K liner valve guides

[Vev]

At one of the engine forums at Temora I heard about an L2 from WA talk about using K Liner inserts in Jab value guides. I presume this is the same process used on taxis when converting engines to LPG to make the guides more durable?

 

The L2 at Temora said it has fixed the valve guide wear issues and reduced oil burn to very low levels.

 

By the way ... why doesn't Jab run valve stem seals?

 

Anyone out there tried K Liner guides replacements or have a view?

 

Cheers

 

Jack

 

 

[Bruce Robbins]

 

Jack,

 

From the internet. I have no personal experience with K Liners.

 

VALVE GUIDE LINERS

 

Boring out the original guides and installing thin wall bronze liners to restore proper clearances is not only a fast and economical guide repair option, it also provides the benefits of a phosphor/bronze guide surface (better lubricity, scuff resistance and wear characteristics than cast iron).

 

Though liners are most often used to repair integral guides in cast iron heads, they are also a very effective way to repair replaceable guides in cast iron or aluminum heads, which saves time and eliminates the risks associated with driving out the old guides and pressing in new ones.

 

Liners also save the cost of having to replace the valves. If the original valves are not worn, standard sized liners can be used to restore the inside diameter dimensions of the guides. If the valves are worn, the stems can be turned down .0050 in. to accommodate liners with slightly undersized inside diameters.

 

Jerry Qualiana, vice president of aftermarket sales at K-Line Industries, Holland, MI, says their K-Line Bronze Bullet Guide Liner system has been authorized by Ford Motor Company and meets Ford Q-1 quality standards.

 

According to Qualiana, the Bronze Bullet Guide Liner design is an enhanced design over previous bronze liners, incorporating an "Interrupted Spiral" which assists in retaining oil in the guide, while eliminating oil flow through the guide. In conjunction with the previously mentioned lubricity characteristics of phosphor bronze, Bronze Bullet Guide Liners offer improved guide life in today's oil starved valve guide environment. Also, Qualiana points out that because of the lubricity in the phosphor bronze, K-Line has always advocated valve to stem clearance at the low side of the manufacturer recommended specifications.

 

Mike McElmurry, vice president of production at Sequal Corp.,Willow Springs, MO, says regarding K-Line's Bronze Bullet Guide Liner, "Because the final size is so easy to control, we have been able to tighten all of our valve to guide tolerances by at least .001 inch. This, along with the liner's ability to resist

 

galling has reduced our warranty claims by as much as 75% "I have looked at other methods of valve guide repair, .015 inch overised valves, new and rechromed, .003 in undersize valves with replacement cast iron guides, but have found nothing that was cheaper to use than K-Line with .003 in. undersize valves. We grind our own valves and enjoy over $0.80 per guide savings over any of the combinations listed above."

 

The key to using the Bronze Bullet Guide Liners successfully is proper installation. Qualiana says if the original guides are not worn more than .030 in. or cracked, they can be lined. Otherwise, replacement would be recommended.

 

Installation of the Bronze Bullet Guide Liners is a five step process:

 

 

 

 

1. First, the old guides have to be bored out to accept the liners. Qualiana recommends using a KL1725CB Black Beauty carbide reamer in an air drill with a no load speed of 2100 to 3000 rpm. K-Line's KL9900 Boring Fixture has centering pilots that center the reamer off the valve seat (which maintains seat concentricity), and an air clamping fixture that holds the head securely in place while the guides are being bored. The guides should be bored dry with no lubricant, using steady consistent pressure.

 

Once the guides have been bored out, they should be blown out and checked with a go-no go gauge to make sure they are the proper size.

 

2. The liners should then be pressed in from the top side of the head using an air hammer and K-Line's Auto Installer tool. The liners go in with the tapered side facing the guide hole. The liners are then driven in flush with the top of the guide boss.

 

 

 

 

3. Next, the liners are sized. Any of three different techniques may be used: roller burnishing (use with lubrication), broaching (driving a calibrated ball through the liner with an air hammer), or using K-Line's ball broach tool in an air hammer.

 

Sizing the liners is a critical step because it accomplishes two things: it provides the proper clearances between valve stem and liner for proper lubrication and oil control, and it locks the liner in place so it will transfer heat efficiently to the surrounding metal for proper valve cooling. Bronze actually conducts heat more efficiently than cast iron, but requires a tight fit and metal-to-metal contact with the surrounding guide for good heat transfer. If the liner isnot sized properly, it may cause the valve to run hot, or worse yet, come loose.

 

 

 

 

4. After the liners have been sized, turn the head over an trim the liner to length. The liner should be cut flush with the guide boss in the port. This step is not necessary if precut liners are being used that have the correct length for the application.

 

5. The final step is to Flex Hone the liner after any seat work that is necessary has been completed. The Flex honing step removes any burrs left from trimming the liner to length, and leaves a nice crosshatch finish that improves oil retention. One pass in and out is all that is recommended to hone the liner. A flexible nylon brush should then be passed through the liner to clean the hole.

 

Though the just described procedure sounds more complicated than it really is, a typical four cylinder or V8 can be relined in six to seven minutes says Qualiana. Also, the majority of the detailed steps listed regarding cleanliness and accuracy in the guide area are requirements no matter which method of guide repair the rebuilder chooses.

 

 

 

[facthunter]

K-line valve guide restoration.

 

Have used these but there are a couple of possible shortcomings depending on the application.

 

There is no positive location process when oversizing the old guide to accept the bronze liner, so there is a tendency for the new hole to follow the wear pattern. This means your valve goes off centre and more metal must be removed from the valve seat to reseat it, pocketing the valve and potentially upsetting the rocker geometry, and gas flow.

 

I have had no luck in situations where the exhaust port is very hot. This is in predominantly side valved engines that have cast iron cylinders and are air cooled. The bronze sleeve is broached to size. ( This as well as giving it its final size also expands the sleeve in the guide, and helps it to stay there and dissipate heat by conduction through the metal from the valve). and under the high temp conditions lost it's internal dimension and closed in on the valve stem and seized the valve. EXTRA clearance might have postponed the seizing but I believe that the interference fit is destroyed by the excess heat, in any case. Have had the same thing happen with small end bushes to a lesser extent.

 

The K-lines that I have used have a split running the length of them. This prevents resizing with a reamer, if you wanted to increase the clearance.

 

I don't know whether I would use them in a Jabiru motor. Possibly in the inlets but not so sure about the exhausts . I think the best would be real good bronze alloy guides with hard chromed stems, Nev

 

 

[stanzahero]

K-Line Guides

 

I have had a lot of experience with them (though none on aircraft engines), and I have found them to be an excellent device for repairing some guides.

 

As fact hunter had previously said, they used to have a straight groove down one side to assist in the installation of the guide. This was changed into a stepped groove (in the genuine item anyway) to prevent the guide turning inside the guide boss.

 

I have never seen a k-line guide grab except when there was a carbon build-up at the head of the valve.

 

A major advantage to these guides are they are more tolerant of low oil lubrication.

 

A major drawback of them is that an uneven weight distribution (compare the weight of the valve head to the valve stem) tends to wear the guide unevenly because it is a softer material than the cast it replaces (compare "hardness" to "toughness").

 

I have found them to be good on low-weight valve (DOHC engines - 3FSE/5SFE Toyotas and the like) or where the original has an integral guide (early red/blue motor, early Chev 6 & 8's) and not so good on engines where the valves sit at an angle or flat (some Mercedes, Subaru)

 

My opinion is if the OEM guides are easily replaced and obtainable, use them instead - especially for a flat engine.

 

The manufacturer spends a lot of time researching the engine components and if they deemed them necessary, they would have used them in the first place.

 

Stanzahero.

 

 

[Vev]

Thanks guys.

 

 

The originals guides are aluminium / bronze but seem to have a very short life 300 – 400 hrs … not sure if they are too soft, get too hot or bad geometry of the rockers???

 

 

Despite still having a good compression test and leak down result the valve defection is beyond serviceable limits. You can see the amount of carbon build up on the back of the inlet valves owing to oil bypass, which to me suggests that valve stem seals would have been a good idea in the design. I’m at a point in time I need to replace my guides and I’m looking at the alternatives to improve durability as well as manage oil bypass (may be with valve stem seals).

 

 

I’m not keen to play pioneer or test pilot but I hear there are engines out there with this mod and would really like to hear how things are going?

 

 

Cheers

 

Jack

 

 

[stanzahero]

You can see the amount of carbon build up on the back of the inlet valves owing to oil bypass' date=' which to me suggests that valve stem seals would have been a good idea in the design[/color']

Back in the early days of my career (first 10 years) I used to work with Bedford diesels.

 

Some of these engines had no valve stem seals by design. When they were fitted, they increased the stem and guide wear considerably because of oil starvation. This not only made some heads unserviceable (they had integral valve guides and once more than .025" wear was indicated thin wall guides could not be fitted), but it also killed the life of the engine valves.

 

 

 

Most manufacturers will life a part to save a more expensive / critical part (don't start me on Alfa's) which is why timing belts are changed on cars at a odometer reading rather that when the belt starts to deteriorate.

 

 

 

My Opinion:

 

Adding stem seals is not a good fix for the issue. This may lead to stem wear at best and "valve no worky" problems at worst.

 

 

 

Tommo may be a good reference for this conversation as he is also in the industry.

 

 

[Tomo]

You can see the amount of carbon build up on the back of the inlet valves owing to oil bypass, which to me suggests that valve stem seals would have been a good idea in the design.

Are you sure that that is oil build up? not carbon build up from Avgas? I realize you run PULP as well, but Avgas is pretty yuk stuff for causing carbon. I do also realize it's on the inlet valve so not real likely I guess.

 

I'm of the opinion with Stanzahero above - using guide seals wouldn't be the best idea if you could help it.

 

We don't fit them to engines in ski boats (Chev, Windsor, Cleveland etc) due to sometimes running a bit dry and when sitting for a while the moisture from the water will start to cause rust on the guides, they may use a tad of oil (haven't really noticed it though), but it better than having to pull your head (s) off every time you want to take it out. We fit the hardened valve guides as well so you can run unleaded in them without adding any suppliment.

 

 

[facthunter]

carbon build up inlet valve underside.

 

Common on cast iron engines. (Valiants on gas). The inlet port becomes nearly blocked and the engine performance suffers. Sometimes blamed on the blow-by gases from the engine going through the PC valve, (having a lot of oil mist in it. I agree with this, and oil passing through the worn guides likewise. Although plenty of cars successfully fit valve guide seals they generally are watercooled, running cast iron guides and the valves are phosphate coated. Some european ones are chrome plated.stems.

 

3-400 hours is not a good life and I would check the rocker geometry and the wear in the rocker bearings. Both factors will put a side load on the valve stem. Inspect the surface of the valve stem under a magnifying glass and see how shiny the wear surface is. If the metals are wearing OK there will be no sign of galling. (Coarse scratching and metal pick-up). If there is galling then there is a problem with the choice of materials, excess side load or lack of oil. I would not fit seals to this engine if it is used in an aircraft. Also loose guides can cause the head to detach fro the valve. This is not unusual in Jabiru's. Nev

 

 

[brilin_air]

We fitted K Liners to our 2200 engine about 30 hrs ago and all seems good at the moment, I will remove a head in another 70 hrs or so to check whether it has been a good thing to do or not, but at the moment we are very happy.

 

Brian

 

 

[Vev]

No question in my mind Tomo that the oil is come via the giudes ... also seeing way too much carbon build up on the piston crown and ring lands too.

 

Nev, I have found wear on the rockers shafts and valve stem contact points. Jab has sent me an upgrade with new hollow push rods and oil gal rockers to improve lubrication around these components. I think the geomertry looks NQR and agree with your thinking that this could be one of the reasons for a short guide life.

 

I'm also concerned about heat as well as this may place too much thermal load for the lubricant. I dont think it is draining back fast enough to the sump from the rocker chest, despite the factory upgrade to drill a vent hole. I think the warn valve guides are causing a pressure drop in the rocker chest via the inlet guides as it sucks the oil through???

 

Cheers

 

Jack

 

 

[Vev]

We fitted K Liners to our 2200 engine about 30 hrs ago and all seems good at the moment, I will remove a head in another 70 hrs or so to check whether it has been a good thing to do or not, but at the moment we are very happy.Brian

Hi Brian,

 

Thanks for your feedback mate .... do you know what type of K liners you used? What made you decide to use them.. did anyone recomend them to you?

 

Look forward to hearing how things go?

 

Cheers

 

Jack

 

 

[jetjr]

Interesting test showing sensitivity to external pressure on rocker covers

 

If it isnt right could be pressurizing oil or runnng valve gear dry

 

 

Why does this seem to be a 4cyl issue?

 

 

[facthunter]

Oil Amount.

 

Don't think you would ever want the rockers full with oil. Pushrod engines do not need that much. Certainly fills up quickly.so the supply amount is more than adequate, or else it is sucking the oil that is draining, back up the pushrod covers (tubes)...Nev

 

 

[jetjr]

Nev, 100% right, Im amazed that by moving breather tube into and out of airflow was able to make this much difference

 

Theres so much "black art" in air pressure under cowl and variation between installations the valve guide wear issue and oil burn rate could be linked.

 

Also airspeed changes these pressures. Could they be full of oil at one stage of flight and empty at another?

 

The type of use of an AC could explain why some last 300hrs others up to TBO

 

Theres another video showing 4cyl running normally fast idle and theres no oil in rockers at all

 

 

[facthunter]

OIL feed.

 

While ever there is oil pressure there should be oil in the lifters, pushrods and rocker gear, shouldn't there? It should drain straight back through the pushrod tubes...Nev

 

 

[jetjr]

yeah but its the rate at which it drains most likely, put some positive pressure in there it will rush out

 

Negative pressure it will hold the oil back filling rockers up

 

Do hydraulic lifter engines suffer this valve guide issue more than solids?

 

 

[Vev]

What an interesting video clip … thanks for sending JR.

 

 

My understanding … there is insufficient free air volume in the crank case (see Jabs Service Bulletin JSB 013 -1) which causes a positive pressure and is compounded by a low pressure in the rocker chest from the inlet value guides allowing air to be escape through to the inlet induction. Jabs fix was to get us to all to drill 3/23 holes through the heads to atmosphere to vent the rocker chest… the hole is on the pressure side of the ram air cooling side. Later model engines had deeper sumps which increased the free air volume in the crank case and reduce pressure build up… they also increased the drain back holes at the base of the push rod tubes to improve drain volume to the sump.

 

 

I agree again with Nev’s comment … you really don’t need that much oil to lubricant the rockers. In my mind, it’s more about getting the lube into the right place and having it drain away quickly thereby taking away the heat without damaging the lubricant. A long dwell period of lubricant caught in the rocker box just exposes the oil to possible burning and oxidation as well as of loss of the lubrication characteristics. I don’t really think I’m telling anyone anything new as Jab have publicly documented this issue and make this point quite clear in their Service Bulletin.

 

However I am concerned that their vent fix doesn’t keep up with the pressure differential when the guides wear, which in part starts a damaging cycle of wear on the valve train. Hence one of my initial questions if valve stem seals would have been a possible fix to allow the oil to drain and save the rocker gear despite valve guide wear.

 

Cheers

 

Jack

 

 

[facthunter]

Valve guide wear effect .

 

Jack, I don't think that valve guide wear could be enough to cause suction to effect the oil level. The rocker box venting would cope with it. There would have to be a LOT of air going past the guide, the slow running would be affected and the oil consumption would be elevated to the point that smoke in the exhaust would be evident at times. I have never seen a jabiru do this and the engine would carbon up considerably too.

 

The biggest concern with guide wear is the exhaust, where the head of the valve can detach as a result of excessive guide wear. This is caused by heat and misalignment causing repeated slight bending of the stem. You should be able to check the guide wear without removing the heads. Just turn the motor till a particular valve is just off its seat and move the stem in the guide with a dial gauge touching the valve stem, and note the change of reading. They will wear oval with the maximum wear indication being at right angles to the rocker pivot axis..ie. up and down. I would suggest a limit of 006". Check what Jabiru say. Nev.

 

 

[brilin_air]

Hi Brian,Thanks for your feedback mate .... do you know what type of K liners you used? What made you decide to use them.. did anyone recomend them to you?

Look forward to hearing how things go?

 

Cheers

 

Jack

Hi Jack,

 

I will check and find out which exact ones I used. I will get back to you. It was a suggestion from my Engine Reconditioner that does my machining, (they do alot of perfomance engines), and after a discussion with him I was happy to try it.

 

Brian

 

 

[Vev]

For what it’s worth, I have decided to replace the exhaust valves owing to excessive seat wear and as a precaution … I’m concerned about how much fatigue the exhaust valves may have suffered with the amount of guide wear… the valve are as loose in the guides as Tiger Woods wedding band…. no need to measure the defection in this instance.

 

 

I also need to measure and compare the new replacement oil fed rockers (they turned up in the mail today) with the old splash/mist oil rockers as they look to have a different geometry…. This may help reduce the side loading on the guides. ..I will let you all know if different once I measure them.

 

 

Cheers

 

Jack

 

 

 

[xair1159]

A slight tangent to the original topic, but related.

 

Ref. crankcase pressures and oil breathers - is there a definitive oil breather set up with guaranteed results, or any popular "improvements" to the book system? I have read of various large bore plumbing jobs with bigger spigots welded to the filler neck.

 

What actually works best with the hydraulic engines?

 

Nick

 

 

[Vev]

Hi Nick,

 

 

I can’t say I have seen anything that has excited me in terms of engine breather improvements. There have been a couple of attempts at fitting inline oil condensers before the oil/separator, but these in my view could create more problems in terms of back pressure and therefore higher crank case pressures.

 

 

I think the only sure fire improvements to reduce crank case pressure in the 4 cylinder is the larger crank case sumps as fitted on the latest model engines.. However this will be an expensive retro fit upgrade.

 

 

Others may know more???

 

 

Cheers

 

Jack

 

 

[brilin_air]

Jack, The K Liners are a brand of valve guide insert, you can get them from other makers but the K Liner brand seem to do the trick.

 

Brian

 

 

[Vev]

I had a good conversation with the South African Jab distributor this evening who has been inserting K liners into Jabs for a couple of years with very good success. He said he has seen engines comfortably run out their 1000 hrs without problem.

 

However, having said that, he believes that lean cruise burn is the root cause in terms of premature valve guide wear; despite the introduction of rich kit from Jab he says more fine tuning is required in most applications. He is of the view jetting can vary between aircraft owing to minor variations in set up and use… he said to target < 700 deg C EGT at 2750 rpm (being the transition phase on the needle) is good place to start to extend he life of valves and guides.

 

Any thoughts about these comments are welcome?

 

Cheers

 

Jack

 

 

[slartibartfast]

Jack, any update on your guides? Did you fit the K Liners? How are things now?

 

I'm faced with the same issue (at 300 hours too). I have excessive oil burn, and noticed pools of oil inside 1 and 3 (viewed through the plug holes).

 

It still starts first turn every time, and I haven't noticed smoke (it may be there - haven't had anyone handy to check). Definitely burning too much oil though.

 

Compressions are OK, so Don suggests valve guides are the most likely cause.

 

I'll pull the heads off this weekend and find out, but I'm thinking that a trip to the machine shop and some K Liners are the way to go.

 

How's yours Brian?

 

Anyone else have ideas?

 

Cheers,

 

Ross