Ford Windsor 408's HP Plateaus @ 5,600

[NewbVetteGuy]

do you have lbs/hr of fuel used per rpm? air flow through the carb? did the carb go fat? lean? did the air flow keep going up? or fall? show us the data

Unfortunately, no. Not documented in any of the printouts from the dyno operator and supposedly they can't pull and reprint it now... ;-(


Adam

[NewbVetteGuy]

In those Cam lift spec's you posted how is it that two different lobe lift numbers give the same amount of gross valve lift?

I think those are advertised duration, not lobe lift?

Correct the first #'s were ADV duration; not lobe lift #'s. Updated for clarity below.

Anderson Ford hyd roller N-111 cam: ADV duartion:315/325, 0.050" durations: 248/258, lift: 5.76"/5.76" (1.6 Rockers); 110 LSA ICL 105

[NewbVetteGuy]

Maybe too much spring pressure for these lifters?

Agreed too much pressure. (From spring pressure+velocity.)
-I THINK the increased rocker ratio increases the pressure on the plunger, too but I'm not super confident in that...

Would a rev kit help here as it's applying pressure to the lifter body? (does it decrease the pressure on the plunger, or would that only be helpful if there's also a decrease in the actual spring pressure?)



Adam

[NewbVetteGuy]

With that bore and stroke I come up with 5800rpm for a average CSA of 2.165".

Average CSA of 2.165" x port length 5.77" x 16.387 = 204.7cc
If those heads are as cast there might be some turbulence issues like most as cast heads i have seen.

Thanks Steve!

I got the same numbers.

-They ARE as-cast heads and that helps make sense why it seems to have stopped increasing at power @ 5,600 vs 5,800 where the Min CSA / Velocity calculations estimate choke to set in. I've heard it recommended to lightly sand the SSR on as-cast heads against the direction of air flow. I assumed it was to help keep turbulence down and help the air make the turn at high speeds. It sounds like that's actually an issue sometimes.

CSA definitely an issue. Lifters; maybe?

Adam

[Tuner]

If this is the head and combustion chamber the engine has, I would be surprised it is happy with 36 degrees total. I have tuned a few SBF with this head and similar heads in the last 10 years or so that were happy with 30 or less .... 26. Too much timing, even if it doesn't knock, will make the engine feel like the brakes are dragging or the car is towing a parachute.

I've found this type of fast-burn SBF head likes an advance curve that creeps about 1 degree per 1000 RPM from about 2500 up to beyond peak.

https://www.flotekheads.com/store/Small ... p131024586

[mag2555]

What! 325 advertised duration from only 258 @ .050"?

[PRH]

One thing that seems odd to me is how close the tq and hp peaks are to each other.

As a comparison to something with quite a bit smaller heads.......
416” SB Mopar, bowl blended Ede RPM heads(170cc..... flow about 270, 2.02/1.60), SV intake, old school solid cam with smooth ramps, 265/270-106, 1.5 rockers, .563/.563, 1-3/4 to 1-7/8” headers, 850 carb.

Peak tq@4600(542), peak hp@6300(561).

My experience has been that when the valvetrain/lifters get unhappy, the fall off is more abrupt that what is seen in the graph for the Ford......... but since the TQ peak is happening at a sufficiently high rpm(along with the tq/ci value being pretty good), and the combo “looks” like something that would peak noticeably higher than 5600........ I’m going to be suspicious that the problem is somehow valvetrain related.

[brentry]

One thing that seems odd to me is how close the tq and hp peaks are to each other.

As a comparison to something with quite a bit smaller heads.......
416” SB Mopar, bowl blended Ede RPM heads(170cc..... flow about 270, 2.02/1.60), SV intake, old school solid cam with smooth ramps, 265/270-106, 1.5 rockers, .563/.563, 1-3/4 to 1-7/8” headers, 850 carb.

Peak tq@4600(542), peak hp@6300(561).

My experience has been that when the valvetrain/lifters get unhappy, the fall off is more abrupt that what is seen in the graph for the Ford......... but since the TQ peak is happening at a sufficiently high rpm(along with the tq/ci value being pretty good), and the combo “looks” like something that would peak noticeably higher than 5600........ I’m going to be suspicious that the problem is somehow valvetrain related.

I think that is a very good point

[steve cowan]

One thing that seems odd to me is how close the tq and hp peaks are to each other.

As a comparison to something with quite a bit smaller heads.......
416” SB Mopar, bowl blended Ede RPM heads(170cc..... flow about 270, 2.02/1.60), SV intake, old school solid cam with smooth ramps, 265/270-106, 1.5 rockers, .563/.563, 1-3/4 to 1-7/8” headers, 850 carb.

Peak tq@4600(542), peak hp@6300(561).

My experience has been that when the valvetrain/lifters get unhappy, the fall off is more abrupt that what is seen in the graph for the Ford......... but since the TQ peak is happening at a sufficiently high rpm(along with the tq/ci value being pretty good), and the combo “looks” like something that would peak noticeably higher than 5600........ I’m going to be suspicious that the problem is somehow valvetrain related.

I would of thought that mopar combo would of gone into sonic choke earlier with small cc head,pretty impressive i think

[PRH]

Compared to the 416-

A 10.5:1 more street oriented 410 with 14* less cam, 1.5 points less CR, a smaller intake manifold(Victor), and smaller headers made peak tq@4700, and peak hp@5900........ but from 5700-6300 it’s within 4hp.

To me, the Ford peaking that early just seems off.

Here’s another one..... 422” SBC, ootb AFR 220(supposedly a min csa of 2.18), ootb SV(2925), QFT 950, 1-3/4 to 1-7/8 header, 262/268-108 roller(Comp Hi-Tech .420 lobes), 1.5 rockers.
Peak tq@4900, peak hp@6300

[travis]

If this is the head and combustion chamber the engine has, I would be surprised it is happy with 36 degrees total. I have tuned a few SBF with this head and similar heads in the last 10 years or so that were happy with 30 or less .... 26. Too much timing, even if it doesn't knock, will make the engine feel like the brakes are dragging or the car is towing a parachute.

This is where I would start, as this is exactly what I’ve seen with the 351w/180cc Pro-maxx head combo in one of my trucks. 10.0-1 compression with a small 264/268@.006” hydraulic roller cam. With 36* total, it seemed lethargic and would just quit pulling at 5300 rpms, but no pinging. Now with 30* total it pulls cleanly to 5800, and is more responsive across the board

[n2omike]

People look at dyno numbers from an AFR 205 headed 408, and think they will get similar performance from a Chinese 205 head they got for 'half price'... only to learn that money they 'saved' killed their entire combo. The heads are junk. Sell them on Ebay to some other fool, and put a decent head on the engine. Will immediately pick up a TON of power, and pull more rpm.

[brentry]

Knowing the csa was given in this post.
I assumed they where flowed.
Now i am guessing they where not, as flowtek does list csa on there website. There published flow chart doesn't look all to happy and it starts at 400 lift?

[Walter R. Malik]

All,

Looking for help solving a mystery. Not my engine, but I have my theory...

Ford Windsor 408: 4.030" bore, 4" stroke; 6.2" rods; 10.85:1 CR
FloTek SBF 205cc / 60cc heads 2.08 / 1.6" valves
Dual springs with dampners 150lb seat; 450 lb open
1 3/4" headers 3" collectors
FST 750 DP carb
Anderson Ford hyd roller N-111 cam: 315/325, 248/258 @ 0.050", 5.76"/5.76" lift with 1.6 Rockers; 110 LSA ICL 105
Stopped liking timing @ 36 deg
Edelbrock Super Vic intake
93 octane; Stuska dyno

.040 plugs; recommended heat range; msd something something ignition box

Guy was expecting it would pull to 6,500 but curve goes flat @ 5,500 - 5,600 and stays that way for 700 rpm...


If that image doesn't resolve; I'll go post it somewhere and come back and repost...
Adam

Just guessing from past happenings;

It is an ignition issue, (rotor phasing, wrong ignition timing, spark plugs, etc).
Maybe the heads. They need to flow about 140@.200" & about 295@.600" at that port volume ... "as cast" I would wager they don't;
or, the lifters are giving-up and collapsing at higher RPM for whatever reason.

[rustbucket79]

Valve float on the dyno looks like someone pulled half the plug wires off in an instant, it’s that massive a loss.

What lifter collapse looks like, I don’t think I’ve encountered it. I would assume major valvetrain noise with the added lash.

Apples to bowling balls comparison, but personally, I had a 406 Chev on the dyno, 14.5:1, big duration roller cam, ported iron bow tie heads, Vic jr intake produce a very similar dyno graph to this one in terms of hitting a peak and maintaining. It was annoyingly similar to its previous build with 11.5, solid flat tappet, but same heads and intake. (Big $$$ upgrade for no real gains)
Same rotator, same solid roller, same intake, more lift due to rocker ratio, and AFR 245’s, powerband continues to climb rather than plateau, and in fact peaks about 1500 RPM higher than with the iron heads.

I think your heads are the cork, but your results are decent regardless of the early peak.