Old cam, will computer like it?

notch22 · Aug 2, 2006

Need some help guys. I have an aftermarket cam, it is a solid hydraulic cam with 292 degrees duration and .518 lift. I also have an A9L computer that will be going in the car. Is the computer going to accept the cam?

vristang · Aug 2, 2006

I assume that is advertised duration.
What is the .050 duration?
What is the LSA?

I am not sure I can really answer the question for you, but others will ask these questions.
And I am curious how others will respond.

jason

notch22 · Aug 2, 2006

To be perfectly honest with you, I dont know. This cam is older than I am. My dad had it in the 302 that I will be putting in my car. This was back in the 80s, so of course he isnt going to know all of those numbers either. He said that it had a pretty good lope though. That is all the info that I have to go by. Can anyone help me?

DMAN302 · Aug 2, 2006

I would stick with the stocker or purchase a new pc. I wouldn't install a "cam" just to say it has one..they are all very different, and they don't all work well with just any parts. You need to work at putting parts on the car that you KNOW will work together in the same power and operating range or you could end up with a ride that just isn't all that much fun to drive.

vristang · Aug 2, 2006

^^^What the DMAN said^^^

You should be able to find some kind of part number on the cam. Armed with the part number you should be able to call up a couple of cam companies and find out what it is.

Mostly I would worry about the difference between roller and flat cams. Odds are that a cam that old is flat tappet.

Basically, you need to do some detective work to find out what the cam is first.

It may still turn out to be a good cam...

Then again it could be total junk for your efi motor.

Let us know what you find out.

jason

notch22 · Aug 3, 2006

So is it safe to assume that the part number is imprinted on the end of it? I know that he dont have the paperwork on it anymore....but he does know for a fact that it ran VERY well with it in there.The CR is 11:1 and he and a couple of his friends from high school remember vividly the truck that he had it in could easily wax a 396 Chevelle.

notch22 · Aug 3, 2006

Ok, another question....is there anything in the part number that would tell me what brand the cam is?

bullitstang1313 · Aug 3, 2006

If your cam is a solid flat tappet cam you won't be able to use it in a 5.0L hydraulic roller cam block without some serious machine work.

notch22 · Aug 3, 2006

Like I said before, I have the whole motor. It has been run and everything. I KNOW that the cam will work in this motor! My question is, will the computer accept it, let it run, blah blah blah. There are no clearance issues, no problems with the cam itself. Is there anything else I would need to find out other than the firing order of the cam?

DMAN302 · Aug 3, 2006

Since we don't know the LSA and you don't know what cam it is..really no way for us to answer you question any better than 'maybe'...sorry that's the only answer that applies. No matter the cam choice..some cars just will not run correctly without a dyno tune, so good luck and I hope it works out.

STANGateURlilSS · Aug 3, 2006

notch22 said:
To be perfectly honest with you, I dont know. This cam is older than I am. My dad had it in the 302 that I will be putting in my car. This was back in the 80s, so of course he isnt going to know all of those numbers either. He said that it had a pretty good lope though. That is all the info that I have to go by. Can anyone help me?

take it to a shop that grinds custom cams.. they can figure out the duration of of the cam.. and if the cam was in a 302 in the 80s chances are that its a flat tappet..

notch22 · Aug 3, 2006

So in short, you are saying that a flat tappet wont work, and to get a roller. Am I understanding this right? If so, then no problem. I can get another cam for crying out loud....

notch22 · Aug 3, 2006

Now can someone suggest a cam that has about the same specs as far as lift and duration?

DMAN302 · Aug 3, 2006

Are the heads stock? If so I would really take a long look at the stock cam, it really works quite well on the street. I get the feeling you want a cam installed just so you can say you have one.

notch22 · Aug 3, 2006

Well it seems to me like you are gettin the wrong feeling. Common sense says, dont buy something unless you need it. Likewise, if this cam would work with the computer, I would keep it. Why would I want to buy another cam if I dont really need it? Like I said, it ran like a champ when it was carbed, I want it to run with efi. Plain and simple.

vristang · Aug 3, 2006

Notch22-
I am having a horrible time trying to envision what your situation is. Let me know if this is wrong.

You currently have a 2.3 that you want to convert to a 5.0 with EFI.
You have an old 302 from your dads truck (which ran well in the 80's).
I am guessing the 302 is either sitting in the garage or still in the old truck?

Now some questions.
What was the setup on the 302?
Carb?
Intake?
Heads?
I assume all of these parts are still on the 302, and that they would all be swapped to your car? (less the efi of course)

Now for your conversion questions.
The A9L will be the most flexible in adapting to long duration/short LSA cams. However, there is only so much the computer can compensate for. That is a lot of compression too.
There is also the issue of firing order. Obviously the cam firing order must match the computer firing order.

With some trial and error you should be able to figure out the firing order of the cam. After #1 hits TDC then look for TDC is either cyl #5 or #3.
Early 289 & 302____________1-5-4-2-6-3-7-8
302HO & 351w____________1-3-7-2-6-5-4-8 (this is all 83-93 Mustangs, and all 5.0 Explorers)

If you find that the firing order is correct, then I would suggest pulling the cam and finding the part numbers. There most likely will not be any company logos to go on, but you should be able to find the part number format on a website somewhere. Actually, you could probably just type the part number in to Google and find out ALL the cam specs that way.

If your LSA is between 110-114 then you should be good. If you have something outside this range then you will most likely have some idle issues. I think carb cams can get down to 106?
It isn't so much the duration that will be hard on the computer. The valve overlap is the major factor, and this is heavily influenced by the LSA.

Are emissions a consideration?
This will play a major factor in cam selection.

That is all I can offer up, sorry it's not more.

Let us know how it goes,
jason

notch22 · Aug 3, 2006

You are exactly right about pretty much everything, vri. The motor has been taken apart and has been balanced not too long ago. Right now, the only thing that is assembled right now is the block (of course), crank, rods and pistons, I think that is all. It is sitting on a motor stand right now in plastic. When the motor was in the truck, it had a single plane Offenhauser intake with a 750 Holley double pumper with mechanical secondaries. The heads are stock closed chambered heads, which is where part of that high compression comes from. Lastly, yes I was planning on just adding efi and dumping it in the car. After looking back through this thread it seems as though everyone thinks I also have the stock cam, but I dont. The only thing I have is everything from this one motor. Sorry for the confusion guys.

As far as the CR goes, are you saying that the A9L wont work with that much compression? When I get this cam number, will the part number be firing order specific or will I need to have the cam in the engine to find out? To answer the question about emissions, no I wont really be worrying about it being legal.

vristang · Aug 3, 2006

OK, the pieces are falling into place.

The part number of the cam will tell you the firing order.
I mentioned the "detective method" only because it sounded like the cam was already in the motor.

I'm not really sure how to explain the CR affect on the computer, other than it tends to "roughen" the idle.

My friend has a 110 LSA cam with over 10:1CR on his A9L. That engine sounds nasty when it idles. (I don't remember his other cam specs though).

jason

notch22 · Aug 4, 2006

Ok, I had previously gotten my wires crossed with my first post. This cam is a not a solid flat tappet cam, so that is nothing to worry about. I talked to my dad last night to tell him to get me the part number so I will have that today. More good news, he said that it was a Crane cam so no looking for the brand either. If LSA is good then I am set......

vristang · Aug 4, 2006

notch22 said:
Ok, I had previously gotten my wires crossed with my first post. This cam is a not a solid flat tappet cam, so that is nothing to worry about. I talked to my dad last night to tell him to get me the part number so I will have that today. More good news, he said that it was a Crane cam so no looking for the brand either. If LSA is good then I am set......

Just to clarify the LSA is the angular spacing between the intake and exhaust lobes.

The problem with LSA's below ~110 is that this tends to create more valve overlap.
The computer can have a hard time with this.
The computer knows when it should fire each injector based on the specs of the stock cam. When you change the valve events with an after market cam, you run the risk of messing up the very precise timing of when the injector fires. What you then end up with is the injector firing while the exhaust valve is still open. Obviously this early injected fuel is sucked right out the exhaust. Only part of the fuel mixture remains in the combustion chamber, so you end up with a lean mixture in the combustion chamber.
To make things even worse for the computer, the fuel that was pulled directly out the exhaust hits the O2 sensor, effectively telling the computer that the car is running rich.

A custom tune can clear this up. If you will not be tuning the car however, it would be best to avoid the high overlap cams.

I don't remember how to calculate the overlap, but it should come up on the web somewhere

I guess what I am trying to say is that whether or not you will be happy with the cam is difficult to say.

I am curious what you find out though.
jason

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