Suprise after top end removal.

[niclpnut]

I had never gotten around to working on the top end of my 83 1100E, but after being frustrated by scored cylinders on the ES, I decided to wrench on the E a bit.

Got the head off and everything looked pretty good. Did a leak test on the valve seats and they held gas for quite a while, so will probably only need a kiss with a lapping stick.

Pulled the jugs which were a bear to get off, and found pistons that showed little blow by. They also looked a bit different than stock, and were held on by wrapped wire clips, not the stock C- circlips that I am used to.

On my micrometer they read just about 74mm so it looks like some time down the road the old girl got a bore kit. I'm not too sure what brand though.

Pic of one cleaned up:

There is a "C" stamped into near the center of the top, and "EXH ^"

The Bad news is that 2 of the bores have some scoring. Not nearly as bad as on my ES but slightly visible after a touch of the flex hone.

Was really hoping to be able to slap a spare set of standard rings I have on, and get it put back together, but that's not happening now!

I do have a spare block now from the ES so I suppose I can have it bored to match the pistons :-k

Have no idea how long the kits been in there. No blow by discoloration on the pistons, so wonder if the rings will be ok. Not sure if measurements would be the same as on stock components.

My luck has kinda been a double edged sword as of late :twistedevil:

Nic

 

[7981GS]

I may very well have a set of rings for those pistons if you need them.
I would have to check my inventory tomorrow...

Daniel

 

[niclpnut]

Got the head apart. Everything looks pretty good. Appears that the stem seals are working well. Should I go ahead and change them though?

They feel flexible on the top and look to be sealing the valves up well.

Worst exhaust valve:

Intake valves have a nice clean ring on the seats.

Nic

 

[SqDancerLynn1]

I would change the valve seals regardless...

 

[Guest]

Got the head apart. Everything looks pretty good. Appears that the stem seals are working well. Should I go ahead and change them though?

They feel flexible on the top and look to be sealing the valves up well.

Worst exhaust valve:

Intake valves have a nice clean ring on the seats.

Nic

You are there now might as well replace them

 

[FiremanBob]

Yup, you already know that the valve stem seals are one of those "While you're in there..." items.

 

[niclpnut]

Yeah I know, just seems they are in good comdition.

Took the jugs down to a local shop in KC: Cafe Racer after I finished the hone.

Head mechanic who does machining in house says even with the scuffs/scores the bores look really great. Not much out of round/taper. Dan gave a resounding yes, use them.



Nic

 

[niclpnut]

Also laid an eom stock head gasket over the bores and it looked like I is clearing the bores.

The old gasket looked to be composite fiber and had round bore openings. The oem has rounded corners but flat at 12, 3, 6 and 9.

Edit: Well since the 1150 is a 74mm bore and the head gaskets are interchangeable I guess it will work.


Nic

 

[trippivot]

grease the old valve seals check end gap of your rings if top ring under 0.030" put it back together and ride it until you get tired.
or not
I understand making things perfect but if you can whip into your stuff like I can , why spend money on parts that will live a few more years(thousands of miles).

however! now would be the time to weigh your piston assy's on a micro scale and make them all within 1 gram of the lightest one--

high performance reciprocal balancing and give yourself $200 for doing it.

APE thin wall tool steel wrist pins are a nice addition too

 

[niclpnut]

Are aftermarket ring tolerances such as ring end gap the same as stock?

Nic

 

[niclpnut]

Well, It looks like ring end gap should be .0145" or .355mm according to :

http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

I don't have an inside bore micrometer, so I'm trying to measure piston to cylinder clearance with feeler gauges.

I've inserted on piston minus rings into the bore and measured between the pin bore and wall, pushing the piston as firmly to the other side as possible at different locations.

Worst spot (again can't be certain how accurate this is) I was able to just get a .007" feeler in there. So divide by 2 and I should have .0035" clearance...

If I measure from the bottom of the skirts to the piston wall, the largest size I can get in there is .004" or .002" clearance.

My understanding is that piston to bore with wiseco is set up to .002-.003" clearance.

Is the bottom of the skirt the measurement I should use?

Thanks,

Nic

 

[niclpnut]

I guess search feature is your friend

03-31-2007, 12:07 AM
Nessism

Senior Member
GSResource Superstar
Super Site Supporter
Join Date: Mar 2006
Location: Torrance, CA
Posts: 17,808

You measured at the top of the piston which is the wrong place. The piston has a smaller diameter at the top because it get the hottest and expands the most. You need to measure at the bottom of the piston skirt. Only way to do this is to take the cylinders off.
__________________
Ed

Thanks Ed :lol:

 

[Steve]

I don't see how you can get accurate piston-to-cylinder clearance measurements with feeler gauges.

.

 

[trippivot]

feeler gauges are kinda old school no dividing by 2 ! OR Weisco would say 3 thou per side.

.003"~.004" at the lower skirt area

ok 15 ~20 on the top 2 ring gaps would be better than 30

I have torn down some real smoker engines that ran like the dickens . pitty they run so good just before they..........

My last engine had 8 thou pist.-cyl. and barrel shaped by 5 on the worst cylinder. ring gap was 26 .. not all were the same but they were close

I chose to go with new pistons at those measurements

 

[niclpnut]

For some reason I was thinking to divide the measurement by 2. The piston was not centered in the bore without the rings, so the gap would be roughly 2 times as wid with the piston pushed to the opposite side of the bore from the measurement.

I know bore gauge is the way togo, but I wanted to get an idea of where I am at untill I can to a machine shop.

Nic

 

[Guest]

Glad Cafe Racer took care of you... Greg and Dan are good guys



-local KC guy...

 

[niclpnut]

Glad Cafe Racer took care of you... Greg and Dan are good guys



-local KC guy...

Yup.

Good people there. And Jim over at Cyclops in Shawnee. Always willing to answer my dumb questions


Nic

 

[Normk]

Nic, not sure if you have the measurement questions answered to your staisfaction?

Piston to cylinder wall clearance should be measured towards the bottom of the skirt as someone pointed out. Clearance at the top of the piston and in particular above the compression ring land is almost meaningless.

If using a feeler guage, which is how this has typically been done very accurately for a century, is performed by slipping a long feeler guage against the "side" of the cylinder wall at 90 degrees to the crankshaft, then sliding the piston in against the feeler.

The feeler will be able to be withdrawn subject to a light drag if the clearance is equal to the thickness of the feeler. On motorcycle and other small diameter pistons it can be useful to utilize a long narrow feeler guage rather than a standard width feeler.

A feeler guage will provide accurate clearance in the hands of someone who is advised. The alternative, use of an inside mic or cylinder bore guage compared against that of an outside mic of the piston is a more difficult means to almost the same end. While it may seem that the micrometers or micrometer and bore guage method must be more accurate, consider that this method introduces to variability issues rather than a single one.

I prefer the use of a feeler for checking piston clearance even though I prefer an inside mic or bore guage for checking out of round and taper.

Another useful lesson is that of always checking piston clearance at several points after a re-bore. We once received an engine back from boring which had more than 12 thou" of cylinder taper....but let's not go there!

Piston to cylinder wall clearace (as long is it isn't too little) is not a huge issue or at least not to the degree of excessive cylinder taper or out of round. I have knurled pistons in dozens of engines to correct a bit of excess piston clearance with the engines often lasting longer than from new.

HIH

Norm