422 dyno fail

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SixPaksRule said:
just another over cammed stroker engine
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overcammed? If it was mine it would be a solid flat tappet 20 degrees bigger @50, and then run an 8 inch convertor with it.
Strokers eat up duration, I have never ran less than 260@50 on any stroker I have ever had..
Except one. Years ago Hensley built me a 416, stuck a 248/258 540/560 Crane solid in it. What a friggin dog. Car ran 11.70’s with that cam and stock Eddie’s and 10 inch vert.
Swapped out vert for 8 inch, cam for a Dwayne specc’ed 260/266 solid, car later ran 10.70’s with very minor porting of the heads by Hensley
 
^^^^Don has a point there on cam size. My 408 is 251/256@050 SFT on a 106 LSA. If I had it to do over again, it would be a bigger cam. There's plenty of "room" at idle for more cam, almost too smooth! 5000 stall 8" converter, Hooker Super Comps, Super Victor and an 850 DP. More cam for me next time!!
 
Demonx2 said:
^^^^Don has a point there on cam size. My 408 is 251/256@050 SFT on a 106 LSA. If I had it to do over again, it would be a bigger cam. There's plenty of "room" at idle for more cam, almost too smooth! 5000 stall 8" converter, Hooker Super Comps, Super Victor and an 850 DP. More cam for me next time!!
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And IF idle quality is an issue, you can always go wider, to like 108, 106 is narrow and spicy regards idle quality, mine is 106 too, but I love it. Just turn the idle up to 1100 or so..lol
 
First off I just want to say thanks for this thread it's been a fun one to follow and participate in. Even though I think there's a little more in there (possibly bigger headers possibly springs and tune) it looks like and I may be wrong that you're just starting to run out of head numbers reflect what you would expect to see if that were the case. It seems like there should be more in a well built X but??I would still be very excited to get it in the car and see what it does I think it'll all ***
 
Swap in a set of Trick Flow heads and watch the dyno #'s wake up.
I think the top end is the culprit. It's not breathing.
 
I wonder if the heads were really ported?
I hope the OP is able to get #'s he is happy with, without swapping too many parts.
 
fishmens67 said:
Swap in a set of Trick Flow heads and watch the dyno #'s wake up.
I think the top end is the culprit. It's not breathing.
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thats a huge cash outlay and kills his objective of keeping it mostly stock looking.
Some IndyX heads would be the best thing for this. Lol, ive got a new set prepped by IMM. Will trade for trick flows!!! Haha.
 
4spdragtop said:
I wonder if the heads were really ported?
I hope the OP is able to get #'s he is happy with, without swapping too many parts.
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There's porting and there's proper porting.
Heads in the wrong hands can be ruined.
I don't know what the op has for heads, but the big hp gain from an intake and carburetor change tells me it's wanting to breathe.
 
I believe stock ported j heads. As I mentioned, I'm no builder, but a stock 340 put out almost same #'s the OP initially had. I think they "flowed" 255 @.600.
To me i would question the quality of the build OR defective parts.
fishmens67 said:
There's porting and there's proper porting.
Heads in the wrong hands can be ruined.
I don't know what the op has for heads, but the big hp gain from an intake and carburetor change tells me it's wanting to breathe.
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Just a question to people with retrofit hydraulic roller experience…

Could the retrofit hydraulic roller lifters be having an issue in this particular 340 block? (I’d guess 68-73 340 block)

If they were bleeding a little oil would the dyno numbers look like it was floating valves? Or had a small cam?
 
I would take D.Vizard's advice, tester of 19,000+ cams. If you want a smoother idle, you do NOT widen LSA. You reduce duration & keep the same 106 LSA.
 
Bewy said:
I would take D.Vizard's advice, tester of 19,000+ cams. If you want a smoother idle, you do NOT widen LSA. You reduce duration & keep the same 106 LSA.
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Not sure if he said that or not, but I believe it to be untrue based on personal results .
Hot Rod magazine doesn’t agree either.. this quote explains it pretty well

“Tight LSA cams make excellent low-end torque and have a beautiful power curve. But nothing comes without a cost, and idle vacuum suffers as LSA shrinks. This causes the engine's street manners and tuning to become fickle. A cam with a tighter LSA will require a looser torque converter, may not be able to run vacuum-assisted brakes, and doesn't play nice with fuel injection”

Camshaft Shootout: Lobe-Separation Angle Tested and Explained
 
Obviously the OP didn't purchase his parts from the bottom line of the catalog.. That's the problem..
 
B3,
And how many cam combinations have HRM tested? Anywhere near the 19,000+ that DV has?
Try getting your facts right before say somebody else's comments are untrue.
DV says this on p. 97 of his BB Chev book:
'If maximising power & tq are the goal, spreading LCA [ LSA ] to improve idle & low speed drivability is a veeeeery counterproductive move. The correct answer is not to spread the LCA, but to go for less duration.'
Also, Richard Holdener recently tested identical cams except for LSA on LS engines. From memory tightest LCA was 108, won overall, & worked fine with the EFI.
 
Bewy said:
B3,
And how many cam combinations have HRM tested? Anywhere near the 19,000+ that DV has?
Try getting your facts right before say somebody else's comments are untrue.
DV says this on p. 97 of his BB Chev book:
'If maximising power & tq are the goal, spreading LCA [ LSA ] to improve idle & low speed drivability is a veeeeery counterproductive move. The correct answer is not to spread the LCA, but to go for less duration.'
Also, Richard Holdener recently tested identical cams except for LSA on LS engines. From memory tightest LCA was 108, won overall, & worked fine with the EFI.
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I said I have found it to be untrue. I have.
Narrower LSA makes a car want to idle rougher because of less vacuum. Because typically there is more over lap.
I agree less duration will help solve the problem, but that isn’t what you originally said.
If the duration is the SAME, the narrower cam WILL idle rougher. I don’t care what Vizard says.
 
SixPaksRule said:
just another over cammed stroker engine
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Gonna have to jump on the disagree train here as well. I'm running the cam I got from @PRH that was originally spec'd for my 360 build. [email protected], 370 lobe lift, mech roller. In the 416 I ended up building it's idle is like a kitten purring and it pulls 16 in/hg. I wish I'd done at least another 20deg and .020, but cam cores were getting thin even back in early 2020.
 
As @PRH said. It smells like a valve control issue. I just watched “engine masters” show on valve float and it was very insightful. The exact cause of the lack of control could be many items including just weak springs, but it could be long, heavy lifters, flexing push rods etc. While I am not a builder of motors, the up and down of power through the chart tells me that it is not merely choked or cam timing that causes it to fall flat. Perhaps it is electrical that causes the blipping of power as the rpms ramp up.
 
Purely by the comment that the cam was installed straight up leads me to believe there was no degree wheel put on this cam.. then it leads me down a whole complete other train of thoughts of what they didn't do... If I paid for a dino pull I would absolutely want to be there to see it and hear it... Not get a call saying it was done... Lots of red flags here..
 
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Power output a side, a smoother idle will have a wider LSA. That’s what I experienced. Same as B3422.
 
PRH said:
The bsfc numbers with the new intake & carb are horrific.
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Doesn’t that measure efficiency and may indicate that the gases are not being exchanged between, intake and exhaust ? Weren’t the first 2 bsfc numbers ok? What would cause the hp and torque to increase but the efficiency to go down?
 
Bsfc is more or less an efficiency report card.
How much power can you make from “x” amount of fuel.
It is not a measurement, it is a “result” of other measurements.

The lower the bsfc number, the more efficient the engine is at turning fuel consumption into hp.

It is derived from dividing the fuel flow by the uncorrected hp.

.50 is so-so.

On the second sheet posted, at 5400rpm the uncorrected hp was 372.0, fuel flow was 184.4....... bsfc was rounded up to .50

At 5400, the sheet with the new carb and intake made 376.3 uncorrected hp, but used 231.1 lbs/hr of fuel to do it...... for a bsfc number of .61

The difference in fuel flow at that rpm is 46.7lbs/hr.
Even at a rather poor efficiency/bsfc number...... of .61...... that 46.7 lbs/hr would be worth 76.5hp...... uncorrected!!!
But instead..... it only made 4.3 more?
Even if the bsfc number has gotten as bad as .56(instead of .50), that would have put the motor at 412.6hp....... uncorrected.

One big problem when you’re trying to compare numbers from different dynos is....... you’re not only comparing the dyno itself, along with all the data acquisition....... but also the entire “facility”.
The room, the ventilation system, the exhaust, the operator...... everything.

At this point, my confidence level for the facility in question during this test session is....... low.

If for no other reason than it doesn’t sound like there was even any discussion about just how bad the bsfc numbers are.

A bsfc number of .70(for gasoline) is painfully bad.

Unfortunately, there isn’t really enough data on the sheets to effectively troubleshoot where the shortcoming is.
When you test a build that’s doing what it should, you can get away without a lot of data.
If the Hp/tq numbers are good, and happening where they should...... that and a plug reading, you’re good to go.
But when the numbers don’t make sense, you need more data.
In this situation, air flow(and with it VE numbers), along with A/F ratio data would be pretty helpful.

The new intake and carb allowed the engine to ingest roughly 50lbs/hr more fuel, yet did very little with it.
Did the 50lbs/hr enter the engine because of a big increase in air volume(drawing the fuel out of the carb)?
Or is the mixture now just super fat?

Those questions are left unanswered with the data available on the sheet.
 
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