Tight when hot

[lendusaquid]

I seem to have a problem when the engine is hot.The piston gets tight when at the top of the cylinder.I was also getting some knocking which i could not get rid of with changing the timing.Took big end shells off to take a look and found a small amount of wear on the bottom shell.They are new shells,about 100 hours.This makes me think that the piston sticking is not my imagination.
Any advise would be welcome.

[Doug]

Check to see if the rod is not bent, and the piston when at TDC is square to the crank.

Check out Hotator or Quins PS kit engines for what this sort mis alignment looks like. The Indians correct this with 1/2 gaskets on the low side. Thats my best guess.

[snail]

Did anyone else think that the subject of this thread was more porn spam?

[t19]

And still you looked... what does that say??

[Stan]

Only if the subject was reversed. 
Stan

[Tom]

Another possibility, if the liner is worn and the rings are coked it could cause sticking at the top of the bore. Pull the piston and check the ring grooves and maybe place a straight edge across the top of the bore perpendicular to the wrist pin, with the piston at TDC and place a feeler gauge under the straight edge and see if the piston top is parallel to the top of the bore. If it is not something is likely to be bent.

[mobile_bob]

also take a very close look at the rod brgs, see if the wear pattern is even across the brg surface
if it is concentrated to one side or the other indicates either the cylinder bore axis is not perpendicular to the crank, the
rod is bent, the crank is not parallel to the deck, or the cylinder casting is cocked with improper gskts. or maybe even a piece of swarf or
sand is under the cylinder.

you made mention of a wear spot on the bottom shell? if so take a look at the top shell it is the one that should have the most wear
and you might have a crank journal that is egg shaped or tapered as well.

sounds like a good time to take her down to the ground and closely inspect each and every piece, the clues will lead you to the problem
if you look very carefully.

bob g

[lendusaquid]

I thought that title might interest the base instincts of you guys.If i had a leaking head gasket the title would have been " Hot steamy head".

Meanwhile more details.Its got a new dry liner fitted and the cylinder was skimmed 8 thou after fitting.New Indian piston was given to the people fitting the liner.The top of the piston is not flat but iam not that bothered.Just makes it a bit more difficult to get the bump clearance correct.Because of the 8 thou having been removed i needed more gaskets under the cylinder.The head gasket is now at 32 thou having been used a number of times.I think that because there is so many gaskets under the cylinder that it is no longer sitting true.I have a plan to use the two copper parts from an old head gasket to make a more solid gasket for under the cylinder.Your thoughts please?.
 I did notice the part of the piston above the top piston ring is bone dry.Maybe i should alter the gap spacing a bit to let more oil throu.When i first got the engine the crank was bent but i levered it to make it central in the hole of the case.   

[Stan]

Bent crank?   
Stan

[lendusaquid]

I just measured the gap between the crank and the big crankcase bolts on either side and there is less  than a 1 mm in it,so it cant be that bad. If another conrod came my way i would use thou. For a start it wont go up the cylinder when trying to remove.Its because its so old its a Lister L part.

[oliver90owner]

lendusaquid,

You seem to have a problem or two.  Maybe a quick jaunt to 'stuckinmuck' might get a crank without a wobble in it.

8 thou is not a lot.  I would not recommend using a head gasket as a cylinder to crankcase gasket.

Simply, they are compressible, so may change like your actual head gasket, or each layer separated will be thin and flimsy.  They are expensive compared to the proper gasket material.  Gasket material is available in different thicknesses from about 1 thou up to 125 thou or more.  You will still need an appropriate gasket thickness to set the head clearance, anyway.

Not sure what you mean by the new pistonis 'not flat'.  Can you expand that a bit more?

You should only need, at most, three or four gaskets (don't know how many 'so many' might be) under the cylinder if you have a range of thicknesses to choose from.  These gaskets are readily available from suppliers but a small ball-pein hammer is really all that is needed to make these gaskets, once the hole for the cylinder spigot has been cut out.

Altering the ring gap, if it is correct, will not increase lubrication to that area, it will just allow more gas leakage into the crankcase and losing some of your much-needed compression.  Temperatures around that area will be quite high.

Unless you sort out why, and rectify as necessary, you may not have a long-lived engine.  Longevity requires things to be running in line and minimum friction to reduce wear as far as possible.  Any continued localised overheating/rubbing will eventually destroy the engine parts and, perhaps, the engine too.

If you had a bent crank, I would think that is a likely area for investigation.  It may need  professional treatment to straighten it to within running specs.  It may even be cracked, or the main bearings damaged. Who knows.  These old engines will take a lot of abuse, but I think, as far as safety is concerned, it is better to find out now, rather than after a flywheel goes into orbit.....

That is my opinion and you can take it for what it cost, but I would feel uneasy running an engine where I knew there was an underlying risk of failure.  I would at least find out that it is safe and sort it out if possible.

Regards, RAB

[lendusaquid]

I wish i new where stuckinmuck's yard was.I would love to take a wander around it.Its just up the road from me but i dont know where.I have asked him a few questions about other engines he has sold but got no reply.
I was thinking about using the copper parts of a head gasket.They are about 6 thou.I have got to make up the 8 thou that was skimmed from the cylinder.I want something that is non compressible.Well not as compressible as half a dozen paper gaskets.
Well the piston top is not flat.When i put a set square on the side of the piston and the top i can see daylight.It is not at 90 deg to the side of the piston.
I need so many gaskets because the head gasket is only 32 thou  and because of the 8 thou skimmed from the cylinder.
And your opinion and advise is more than welcome.

[Quinnf]

Squid,

I found the piston on the Beta Test engine was high abou 0.008" (0.2 mm) on one side, but like you say, it's not really a big deal so long as you plan for that when setting the bump clearance.

Have you checked the ring end gap on that top ring?  Place the ring in the cylinder near the top, then drive it down a bit by inverting the piston in the cylinder until you're sure the ring is square to the bore.  Then measure the end gap with thickness gauges.  It's possible as the ring heats up, it's expanding and the ring ends are coming together.  That will make a hell of a noise and ruin a liner and maybe greak a ring in short order.  Indian spec is 0.012" or so when cold.  If it's less than that, a few minutes with a mill file can open the gap a little.

Paper base gaskets are easy to make and work just fine.  Don't think of them as being compressible.  They don't squish much.  The way to install them is to make and stack up more than you think you'll need.  Then once you assemble the cylinder and piston and start checking your bump clearance using a new head gasket, raise up the cylinder and tear out one gasket at a time until the bump clearance is about right.  Measure the thickness of the paper you're using so you'll know about how many to remove.  If you remove one too many you can tear a gasket in half and reinstall the two halves.  There's very little oil at that point, so you won't be inviting a leak by doing so.  The head gasket on an Indian 'roid is about 0.055" thick; that's only about two paper gaskets, so I don't know if that justifies tapping a gasket out of copper or tearing apart an old head gasket to get the copper out of it. 

The Part II and Part III links here might have something that might be helpful.

http://www.utterpower.com/kit_engines.htm

Quinn

[lendusaquid]

Yes i have been watching with interest what you have been up to.Ive been making gaskets from cardboard folders and inkjet printer paper. I had my bump clearance at about 42 thou and decided to add another gasket to increase it abit. Got it to 55 thou which was abit more than i wanted but never mind. After running for 10 to 15 hours or so i checked the bump clearance again by feeding a strip of lead down the cov hole. This time it read 52 thou.This has happened before which is why i think all the paper gaskets are squishing.I want to build up the bulk with a solid gasket and then only use a couple of paper gaskets to finish off.
I have cheated when fitting them by cutting the holes do i dont have to remove the cylinder completely.
I do like to use the old head gaskets as much as possible.I clean it up and spray with aluminium paint.Haven't had a gasket leak yet.While i have the head off i will have a go at making a solid copper head gasket and see how it goes.Annealed and sprayed with paint as well.

[lendusaquid]

Well boys & girls i done some measuring today.The piston protrudes above the cylinder 17 thou valve side,22 thou water pipe side,22 thou pump side and 19 thou on the other side.O what fun. I put a 3' straight edge on top of the cylinder and measured down to the top of the flywheels.No thou here,i just looked at a ruler.Looks equal to me give or take the thickness of paint.My head gasket is 32 thou so i need a gasket stack of 35 thou to give me 45 thou bump clearance.
Piston ring gap was 20 thou.