Another question for the engine Gurus...

[SLEEPERBUSA]

I'll talk about the intake side only, first, because if my thinking is messed up, no sense to continue typing.

 My current setup is 1441cc at about 12.7 final compression, Carpenter head, .443 cam @ 111.0 CL.
VTP clearance currently is .084" @ 9.8ATDC
This combo is not working for me.
I am asking for you to review my numbers and see if my thinking is on, or am I out in left field?
I want a bit more compression, and I think these new cams will help me accomplish that.
I'll do the intake first.
Current setup. .443"
New cams.     -.415"
Will net me    .028" more VTP
Add that to   .084" and I will then have .112"VTP

Change from .030" head gasket
To                 .018" head gasket
Remove B/G  .010"
and I lose      .022" total

That tells me that if I get my VTP clearance to .112" and then lose the gaskets thickness of .022" total, I'll gain compression and still have .090" VTP clearance, which is .006" more than I currently have..

Input please. 

 

[sportbikeryder]

That's a big cam.

The smaller cam probably will dwell at max lift a little longer, possibly making the min PTV at a different crank angle.
you really can't just add things together and hope it will work, you need to mock it up and measure the mins.

What do you mean by "not working for you"? Where is the Tq and HP peak with that setup? Probably above 10,500 rpm.

[SLEEPERBUSA]

Here is the 1441 compared to my stock motored bike on MR12.

[fvance]

The 216hp is the 1441??

[SLEEPERBUSA]

Yessir.

[entropy]

who the hell built that pussy motor

you know my thoughts, and i'm thinking that you gotta decide what yr objective is.

1. is it a street bike, gonna run street gas? 

2. are you gonna spray it hard?  on street or 1/4mile or 1 mile tracks?

answer those questions, THEN design the internals.

For me 216hp @ 12.7:1 CR, pumpgas is about right +/-

If yr gonna spray it, i wouldn't bother screwing with cams.

[SLEEPERBUSA]

I have NO issue with the assembly at all. I know the guy pretty good. It's not coming apart.
Johnny beat on it pretty good on the dyno, and it lived thru that, so i'm good there. 

I have 3 issues with this motor,and they may not be logical to anyone but me, but this is them.
1st is the fact that over 5 years ago, I had a 1397 that went thru a home made header that made over 212/115. It's hard to believe that this larger motor is supposed to make the same HP. GENII design, larger cams and a real header.

2nd is, it's hard for me to see that chart where a STOCK motor on MR12 kicked it's ass till 7,400rpms.

3rd is it follows the stock HP and TQ curve like a mirror.
I have had 2 prior Carpenter head cam packages that Johnny had to extend the ecu because the power was still rising when it hit the rev limiter.
Ive decided to put this engine in my streetbike with smaller cams, in hopes that the HP/TQ picks up. Too many people have told me that these big cams will beat up the valve train on the street. So while I was there, I wanted to bump up the compression at the same time. I'm gonna have a large motor built for the drag bike.
 

[05calibusa]

I gotta say that those dyno numbers are depressing.  My buddy built a 1397, with a ported head and two stock intake cams set to 106/106 and peak hp was 215 at 11.5K.  BTW, his dyno run was using Chevron 91 octane pump gas. 

This thread is of particular interest to me because I am in the process of putting a 1441 together and I am expecting at least 220hp.  If I can only pull 216hp with the 1441, then I pretty much wasted all of that $$$ on the crank...could be put to better use.

[sportbikeryder]

I gotta say that those dyno numbers are depressing.  My buddy built a 1397, with a ported head and two stock intake cams set to 106/106 and peak hp was 215 at 11.5K.  BTW, his dyno run was using Chevron 91 octane pump gas. 

This thread is of particular interest to me because I am in the process of putting a 1441 together and I am expecting at least 220hp.  If I can only pull 216hp with the 1441, then I pretty much wasted all of that $$$ on the crank...could be put to better use.

Really? 220hp and you will be content, but 216hp and you will feel you wasted all that money?

4HP is only a 1.9% difference in power. If you are that hung up a dyno reading that is 4hp difference, you will probably be better suited to get into a new hobby.

[05calibusa]

I gotta say that those dyno numbers are depressing.  My buddy built a 1397, with a ported head and two stock intake cams set to 106/106 and peak hp was 215 at 11.5K.  BTW, his dyno run was using Chevron 91 octane pump gas. 

This thread is of particular interest to me because I am in the process of putting a 1441 together and I am expecting at least 220hp.  If I can only pull 216hp with the 1441, then I pretty much wasted all of that $$$ on the crank...could be put to better use.

Really? 220hp and you will be content, but 216hp and you will feel you wasted all that money?

4HP is only a 1.9% difference in power. If you are that hung up a dyno reading that is 4hp difference, you will probably be better suited to get into a new hobby.

I said that I am expecting "at least 220hp"...hoping for much more, and YES if I can only get the same 216hp with 1441 that I could with 1397, then the crank IS wasted money in my book.  You might be good at building bikes, but maybe not so good at finance and ROI.  I intend to be good at both, so I will keep my "hobby".  I wonder why Sleeper posted in the first place...proably not happy with 216hp on his 1441.   

[SLEEPERBUSA]

Yep, not happy with the final outcome.
212hp 5 years ago with a smaller motor.
Fast forward 5 years, bigger motor, supposed to be a better head design, and $6,000 to get the same results?   
So, The main reason that I posted is,
I'm stuck with what I have. OK...
BUT, I wanna make it the best I can. People tell me now that the cams are too big and will eat up the valve train on the street, so the question I have is,
does anyone think the .415/.395 will be a better match for this combination, and will tightening up the gaskets help also?

Current cams are .443/.425

[05calibusa]

I'm with you brother...I will have $6G's in mine too when all is said and done, and no turning back on the crank either.  I hope you can find the issue.

[sportbikeryder]

Yep, not happy with the final outcome.
212hp 5 years ago with a smaller motor.
Fast forward 5 years, bigger motor, supposed to be a better head design, and $6,000 to get the same results?   

does anyone think the .415/.395 will be a better match for this combination, and will tightening up the gaskets help also?

Current cams are .443/.425

the smaller cams (as well as degreeing them more for bottom end) will probably increase the bottom end, but you likely aren't going to gain up top.

I would try setting your intake to about 106 or so and see what that does for you. It's easy enough to try.

I have never seen any big gains by putting in a slightly stroked crank. If you go big, sure, there is gain, but increasing displacement by stroke never seems to add as much power as by bore.

I'd runt eh bike with less advanced intake timing and with the MR12 and see how it does before spending any more money on parts. 

Is that .443 the cam Carpenter recommended with that setup?

Do you have a sidewinder on this bike by chance?

[fvance]

Chris both my motors have the 443/425 cams the low comp.(13-1) 1340 are degreed 110/112. Tight squish .032. gen 2 pistons.

[speedduck]

I have been in that situation several times, new parts are "bigger" but power gain is very modest or nothing at all. There is always place for good advice from experienced engine builders. But if you want to make it look like yours and feel you have made it work, then maybe you should just continue testing little changes at a time.
Why is your lobe center so high ? It drops already low compression when intake closes so late. Can you get CR over 13 ?
How much valve spring pressure ? I would keep that .443" and run it with 55lbs springs. It may wear in time, but are you driving coast to coast every week.
I`ll bet that Carpenter head can handle that cam.
VTP .090" is plenty, for intake. I have used .042", but then it should work like a clock, .060" is adequate.

[SLEEPERBUSA]

Well, here's another deal.
I have 2 bikes, 2 engines.
I am going to go ahead and run this one in my streetbike.
I've already ordered the cams, so my asking as mainly conversation and to see if my thinking was ok, because I want abit more compression, but VTP is at what I understood, the minimum already.
I don't like the cam that I got from Carpenter, because he sent me a GENI cam and I had to buy the Brock pin to make it work. I have also had several people tell me that the pin could be causing a HP loss also. I am taking the pin out of the equassion. That cam is sold.
I will be using the stock motor and having it built. This engine is important, as I want all of my stuff to fly, but the next one will be the builders complete design. I'm gonna give it to him and keep MY hands out of it, as I am NOT a builder or designer.

I just break shit!

Thanks greatly for everyone's input. Feel free to continue. I am always willing to try to learn something.

[fvance]

Chris, I hope the builder is JC or Knecum!! MR12 Would give you close to 225hp with the present setup.

[SLEEPERBUSA]

Yes,
Johnny has built all of my motors up until now. I am very happy with all he has done and will continue to do.
I've talked to Steve about doing my next engine.
 

I bought parts for this motor. Parts that "I" thought would work.

I want the next one to be a complete Knecum design. The only thing that I will give him is the crank, and hopefully he can use the .425 exhaust cam that I already have. If NOT, that's ok. I want this to be his design and build.   

[entropy]

..., but VTP is at what I understood, the minimum already...

if i'm looking at the right build info (i gave you the notes, but have some info in my build worksheets)

yr intake   min PTV = .084"@9.8aTDC, int cam CL = 111.0, ave int shim size = 266

yr exhaust min PTV = .060"@8.5bTDC, exh cam CL = 112.5, ave exh shim size = 303

Like speedduck says, yr min int PTV @ .084" has plenty of clearance.

But min exhaust PTV @ .060" is about as low as i like to go when measuring only one valve.

As you know, I believe you could gain significant hp by simply jacking up CR.
But with yr tight exh PTV, you can't safely incr CR by going from .030" to a .018" HG unless you sink the exhaust seats.

Mr. streetbikeguy feels that trying lower cam CL's is worth doing.
I 110% agree with him (as usual  ), and you could likely get to 106 on intake while keeping .040" or more on min int PTV.
But exhaust PTV is already about as tight as i'd go.

If I were you, I'd prob sink the exh seats.
how much?
Here it gets interesting bc sinking the seats lowers the CR and you need more CR, not less 

if it were me, i wouldn't fret about 5-10hp, wouldn't even take the valve cover off.
I'd spray it like you originally planned.

[entropy]

Chris,
on a related note, you were concerned about the hp curve nosing over at 11k, whereas yr 1397 kept climbing.

FWIW, my 1635 with stock TB's nosed over at 11.2, whereas on my other 1635 with OS TB's & bigger cams, the hp was still strongly climbing at 11.5. 
go figure.

I spent 3 years and a fukken boat load of cash getting the "last 5-10hp"outa my Zx12.
In the end, i got that hp but i learned my lesson...

karl

[SLEEPERBUSA]

Too late. Valve cover is off, cam has been shipped. New cams ordered.
Like I said, i'm gonna go ahead and use the engine......almost.........like it is now. Just a couple small changes. Even if I don't change the head gasket to the .018, the cams and valve springe are getting changed,  I seem to be riding this bike more than I first thought i would.. I don't ride long distance, but I don't want problems later, so i'll make that change before I use it.
Karl, those numbers are what you gave me too. I was under the impression that if you moved the CL numbers down, the VTP got closer, so I didn't even  consider using the cams and moving them, another reason I opted for abit less lift on trhe new cams. This engine WILL get ran. I decided not to tear the bottom end down. You put way too many hours in to help me, for me to just bring it home and take it apart. Tweaking is one thing. Taking it apart is another.

[entropy]

Too late. Valve cover is off, cam has been shipped. New cams ordered.
Like I said, i'm gonna go ahead and use the engine......almost.........like it is now. Just a couple small changes. Even if I don't change the head gasket to the .018, the cams and valve springe are getting changed,  I seem to be riding this bike more than I first thought i would.. I don't ride long distance, but I don't want problems later, so i'll make that change before I use it.
Karl, those numbers are what you gave me too. I was under the impression that if you moved the CL numbers down, the VTP got closer, so I didn't even  consider using the cams and moving them, another reason I opted for abit less lift on trhe new cams. This engine WILL get ran. I decided not to tear the bottom end down. You put way too many hours in to help me, for me to just bring it home and take it apart. Tweaking is one thing. Taking it apart is another.

yes indeed, if CL numbers get lower, the min PTV gets smaller.

what springs are you putting in it?  You for sure don't want to go too soft.

Is the motor on the bench?  Have you pulled the head?

[SLEEPERBUSA]

I don't know which springs. Bill is getting them for me to match the cams.
The motor is still in the other bike. I just got the cam out because it sold. I'll be getting it out within the next couple of weeks when the cams come in.

[speedduck]

Just wondering, how it is possible to have exhaust PTV so close with 12.7 comp and 112.5 CL 
My friend has a head that was made by somebody who mostly does heads for car engines, he opened up the chamber too much and after that never could get the CR right, it flows great though.

[knecum]

So just take the .030 out and install .018... No don't do it !! How much is deck?  PTH? Rocked up on ex side, block torqued down!!