We've used the 6mm, 6.5mm & 7mm depending on track conditions.

I have a couple of 21-4 engines and they have both been supplied with 28026 buttons which i replace with turbo button 28002.

I just got a 21-4C and it has a 28002 button included as standard with a turbo glow plug C6TGC. And I also picked up a 21-4C Team engine and it has a 28028 which is listed standard button also however on the exploded view it comes with a turbo C6TGC glowplug. Can anyone shed any light on this?

anyone know why there are differences across the 21-4 range?

Mostly marketing would be my guess. How do you take the same product with complete interchangable internals and continueally raise the cost and maintain interest? By making suttle changes to make it sound new and state of the art when in reality it is the same old design with a new twist. It doesn't mean it doesn't work well because it sure as heck does. It just a way to keep people interested in a product without spending loads of money to continually redesign the entire engine model after model. It wouldn't be very business saavy to do that. Not in this industry when there are so many engines and so many people who jump around engine to engine. So they jazz up the older one a little, make it sound sweet and bam, new engine trend. As far as why your engines come with different buttons, the 28002 turbo is for the original head height and the 28028 that comes on the team is for the head that was lowered 3mm so they increase the head button thickness to keep the cooling head from interferring with the case fins. They did the same on the Toro Nero as well. Same internals with a lowered head and rear ceramic and you have the Team version which sparked a surge of sales because people wanted what they thought the pros had. It is good marketing on Novarossi's side. Minimal changes to keep production costs down while gaining maximum profits while still maintaining interest.

Wow , serious?
so the full cnc "team" piston is just a marketing ploy?


There is a little more to it than what is described above and many of the changes made to th novarossi engine line up are actually upgrades for the better

While I do agree with mark to a certain extent, there is more to it than that

Alright so I forgot to mention the piston and while it may add some strength and some increased longevity, it isn't like the engine goes from "Eh, it's alright" to "OMG this thing is awesome". I have run every Plus 4 they ever made and all of them ran very similar to each other. While there have been a few changes here and there, none of them by any means for the worse, there hasn't been this revolutionary movement of the Plus 4's either. They have added some ceramics along the way and they went from a cast to bar stock billet on the piston and they lowered the head a little blah blah blah, but case in point is the $250 original Plus 4 is still very competative with the new $400+ BTT versions. So if someone has a limited budget, they shouldn't have to feel inferior to the newer models. They are all very good and run strong. The billet piston tends to hold up better to abuse so that is worth a few bucks but other than that, not to much else will matter much. The ceramics are ok but not needed as the stock steels have always held up great and the new front ceramic that raises the cost even higher still leaks like the stock steel did so you still end up with grit and debris inside the engine within the first gallon or two so how much is it really worth????

Some people have had good luck with it but I have personally serviced dozens of stock engine with stock fronts after 3-4 gallons and most of those engines had a nice coating of black grit all over the inside of the engine and not too many of them were saveable and these same guys thought the stocker was a good bearing and thought it would go alot longer without service but they learn the hard way that bearings with seals on the outside whether one seal or two have a positive lip and that allows penetration. I personally use double shielded oppossing seals and get no less than 4 gallons out of them with a squeaky clean inside and have been using them for years with that same success. Once in a great while you get one that isn't as good as the others but they seem to be far and few. To each their own but this is what I see first hand all the time and I do my very best to look for the customers pocket book as I'm sure most other engine guys do. I'm not saying the bearings I use are the end all be all but I certainly have not had luck with the stockers and I certainly wouldn't pay even more to get the same bearing with ceramic balls in them so they can sh#t the bed just as early and ruin my engine way short of it's life expectancy. No Thank You

Well, for me the new front BB in the + series of engines is by far the best front BB out there. I hve started using them instead of TKO bearings and original OS bearings.

As for the rest of the engine, i agree that for the guy on a budget, the 2010 team is the best bang for the buck out there today. The new BTT feels like it has more grunt out of the box. I have not messured that engine yet, so if they have changed some timing i am not shure of..

i feel the same way and with ceramic balls installed in the 17011 front bearing the clearances are tighened up a little which has made for a better sealing bearing that lasts longer

novarossi products are of the highest quality and i will continue to support them as long they remain as such

The only difference with the new one other than the obvious is the exhaust port has been reshaped a little. The timing specs are the same as all the rest of the plus 4 family. The piston, rod, case, crank, case internal, bearings, head button etc are the same as the 4c team. What you may feel with the btt is maybe a little more initial pop with the exhaust port being wider at the top. It allows for more initial blowdown which would give it a stronger feel on the bottom but as far as timing specs, it still remains plus 4. I have several guys running them and it is a split. Some guys feel the btt is a little stronger on bottom and some feel it is on par with the other versions so it comes down to setup as to how it will feel in general.

I also agree that novarossi makes a great product and I will also continue to carry and use them as long as the quality remains near the top as they have been for years.

thanks - so what turbo button should be used on the team engine that came with the 28028?

The team head and the 28028 head button go together, you just can't use the team head with the 28002 , 28023 or 28026 combustion chambers


Hope this helps

earlier in the year I bought a +4 from amain and the description said turbo head etc etc but when it arrived it was a standard head?? amain sent me a turbo button but there is some confusion on what is turbo and what is not? they should of done them all turbo and be done with it, and who runs a standard plug these days when you can get turbo odonnells for under $5.
cheers

so is the 28028 a turbo button for the Team engine?

with my plus 21-4 engines I install the 28002 turbo buttons and use the turbo plug.

The combustion chambers mentioned will all fit in each different engine but you need the 28028 in order to use the more recessed team head .


Hope this helps

The 28028 is thicker and uses the orange outer oring to keep the dirt and grit from getting into the sleeve/case lange that can create removal issues. You can use the 28028 on the older engines, the cooling head just sticks up higher in the vehicle but you can't use the 28002 on the team head as it will interfere with the case unless you machine down the cooling fins on the upper case to allow clearance.