Polaris ATV Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
526 Posts
Discussion Starter #1
As far has setting new rings and any replacement parts on a rebuild does idle time help in the breaking in of new parts or does one need to have the engine under load? Thanks

What about for brand new engines?

It is assumed the engine is monitored and there is no over heading, low oil conditions, etc.
 

·
Registered
Joined
·
553 Posts
It all counts but Idle time should be kept to a minimum during break in.
 

·
Registered
Joined
·
862 Posts
for rings not really. at idle combustion pressure is lower and thats what forces the rings against the cyclinder walls. it does help with the rotating assemble because its still in motion, but prolonged idle should be avoided due to lower oil pressure and lack of cooling.
 

·
Registered
Joined
·
376 Posts
Ride it like you stole it, then you'll know if something gunna break, are you talking about those junky 325's?
 

·
Moderator
Joined
·
11,130 Posts
You don't need to let a new build idle much and don't run it at steady constant speed or WOT. Ride easy and vary speed up and down for at least the first few hrs. of run time. Some folks subscribe to Xploder's philosophy and in fact there is a certain race engine builder who has an article online that makes a good case for that style of break in.

I had to look for a minute but here it is.
http://www.mototuneusa.com/break_in_secrets.htm
 

·
Registered
Joined
·
526 Posts
Discussion Starter #7
Thanks guys. While we have put new rod bearing inserts and piston rings in each of our 2000-2002 325 Magnums my main concern is can we save the engine in the last one that had spun the rod bearing insert when the guy blew an oil cooler hose running down the road and did not know it. The chassis is really in mint like condition compared to the other twin like Magnum because it has not been trail/swamp ridden. Even the flywheel is clean.

While we did work on the crankshaft through the jug hole opening trying to clean it up some of the spun bearing material it was still far from ideal unlike the other 325 that's crank is smooth as glass and the insert showed mo measurable wear.

They are parked in a place where I need help getting them out and the kids left to build houses in Mexico yesterday day and will be gone for a week. We did get both running Friday night but getting the one with the spun bearing running has been the main focus. The other one should be good to ride when we get its clothes on it.

The goal is to ceramic coat the insert and crankshaft on the one that had spun the rod bearing before we got it using hexagonal boron nitride in the engine oil.

Different sources say differ things but it seems to take somewhere between 10 and 20 hours of run time and the higher the forces are on the moving parts the faster a few microns of very hard and smoothing ceramic coating occurs on the moving parts protected by motor oil.

So in this case I am experimenting to see if the coating can occur before making rod bearing carry more than min forces.

After nine hours of mostly idling with some small increasing of RPM up and down from time to time hopefully some ceramic coating of the crank has occurred. Of course we would have to pull off the rod cap to know if it is working. :)

The first hour was a struggle for sure then with the same idle setting it became faster and the engine seemed to be in less strain. I have been with the engine monitoring cycle and oil cooler temps with an IR gun or doing other things close enough to listen to the engine.

The hottest cylinder temps was the first hour but did not record a temp of over 335F and for the last 8 hours it has been peaking at about 300F when measuring between the fins. It is taking longer and longer to the temps to rise on each start up.

The oil cooler temps run more like 260F with peak being just under 300F. The fan came on briefly twice that I heard.

Where it holds or blows still remains to be seen. The main objective is for the son to get some wrenching time. I did one then he did the other. He totally removed, replaced and torqued the rod bearing on the second engine. He torqued the heads on both of them by the Polaris shop manual.

The source we selected for the hexagonal boron nitride after a lot of research and input from some here was Liqui Moly Ceratec.
 

·
Registered
Joined
·
526 Posts
Discussion Starter #8
Today got the run time total up to 11 hours which is be long enough to have valid test results as to how well running hexagonal boron nitride additive does at ceramic coating.

At more like 2500 RPM I still hear a sound that I do not know what it is so I got started on getting the other 325 Magnum's gas tank, exhaust, etc back on so I could listen to the sound of it because it has a known good crank shaft.

If I determine it is a rod knock we will tear it back down and study all of the parts and try to find a good used or new crank shaft and start over doing it all to spec.

Because we had decided to make this project engine the test host for the use of hexagonal Boron Nitride we put it all back together with the old parts except for the connecting rod that got heated, chewed on to the point it would not hold its connecting rod bearing inserts. The piston and cylinder showed tracks from be ran without motor oil so we can see if the hexagonal boron helped, hurt or did nothing to these galled places.

The old garage we fixed up to get the ATV's inside so we could work on them this winter is working out better than expected and the heavy steel workbench will make a good place to split the engine if it comes to that.

As the posts warning about oil pressure that is good advice. This generation of 325 came with the high pressure oil pump so at idle they will pump volumes of oil to the top end unlike the 500 engine.

Before we had Liqui Moly Ceratec in other vehicles I wanted to test it on this engine with so much internal damage. The other 325 just has the stock High Mileage 10W-40 Mobil 1 oil which does contain moly.

Has anyone had any experience with adding hexagonal boron nitride from any source to the crankcase oil?
 

·
Registered
Joined
·
526 Posts
Discussion Starter #9
Results of using Liqui Moly Ceratec after 11.5 hours.

We finally got the 2002 Polaris 325 ATV engine top end torn down and removed the connecting rod after getting 11.5 hours of run time at a fast idle on the engine running Liqui Moly Ceratec in Mobil 1 10w-40 High Mileage engine oil.

We bought this 'project' ATV with a known damaged engine due to being ran bone dry of motor oil when the guy blew an oil cooler line when running down the road. It turned out the crankshaft was chewed up as well as the connecting rod after being ran with the rod inserts spinning in the rod cap.

Picked up a used rod off of eBay and went back with Standard size rod inserts and a new set of rings after we smoothed off the crankshaft some 180 grit emery strips by hand with the crankshaft still in the ATV (did not split the engine case) then hit it a bit with 800 grit paper.

After about 10 total hours of idle time with it setting in an open shop I could hear a knock when getting on the throttle hard at no load.

While there was little hope it would hold up I was surprise after over 11 hours of run time as noted above that it still was making good power and on tear down the rod inserts were getting thinner but had NOT spun and the used connecting rod looked fine after about 11.5 hours. The crankshaft still has groves in it from the initial damage of running without motor oil but the groves now feel smooth in the direction of rotation but are still there if you feel from side to side of the rod journal on the crank.

The test of Liqui Moly Ceratec was a success in that the kids got some wrenching experience after two tear downs and one assembly and we know the Ceratec does lay down a smooth glassy looking coat in places of imperfections on inspecting the cylinder and cam on tear down.

We only had a window of about 6 hours where it was warm enough to tear down and look at the parts after the engine had idled for the 11+ hours with Ceratec in the oil at the rate per Liqui Moly states on the can.

I can tell you the piston shirts still looked bad. Keep in mind we put the engine back together with the same 12 year old parts that are OEM except for the used rod and new standard size rings and rod bearings that it had when it was driven without motor oil running down a paved road until the farmer heard the engine knocking over the tire and wind noise.

From just the piston skirts it seems Liqui Moly Ceratec will NOT leave a ceramic finish on imperfect parts if the is not real friction/pressure between the moving parts of the engine.

We have picked up a very tight bottom end that includes the crank and connecting rod so when we get ready to 'quit' having fun tearing down and rebuilding we and put it back together with a good crank.

We have proved to ourselves that Liqui Moly Ceratec does as Liqui Moly states on their website. For an engine with a bad crank (rough and slightly under size) to run for 1,000,000 revolutions would be hard to explain with just motor oil in my mind. For the first hour it was a struggle for the engine and I expect that was when it was making a lot of metal.

Our control for the evaluation of Liqui Moly Ceratec is a 2001 with the same 325 Polaris ATV engine. We tore it down and put the same new rod bearings and brand of standard size rings using the same motor oil but the crankshaft was very good and the removed rod bearings showed no measurable wear after 13 years of a much harder life than of the 2002 until it blew the oil cooler hose.

The cylinder temps of the 2002 with the bad crank during the first hour of running hit 350F degrees the 2001 as our 'control' never went over 300F degrees but it only was idled for about one hour.

I guess we will put Ceratec in the 'control' ATV at some point but it will be after our Mini Ice Age. :(
 
1 - 9 of 9 Posts
Top