Searching for info on Sunnen CV-616 stroker mod.

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crosshatch
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Searching for info on Sunnen CV-616 stroker mod.

Post by crosshatch » Fri Apr 14, 2006 8:14 pm

I was hoping someone here knows where I can get some info on modifying the Sunnen CV-616 stroke mechanism to manually dwell at TDC.
Preferrably a blueprint or photos showing how to mod it myself.
But if there's anyone selling this accessory, I would be interested too.
I have been told this mod is called a "Nascar bar".
I have tried a google search for it but couldn't come up with anything.
Thanks,

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picture

Post by ted66mustang » Fri Apr 14, 2006 10:26 pm

http://www.samracing.com/docs/activitie ... ities2.htm

Go down to the honing picture on the right[/img]

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Post by crosshatch » Sat Apr 15, 2006 12:36 am

I have seen this photo before. That's what got me wondering about it.
But it doesn't show what's happening underneath the belt guard. :-k
I don't want to tear apart my machine with only "guesses" based on what I see in a tiny photo.
I need more details.

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Post by BCjohnny » Sat Apr 15, 2006 6:48 am

I've done a fair bit of work on my CV616 and THINK (I havn't the luxury of a factory wiring diagram) the BDC dwell works on the follownig principle;

The dwell button/rotary dial is Normally Closed (N/C). When operated it breaks the feed to the contactor, stopping the recip mech from functioning. When released the circuit is remade but there is no power to it until the micro switch at the rear of the head (R/H side) pulls the cotactor back in re-engaging the recip drive. The micro switch is tripped by the oscillating lever near the main motor, but inside the head.

By rigging up another button/micro switch to duplicate this at TDC should achieve the same effect.

I would be VERY careful about this and you use the above info at your own risk. It's easy to take a finger off if you fool around, especially with the machine running.........

And I would speak to Sunnen before attempting ANYTHING.

Go on then.....I've got to ask. Why?

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Post by GJ » Sat Apr 15, 2006 9:03 am

I made my own and it works great . I went to SAM and used the nascar bar and I loved it . That was my first modification to my cv616 when I got it . Here's a pic of mine :
http://community.webshots.com/photo/533 ... 0714AIJKOr
I will try to take more pictures of the whole working on it today if I get a chance .
GJ

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Post by CNC BLOCKS » Sat Apr 15, 2006 11:48 am

GJ wrote:I made my own and it works great . I went to SAM and used the nascar bar and I loved it . That was my first modification to my cv616 when I got it . Here's a pic of mine :
http://community.webshots.com/photo/533 ... 0714AIJKOr
I will try to take more pictures of the whole working on it today if I get a chance .
GJ
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Post by GJ » Sat Apr 15, 2006 2:26 pm


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Post by Keith Morganstein » Sat Apr 15, 2006 2:32 pm

lawn mower technology for the machine shop, cool :)


BTW, nice shop. Looks like a freaking Sunnen showroom.
Automotive Machining, cylinder head rebuilding, engine building. Old school shop, semi-retired moonlighter. Can't seem to quit #-o

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Post by GJ » Sat Apr 15, 2006 10:29 pm

thanx max effort
The way this bar work is that when you press it , it push the tensioner pulley that does the stroking . The belt slips and the honing head stays there .
GJ

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Post by BCjohnny » Sun Apr 16, 2006 4:31 am

So it doesn't actually dwell in the same way as it does at BDC, for one/several cycles and re-engage. It's a manual operation. My earlier post assumed you wanted to duplicate that.

And again and at the risk of beginning to sound a bit thick.....Why?

I've had to attend to the odd "barrelling/taper" problem now and then but there are fair effective known methods to do that. What does this bring to the party?

I'm by no means inferring it is, but I've always been a bit wary of the "trick of the week stuff". I've got big shoulders (don't by any means know all of it, or come to that, half of it) so educate me.

Cheers John.

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Post by Wolfplace » Sun Apr 16, 2006 12:32 pm

BCjohnny wrote:So it doesn't actually dwell in the same way as it does at BDC, for one/several cycles and re-engage. It's a manual operation. My earlier post assumed you wanted to duplicate that.

And again and at the risk of beginning to sound a bit thick.....Why?

I've had to attend to the odd "barrelling/taper" problem now and then but there are fair effective known methods to do that. What does this bring to the party?

I'm by no means inferring it is, but I've always been a bit wary of the "trick of the week stuff". I've got big shoulders (don't by any means know all of it, or come to that, half of it) so educate me.

Cheers John.
=
Ok, I am all ears :lol:
Exactly what are your "known methods" of fixing a bore that has gone nuts with a torque plate?

In my opinion that is not a trick of the week, it is something that should have been on the CK10/616 from the beginning.
I have had it on my CK10 forever but I don't remember who sold the kit.
It will let you manually dwell anywhere in the stroke not just at the bottom & it has allowed me to get the bore straight that has "tightened" at the top. or as I said gone nuts with a torque plate.
Sunnen says to lower the block,,, well in my opinion this is crap in some cases.
The way I see it the less time you spend in a hole with a hone trying to straighten it the less problems you have & trying to raise/lower a block you cannot measure is not the best way to achieve a straight hole.
To me, the best time to straighten the hole is when you are rough honing & you only have so much time to do it.

Also, unless you are honing a Bowtie, Dart, World etc that has some wall the load gauge can & will lie to you.
Don't believe it,,, try honing a Harley barrel.
The gauge will always tell you the bottom is big, Wrong,, it will be small every time unless you support it with a clamp of some sort.
Some Fords will do this too in the unsupported part of the bore.

If you want straight holes to me this is a "must have" item :wink:
Mike
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Post by BCjohnny » Sun Apr 16, 2006 1:47 pm

You've probably done a lot more honing than me and you've also answered your own question but one thing comes to mind........

I try as I might to keep abreast of "developments" but being this side of the pond we're not always au-fait with all. How long has this "bar" been in common use? The CK's have been around, what, 40 years or more. How come this "problem" has only recently need "fixing". And torque plates have been used for just as long.

No I haven't done a lot of Bowtie stuff, but there are a lot more engines out there that I have and have never encountered the problems you mention. Perhaps it's because I don't rely on the load gauge, only as an indication of average pressure. What I do do is take my time and measure a lot. And the bore is always smaller at the bottom, unless your set up/tooling/ method suck. That's why Sunnen put a dwell facility there. And if you back off your pressure a bit you might not push the walls so hard they flex.

"Must have item"? How is it must have if 95% of my bores come out at 2 or 3 Tenths? With or without torque plate. Or do you consider that a sloppy tolerance? And with the controls as manufactured.

The question was to gauge the mods merits, and whether I might go to the trouble of fitting one. If it works then great. Shame Sunnen spent millions to develop the machine and miss that one. I can use the machine as made but if there are GENUINE improvements then I'll listen.

Or is it just a crutch for people in a hurry who can't be bothered to measure properly?

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Post by Wolfplace » Sun Apr 16, 2006 2:13 pm

BCjohnny wrote:You've probably done a lot more honing than me and you've also answered your own question but one thing comes to mind........

I try as I might to keep abreast of "developments" but being this side of the pond we're not always au-fait with all. How long has this "bar" been in common use? The CK's have been around, what, 40 years or more. How come this "problem" has only recently need "fixing". And torque plates have been used for just as long.

No I haven't done a lot of Bowtie stuff, but there are a lot more engines out there that I have and have never encountered the problems you mention. Perhaps it's because I don't rely on the load gauge, only as an indication of average pressure. What I do do is take my time and measure a lot. And the bore is always smaller at the bottom, unless your set up/tooling/ method suck. That's why Sunnen put a dwell facility there. And if you back off your pressure a bit you might not push the walls so hard they flex.

"Must have item"? How is it must have if 95% of my bores come out at 2 or 3 Tenths? With or without torque plate. Or do you consider that a sloppy tolerance? And with the controls as manufactured.

The question was to gauge the mods merits, and whether I might go to the trouble of fitting one. If it works then great. Shame Sunnen spent millions to develop the machine and miss that one. I can use the machine as made but if there are GENUINE improvements then I'll listen.

Or is it just a crutch for people in a hurry who can't be bothered to measure properly?
-
Umm, sorry if my post ruffled your feathers but do not assume I don't know how to hone a block.

I have been doing this stuff for about 40 years & I have a Sunnen CK10 that is about 30 years old & I do know how to hone a cylinder.
To answer your question this modification has been around for at least 20-25 years that I know of.

I am not here argue with you, I gave you my opinion.
Don't agree with it,, fine but do not tell me I am in a hurry or don't know how to machine a block.

If you take the time to look at the newer machines you will find they have the ability to dwell at any position & there is a reason for it.
If you cannot understand that a torque plate distorts the top of the block & there are times you need to dwell here than apparently you have not done a lot of blocks.

And just for info, I am not a person who can't be "bothered to measure "properly"

Also, just for your info, the torque meter works very well on the heavy wall blocks, the only place it fails to tell you the truth is with thinner wall stuff & I am aware you can back off the pressure to alleviate the wall flex issues but it will still be there in some blocks.
Take a 302 Ford & stick a bore gauge in the bottom sometime & squeeze the unsupported cylinder with you fingers & then tell me it doesn't move even with small pressures,,,
Mike
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Ruffled feathers..

Post by BCjohnny » Sun Apr 16, 2006 4:23 pm

Sorry Mike, didn't mean to poke you with a stick. And I would not doubt/question your abilities. Your work probably knocks mine into fits, and the "crutch" phrase was aimed at shops who probably have to work against the clock.

But no I've done plenty of blocks and just not found it to be a problem, with plates or not. And my machine's about 30 yrs old too, though I've only had it for 15 or so.

If it's such a help I'm surprised I've only just come across it. That was the question.

Will ring my contact at Sunnen Weds morn to get his views.

The newer Sunnen machines have this as standard? Not seen that on the ones brought to Uk. Or perhaps I need to look harder.

And I've a couple of 302 blocks stripped and I will check what you say and post back. It's not something I've even thought to do in the past.

John.

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Re: Ruffled feathers..

Post by Wolfplace » Sun Apr 16, 2006 5:04 pm

BCjohnny wrote:Sorry Mike, didn't mean to poke you with a stick. And I would not doubt/question your abilities. Your work probably knocks mine into fits, and the "crutch" phrase was aimed at shops who probably have to work against the clock.

But no I've done plenty of blocks and just not found it to be a problem, with plates or not. And my machine's about 30 yrs old too, though I've only had it for 15 or so.

If it's such a help I'm surprised I've only just come across it. That was the question.

Will ring my contact at Sunnen Weds morn to get his views.

The newer Sunnen machines have this as standard? Not seen that on the ones brought to Uk. Or perhaps I need to look harder.

And I've a couple of 302 blocks stripped and I will check what you say and post back. It's not something I've even thought to do in the past.

John.
=
Thanks John,
Stick removed :lol:

We are all learning, that is why we are here & I am always interested in the stuff I don't know which seems to grow larger rather than smaller with passing days :cry:

I would be interested in what your Sunnen guy has to say as I can remember years ago when Sunnen said this did not work, wasn't necessary, waste of time,,, now they have it??
Deal is I don't think it was Sunner that came out with it, so it was probably someone else was making the money on it.
Wish I could remember who came up with the idea but I am sure someone on here will remember.
All I know is I would not have a CK/CV hone without it anymore.

You might be interested in reading this:

http://sunnen.com/newsDetail.jsp?id=30&catId=0
Mike
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A few of the cars I have driven & owned
A tour of my shop
The Dyno
And a few pics of the gang

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