Nova 45 DD going lean?

[Elias Vazquez]

Well it's a no go for Al's motor, tested a couple more things quickly with no change and packed it in.

Tim

Sorry to hear that Tim. Looking forward to hearing of what, if anything is found with the motor if you decide to send it to Glenn. As mentioned before there are 4 of us in Dist.3 running the DD's in riggers successfully. Only know of one that is experiencing issues which is Tom Foley...wish you all lots of luck! I'm available if you think I could be help. I'll be keeping an eye on this thread for any new development.

 

[Tim Kish]

Well it's a no go for Al's motor, tested a couple more things quickly with no change and packed it in.

Tim

Sorry to hear that Tim. Looking forward to hearing of what, if anything is found with the motor if you decide to send it to Glenn. As mentioned before there are 4 of us in Dist.3 running the DD's in riggers successfully. Only know of one that is experiencing issues which is Tom Foley...wish you all lots of luck! I'm available if you think I could be help. I'll be keeping an eye on this thread for any new development.

Thanks Elias

I am going to take it apart and measure the crank to case clearance tomorrow, maybe we just got a bad couple of engines?

To bad from what we seen in testing without even pushing it the motor is making real power.

Tim

 

[Tom Foley]

Well it's a no go for Al's motor, tested a couple more things quickly with no change and packed it in.

Tim

Sorry to hear that Tim. Looking forward to hearing of what, if anything is found with the motor if you decide to send it to Glenn. As mentioned before there are 4 of us in Dist.3 running the DD's in riggers successfully. Only know of one that is experiencing issues which is Tom Foley...wish you all lots of luck! I'm available if you think I could be help. I'll be keeping an eye on this thread for any new development.

Actually Elias I have very little run time on mine and certainly not enough to come to any conclusions but I will say this , I had to richen the engine almost to the point of not being able to get it off the bench so it wouldn't lean out on the course . Same setup as my old Mac 45 , HR 45 , VAC 45 in terms of tanks and pipes . I need to get out soon before Charleston . I have seen many others in D 3 running blistering fast with this engine so I am watching carefully .

 

[Andy Brown]

Al's and Olly's engines. Are they stock? If not stock, is there something commonly different about them?

 

[Tim Kish]

Al's and Olly's engines. Are they stock? If not stock, is there something commonly different about them?

Al's yes, Olly's not sure but would guess yes.

 

[Marty Davis]

With the 46 wrap around engine and also the outboard 46, we found that the engine needed to be loaded a BUNCH to run correctly. Also, the choice of pipe was critical too. The latest nitro pipe that Glenn sells is the one that works for us.

We couldn't get the engine to run well at all initially until we loaded it, broke it in and got the correct pipe.

 

[aaron alberico]

With the 46 wrap around engine and also the outboard 46, we found that the engine needed to be loaded a BUNCH to run correctly. Also, the choice of pipe was critical too. The latest nitro pipe that Glenn sells is the one that works for us.

We couldn't get the engine to run well at all initially until we loaded it, broke it in and got the correct pipe.

Nova 46 pipe nitro and muffled work great with either 46DD or wrap around motor!

 

[aaron alberico]

Well it's a no go for Al's motor, tested a couple more things quickly with no change and packed it in.

Tim

Sorry to hear that Tim. Looking forward to hearing of what, if anything is found with the motor if you decide to send it to Glenn. As mentioned before there are 4 of us in Dist.3 running the DD's in riggers successfully. Only know of one that is experiencing issues which is Tom Foley...wish you all lots of luck! I'm available if you think I could be help. I'll be keeping an eye on this thread for any new development.

Actually Elias I have very little run time on mine and certainly not enough to come to any conclusions but I will say this , I had to richen the engine almost to the point of not being able to get it off the bench so it wouldn't lean out on the course . Same setup as my old Mac 45 , HR 45 , VAC 45 in terms of tanks and pipes . I need to get out soon before Charleston . I have seen many others in D 3 running blistering fast with this engine so I am watching carefully .[/

 

[Andy Brown]

With the 46 wrap around engine and also the outboard 46, we found that the engine needed to be loaded a BUNCH to run correctly. Also, the choice of pipe was critical too. The latest nitro pipe that Glenn sells is the one that works for us.

We couldn't get the engine to run well at all initially until we loaded it, broke it in and got the correct pipe.

You could be right about being broken in Marty. Glenn's first test engine was having problems just "Stopping" for no reason. He called me and we discussed the issue probably an hour. From our discussion I finally detected the problem of a piston out growing the liner. I suggested that he loosen the fit and see what happens. He did this and I think it may have helped but not much. He sent the engine to me and I ground a long taper on the top of the piston. By now the fit was VERY loose...basically no seal at all. But it ran like mad and never stopped again. It ran 82 mph consistently and had awesome acceleration with a 1655 cupped 4.2" Glenn then talked to Nova about grinding the taper on the pistons, which they did, but I suspect as you mention, that they will need to be well broke in before they are going to run consistently.

A "pinch" is not always a good thing!

 

[Elias Vazquez]

Have found the same thing with these motors have to run them rich, load the motor up correctly, and wait till they build up some heat.

 

[Marty Davis]

It took over 2 gallons of fuel to break the engine in but then it has held and runs perfectly. Another was an outboard and with not nearly as much break in, stuck a piston (like Andy said) because it was too tight and probably run to lean and without enough load. I can tell you for sure, that you MUST load the engine with a lot of prop to make it happy and consistent.

 

[Greg Bonahoom]

What a fantastic thread!

Is it possible that there is a vibration problem with this motor? Maybe some motors are worse than others or some guys are using better motor mounts that reduce more vibration? The reason I bring this up is because I had one that broke a screw on the carb, and I was using a servo saver so it was not from the servo trying to push it to far. Also, check out what happened to my carb:



I brought the boat back to the dock, (no crash or anything) and that is what my carb looked like.

FYI Frank orlic sent me a new one free of charge.

 

[Marty Davis]

Bob:

Actually, we are getting ready to measure all the components in the wrap-around engine to see what kind of balance formula it was designed with. The engine is rough at idle and low end but really can rev at the top. Not sure if there is something that makes the very high rpm's partly a function of balance, but we will see what it shows and test it on other engines to see if it makes a difference.

Probably one of the roughest engines that I know of at the bottom, but also one of the highest rev engines that I know of.

 

[Tim Kish]

I think I have found the problem, will post finding tonight after work.

 

[Joe Wiebelhaus]

What about the angle of the boost and transfer ports ?

 

[Tim Kish]

It's definitely a sealing issue, will share findings tonight .

To much to do by phone .

 

[Tony Jacuzzi]

This has been a great thread, great job to everyone working the issue

 

[Tim Kish]

First off not pointing fingers here just posting what I found and believe the issue to be.

I brought the engine to work today and measured everything that I thought would cause this problem so mainly just the diameters of the crank, engine case, PTO housing and PTO shaft.I used a very high quality Swiss bore gauge and Mitutoyo digital micrometer.

What I found was this.

First I measured the crank case I.D. at .6330 , this was the area of the case that is designed to seal the engine and crank with very little clearance between them and the oil from the fuel.

I then measured the crankshaft and it was .6295, so that is perfect , typically I have seen a .003 to .004 range used between the crank and case to seal the engine.

Nothing wrong there.

Measured the PTO housing at .455 it's a straight bore unlike a case that has the seal bore and then clearance bore.

This is where I believe the problem is, the PTO shaft is stepped down(two different sizes), the largest dia being the bearing fit dia was perfect but the shaft dia is reduced right after the bearing to .4475 which leaves almost .008 clearance between the housing and the shaft.

If Nova Rossi just extended the bearing dia on the PTO shaft by .375 and opened the PTO housing .001 more I believe the issue will be solved and the engine will seal properly.

Tim

 

[John Beardslee]

Hi Tim,

If there is no seal on that PTO then that is the problem. Good work!!! There has to be a seal area on the PTO just like the crankcase. Must have been done during set up on the cnc or?

John

 

[Glenn Quarles]

First off not pointing fingers here just posting what I found and believe the issue to be.

I brought the engine to work today and measured everything that I thought would cause this problem so mainly just the diameters of the crank, engine case, PTO housing and PTO shaft.I used a very high quality Swiss bore gauge and Mitutoyo digital micrometer.

What I found was this.

First I measured the crank case I.D. at .6330 , this was the area of the case that is designed to seal the engine and crank with very little clearance between them and the oil from the fuel.

I then measured the crankshaft and it was .6295, so that is perfect , typically I have seen a .003 to .004 range used between the crank and case to seal the engine.

Nothing wrong there.

Measured the PTO housing at .455 it's a straight bore unlike a case that has the seal bore and then clearance bore.

This is where I believe the problem is, the PTO shaft is stepped down(two different sizes), the largest dia being the bearing fit dia was perfect but the shaft dia is reduced right after the bearing to .4475 which leaves almost .008 clearance between the housing and the shaft.

If Nova Rossi just extended the bearing dia on the PTO shaft by .375 and opened the PTO housing .001 more I believe the issue will be solved and the engine will seal properly.

Tim

Hey Tim, there should be three different sizes on the PTO shaft. There is the dia for the bearing (about .4528 on the one I measured), the turned down middle section to reduce drag (about .415) and the front seal area (aprox .225" long) that measures .4522. I have never seen one without this seal area unless they have been modified. I will see if I can get a clear enough picture to show what I mean.

GQ