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Swaping my 351 cleveland for 408w stroker
#71
(11-26-2018, 09:07 PM)barnett468 Wrote:
(11-26-2018, 08:12 PM)barnett468 Wrote:
(11-26-2018, 02:16 PM)EvilPuppetMaster Wrote: I found this on another forum... This guy had the same question and i guess result is going to my favor:
This is what he wrote:

I figured out the reason for the difference. The Comp Cams XE series is based on .0006 lift, where the Lunati VooDoo numbers given for valve events is at .050 lift. So I need to obtain the advertised numbers from Lunati to be able to get an idea of what my dynamic compression will be.
From doing some searching, I believe it will comparable to the XE (around 63 degress ABDC) which would put me right around 8.5:1 dynamic CR.
I knew the 42.5 ABDC wasn't right, it had my DCR over 9.5:1, I don't think there is a pump or race gas available to handle that.

Does this make sense? Using your ABDC calc this would bring me to 8.5 dynamic CR which is great

Alex

The dynamic compression changes throughout the rpm range and is affected by several factors including ivc, overlap, lobe profile (ramp angle), header type, and amount of scavenging that is occurring etc, therefore, not even a sophisticated computer dyno program can accurately determine what it will be but they can give a general idea and are useful for comparative purposes. 

The more volumetrically efficient and engine is, the higher the dcr will be.

The potential for engine "ping" is also determined by the load on the engine which can be reduced with numerically higher gears if all else remains the same.
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#72
(11-26-2018, 09:11 PM)barnett468 Wrote:
(11-26-2018, 09:07 PM)barnett468 Wrote:
(11-26-2018, 08:12 PM)barnett468 Wrote: The dynamic compression changes throughout the rpm range and is affected by several factors including ivc, overlap, lobe profile (ramp angle), header type, and amount of scavenging that is occurring etc, therefore, not even a sophisticated computer dyno program can accurately determine what it will be but they can give a general idea and are useful for comparative purposes. 

The more volumetrically efficient an engine is, the higher the dcr will be.

The potential for engine "ping" is also determined by the load on the engine which can be reduced with numerically higher gears if all else remains the same.
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#73
That's some great info there... 
Thanks for all your help. Just ordered everything I need so will let you guys know after the initial cam break in.

I believe it will take engine shop guys few months to build it so stay tuned

Alex
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#74
(11-26-2018, 09:30 PM)EvilPuppetMaster Wrote: That's some great info there... 
Thanks for all your help. Just ordered everything I need so will let you guys know after the initial cam break in.

I believe it will take engine shop guys few months to build it so stay tuned

Alex

That info is the reason I mentioned that you would be safe with 9.3 static compression with that cam in your app instead of giving you a dynamic compression number.
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#75
OK guys, 

so after almost one year the engine was built and dynoed today. However, we have an issue....

So as i said, i went with the 408 cleveland stroker kit and speedmaster 220cc 3v aluminum heads. All internals (valve train) that came with the heads have been replaced with quality parts.

Anyways, i bought 3v speedmaster intake as well to match the heads.


So long story short it made 422 HP at 4600 RPM and 482 lb-ft of torque at 
same 4600 RPM

at 4700 RPM fall of on its face hard... It goes down to 429 lb-ft of torque and 384 HP
from then down it keeps dropping power. We never pushed it past 5000 RPM...

So builder thought it is ignition problem so we changed ignition and boom same problem at same RPM.

Changed spark plugs, wires, checked Fuel Pressure, cleaned fuel filter, changed 3 carbs ... Same problem at the same RPM

They said it should not be valve float since they checked the spring pressures and it is matching cam...
Suspected lifters issues but ruled that out later because it does not matter if its cold or warm engine pull it drops down at 4600 RPM.

You can tell that it wants to climb up higher but something is happening and it is falling on its face.

So the last thing it was suggested is to replace crappy Chinese intake.
It is the low profile speedmaster intake manifold. 
  
Overall , i am happy with the build and 422 HP and 480 lb-ft of torques at 4600 RPM but i feel that it is much more capable than that

So i am planning to replace the manifold with again speedmaster highrise 3v manifold but i am not sure if I am going to have clearance issues with my hood.

Do you guys think that manifold could be an issue and what other intake manifold could fit these speedmaster 3v heads?

(sorry, i just noticed that Graph and data image are from 2 different pulls but they are all almost identical)


I am attaching dyno sheet.(nice Christmass tree Big Grin )

Thanks
Alex


[Image: 20190912-205842.jpg]

[Image: 20190912-205853.jpg]
  Reply
#76
(09-12-2019, 08:26 PM)EvilPuppetMaster Wrote: OK guys, 

so after almost one year the engine was built and dynoed today. However, we have an issue....

So as i said, i went with the 408 cleveland stroker kit and speedmaster 220cc 3v aluminum heads. All internals (valve train) that came with the heads have been replaced with quality parts.

Anyways, i bought 3v speedmaster intake as well to match the heads.


So long story short it made 422 HP at 4600 RPM and 482 lb-ft of torque at 
same 4600 RPM

at 4700 RPM fall of on its face hard... It goes down to 429 lb-ft of torque and 384 HP
from then down it keeps dropping power. We never pushed it past 5000 RPM...

So builder thought it is ignition problem so we changed ignition and boom same problem at same RPM.

Changed spark plugs, wires, checked Fuel Pressure, cleaned fuel filter, changed 3 carbs ... Same problem at the same RPM

They said it should not be valve float since they checked the spring pressures and it is matching cam...
Suspected lifters issues but ruled that out later because it does not matter if its cold or warm engine pull it drops down at 4600 RPM.

You can tell that it wants to climb up higher but something is happening and it is falling on its face.

So the last thing it was suggested is to replace crappy Chinese intake.
It is the low profile speedmaster intake manifold. 
  
Overall , i am happy with the build and 422 HP and 480 lb-ft of torques at 4600 RPM but i feel that it is much more capable than that

So i am planning to replace the manifold with again speedmaster highrise 3v manifold but i am not sure if I am going to have clearance issues with my hood.

Do you guys think that manifold could be an issue and what other intake manifold could fit these speedmaster 3v heads?


I am attaching dyno sheet.(nice Christmass tree Big Grin )

Thanks
Alex
That seems strange. If you have hydraulic lifters it should go all the way up to 6k or 6.5k. I am sure there will be others here with more knowledge replying. I don't know if that will all be due to the manifold. It is choking somewhere. Maybe the lifters, or something not well adjusted with the valve train. Did you measure total valve lift with oil pressure (if hydraulic lifters)? Cam advance? Did you guys degree the cam?

[Image: 20160929_171923_edit2_small.jpg]

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump
Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes
  Reply
#77
(09-12-2019, 08:38 PM)tony-muscle Wrote:
(09-12-2019, 08:26 PM)EvilPuppetMaster Wrote: OK guys, 

so after almost one year the engine was built and dynoed today. However, we have an issue....

So as i said, i went with the 408 cleveland stroker kit and speedmaster 220cc 3v aluminum heads. All internals (valve train) that came with the heads have been replaced with quality parts.

Anyways, i bought 3v speedmaster intake as well to match the heads.


So long story short it made 422 HP at 4600 RPM and 482 lb-ft of torque at 
same 4600 RPM

at 4700 RPM fall of on its face hard... It goes down to 429 lb-ft of torque and 384 HP
from then down it keeps dropping power. We never pushed it past 5000 RPM...

So builder thought it is ignition problem so we changed ignition and boom same problem at same RPM.

Changed spark plugs, wires, checked Fuel Pressure, cleaned fuel filter, changed 3 carbs ... Same problem at the same RPM

They said it should not be valve float since they checked the spring pressures and it is matching cam...
Suspected lifters issues but ruled that out later because it does not matter if its cold or warm engine pull it drops down at 4600 RPM.

You can tell that it wants to climb up higher but something is happening and it is falling on its face.

So the last thing it was suggested is to replace crappy Chinese intake.
It is the low profile speedmaster intake manifold. 
  
Overall , i am happy with the build and 422 HP and 480 lb-ft of torques at 4600 RPM but i feel that it is much more capable than that

So i am planning to replace the manifold with again speedmaster highrise 3v manifold but i am not sure if I am going to have clearance issues with my hood.

Do you guys think that manifold could be an issue and what other intake manifold could fit these speedmaster 3v heads?


I am attaching dyno sheet.(nice Christmass tree Big Grin )

Thanks
Alex
That seems strange. If you have hydraulic lifters it should go all the way up to 6k or 6.5k. I am sure there will be others here with more knowledge replying. I don't know if that will all be due to the manifold. It is choking somewhere. Maybe the lifters, or something not well adjusted with the valve train. Did you measure total valve lift with oil pressure (if hydraulic lifters)? Cam advance? Did you guys degree the cam?
The engine builder did all the work. I assume he knows what he is doing. they build mostly big blocks and race engine but definitely very knowledgeable
BTW, oil pressure stayed around 77 PSI the whole run. We did more then 10 in total. each time we changed something to see if the issue goes away. The engine runs strong. No valve train noise. The whole dyno session and troubleshooting lasted almost 7 hours Smile


Alex
  Reply
#78
Not to sound like i dick, but i would guess its the speedmaster heads and intake. Pay for cheap parts you get cheap results. While 422HP is very respectable, that motor has WAY more to it than that. My guess would be in the casting of the heads and or intake. At that RPM there may be a distrurbance/turbulance in the runners that is messing with the flow of air and fuel. Depending what cam you are running that motor should easily pull 550-600hp with a good set of AFD or CHI heads. I have heard of some of the chevy guys buying the cheap speedmaster/procomp heads and putting good valves in them but they usually have the seats beat out of them in no time and the guides go quickly. Good luck with it, i hope you figure it out.

Also, I have my rev limiter set at 6,700 rpm for my 408C and its still pulling like a freight train at that RPM. Definitely think its something internal in the flow of the air/fuel mixture.

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 044.jpg]

https://youtu.be/SoW1fhaFPzY
  Reply
#79
turtle5353 Wrote:Not to sound like i dick, but i would guess its the speedmaster heads and intake.  Pay for cheap parts you get cheap results.  While 422HP is very respectable, that motor has WAY more to it than that.  My guess would be in the casting of the heads and or intake.  At that RPM there may be a distrurbance/turbulance in the runners that is messing with the flow of air and fuel.  Depending what cam you are running that motor should easily pull 550-600hp  with a good set of AFD or CHI heads.  I have heard of some of the chevy guys buying the cheap speedmaster/procomp heads and putting good valves in them but they usually have the seats beat out of them in no time and the guides go quickly.  Good luck with it, i hope you figure it out.

Also,  I have my rev limiter set at 6,700 rpm for my 408C and its still pulling like a freight train at that RPM.  Definitely think its something internal in the flow of the air/fuel mixture.

Hey, no hard feelings here. I knew what I was getting into. It was simple decision to save money. CHI heads are about 2400 dollars while these heads cost me 1000 and that is with all updated valve train components.

This is not going to be racing engine and it will not see lots of action past 5000 rpm but I am puzzled with this issue and would like to get to the bottom of it.

So while my engine is still on DYno, I would like to try maybe replacing manifold and lifters to see if this condition improves.

I forgot to say, that our last test was with the vacuum gauge attached to the manifold. We expected to see turbulence at that RPM but we did not get anything major...
It was fluctuating a bit around 0 . I'll see if I can add that run to youtube and I'll post the link here.
link: https://youtu.be/7taRhWLBW-8

I was wandering if I can use let's say CHI 3v manifold with these speedmaster heads?

I will call the vendor later to ask.

Alex
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#80
Iron closed chamber or open chamber heads, with minor port cleanup, will do better than that at 351 cubic inches, and in the 500+ horsepower range with a 408.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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