Engine Cam idle and timing questions - big cam, little knowledge

Justin87

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Aug 7, 2017
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Hello all:

I have a couple questions about my motor setup as I recently got it up and running.

It's a long story but I purchased a built motor and transmission from a long time family friend. He paid to have it built but never ended up using it. He left it in climate controlled storage for a while and eventually basically gave it to me for next-to-nothing.

Everything listed (minus the intake manifold, injectors and MAF) was built and assembled by DSS Racing and it's how I got it. Admittedly the setup is probably a little strange, but it's all I have to work with at the moment. The motor was built for a street/strip car with an emphasis on strip. My car will not be a daily driver so that's fine. The setup is:

DSS 306 block with main girdle and windage tray
DSS Forged Pistons
DSS Forged Rods
Mircopolished crank
1.6 Scorpion roller rockers
Ford Racing X303 cam
Trick Flow 58cc twisted wedge heads
Explorer upper / lower intake
Pro-M 30# injectors
Pro-M 75mm Mass Air
Areomotive Fuel Pressure regulator
Stock TB

(Shouldn't be relevant for this discussion but it has a built C4 transmission with a 2800 stall, hammer shifter, and 3:73 gears.)

A couple weeks ago I asked about timing. Basically, I was/am a complete novice and had no idea what I was doing. After taking the advice given on the thread, I got the car to start, and I set the timing at 12 degrees. It was running at about 650rpm's. However that was only accomplished by also jacking up the throttle screw to a fully open position. This also made the engine very choppy and it often sounded like it was going to die. (I realize the X-cam is a very choppy cam, that adds to my confusion) It also made setting the base idle difficult even with widening out the screw holes.

So on to the meat of my questions...
  1. I have read on The Corral, and on previous threads here on Stangnet that the idle with an X-cam smooths slightly and it is more stable around 800 rpms. Does anybody have experience with that?

  2. Is that what I should be shooting for?

  3. At 12 degrees currently, the distributor is nearly hitting the thermostat housing. That, combined with the throttle screw being all the way open and it running pig-rich, makes me wonder if I might be a tooth off on the dizzy. How does one tell if your are a tooth off? I found TDC and the rotor does appear to be pointing at the number 1 spark plug, but I am just asking.

  4. Is it possible that I just don't know what I am talking about and the thing is idling fine?

For comparison sake, here is my car at it's current idle: (shes been sitting in the garage for a year and a half so she's filthy)

View: https://www.youtube.com/watch?v=pnjh5YeI64k


Here is another video I found, supposedly with an X-cam:

View: https://www.youtube.com/watch?v=SfhPNZg2Zew


But then also this one:

View: https://www.youtube.com/watch?v=jhIC4kglNLw


Maybe comparing the idle isn't helpful but again, as a total novice I am just trying to get myself into the ballpark. I'm not expecting the car to run perfectly with a stock computer in it, but I feel like I should be able to be confident in it's ability to tool around in, which at this point I am not.

Any questions or clarifications please reach out.
 
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Vinnyc1487

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are you running a stock ecm? Correct timing is crucial and I agree you should be around 850rpm or so at idle. I have the Anderson N41 cam in my car which is similar to the x cam but I also have the Holley terminator x efi on my car which allows me to tune as I go. What exhaust set up is on your car? 12 degrees is almost base timing for a stock cam would would say you want to be around 14-16. Let me see a picture of your distributor. View: https://m.youtube.com/watch?v=AzeC7mOnvVE&feature=youtu.be
 
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Justin87

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are you running a stock ecm? Correct timing is crucial and I agree you should be around 850rpm or so at idle. I have the Anderson N41 cam in my car which is similar to the x cam but I also have the Holley terminator x efi on my car which allows me to tune as I go. What exhaust set up is on your car? 12 degrees is almost base timing for a stock cam would would say you want to be around 14-16. Let me see a picture of your distributor. View: https://m.youtube.com/watch?v=AzeC7mOnvVE&feature=youtu.be

I don’t have a picture of the Dizzy at the moment (I’m on break at work) but I’ll get one for ya later.

Yes, I am running the stock ECM at the moment. Not an ideal situation and a stand-alone is definitely in my future but just not at the moment. I’m hoping with the calibrated MAF I can at least get it to run decent enough to tool around and break the engine in.

My exhaust set up is:

BBK unequal shorty headers
JEGS 2.5” O/R H-pipe
2.5” thrush glasspacks with turndowns form Advanced Auto Parts :shrug:

I needed something cheap to quiet it down a little until I figure out what I want to put on it permanently.
 

Vinnyc1487

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I don’t have a picture of the Dizzy at the moment (I’m on break at work) but I’ll get one for ya later.

Yes, I am running the stock ECM at the moment. Not an ideal situation and a stand-alone is definitely in my future but just not at the moment. I’m hoping with the calibrated MAF I can at least get it to run decent enough to tool around and break the engine in.

My exhaust set up is:

BBK unequal shorty headers
JEGS 2.5” O/R H-pipe
2.5” thrush glasspacks with turndowns form Advanced Auto Parts :shrug:

I needed something cheap to quiet it down a little until I figure out what I want to put on it permanently.
Yeah a calibrated mass air flow sensor and a 65mm or 70mm throttle body will make it run a lot better. There is obviously only limited things that can be done with the stock set up but you should still be able to get it run decently. Have you tried to relearn the IAC and throttle position?
 

Justin87

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Yeah a calibrated mass air flow sensor and a 65mm or 70mm throttle body will make it run a lot better. There is obviously only limited things that can be done with the stock set up but you should still be able to get it run decently. Have you tried to relearn the IAC and throttle position?
One of the limiting factors is the stock TB I am using.

It’s on the list of things to upgrade but I really was just trying to get the thing on the road with the limited summer we have here in Wisconsin.

The first thing I tried to tackle was the timing. Like I said, I did do a base idle reset, but the idle screw is fully open and I’m not at 800rpm’s yet. At this point it’s so choppy that it will occasionally knock the header into the steering shaft, even with poly motor mounts.

that’s one of the reasons I thought maybe I was a tooth off on the dizzy. However, I’m going to try and see if she’ll turn enough to get to 14-16 degrees before pulling it out again.
 

Vinnyc1487

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Do you have a gauge on your aeromotive fuel pressure regulator? Do you know what psi your fuel is cranking at? Or at while running?
 

7991LXnSHO

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A nasty idle is a good thing to many drivers. How does it run down the road?
Reinstalling the distributor over one tooth will not change your timing. You will still set it to the same number of degrees. It can give you more room to adjust that timing without the distributor to not hit other parts.
Up the idle speed a bit, go through the surging idle checklist, and the idle sounds right for an X cam with glass packs.

The larger TB will help full throttle flow, but for cruising, it will be fine. The injectors are likely one size bigger than you need. If the MAF is calibrated for them, it can work.
the Explorer intake will make you happier if you have the lower porters by tmoss, and portvthe upper to match the new TB size.
 

Dan02gt

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You're definitely 1 tooth off on your distributor.
This guide shows you where it should point when #1 is at TDC.

http://efidynotuning.com/ignition.htm

12* of timing is fine and it should run with that. The fact that you have the throttle blade stop screw all the way in to get it to idle tells me something is bad wrong. Things I would check:

Proper firing order to make sure you didn't get a plug wire crossed.
Double check your rocker arms to ensure they are not to tight.
Double check that your injectors are on the proper cylinder.
Triple check for vacuum leaks.
Check that the cam is timed correctly, but if your going that far do yourself a favor and trash/sell that cam. There are lots of cams out there that will run better in an auto with a stock ECU.

The stock computer will try to idle the car around 675 RPMs and while you can turn the screw in to idle it higher the computer doesn't really like that and my throw a code to related to "unable to control idle speed".
 

Justin87

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Do you have a gauge on your aeromotive fuel pressure regulator? Do you know what psi your fuel is cranking at? Or at while running?
I do have a fuel gauge on my fuel pressure regulator and I just realized fuel pressure is way to high. Nearly 50psi and it should be like 39 or 40 psi with the bigger injector right?
 

Justin87

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A nasty idle is a good thing to many drivers. How does it run down the road?
Reinstalling the distributor over one tooth will not change your timing. You will still set it to the same number of degrees. It can give you more room to adjust that timing without the distributor to not hit other parts.
Up the idle speed a bit, go through the surging idle checklist, and the idle sounds right for an X cam with glass packs.

The larger TB will help full throttle flow, but for cruising, it will be fine. The injectors are likely one size bigger than you need. If the MAF is calibrated for them, it can work.
the Explorer intake will make you happier if you have the lower porters by tmoss, and portvthe upper to match the new TB size.
Oh I love the idle, I think this thing sounds like a dang NASCAR and I am happy-as-a-clam with how it sounds! I'm glad it sounds about right tho, thats encouraging. Part of the problem is definitely just my inexperience and not knowing what is SHOULD sound like.

My concern with the idle is that it might be to unstable at this point to drive it. Everything in car is brand new and when it idles at this current state the motor is really shaking, even though it has brand new poly mounts and trans mount. SFI flexplate is balanced and matched with the brand new Romac Balancer and at a slightly higher idle (like when I give it a little gas) it evens out a little while still being choppy.

I haven't driven her yet, all I did was bring her through the break in idle procedure that DSS Racing recommends in the paperwork that came with the motor.

The MAF is calibrated for the injectors. I got them both from Pro-M racing and they recommended the 30's instead of the 24's I was planning on.
 
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Justin87

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You're definitely 1 tooth off on your distributor.
This guide shows you where it should point when #1 is at TDC.

http://efidynotuning.com/ignition.htm

12* of timing is fine and it should run with that. The fact that you have the throttle blade stop screw all the way in to get it to idle tells me something is bad wrong. Things I would check:

Proper firing order to make sure you didn't get a plug wire crossed.
Double check your rocker arms to ensure they are not to tight.
Double check that your injectors are on the proper cylinder.
Triple check for vacuum leaks.
Check that the cam is timed correctly, but if your going that far do yourself a favor and trash/sell that cam. There are lots of cams out there that will run better in an auto with a stock ECU.

The stock computer will try to idle the car around 675 RPMs and while you can turn the screw in to idle it higher the computer doesn't really like that and my throw a code to related to "unable to control idle speed".

Thanks for the input and the link to that website!

Tomorrow morning I am going to start poking around and run through the idle checklist and will check the distributor.

I will say, I did check vacuum and it was running around 18 HG at idle and I did check the rockers before I put the valve covers on and dropped the motor in. (doesn't mean something might not have happened) I used a feeler gauge and the spec in the DSS paperwork.
 

7991LXnSHO

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The write up from jrichker says you may need to adjust to a higher idle speed, so it’s not like we are preaching heresy at 800 rpm here. Once you make it through the surging idle check list, you should have confidence in it and not shake quite as much. A manual will tolerate the cam better than a stock auto torque convertor. Someone mentioned an auto?
 

Justin87

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The write up from jrichker says you may need to adjust to a higher idle speed, so it’s not like we are preaching heresy at 800 rpm here. Once you make it through the surging idle check list, you should have confidence in it and not shake quite as much. A manual will tolerate the cam better than a stock auto torque convertor. Someone mentioned an auto?
Oh I totally agree!

I have seen other posts on here and The Corral and a decent amount of guys talk about 800rpm being the sweet spot for the Xcam so that’s definitely where I am headed.

Yeah The car has a built C4 with a 2800 stall and a hammer shifter (shifter not installed yet)

Anywho, Just gotta cover all the bases.
 
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Dan02gt

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Here are the idle parameters from the stock A9L manual calibration (I don't have a A9P calibration file handy).
NUBASE is idle in neutral and DRBASE is idle in drive. These are what the ECU is trying to achieve. Sure you can crank it up with the throttle stop screw to whatever you want, but you are removing the ability of the computer to properly control the idle via the IAC and implement dashpot (anti-stall). It might work for you but it's not right and drivability can suffer.

Guys I'm not saying don't use a 800RPM idle. You're probably going to need it with a X cam. What I'm saying is you would have better results if you achieve it with a tune. A Quarterhorse can be had for $250 and would really help out.

1625761405841.png
 

Justin87

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Here are the idle parameters from the stock A9L manual calibration (I don't have a A9P calibration file handy).
NUBASE is idle in neutral and DRBASE is idle in drive. These are what the ECU is trying to achieve. Sure you can crank it up with the throttle stop screw to whatever you want, but you are removing the ability of the computer to properly control the idle via the IAC and implement dashpot (anti-stall). It might work for you but it's not right and drivability can suffer.

Guys I'm not saying don't use a 800RPM idle. You're probably going to need it with a X cam. What I'm saying is you would have better results if you achieve it with a tune. A Quarterhorse can be had for $250 and would really help out.

1625761405841.png
No no, absolutely I get what you are saying, a tune or a fully programmable PCM is definitely in the future for me! I appreciate your input 100%
 

7991LXnSHO

wanna catch the space herp
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Sep 1, 2010
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Here are the idle parameters from the stock A9L manual calibration (I don't have a A9P calibration file handy).
NUBASE is idle in neutral and DRBASE is idle in drive. These are what the ECU is trying to achieve. Sure you can crank it up with the throttle stop screw to whatever you want, but you are removing the ability of the computer to properly control the idle via the IAC and implement dashpot (anti-stall). It might work for you but it's not right and drivability can suffer.

Guys I'm not saying don't use a 800RPM idle. You're probably going to need it with a X cam. What I'm saying is you would have better results if you achieve it with a tune. A Quarterhorse can be had for $250 and would really help out.

1625761405841.png
Back ordered until at least August.
 

Justin87

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Update:

I am off work today and tomorrow so I’ve gotten to get some wrenching done.

1. Adjusted the fuel pressure down to spec to 40psi.

2. Found TDC and pulled the dizzy. Seems to
Me like it’s basically in the same place as before, but it immediately seemed to respond better at idle and in the throttle.

3. Set the timing to 12 degrees, maybe 12.5 (assuming decimals are a thing in timing) it’s just slightly advanced from the little hash mark in the block and distributor.

4. Did a base idle reset, still had to adjust the throttle screw UP, not nearly as much, and this time and the idle is now at like 875rpm in drive, probably like 1100 in neutral. (So it’s actually probably a touch to high) but for now I’m going to keep it just so I can get this thing moving.

My daughter is up from her nap now so wrench time is over, but I’m going to bleed the cooling system and top off the transmission fluid tonight before trying my first drive.

Car seems to enjoy where it’s at right now, but I’m not going to know for sure until physically drive it.

What are some things to watch out for that the timing may not be right? 12 degrees is basically stock and this thing is hardly stock so I just want to be prepared to adjust it.

keep at eye out for spark knock or what?

here is a video (excuse my absolute disaster of a garage)

 

Monkeybutt2000

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You're gonna have to drive it first,then go a degree at a time and see what happens. If it starts knocking,back it off in small amounts.
 
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jrichker

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You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the [URL=" http://forums.stangnet.com/showthread.php?t=698148"]Surging Idle Checklist[/URL]. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix. :D



It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 250,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
 

Justin87

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You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the [URL=" http://forums.stangnet.com/showthread.php?t=698148"]Surging Idle Checklist[/URL]. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix. :D



It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 250,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
Oh I absolutely use the surging idle checklist. It’s a permanent tab on my internet browser.

I guess maybe I didn’t know I could continue to post in that thread to ask additional questions. So that’s my bad.

the reason I asked a question and made a new post was specifically because my X-cam in my car and not knowing how choppy is “should” or “shouldn’t” be.

but the whole reason the car runs at all now is in credit to the checklist!