Brian Builds the Kerzel Hit and Miss I.C.

[jpeter]

Been there. I feel your pain. Find a way to put the valve unit, (head, block, valve body, etc.) under pressure, blown from the mouth with a tube, while under water and look for bubbles. Its a good way to prove out your valve work.

My buddy can hear valve leaks when blowing on them. I'm too deaf.

Maybe it's not the valves.

 

[dvbydt]

Brian,

You've got us all hanging on the edge of our seats hoping you are going to solve this one. I am surprised that none of the builders here hav'nt been in your position and can offer a solution. How about putting stronger springs on the valves and seeing if this gives you compression?

Ian

 

[lathe nut]

Brian, I have been one of the almost 20,000 who have looked at the start of the project and won't see the finish, you cannot do that to us, take some time to cool off, leave it on the bench and it will come to you in the middle of the night what is wrong and bingo it will be running, I for one would love to build one someday but know that if a fellow like you has problems I would not have a chance, I have really enjoyed this post and will hope that you get it soon, not knowing will kill us all, again, thanks for what you have done and looking forward to noise of victory, Lathe Nut

 

[ozzie46]

Brian, I'm sorry it didn't work out right now.
But I know when you start chasing your tail it is time to take a breather and regroup.

Put it away for a while and come back to it. Start fresh after a rest and it will most likely be easy to figure out.

Ron

 

[Brian Rupnow]

I have to take a break for a while, because the project is beginning to eat me. I know whats wrong. The valves aren't sealing. Thats it--totally. And right now, with the state of my machining ability and the state of my old Chinese lathe, I don't seem to be able to make them seal. I have remade the valves, I have made valve cages, I have made a tool to ream the valve seats "in place"---and all to no avail. I am sure that if I could get the valves to seal and give me that elusive compression I have sought and felt "sometimes" that the engine would run like stink!!! My lathe has concentricity issues between the centerline of the tailstock and the centerline of the chuck. It doesn't seem to be a direct linear offset, as much as an angular offset, and the farther out I get from the tailstock, the more pronounced these issues become. This I'm sure has been the major factor in why I'm having these problems. This engine is one of the "prettiest" engines I have built, and one I would really like to see finished and running. I'm out of options right now. If I had a friend in the area who was a better machinist/innovator than I am, I would seek them out and ask for help, but I'm the biggest toad in the puddle around here when it comes to model engines so I don't have anyone to go to for help. I need a John Bogstandard or a Cedge living next door or down the street, so I could drop by for a pep talk and some hands on help. I have never absolutely "failed" at anything technical in 64 years, so you have to realize my frustration right now. I need a break, a breath of fresh air, and time to come up with a better game plan. I do have a friend in town with a Sherline-----

 

[rleete]

Take a break, let it sit, and maybe something will come to you. There's no time limit here, and if it's making you frustrated, it sucks all the fun out of it. It doesn't hurt to set it aside for a while.

You've got the whole forum waiting for that final post of the video of it running. I wish I could offer some constructive help, but I have yet to try an IC. You'll get it eventually, and we'll all be here to cheer when you do.

 

[lee9966]

Brian - what steps have you taken to analyze the problem?

Can you verify the valves are closing all the way when all is assembled? Are the springs really pulling them closed?

If there is no compression at all you should be able to hear where the leak is. Listen at each port while cranking. You can use tubing like a stethoscope to localize where you are listening. Note: plugging the tubing tight into your ear and sealing the other end to the exhaust port is not suggested. Not at all. Not even a teeny bit.


Lee

 

[tel]

In those days, the valve grinding compound came in a container that had dual tops to it. One side had semi-coarse grinding compound, and the other side had fine compound, and you started with the coarse and finished with the fine.

Yep, I have a (closely guarded) very old tin of it as well, but toothpaste will work, and for ultra-fine try Moty Paste.

 

[Lakc]

Brian, we all wished you better luck then this. Your probably not much worse off by putting it away for a few days at least. If your anything like me, you will have a revelation while trying not to think about it. :big: Its not a bad thing really, just sometimes, things wont cooperate with your timetable.

 

[metalmad]

Hi Brian
on the note of your lathe tailstock.
Have u made a test bar to run between centers,with two identical raised areas ,say 8 inchs apart
so u can test tailstock alignment with a DI?
once u get it right its easy to check next time too
u will not believe what I use for my valves
auto cut and polish lol.
PS dont give up mate, u will get it ( I bet its something really simple )

 

[Maryak]

Brian,

Like the rest of the Guy's, I feel your pain.

Take a break, it will come to you when you least expect it and I don't know of any deadlines in the hobby world.

Best Regards
Bob

 

[Tumbletown]

Brian
I'd like to tell you you are not on your own. I built a Ridders 2 stroke engine recently - I think to a pretty high standard. It did EXACTLY what yours did. It popped and banged under the starter and once ran for about 20 secs on its own, never to be repeated. I made a new piston and intake valve to follow up compression. I've had the timing advanced and retarded. I made two ignition systems and have run it lean and rich and all shades and combinations in between. After tearing my hair out and following some backfires and scoring the crankshaft under the flywheel, I have decided to place this creation in a plastic bag and place it in a drawer for projects that need re-visiting! A break will do me good. As a sucker for punishment I've decided to build a Webster and will revisit the Ridders if and when my Webster bursts into life. Please take heart. Your posts on this forum are interesting and informative and I'm sure everyone following your progress feels for you. Take a well-earned break and have a brilliant Christmas
Regards from the other side of the pond
Adrian

 

[Ken I]

When I have compression problems on full sized car engines - I have a range of old spark plug bodies with airline quick couplers silver soldered in.

Drive the cylinder to TDC and apply 100 psi via the spark plug fitting and listen to where it is leaking out.

Pretty straightforward.

Regards,
Ken

 

[NickG]

Submerge it in water and you'll see where the bubbles are coming from.

I think you're best starting with no valve seat - a sharp, square edge then lap a little until you've got a shiny ring all the way around - like a poppet valve.

You made working valves for webster, what's changed? As bob said though, there are no deadlines in this hobby. I had a similar situation with my Ridders flame gulper but got there eventually.

Nick

 

[cfellows]

Brian, I've done the same thing with my 2 cylinder open column IC engine. I'm still not happy with the compression, so I've set it back on the shelf and moved on to other things. I'll get back to it one of these days.

Don't let this setback keep you from other projects. Try making a new tool next or maybe another steam engine design. Tons of things to make out there.

Chuck

 

[Brian Rupnow]

Chuck---I'm down but I'm not out!!! I need a break from the engine, and I need a way to test valves and valve cages BEFORE they get installed on an engine. This will be a nice "side project". Can you tell from the drawing what I am doing??----Brian

View attachment ASSY-VALVE CAGE TESTER.PDF

 

[doc1955]

I know you may have already checked this but are you sure it's the valves that are leaking? It does not take a huge leak to lose compression. I know from my 6 cycle engine I built I couldn't get it to run very well turned out that even though I thought I had the spark plug threads and seat good I had a leak. I placed a soft copper ring under plug and wouldn't you know ran like a champ.
It's just a thought and like I said you may have already addressed that.

 

[Brian Rupnow]

Doc---That engines as airtight as a ducks behind.

 

[Admiral_dk]

Just a thought ....

If the diameter of the venturi in your carburetor is too big, you might get at a pop or a few on a port prime, but the engine will never run continuously .... simply because there's not enough vacuum to suck fuel from the tank.

Have a look at : http://modelenginenews.org/ , click on "Editorial Index" and choose the October 2010 issue, go down to "Sparey ".8" Inlet Woes".

I really hope that you solve the problem soon.

 

[Maryak]

Doc---That engines as airtight as a ducks behind.

What a great way to say watertight. :bow:

Best Regards
Bob