Valvola/MAC Piston/Liners

[tnrcboatracer]

Andy, I sense an opportunity here for replacement P/L for engines other than hte MACs. Just what you need to keep the chips flying on the Mazak.

 

[AndyBrown]

Andy, I sense an opportunity here for replacement P/L for engines other than hte MACs. Just what you need to keep the chips flying on the Mazak.

"Just what you need to keep the chips flying on the Mazak."

......and a little extra manpower to help get all of these parts rolling.

Come to Fla. Jon ......I could use your help!!

 

[tnrcboatracer]

I'd love to come down there! My dad lives in St Pete Beach. My wife loves the sand. The only thing holding me back is $$$,$$$. That's the problem with a good paying technical job, it locks you in. There are times I would drop the headaches in a minute, if only it didn't pay so well :huh: :huh:

Speaking of CNC, I have a probem with some drill chips getting in the water jacket of the heads we are machining. The chips fall out when they install the head to the block, and cause head gasket leaks. That makes the assembly side and vehicle plant somewhat upset. Not to mention, the dent in the head and block mating surfaces scraps the engine assembly. I'm thinking of trying to bore the 16.5mm hole by using a 12mm end mill through the 8mm cored hole and interpolating the final ID. That should keep the chips small enough to wash out of the water jacket. The things we sometimes have to do!

Also, had to change a set of inserts today to fix a clogging chip separator issue. The chips were tight spirals about 1" long that would bunch together and clog the centrifugal separator. It then would shut down the entire line until the clog was cleared. The problem is we had to premature the insets at 2/3 life. We can't afford to do that, the life was supposed to be 60,000 cuts, but we only got 40k. We looked at the inserts under a microscope, and found some excessive wear on the edge and some build-up on the chip breaker. The wear on the diamond may have been caused by a low coolant concentration for that last 4 weeks. The new inserts reduced the chips to a random pattern of 1/16" ~1/4" long pieces; the clogging of the separator was fixed.. But I can't afford to fix the problem this way. These new chip breaker inserts don't pay out is I can't run them 60k cuts. See what I mean about all the details that go around with highly automated equipment?

 

[Marty Davis]

http://cgi.ebay.com/CMB-21-3-5cc-VALVOLA-E...oQQcmdZViewItem
Says 36 available.

Ian:

Thanks, that was a great tip. I have ordered 4 L&P's and should be set.

Thanks,

Marty Davis

 

[Marty Davis]

The order of 4 L&P from this Chinese Company arrived today.

WHAT SERVICE.....

I will be buying from them again.

Marty Davis

 

[Marty Davis]

http://cgi.ebay.com/CMB-21-3-5cc-VALVOLA-E...oQQcmdZViewItem
Says 36 available.

Ian:

I just got my L&P's today. They are not what is shown in the image on Ebay. The L&P's that I got are the latest ones with the tiny exhaust port ears coming in the newest CMB's. If I had known that, I could have bought them from Stu and saved some $$$.

I was excited to finally find some L&P's with the early exhaust port configuration.

I don't see this as a problem though....

The tiny ears will not even be open in the MAC since the case will block it from the inside. It should serve me fine, but I am not really happy that I was shipped something that was not presented correctly.

Marty Davis

 

[AFIRacing]

Sounds like the shell was cracked on that golden egg you found.

Steve H. BUT if you say they'll work then I'm in also!! I need a L&P myself.

 

[Ian Inverarity]

<a href="http://cgi.ebay.com/CMB-21-3-5cc-VALVOLA-E...oQQcmdZViewItem" target="_blank">http://cgi.ebay.com/CMB-21-3-5cc-VALVOLA-E...oQQcmdZViewItem</a>
Says 36 available.

Ian:

I just got my L&P's today. They are not what is shown in the image on Ebay. The L&P's that I got are the latest ones with the tiny exhaust port ears coming in the newest CMB's. If I had known that, I could have bought them from Stu and saved some $$$.

I was excited to finally find some L&P's with the early exhaust port configuration.

I don't see this as a problem though....

The tiny ears will not even be open in the MAC since the case will block it from the inside. It should serve me fine, but I am not really happy that I was shipped something that was not presented correctly.

Marty Davis

Marty,

That is unfortunate, try emailing him directly (or calling) and explain that what you needed was parts for a greenhead not a red-head. I have had similar confusion with him getting a greenhead drum and housing, initially he supplied parts for a red-head but did get me the right parts after I returned the red head parts.

Ian.

 

[Don Ferrette]

<a href="http://cgi.ebay.com/CMB-21-3-5cc-VALVOLA-E...oQQcmdZViewItem" target="_blank">http://cgi.ebay.com/CMB-21-3-5cc-VALVOLA-E...oQQcmdZViewItem</a>
Says 36 available.

Ian:

I just got my L&P's today. They are not what is shown in the image on Ebay. The L&P's that I got are the latest ones with the tiny exhaust port ears coming in the newest CMB's. If I had known that, I could have bought them from Stu and saved some $$$.

I was excited to finally find some L&P's with the early exhaust port configuration.

I don't see this as a problem though....

The tiny ears will not even be open in the MAC since the case will block it from the inside. It should serve me fine, but I am not really happy that I was shipped something that was not presented correctly.

Marty Davis

Marty,

That is unfortunate, try emailing him directly (or calling) and explain that what you needed was parts for a greenhead not a red-head. I have had similar confusion with him getting a greenhead drum and housing, initially he supplied parts for a red-head but did get me the right parts after I returned the red head parts.

Ian.

Well at least you got your replacement parts, I've been trying to get a refund or a credit for 4 props I returned months ago. They have not answered any of my e-mails since I sent them all the tracking information showing them returned. I had nothing but good experiences with Nelson Wong & his people up until that point but I don't expect that I'll be doing any business with them in the future. :angry: :angry: :angry: :angry:

 

[Josh Stollfuss]

I've bought a few things from Nelson Wong Via Ebay and have had really good experiences. But they are really bad when it comes to responding to emails. In fact I think that have been about 1 for 10 in responding.

Josh-

 

[waltr]

Nelson took 2 months to get me a refund last year.

After many,many,too.... many e-mails, I finally got the refund.

Unless it's something rare, I won't be doing business with him again.

Marty, Andy's getting close if you can wait a bit longer.

I think the 21 liners are at the chrome shop now.

 

[Marty Davis]

Just installed 3 of the liners in MAC engines and it was amazing that the timing was almost perfect without any modification. The timings were perfect with the amount of Blow Down that I like and intakes where I like them.

That must be a first to be able to install a liner and piston set and have the timing be correct.

I can say that installing the newest CMB liner and piston in the MAC is a grreat deal. The little side exhaust ports do not have an opening in the case of the MAC (what I preferred) so they are just hidden and no effect.

I can reccomend this replacement L&P for the MAC without reservation.

Marty Davis

 

[Marty Davis]

At this point, the only question that I have is whether the Time/Angle/Area of the exhaust port has been reduced too much. If so, I might have to enlarge the exhaust port a little. I had to lower the liner to get the intakes smaller (Time/Area) so I bet that this configuation might be some better.

Marty Davis

 

[Chris Wood]

At this point, the only question that I have is whether the Time/Angle/Area of the exhaust port has been reduced too much. If so, I might have to enlarge the exhaust port a little. I had to lower the liner to get the intakes smaller (Time/Area) so I bet that this configuation might be some better.
Marty Davis

Marty,

what kind of numbers are you shooting for??

chris

 

[Dan_Cousin]

Marty,

About those little holes in the liner that don't have an exit through the case. Is there come concern that some fuel will get caught in there and interrupt the flow if the gasses out of the exhaust. Or cause some excess heat to be generated?

 

[Marty Davis]

Marty,
About those little holes in the liner that don't have an exit through the case. Is there come concern that some fuel will get caught in there and interrupt the flow if the gasses out of the exhaust. Or cause some excess heat to be generated?

Don't think so, but who knows...

Marty

 

[Marty Davis]

At this point, the only question that I have is whether the Time/Angle/Area of the exhaust port has been reduced too much. If so, I might have to enlarge the exhaust port a little. I had to lower the liner to get the intakes smaller (Time/Area) so I bet that this configuation might be some better.
Marty Davis

Marty,

what kind of numbers are you shooting for?? Are you talking about the port time/areas?

chris

Chris:

Not quite sure what you are asking???

Marty Davis

 

[Chris Wood]

what timing numbers do you like to run exhaust and boost and transfer.

chris

 

[Marty Davis]

what timing numbers do you like to run exhaust and boost and transfer.
chris

Chris:

Just giving you Exhaust & Transfer Port duration is not going to be helpful to you at all. You run Nova Rossi Engines and I run MAC Engines. There is not a common set of numbers for both that is correct for both.

I would suggest that someone who can measure the EXACT port areas of the Nova Rossi do so and then develop a set of timing durations which will have to correct balance of Time/Angle/Area for that SPECIFIC ENGINE.

I have done that with the MAC .21 engine, so I know exactly what is required to get the performance that I want. Now with the smaller exhaust port that I have found with the new model CMB liner, I believe that I will be able to extend the Transfer duration some. That should be VERY helpful to peak RPM. My engines will "pull stumps" with the low Transfer Duration, but I am suffering with peak RPM.

With the Nova Rossi, EVERYTHING is different in Time/Angle/Area and I would suggest that you develop a team to get some good data to optimize that engine. Maybe you will want to just get it done between yourself and your very technically minded Father.

As you know, I ran Nova Rossi engines until I found that the MAC was a better performing engine. So I do have an opinion of what worked best for me. I liked 124 or 125 degrees of Transfer Timing with the Exhaust Duration at 184 or 185 so that I had 30 degrees of Blow Down Duration. I raised the exhaust port using a top hat cut that was barely under 1/3 of the total width of the port. I also had the ability to maintain the curved top using a rotary table, so my top of the top hat was curved. I ran a CR of 10.25:1 and a squish percentage of 65%. I would guess that this is what you wanted, but is not developed from a Time/Angle/Area analysis, but from MANY liners cut and tried and verified on the dyno. Since I no longer run Nova Rossi, I would bet this information would be helpful to others.

I would suggest that you also make a study of Blow Down Duration, as it is VERY important in the total equation.

I know that this is not what you wanted to hear, but it is the best advice I can give you. Maybe Franco Orlic and Rod Geraghty will share their timing durations with you. As you know, they are the best Nova Rossi Mechanics around. I am sure that Rod will share his information with you. He is very open with his knowledge. Not sure about Franco, don't know him very well. I am positive that everyone running .21's would benefit from them sharing information.

Marty Davis

 

[Chris Wood]

thanks marty, got everything i needed right from that post.

chris