your numbers are drag racing cam numbers in terms of vacuum.  Also, if you can post which pistons, crank, rods, and heads you used (chamber and dish size especially for heads and pistons) we can likely get you there

[machoneman]

-I'm grasping at straws on the whole vacuum thing. It is starting easily and running ok, but it is quite variable. It is hesitant and jerky on steady cruise some times, and quite happy at others.
-It is also still firing backwards on shut down sometimes.
-When it doesn't fire backwards it shuts down cleanly, before the reduction in jets and powervalve it was running on or firing backwards. BTW with vacuum at 6 inches the stock powervalve was probably open at idle.

I edited various passages above. This is a classic example IMO of badly retarded cam timing.

You've described all the symptoms quite well but need to verify the cam specs versus the installed timing chain/gearset. You can check this in-car w/o yanking all the front dress but that requires a magnetic base dial indicator and pulling the balancer for the degree wheel. Lot of work but....   

[Yellow Truck]

Guys - as usual I really appreciate the thoughtful replies. I have been reviewing the cam card, looking at info on degreeing the cam, and trying to remember exactly how we did it. I probably used the wrong term when I said "zero degrees", what I meant was we didn't advance or retard it but installed it as the cam card indicated.

At present my immediate problem is that I really wish this summer had never happened. My wife and love of 38 years had open heart surgery on the 4th of July, and on Wednesday last week my brother and closest friend was taken into the trauma unit with a brain bleed and they opened him up and worked on him for about 5 hours to save his life and as much of his mind as they could. Jury is out on the latter but his life seems secure.

I am thinking that we didn't test the cam to see if it was correct, and installed it as spec'd. From what I have seen a few degrees off is not that rare and we may have to go back. I do know we didn't have any kind of tool to test where the cam started to open or close on the intake or exhaust. Most of the stuff I've seen assumes you have a lifter with a shaft attached that you can put a dial gauge on and confirm the cam movements to the degree wheel on the crankshaft.

Given the other things going on I'm going to put off a planned hip replacement in a few weeks, and may have some time for this in the next month. I will come back for specific suggestions on how to confirm cam position with a hydraulic roller cam - I don't believe I can use the lifter since it has movement, but I could be wrong.

Topping it all off I had to put one of my old dogs down this week. All in all a summer to forget.

[My427stang]

Sorry to hear the challenges, health comes before hot rods, hope everyone is hanging in there.

Often tolerance stack can retard a cam, sometimes the parts you get aren't what you think they are, compression often ends up lower.   Although degreeing tools are not expensive, they can save your bacon if you get the wrong cam in the box.  A less desirable option alternative is advance it 4 degrees and check intake valve clearance.  If it's clear, it WILL raise your vacuum, and hopefully enough, but don't do it without checking valve clearance, you could put an intake valve into a piston

[Yellow Truck]

Ok, getting back to the truck finally. Because of my family issues I did give it to a shop I use to put in the O2 sensor bung, re-do the parking brake (nice to have it stay where I put it), and do a little basic adjustment on the carb. Stock the QFT came with:

High Speed Air Bleed   28
Idle Air Bleed Size   70
Primary Main Jet   78
Secondary Main Jet  86
Primary Power Valve   65
Primary Pump Nozzle Size   33;35

It had been fouling plugs and it made your eyes water with unburned fuel when it idled in the show. He took the primary jet down to 72 and the secondary main jet down to 74, and we put in a 3.5 power valve. Timing is still up around 20 degrees, although the old Ford moves around a bit.

I did put some miles on it, then I got an LM2 O2 sensor kit from Innovate. The MSD distributor ran for 40 minutes and we had to go back to the old Ford, and I have a Duraspark on order from Faron Rhoads. What I saw driving it was it likes to be hot, after 20 minutes it starts to perk up. I got a little highway time on it, and it is sluggish until 3,000, and really comes to life over 4,000. It also likes to run on after shut down.

I put the O2 sensor on it today and saw around 17 at idle, 13 to 14 when on steady throttle, and 12 down as low as 10 on WOT. On off throttle deceleration it was pushing 15.

When in third and hitting the throttle hard at around 2,500 the reading dropped to 10, and you could hear rattle. I always assumed detonation was an issue with a lean condition but it sounds like detonation or fuel burning in the headers. If I give it WOT at higher RPM I don't get the rattle, or it is only momentary.

It has been suggested on here that I probably have my cam retarded. I went over what we did with my friend who did it with me. We did install it as per the cam card, and aside from the rich condition and the issues with too tight/too loose valves it never rattled before. I am wondering if perhaps we have stretched the timing chain. It is a new Ford Racing timing set.

I have a bit of a dumb question, I know Jay has some lovely pieces for adjusting valve timing and he is very gracious about not pushing them, but really how do you get a couple of degrees of adjustment without them? I was thinking it might be a good idea to just bight the bullet and pull of the current pieces in favour of Jay's set and get it on a dyno and make some adjustments and watch what it does.

I can say I would much have preferred to spend my summer burning fingers and scraping knuckles.

[jayb]

Some timing sets have several keyways in the crank gear.  In order to change the cam timing you have to pull the crank gear and move it to a different keyway.  Not something you can easily do on the dyno, though.  There's not really any other way to adjust cam timing.

[My427stang]

Before you buy anything, degree the cam. 

Remember, when you degree a cam you are checking 2 things

1 - That you got the cam you think you got
2 - That it is installed where you need it to be, or in the very least where the cam manufacturer wanted it.  This can turn out different even if you masterfully install it dot to dot due to tolerance stack or poorly made components.

Your symptoms so far look like late cam timing, but it could also be that it isn't the cam you think it is, wouldn't be the first time someone put the wrong cam in a box

[Yellow Truck]

My specialty is figuring the thing out AFTER I've gone further than I needed. I'm starting on checking the cam position. I needed to pull the rad because of a tiny slow weep that has been bugging me, and I had the heater hoses reversed, so tonight I tore into it.

I have the rad, fan, fan shroud, PS pump and brackets, alternator and bracket, belts, etc. out of the way. Time to aske the dumb question - if there is something wrong I'll need to take the water pump and timing cover off, but is it possible to check the cam position without pulling everything off?

I was looking at it and if there was a longer crank bolt and 3/4 inch spacer behind it the degree wheel would clear the water pump drive. Not that I'm lazy (yes, I am), but all that stuff is nicely sealed and if the cam timing isn't wrong, getting it all back tight and dry is not guaranteed.

BTW I did look and realized that Jay's lovely adjustable timing gear and cover are not much help with a mechanical water pump. Ordering one would have been an expensive disappointment. With electric fans and electric water pump I imagine it is pretty slick.

[Barry_R]

A cheap Mr Gasket 7" diameter degree wheel will fit where the front pulley sits and will be plenty accurate for what you are doing.

[C6AE]

Lots of "printable" degree wheels out there.

http://garage.grumpysperformance.com/index.php?threads/printable-degree-wheel.974/

[Yellow Truck]

Thanks Barry. I'm scrambling around to pick up a good used dial indicator (easy part) and an extension to reach down to the lifter. Question to those who have done this - is a 6 inch extension enough to reach down to the top of the lifter? I think the push rods are 8 plus inches.

[Barry_R]

For your purposes you can check for opening and closing points, and max lift right at the at the valve.  Just roll back and forth beyond max lift until you locate the intake lobe centerline.  No need to get exotic, nor for "to the degree" accuracy here.  You are looking for gross errors.

[scott foxwell]

For your purposes you can check for opening and closing points, and max lift right at the at the valve.  Just roll back and forth beyond max lift until you locate the intake lobe centerline.  No need to get exotic, nor for "to the degree" accuracy here.  You are looking for gross errors.

I completely agree with what you're saying about not needing to be "to the degree" accurate here but I've found that, depending on the lobe, ICL can be misleading by as many as 6-7 degrees. I've learned to always degree a cam to the intake opening event. Also, checking at the valve with a hyd. lifter doesn't always work. Not sure if YT has a solid or hyd...just sayin...

[scott foxwell]

Thanks Barry. I'm scrambling around to pick up a good used dial indicator (easy part) and an extension to reach down to the lifter. Question to those who have done this - is a 6 inch extension enough to reach down to the top of the lifter? I think the push rods are 8 plus inches.

6" extension should get you there. You can use a piece of welding rod, coat hanger wire, anything stiff enough to run the dial indicator up and down. You just have to find a flat spot on the lifter or put something on the end of the wire so it doesn't go in the oil hole.