Well, I just about give up.. its got good lowend but thats about all. Peak HP is at 5400-5450 on this chassis dyno.
Peak torque is 3800-3900 rpm with a modified vic Jr and a set a track1 1s that flow 270 at .5 and 285-290 at 6. It has right about 11.2 to 1 compression and a demon that is a little leaner now (I enlarged the hispeed airbleed by .002" today)
Cam is a cammotion hydroller with 239 at .596 and 247 at .603.

Im thinking the cam is just about 6 degrees to far advnced.

See the dirty details at


text


excel

BMP

edit
before we go down the more valvespring route - read this


About 2 years ago, this same motor was on an engine dyno.
superflow
It basically had the same problem. Peak torque was at 4800-4900 however.

When the motor was on the superflow, a performer rpm was tried instead of the vic jr. It make about 10 less hp and 10more ft/lbs but otherwise basically identical curve.

I found out that the exhausts ports were barely flowing 140. They were brought up to 185 without a pipe.

At that time, the valve springs were changed from 125 seat and about 300 open to 140 seat and 365 open (These are isky 8005a) with a titanium retainer.

The motor has had an AFR hydra rev kit from day 1.
Those are not dynojet numbers. They are from an eddy current dyno like a mustang.

 

u need more cam.


what igition u running????

 

The cam was designed to feed the motor to 6300.. should have enough duration for that. Most smallblock motors will make peak Hp at 6000 with 230-235 degrees at .050.

The HOT lt1 cam has 20 degrees less duration (but a 3 degree wider LSA) and makes peak hp at 6000.

Holley anialator with a mallory 9000 unilite.

PS, before we run the fuel system bases.

Its a summit 150gph. The pickup is at the lowest point on the tank and it only has a rise of about 4" before it gets to the pump. The pump has AN8 for the pickup and 1/2" tube all the way to the carb. It goes to a 3 port regulator and one of the ports goes to a return line back to the tank. Fuel pressure never dropped below 6psi on the runs.

 

i could see it going to 6000 rpm with a 350 but not with a 400.extra cubes likes more cam.

 

what rod length are you using? whats the cam in at degree wise?

 

I agree the cam is definatly too small. A solid profile with 255 to 259@.050 ground on 104-106C/L is what you need.
With a Brodix head lift is your friend .630"+

It's hard to over cam a 400.

 

Both comp and cammotion recommend about the same lift &duration for the specific combination. This motor was built to run a hydroller and peak below 6500. Its a 5.7 rod motor.


The cam was installed on the 105intake centerline with a 109lsa.
The heads are not fully ported. They max currently right about .6"

The XE comp hydroller with 242 intake duation makes peak hp at about 6700 in a 350. The comp XE 282 cam in both 383s and th 393 ford crate motor makes peak HP at about 5600-5900 (with a whole lot smaller cyl head volume). And it has almost 10 degrees less duration on the intake.

The 400 they put together in the March 2002 carcraft made peak hp at 5700 and a second slightly lower peak at 5900 with a hydroller that had 234 duration at 050".

There was also the 454 smallblock based on the dart block in the Dec2003 hotrod. It make peak hp at 5700 with 242 degrees of intake duration.

6300 might be a little high.. but the peak should be very close to 6000. Not 5400.

 

You're basing what you think you should be getting on your motor, on HOT ROD Magazine numbers.
Put down the hot rod books and put your motor on a real dynomometer. There is an old saying " Your results may vary"
haveing the gain of a friends experience trying to make real horsepower on a real dyno with a simular motor as your's. I can tell ya. There is something up that is holding it up. The cam is smal for what you're trying to do. You are getting to the limit of the RPM capability of a HYD roller cam setup. More spring pressure probabily won't help. The more "intense' the grind is on the cam the sooner it will valve float wth a specific spring an with a specifc mass of valvetrain. Your cam sounds like a very fast action short duration cam. It will make good torque but will be rpm limited using a specific spring pressure and heavy valve train parts. there is a definate rpm limit of A hyd roller design because of the weight of the lifter and practial spring pressure limitiations. And the inharent stability limitiations of a hyd lifter at high rpm.
Unless you're willing to experiment with a numbers of different cam grinds and $$differnt valve train parts$$ in *Your Motor* on a real dyno, you are just guessing. The cam with the most intense lobe does not make the most power. there is much more to a sucessful cam design than opening and closeing the valves as quickly as possible.

if you want to make real power gains get a real cam not a hyd. You need a solid roller. Consult a real roller cam company like ISKY, Crane or Comp or Lunati. cams. Do not quote Hot rod mag articles with talking to the tech dept.
Talk about what you are using.

Again, something in your combination is wrong and the cam is small. Good Luck to ya A 400 SBC can gobble up a cam like no other motor. To get a peak power past 6500 rpm on a 400 you'll need a cam with 260+duration @.050" 270typical.
the cam u have is a "towing cam" in a 400.

 

edited...

 

jcb, i just looked at your site with your car specs on it, after seeing that id suggest dumping the hyd roller and getting a solid roller, with those parts you have in that engine you should be able to take that thing upwards of 7000rpm with the right cam.

 

How was the A/F ratio, maybe too lean?

 

I know there is something holding it back, but it is not cam duration. Using dyno curves from a mag might not provide valid HP estimations but they CAN be used to predict engine RPM bands. Motors that are undercammed do not normally just drop off like a rock immediately above the peak. The same 454 smallblock was also tried with a HR270 (with 215degrees at 050). It made peak hp at 4900-5400 rpm.

There are several other sources that I used before selecting this cam. Like 3 engine simulators... all of which said the peak would be about 6000.


No desire to run solid roller and replace lifters at 5K miles. It is a street car. In most cases, the benefit would be about 20hp max (compared to a properly performing hydroller of similar design - Joe sherman has admitted such himself).

If anything the AFR was too rich in the higher ranges this time. But that did not cause it to peak at 5400.

There have been many other resources (including brodix) that do this thing for a living that say the cam is sufficent for 6000 in a 400.

 

I typed up a HUGE reply and then my connection crapped out, losing all of it.

Here's the Reader's Digest version:

I looked at your dyno curve

It does look a little odd

I'm not so much worried about the slight flattening at 5400 as I am at the total nose-over at 5900. They may be related depending on....

Did you take your foot out of it at 5900 or is that actual WOT power all the way up? I have ideas but I'd need to know the answer to the question, above.

 

I was not running the chassis dyno or the superflow. From what I can tell about the chassis curve, he started to let off at about 5850 on both runs

 

Not trying to put the smack down on anybody, but there's a couple of misconceptions that need to be cleared up in this thread if we're gonna try to help the poster.
1. The cam should be adequate for a street motor of this caliber.
2. The cam will peak between 5500-5800 rpm's.
3. Solid roller will not require the lifters to be changed after 5k
miles. Only need to have the lash adjusted every 5-15k.

That out of the way, Is this motor completely fresh? If it is, check your valve lash adjustment. As a matter of fact, check all the valvetrain components. Use a dial indicator to check the cam lobes. The motor sounds good, but something is wrong. I'd put my money on the problem being in your valvetrain or maybe a lifter problem. If the problem isn't there, then you're gonna have to tear the motor back down to look for possible loss created by excessive friction, like a slightly cocked piston.

 

OK, here's my $.02 given your answer:

I don't think you're going to peak much higher than that regardless. 400+ci engines breathing through small block heads are like a fat man breathing through a straw, even if they're decent heads. I generally agree with the above comment that you will peak maybe 5500-5800 at the most anyway.

See how it kinda peaks up at 5400 and then drops off, kinda flattens out and then drops some more? That could be some kind of valvetrain harmonic issue. I don't know why my brain keeps going back to valvetrain, but it does. This FEELS like valvetrain.

Without the weird bump-n-fall in the HP graph a nice smooth curve would probably peak around 5600 or so- about where it should. It's the odd bump that's sticking up a little that's pulling the peak down a little lower in the RPM range than you expect. It's what happens just before and after the 5400 peak that makes me think valvetrain harmonic- it's lower on either side. Like it's going into an RPM range where there's a problem, clearing out of that around 5400 and getting into trouble again above that point.

 

I would add what a few others have said already. It sounds like valve lash might be too tight. And to get any more rev's, I think the cam should have a narrower LSA, maybe 106 or so. Like was said, 400's need those valves open. the duration is OK, but for that kind of rpm, you need less seperation.

in any case, a thorough valvetrain checkout is what I would start with.

was this motor assembled with tight bearing clearances? oil pressure doing anything funny during the runs?

heres another question.....how big is the carb? I would think you should be using something like an 850cfm or so. Anything smaller is probably going to start pulling a significant vaccuum at WOT.

 

Usually a cam with about 250 at .50 will usually peak around 6300-6400 in a 406.

You say the cam was designed to feed the motor to 6300. Yet later on. You found out that the exhaust ports were barely flowing 140. It sounds like the guy who recommended the cam to you was just that. Recommending it. In order to design a cam he would have needed to know port volume, mca, mid port length, exhaust flow with a pipe...etc

Also I would still look to valve train. Have you tried loosening the lash? Sometimes that helps. What are you running for the rest of the valve train parts? Also how aggressive is the cam? Advertised duration numbers? Do you know the valve events where they open close?

 

re-reading your first post you stated you think the cam is advanced 6 degrees, you might wanna try retarding it a couple degrees.

 

Everything I have ever seen says street use does not allow enough time above 3000 rpm to sufficently lube solid rollers. Even the direct oil type are recomended to be replaced at regular intervals. And having seen the effects of lifters that were not replaced (on a street motor) and the damage that occurs following their failure, the cost effective solution for me was hydroller.

When the motor was first dynoed on the superflow, the possibility of loss of valve control was considered. Confirming a "problem" on a superflow is normally done like most other situations. You look for the symptoms of the problem. IN the case of valve float, a superflow curve will show several different examples that the problem is occuring. Not only will volumetic efficency fall off rapidly but so will CFM. These symptoms were not present.

However, since I had it apart (for the heads) the logical approach was to replace springs also.

On a similar note, the lash is no more than 1/8 turn down from zero on all rockers.

Mains and rods were .025. No problems with oil flow or pressure.
The carb is a demon 1000 (that is based on an 850). It has 1.56" venturi.

The quote from both cammotion and comp was based on the rated flow rates of Track1s. The complete heads normally have pocket work and gasket match to ensure proper flow (that is normally all it takes to get them close to 170). For some reason, herbert performance elected to just forget about the exhaust ports on my heads. The big lip right in the exhaust valve pocket was never removed by them hence 140max

I have not ruled it out.. but since it did spec exactly like it was supposed to be ground Cammotion does supply a camdoctor readout, but it does not include anything but toal 050 duration, open and closing points at 050, LSA, Intake valve centerline, and lift. It provides a refernce to lobe area in inchs per degree and that i have seen, the number is pretty high indicating it is about an as agreessive hyd lobe roller as you can get.

 

Are you sure the hydra-rev kit isn't your problem? What about the lifters? Are they new or old? Are they working properly? If all these things check out, I'd have to say that I'd send the heads back and tell the guy I paid for the port work now give me the 170 cfm I'm supposed to have. The 140 doesn't seem like a big loss, but it changes the cam requirements. In otherwords, the six degrees of duration difference might have worked with the correct heads, but the airflow you're getting right now might like a duration difference of 8-10 degrees. In short, you paid the guy for all that work and you didn't get it. Now it might be actually affecting your combination. Port work doesn't just affect the maximum lift point, it affects every lift point your cam reaches. It's probably costing you more power throughout the entire power-band, but you notice it the most at the top end where the motor just falls like it's out of gas.

 

OK, since it CAN'T be fuel and it CAN'T be valvetrain (still not sure I beleive that) there's really only one thing left..... ignition. I know you've got the best of everything but you should swap it out temporarily for something else. I keep a known-good HEI distributor laying around for exactly these types of situations. It's certainly good enough through 6000 that if there's something wrong with you current ignition system a swap to the HEI will produce "holy cow" kind of differences.

I had the MSD box on my Malibu get flaky just 2 weekends ago. It still ran fine and all but WOT behavior got "weird". Lots of diagnosis narrowed it down the the MSD box itself. Swapping in my "diagnostic" HEI resulted in a total fix and a much better and stronger running engine. Another friend of mine had his ignition retard system get weird on him and the motor wouldn't run for a damn within a very limited RPM range but was fine everywhere else. Hey, it can happen.

 

The lifters were purchased new for the first 400 (which had a sleave in #5 hole and did not last 20 hours). They were reused, they have a total of 109 hours on them.

As with most hi-po parts, the numbers are just advertised by the manufacturer (no guarentee is provided). The flow of the exhaust is now at least if not better than advertised by the vendor. So the cam should be about right (for a set of "cleaned-up" track1s) or at least close to what was originally speced to cammotion.

I will look into checking the CD box. However, it was not used on the superflow. Only the distributor was used and plugged into the coil and box attached to the superflow.


But, I am just about to the point that I dont care that it does not run as fast as I intended. It is reliable and it runs ok for now. If I ever pull it back out I will probably go solid roller just to elminate that possibility. It will probably never see a dyno again. And I probably wont even mess with taking it to the track until I do figure out what it needs.

I am just glad it is not requiring anymore parts or much time. Things are a little too hetic in my life to spend too much time on the car now.

thanks for the comments.
If I ever figure out what the devil it is I will let you know.

 

One last thing just came to mind. It's probably nothing, but I did see a guy who had a core shift problem that manifested in his lifter bores. The lifter was having some trouble going up and down in the lifter bore and cost him some horsepower. He fixed it by opening the lifter bore up and using a b.b. lifter I think. Anyways, you've tried everything else just about, so why not check the lifter bores to make sure they're not out of round and of the proper size. It's worth a shot. Otherwise, let us know if you find this bugger.