ESR power valve problems!

[k7mm]

I just bought a 265 ESR power valve engine off of a guy here on the site.It was suppose to have only 10 hours on the top end.I bought it for the top end only.I took it apart last night and noticed that the top of the piston looked like it hit the power valve.Well as I went to take the power valve out,the slide was siezed.I looked a little closer and yes the piston hit the power valve and mushroomed the end of the power valve slide.It hit it hard enough to also sieze the top ring on the piston.I had to carefully grind the mushroomed end off of the slide so that I could remove it.Has anyone ever had this happen or heard of it happening?I'm wondering if it was from poor maintanence or what.This is my first power valve of this type.I would'nt think someone would have to worry about the piston hitting the slide!

[k7mm]

piston

[k7mm]

This is how much space I had to work with!

[k7mm]

This cylinder has the newer billet style power valve.

[derby]

Originally posted by k7mm
This cylinder has the newer billet style power valve.

Whats the bore? If they had the cylinder bored and did not relieve the valve that can happen.

[k7mm]

Thanks Derby!I just got off of the phone with ESR and that was the first question they asked.After talking with the guy we figured out that who ever had the engine before,put the power valve slide in upside down.So i'm at least relieved to know why it happened.Now I have to contact the seller and try and get some money back.The seller also told me the engine had a Hinson clutch basket.Well it did'nt,it's a completly stock clutch.Thanks again!

[C-LEIGH RACING]

K7mm,
That looks like a nikisal bore cylinder by the pic & if it is, if the plating is messed up around the exhaust port you'll need to have the bore plated again.
What will happen, if theres a break in the plating on the edge of the port, the rings will drag across it when the engines running & start to pull it up & off the aluminum casting & just a mater of time before it destorys the piston & bore.
Check that out close.

Normaly on the ESR valves, that arch in the blade is cut just about the same amount of taper on both sides & should have been enough to clear the piston.

Have you taken the valve itself apart, to inspect it, because that pv blade is like two pieces screwed together & sometimes they come apart & will drop down to far in the pv groove & cause the damage your showing.
Neil

[k7mm]

Neil.I took the cylinder today to the machine shop,and they confirmed it is nikisal over the steel sleeve.They do'nt deal with nikisal though.The two piece power valve was all the way together when I took it apart.The first group of photos shows how it was put together when I had gotten it,with the slide flipped up side down.There was a definite protrusion into the cylinde bore.I was able to clean the slide up and the second group of photos show it right side up,and there is no protrusion into the cylider bore.The tapered edges are different on this slide.The area around the exhaust port is actually still good,but on the intake side there is some bad pitting.I wonder if a new nikisal coat could fill those pits,so that I could keep it a 68mm bore?I was actually recomended to you for some help with something else.I'll have to PM you sometime about it!I'm so thankful that you noticed about the nikisal.

[k7mm]

No protrusion,

[k7mm]

Slide after I cleaned off the mushroom.

[k7mm]

Pitting on intake side.

[derby]

Originally posted by k7mm
Pitting on intake side.

Re platting will not fill that in. It looks like the sleeve was damaged and someone tried to repair it. You have any details?

[86honda250]

I have bin woundering about whitch way to put the power valve in to. All the mechanices that I talk to said to put it in the way you had it the first time. they all say the reason why you put it in this way is when the valve is open the exhast port is round and uniform, with out a large bump. A few mechanice that I know say that the valve has to be cut back so it does not stick out in to the bore. It makes sense to me why you would want it this way. It does not make sense the way eddie sandlers said to me. I also had a problem with one of esr power valve doing this. It broke in to about six pieces and one fell on top of the motor. I have been trying to find the True answer to this for a will. I have look at power valves off a 425 genises, 600 rotax, and a cople artic cats and they were all oppisit of what eddie sandlers says it should be. Neil it would be nice if you could tell use if ESR is right or wrong. The way in the picture is the way all the other brad motors are.

[C-LEIGH RACING]

Well, it would be hard to think if Eddie designs & builds those pv's himself, that he wouldnt know how it operates.
Could have been some misunderstanding when he was explaining it.
I've only talked to Eddie maybe 3,, 4 times in all these years & its like you can hear him good & then you cant hardly, must be working as hes talking & turning his head or something.

If you look at & study the valve blade, how its made & then inspect the cylinder casting down in the area where the blade operates, you will find the only thing stops the blade from falling out into the bore completely is the little round flat area at the top of the blade.
That little round flat area is a stop, to limit the amound of travel the valve blade can extend.
After a while of use, that flat area on the blade & then the area down in the cylinder casting, both those surfaces will wear & allow the balde to travel farther than its suppost to.

The area on the blade I'm talking about, in that second group of pics where your holding the valve blade, right where your thum is at, that round area.

Its not impossible, that some time or another the valve could have been replaced or who ever had the cylinder might of had another ESR cylinder & got the valves mixxed up.
Say like if they had two cylinders, one was a 250 STD bore & the other was that 265, well the blade for the 250 STD bore, that blade would be longer than the blade that would go on the 265 cylinder.
Your looking at 2mm worth of difference in the size of the bore, so it could be the reason the blade was hitting the piston.

Normaly a new ESR pv cylinder, if you was to take a straight edge & lay it down in the cylinder bore & then measure from the straight edge to the curved face of the pv blade, probably would be around 2mm or more clearance between to keep the blade from comming in contact with the piston.

I dont remember you saying the bore of that cylinder, if you had measured it or not. I know you mentioned 68mm, but is that what it is.

That area damaged in the bore, if it wasnt for the deep gouge in line with the transfer port floor, where a ring might could fall in & snag, you could probably run it.

Because of that you will need to send it to get replated. A plated cylinder cant be patched, it must be stripped, plated over again & then fininsh honed to the proper bore size.

Do you have a pic of the cylinder skirt, because that cylinder sure dont look like it has a sleeve in it.
If it does, the plating is doing a mighty good job of covering it up so you cant see it.
Lot of platers dont normaly plate over an iron sleeve, its just not normal, but those that do offer it, charge quite a bit more for the service.
Neil

[k7mm]

The bore is a 68.50.This cylinder does'nt have a steel sleeve in it.Thanks Neil!I thought it looked wierd that the plating was over lapping the sleeve.I called MaxPowerRPMs today and asked if thier nikisal had any magnetic properties and he said very little,but some.I took a magnet and tried to stick it to the skirt and it would'nt stick,but the magnet was pulling towards it a little,and he said it was an aluminum sleeve.He told me it would be $225.00 to strip and replate the cylinder,and would be about $75.00 if he had to weld in the pits.I also called ESR again today and was able to confirm that Eddy is the one that said to have the hole on the slide facing towards the piston.(second group of photos).There was definitly some kind of failure at one point with this engine,because down in the crank case area on the left side where the bearing goes there is some bad scoring.The engine came with what looks like a brand new short rod crank intalled.I know it's a short rod crank.I can't understand why they would run a short rod crank instead of a long rod with the spacer plate?Unless the old crank went bad,and they just put a short rod in,and eliminated the spacer plate.Also if this was built for National racing,I can't understand why they use a 68.50 piston.My Harold Goodmans Curtis Sparks built National engine runs a YZ 250 piston at 68.mm with the special spacer plate.Anyways the slide stop does not look worn.With the slide insalled like Eddy said,it does have enough clearance.It's when I turn it the other way, it sticks out into the bore.

[k7mm]

does this look cast or what?

[k7mm]

This is how much the slide sticks out into the bore,with the hole on the slide facing down towards the exhaust port.This is how it was insatlled when I had gotten it.

[k7mm]

There is a very small bit of wear in the cylinder,where the stop on the slide stops.Not enough to cause the problem though.

[86honda250]

Neil which way is the slide suppose to go. should the pulse hole face the piston or the exhast port? Every other engine that i have looked at faced the exhast port. The mechanices that I have talked to say that I have to cut my power valve back so that it fites without hiting the piston, with the pulse hole facing the exhast port. I am not an expert on this just what to fix my problem as well as others. I dont under stand why esr says to instal it diffrent then every other one that i talk to.

[k7mm]

This is the way that ESR told me to insall it.This what it would look like compressed into the valve.

[k7mm]

This is the way that 86honda250 is wondering about.This is what it would look like compressed into the valve,with the hole facing towards the exhaust port.

[C-LEIGH RACING]

If you could cut the arch a bit more, so it would clear the piston, it would probably operate better in backwards.
When you have it installed like its suppose to go, that pulse hole facing the piston, the valve would start to operate as soon as the piston uncovered the hole & the valve would have presure that quick to operate it.
Turned around backwards, it would be a little slower reciving the pulse presure & would make the valve work slower all together.

Looking at those new pics, I beleave you are right, no iron sleeve.

I dont know if it has had an aluminum sleeve installed in the casting, theres no parting lines anywhere that I can see, like between the block casting & the sleeve.

When those cylinder are cast, the casting will have a ruff skirt on it & then they do all the machining to it & the results is what you have, or are showing.
If it had an iron sleeve, during the machining process all of the ruff cast of the aluminum skirt would be cut off because the iron sleeve would have its own skirt.

I had a ESR 265 cylinder awhile back, had just a little bit left of the aluminum skirt still in place, but had a thin iron sleeve pressed into the casting & then it was nikisaled.

If your at a 68.50mm piston, that cylinder with a 72mm stroke crank, that engine would be, 265.3411 cc's.
I think according to AMA rule, it might be over the cc limit, but then again open class dont start untill it is at least over 266cc's.
To be classed as open, got to be over 266cc.

Millinumm Tech, their charge to replate a cylinder will run from $179.95 to $279.95 depending on the amount or repair if welding is need be done.
The nikisal plating will normaly be around 0.0030 thick in the bore.


The nice part about that cylinder you have, it is one of the old Pro-x casting & the other hole you see in the block, that means its just a mater of bolting on one of the old Rotax PV's or the CT Racing PV if you wanted to go from the ESR valve.
The old Rotax & the CT valves get their operating pulse up through that hole in the block & they work a bit slower & much better than the ESR unit.
Neil

[86honda250]

thanks neil and k7mm for your help. I have to of the new esr 350 pv i am going to cut one power valve and put it in the other way and see what hapens. good luck on replating your cylender.

[k7mm]

I cleaned it up for a better look and the sleeve is part of the aluminum block cast.No seem at all.Keith