A Little Glitch with K-Lines

[geodoc]

I learned something on my Tonti-engined Loop that I thought worth passing along.

The guides were worn in the donor Convert engine and rather than replacing the guides, I decided to go with K-Line swedged inserts. The shop that installs them reported good service and no complaints in various car & bike engines. Before installing them, their machinist called me up and pointed out that in the process of opening up the guide bores, the oil "scraper" sections on the top of the guide would be removed. I told him to go ahead and see how they did in service. As it turns out, without the scraper sections at the top of the guide, both intake and exhaust had considerable oil traveling down into the ports past the valve stem and guide. Apparently, the scraper sections do a pretty good job of keeping excess oil from entering the guide - valve stem clearance.

I've taken the heads off and we'll now install guide seals, both intake and exhaust Which should solve the problem. It will be a little ore complicated since I'm using a Megacycle X10 cam with about .45" lift at the valve and only about .015" clearance between the top of the guide and the bottom of the upper valve spring keeper. Lucky the machine shop has a fixture that will allow them to remove about 1/8" or so seal lip clearance off the top of the guide in place along with making a groove for the seal.

I also noticed when taking the heads off that the Smith Bros. RH intake push rod had a worn spot (not just rubbed). Where it was located is about mid-way down the tube tunnel in the Gilardoni 950 cylinder. It appears that the casting in there is a little smaller than in the other tunnels, so I'll be opening it up with a die grinder just slightly and getting a replacement push rod.

Learning by doing ...............................

PS: had it on the dyno a week ago to tweak jetting. Ended up with:

MJ: 135
PJ: 60
Slide: 50/3
NJ: 265AB
Needle: K5 lowest notch

1000SP Gilardoni cylinder kits
36mm dellortos
Megacycle 620X10
Stock Loop "cigars" w/ large outlet
Stock Loop airbox / filter
Loop single-point distributor w/ heavier (slower) advance springs and transistor ign. booster

Didn't get a print-out, but ended up with 54 HP @ 6500 RPM after which it started to drop off a little. Torque curve was Guzzi-typical flat. The dyno was a brake-type, not a Dynojet & apparently shows about 10-15% lower HP #'s than the Dynojet.

 

[lucky phil]

Thanks for the info.I have a friend in the motorcycle engine rebuilding and performance modification business and he swears by the k-line system. He has the full capability and skill to make and fit guides but says the k-lines are a better simpler and cheaper option.
I will be doing the same but on a Daytona engine which uses guide seals as std fitment.
Personally I would not have run the 2 valve motor without the scraper section or guide seals but its good info to have first hand.Thanks
Ciao

 

[Chris R]

I am a little surprised by that - I have run K-lines on a few bikes and never seen any increase in oil consumption or evidence of oil on the valves. Pete Roper probably has a comment as he has done a pile of them.

Putting a seal on the intake is not a bad idea in any case - even a little oil causes detonation.

For what I know a seal is not usually required on the exhaust side. If you do put one on I would use a teflon seal.

Thanks for sharing the jetting info - that is really useful.

 

[geodoc]

I am a little surprised by that - I have run K-lines on a few bikes and never seen any increase in oil consumption or evidence of oil on the valves. Pete Roper probably has a comment as he has done a pile of them.

Putting a seal on the intake is not a bad idea in any case - even a little oil causes detonation.

For what I know a seal is not usually required on the exhaust side. If you do put one on I would use a teflon seal.

Thanks for sharing the jetting info - that is really useful.

I was surprised seeing burnt oil and dampness on the valve stems and a bit on the valve head on the exhaust side too. You'd think that exhaust pressure would force any oil back up and away from the port. But there you are.

 

[geodoc]

Found the squish at .080" with the cylinders installed as-is.

.040" off the cylinder bases:

Measured the combustion chamber volume & found it about 8.5:1 before and 9.5:1 after:

the valve to piston clearance is a bit tight so will trim a bit off the pistons to get a more comfortable number. will loose a little on the C.R., but oh well.

 

[DAMMAG]

I had K lines installed in my LM3 (with a LM1000 motor) after an engine reconditioner cut my valve seats off square and wore my guides out in about 1000Km's. I found this out after a valve spring broke, the wrong springs were supplied. Haven't had a problem since.

When I was rebuilding my motor I checked my squish clearance and decided that it was 0.8mm too big so had that machined off the heads. That of course didn't change my squish (learning experience) so I then I had 0.7mm machined off the top of my barrels. Squish was then good but exhaust valve to piston clearance was too small so got the dremel out and all has been good since. I have twin plugged the heads so this has helped with the increase in compression ratio.

Do you think that taking material off the bottom of the barrels might have problems with the top ring hitting a ridge in the bore?

I love mucking about with motors and once tried to build a 95mm bore motor but ran into all sorts of problems.

Damian

 

[Mi_ka]

Measured the combustion chamber volume & found it about 8.5:1 before and 9.5:1

How is that done? Oil volume or so?

 

[geodoc]

I had K lines installed in my LM3 (with a LM1000 motor) after an engine reconditioner cut my valve seats off square and wore my guides out in about 1000Km's. I found this out after a valve spring broke, the wrong springs were supplied. Haven't had a problem since.

When I was rebuilding my motor I checked my squish clearance and decided that it was 0.8mm too big so had that machined off the heads. That of course didn't change my squish (learning experience) so I then I had 0.7mm machined off the top of my barrels. Squish was then good but exhaust valve to piston clearance was too small so got the dremel out and all has been good since. I have twin plugged the heads so this has helped with the increase in compression ratio.

Do you think that taking material off the bottom of the barrels might have problems with the top ring hitting a ridge in the bore?

I love mucking about with motors and once tried to build a 95mm bore motor but ran into all sorts of problems.

Damian

Heh Damian,

The cylinders are Gilardoni / Nikasil & have only been on about 2500 miles so no ridge factor. I can't see that nikasil would develop a ridge until a considerable number of miles, if at all, being as hard as it is. It would have been easier to machine the top of the barrel rather than the base, but with the bore plating you'd almost assuredly chip the plating.

 

[geodoc]

Measured the combustion chamber volume & found it about 8.5:1 before and 9.5:1

How is that done? Oil volume or so?

Heh Mi_ka,

You can see in the picture I made a clear plastic plate to bolt down on top of the cylinder along with a used (squished) head gasket all sealed up with a light coat of grease. Lucky the top of the piston crown didn't quite hit the plastic plate at TDC. I use ATF injected with a syringe through a small hole drilled in the plate to get a volume number. I used the same plastic plate to measure the combustion chamber volume in the head. Added together, they equal the total volume.

After I removed .040" from the cylinder base, I subtracted a calculated volume of .040" (1mm) and an 88mm bore to get a new compression ratio. I won't bother re-measuring when I remove a bit off the piston crown for more valve-to-piston clearance. It will be near 9.25:1 since pre-piston cut as ~9.46:1.

GD

 

[Chris R]

As usual George nice work!

Getting the squish right is about the best no-cost mod you can make and the one no one pays attention to.

Is that a colchester 600? If so lucky man - my favorite lathe.


Chris R

 

[Mi_ka]

I use ATF injected with a syringe through a small hole drilled in the plate to get a volume number.

The shiny redish color in the picture?

 

[geodoc]

I use ATF injected with a syringe through a small hole drilled in the plate to get a volume number.

The shiny redish color in the picture?

Yep ...................... ATF. Easy to see.

 

[geodoc]

As usual George nice work!

Getting the squish right is about the best no-cost mod you can make and the one no one pays attention to.

Is that a colchester 600? If so lucky man - my favorite lathe.


Chris R

Lathe is a "Sharp" made in Canada

 

[geodoc]

relieved the pistons for .080" intake and .100" exhaust valve to piston clearance:

 

[geodoc]

Lash caps are Ducati parts for 8mm valve stem - 1mm thick. stems cut 1mm allow small clearance to the keepers. Caps also available for VW Beetle engines, but hard to find thin ones.

 

[Chris R]

Lathe is a "Sharp" made in Canada

The only Canadian made lathe I have used is a Standard Modern and they are absolutely horrible!

Glad to know we can make something that is actually decent.

We all await reports on how this all works - I have thought of putting in valve seals but never had the time to bother.

What seals did you use?

ChrisR

 

[Mi_ka]

Lathe is a "Sharp" made in Canada

The only Canadian made lathe I have used is a Standard Modern and they are absolutely horrible!

Standard Modern? Not Modern Standard?
French inscriptions? :side:

 

[geodoc]

We all await reports on how this all works - I have thought of putting in valve seals but never had the time to bother.

What seals did you use?

ChrisR

Donno what seals they are exactly, they are ones selected by the shop that did the guide machining to adapt them. I suspect they're Viton, being brown rather than black - metal shrouds w/ Viton ends and springs.

Test ride showed that, oddly, the idle & just off idle jetting that was pretty close with the wide squish (60 PJ / 50/3 slide), is not quite the thing with the .040" squish. Will be fiddling with that & perhaps the timing to get it back t smooth rather than stuttery.

 

[Chris R]

Standard Modern? Not Modern Standard?
French inscriptions?

Standard Modern it is.
Amazingly they are still in business in Brantford - http://www.standard-modern.com/
They used to make the standard wretched school lathe - I hope they have improved.

Test ride showed that, oddly, the idle & just off idle jetting that was pretty close with the wide squish (60 PJ / 50/3 slide), is not quite the thing with the .040" squish. Will be fiddling with that & perhaps the timing to get it back t smooth rather than stuttery.

The fact that the jetting/timing has changed indicates you are on the right track!