Good thread.. and like ANY and ALL threads in a public forum.. full of good info and bad info..
Information is based soley on people's opinions.. nothing more.. How that opinion was formulated is up for debate and how valid the opinion stated is.. is also up for debate.. but to take everything said at face value is just being nieve..
Opinions are derived from many different scenarios.. Some are based soley on what somebody heard or witnessed and others are based on test data (whether it be their own test data or somebody else's) then you ned to question how the test was performed and its validity.. You can test different things using different methods and come up withvery different results.. Trust me on this one.. I did VLSI testing (Writing the tests, integrating the tests, and training) for the US, Brazilan, and Italian Governments for MANY years.
So how about the original question:
1) Comparing 860's: Great topic!! IMHO, the ONLY way to get ANY valid data with respect to this topic is to have ALL the 860's at one place ON THE SNOW and see how they really compare.. Of course, this means that you would need to have ALL 860's properly set-up and running to their full potential. I can not tell you how many sleds are plagued with parasitic losses due to bad bearings, exhaust cans, pipes, clutching alignments, bad belts. etc. etc. etc. the list goes on and on. So, to put a poor running (plagued by other problems) 860 up against and "dialed in" 860 is not fair in the least.. And EVERY engine builder will have those customers that have a sled that is riddled with other issues that hinder performance.. This is just the reality.. So, how do you get the real answer?? Don't know.. but I have always offered to meet up with anybody who wants to compare performance. I did this with all the Pump gas turbos and had a few takers and the results spoke for themselves (even though people were ,and still are, in denial long after the "meet" Again. results are results and they stand on their own merit..
This idea that because you saw any 860 not do so well or you saw one really haul the mail... warrants a "opinion" and "fact" (good or bad) is just not fair to ANY of the engine builders.. Like stated above.. the real way to compare is to actually compare ALL properly set-up 860's to each other in a real world competition.. I am always up for this...
2)OT... Never mind... We all know that story..
3)Tim (tntm7) : some great info.. But again, based on your testing.. other tests will show different results..
Then you have the dome factor, now you have a part that is resting on another part relying on surface contact that chatters from the heat now you have limitted surface contact and the dome is left with 70% of the duty of disapating the heat. Love the dome head for testing, wont run one for nothing on a race motor.
one piece heads for me.
I ride a Cat, and can say there isnt one billet head that cools as good as the factory head as of last yr.
Arctic Cat Heads: Stock cools better than ALL aftermarket heads?? With all due respect.. I will strongly disagree with this.. WHY? Because OUR testing and MANY others testing has proved otherwise.. You are correct that MOST do not do a better job but to state that all do not is simply not true... Obviously you are entitled to your opinion but to state your opinion as FACT is not fair to the readers of your posts.. Especially when we can prove otherwise.. Hopefully you can agree with this?
As for dome chattering.. good call and a big problem with many aftermarket heads.. But, again, different designs and alloys can eliminate this problem.. I can assure you that our dome to shell mating design is very unique and will NOT chatter! and will dissapate heat in the proper manner.. We do TONS on testing with this aspect of the design...Again.. this can be easily proven and to make a blanketed statement like yours is simply not fair to anybody. But, you are entitled to your opinion..
tntm7 break in procedure: Again.. your findings.. we also do MUCH testing with this very subject and the results are very interesting to say the least. I will respectfully strongly disagree with your procedure on this also.. we can leave it at that..
Oil ratio.. Excellent call!! I 100% agree and this is a tough sell to people because they always think that oil cost them power.. SAE papers and real world testing will ALWAYS prove otherwise...In fact, there are MANY threads where people have M running issues and the solution is to REDUCE the oil ratio.. This, is a perfect example of other's opinion and how they can be misleading simply incorrect.
Big Bore reliability: Some 860's are MORE reliable than the STOCK 800 engine.. This is largely due to the MUCH better piston and better porting arrangement and better head design (some 860s more than others
)... The reality is that our 860 will run
cooler and produce subtantial power increases over ANY stock 800R engine. Pistons WILL last LONGER than stock.. We were the 1st to build the 860 and we have MANY thousands of miles and 3 full years on these engines... They are VERY solid!and very reliable with excellent durability.. Despite what OT states...
Great thread, unfortunately the answers to all the questions will always differ from "Great" to "Piece of Sheet" This will always be the case when you have a large number of readers on a public forum..
Kelsey