heli coil

[Hank]

22 minutes ago, A64Pilot said:

‘Plus for items that are often removed, you have steel on steel threads as opposed to steel on aluminum, I believe that’s why our cylinders heads are helicoiled from the factory, but a lot of cars and motorcycles screw plugs into aluminum heads and it works just fine, so maybe not?

They work fine on cars because how often do you pull the plugs and torque them back in? Once? Twice? in the engine's life? Compare that to how often they are pulled and torqued back in in your Mooney . . . . . Much more wear on the soft aluminum if helicoils weren't used.

[cliffy]

Do it right by following the Lycoming instructions and using their tools. 

Its the only "approved" procedure

This is not something to go off the reservation with.  You're life may depend on it.

If you have never done it before get someone who has. This is no place to learn the craft.

[RJBrown]

Head studs on air cooled VW motors pull out of the case. 
These inserts are used to save a used case or protect a higher horsepower engine from coming apart.

Do aircraft engines have similar issues?

No Carusoam, I just walked out to the hangar in the backyard to take the pictures.

[RLCarter]

@RJBrown With the low compression ratios on aircraft engines I doubt it, we used Time-Serts on our Drag Bike motors to keep the cylinders and head in place.

[N201MKTurbo]

38 minutes ago, RJBrown said:

Head studs on air cooled VW motors pull out of the case. 
These inserts are used to save a used case or protect a higher horsepower engine from coming apart.

Do aircraft engines have similar issues?

No Carusoam, I just walked out to the hangar in the backyard to take the pictures.

Most of the cylinders are bolted to through bolts that go all the way through the case from one cylinder to the other. There are two studs in the back that thread into aluminum. They are 1/2 inch and have about 1 1/2 inch of thread engagement.

[RJBrown]

2 hours ago, RLCarter said:

@RJBrown With the low compression ratios on aircraft engines I doubt it, we used Time-Serts on our Drag Bike motors to keep the cylinders and head in place.

Time-Serts are the best thread repair. Quality product. HELICOIL-COILS just don’t stay together as well. Haven’t needed them on my 80 Suzuki GS1100L.

Edited March 23, 2021 by RJBrown
Yes 1100cc

[RLCarter]

2 minutes ago, RJBrown said:

Haven’t needed them on my 80 Suzuki GS100L.

Bump the compression to over 15:1 and take it out 1400cc’s and you will....

[A64Pilot]

10 minutes ago, RJBrown said:

Time-Serts are the best thread repair. Quality product. HELICOIL-COILS just don’t stay together as well. Haven’t needed them on my 80 Suzuki GS100L.

1100 maybe?

The cylinder studs on the old KZ and early Zuki’s were fine from memory, it took a turbo and bike running in the mid 8’s before the trans gears tried to walk over each other and pull the case bolts out. I raced about 80-82 got Married in Jan 83 so racing was out from then on.

Edited March 23, 2021 by A64Pilot

[RLCarter]

2 minutes ago, A64Pilot said:

1100 maybe?

The cylinder studs on the old KZ and early Zuki’s were fine from memory, it took a turbo and bike running in the mid 8’s before the trans gears tried to walk over each other and pull the case bolts out. I raced about 80-82 got Married in Jan 83 so racing was out from then on.

Last one I built was KZ1000 with a Vance & Hines BigBlock (1400cc) and a stock head angle milled 0.080” no turbo or juice, uncorked it would run low 8:40’s but we chipped it to mid 8:90’s... 

[N201MKTurbo]

9 minutes ago, RLCarter said:

Last one I built was KZ1000 with a Vance & Hines BigBlock (1400cc) and a stock head angle milled 0.080” no turbo or juice, uncorked it would run low 8:40’s but we chipped it to mid 8:90’s... 

I had those when I was a kid. I had 3 different ones. I was always tuning it up and zooming up and down the street. I wrecked it one day when a car made a left turn in front of me. The frame was pretty bent up, my dad and I picked it up from the junk yard the cops had it taken to. There were a bunch of bikers down the street and they came over and offered me $500 for it. So I sold it to them, they took the engine and put it on a drag bike. It turned 9.4. Not bad for a teenager's daily driver.

[Guest]

On 3/22/2021 at 9:23 AM, Rick-bond said:

RJ. These are the tools i mentioned. They are $5000. Canadian on aircraft spruce. It would be way cheaper to buy two new cylinders on the port side 

You’re not to far from Kitchener, I could loan you the 18mm tools.

Clarence

[BDPetersen]

14mm plugs were torqued to 20 in/lbs. 

Of course I meant ft/lbs.  I quit posting at odd hours of the night

[PT20J]

On 3/22/2021 at 6:23 AM, Rick-bond said:

RJ. These are the tools i mentioned. They are $5000. Canadian on aircraft spruce. It would be way cheaper to buy two new cylinders on the port side 

I cannot believe how expensive Lycoming tools are. But it is best to make sure that this is done correctly. Besides potential damage to the aluminum threads, there is some concern that if the end of the insert protrudes slightly into the combustion chamber that it can form a hot spot and set off preignition. I've heard that, but I don't know how often it actually occurs. I do know that the spark plug area is generally the hottest part of the cylinder head (that's why spark plug gasket CHT probes read higher than bayonet probes).

Skip

[jetdriven]

On 3/21/2021 at 6:19 PM, laytonl said:

Don’t mean to hijack this thread (no pun) but has anyone used threaded inserts for wheel hubcap screws?  I’ve got two loose screws in one wheel and was thinking of using an insert or taping out to a larger size.  Lee

Yes.  I think it’s a 6-32 screw. Tap the hole carefully and put the helicoil in with loctite 

[jetdriven]

8 hours ago, RJBrown said:

Time-Serts are the best thread repair. Quality product. HELICOIL-COILS just don’t stay together as well. Haven’t needed them on my 80 Suzuki GS1100L.

They also work very well for the integrated Dukes fuel selector bowl.  

[carusoam]

15:1 compression ratio...?

What fuel is used to keep things from detonating?

And How ROP is that engine run?  How is that even measured in a non-steady state acceleration that only lasts 8seconds...

 

Did i ever mention that I enjoy hanging out with you guys..?

+1 For RJ’s collocation strategy of all the cool stuff...    

Go MS!

Best regards,

-a-

[A64Pilot]

On the turbo bikes we ran 158 Octane “Fast gas”. I’ve done some looking and I think that high an Octane isn’t possible with gasoline, so I’m not sure exactly what it was.

Your fuel also cannot be Oxygen bearing fuel either if you racing in a sanctioned race, and or was often checked, it’s easily checked, I think they check specific gravity?

On the Kawasaki 900/1000, you could only bore to 1200 with the stock cylinder, bigger than that and you bore through the solid aluminum and your into the fins. to go higher you needed a “big block” which was essentially a solid aluminum block. They could be purchased with your shops name cast into them if you had a min order. I dont know who the foundry was, ours said Star Cycle but of course Vance and Hines and others sold them too.

‘In 1980 or so the biggest you could go was 1327 CC, I guess 1400 was later, the pistons on the bigger motors had a flat spot on the top of the perimeter as of course the combustion chamber was still for a 900/1000, and possibly due to that they didn’t always work as well as you hoped, our fastest motor was I believe 1070 or so, but a 1200 kit worked great for a carbureted street bike.

On the turbo we ran believe it or not but stock cams set to 110 lobe centers and stock valve springs with titanium valves and retainers, the lighter weight valves allowed for the stock springs, and I think we ran about 8 to 1 or so compression and ran a Fairbanks Morse magneto belt driven off the right side of the crankshaft.

We ran an S&S Super carb bolted to the turbo and had to have an electric fuel pump because fuel wouldn’t drain out of the tank fast enough, it had to be pumped out or you would lean out in the run, that wasn’t as easy to figure out as you would think, jetting was done by plug checks, a new plug was run and then looked  at for color, white was bad.

‘The turbo was easier to start than a stock bike and idled smoothly like a stock bike, maybe even smoother due to lower compression, it was very much a street drivable bike and didn’t get hot at all unless it was making big power, and the turbo kept it much quieter than an open drag pipe. so as you can expect we built a few street bikes

This was the shop I worked at , back then it was Star Cycle, I don’t know why it changed to Star Racing, I was there in 80 and 81

https://www.dragbike.com/star-racing-george-and-jackie-bryce-build-a-small-motorcycle-speed-shop-into-a-drag-racing-institution/

Edited March 24, 2021 by A64Pilot

[cliffy]

The highest octane av gas I know of is/was 115/145 and it was purple. 

[Guest]

6 hours ago, cliffy said:

The highest octane av gas I know of is/was 115/145 and it was purple. 

If you’ve ever seen this stuff, you must be older than you let on.

Clarence

[Guest]

On 3/23/2021 at 5:39 PM, jetdriven said:

Yes.  I think it’s a 6-32 screw. Tap the hole carefully and put the helicoil in with loctite 

Per the K IPC, 8-32 screws.

[cliffy]

40 minutes ago, M20Doc said:

If you’ve ever seen this stuff, you must be older than you let on.

Clarence

It was used mainly in the military and on high power large radial engines

I used to pump some of it.

Ya I'm older than dirt

How about brown av gas? :-)

[cliffy]

I've got a set of mint unused covers that I can't use because MY wheels aren't drilled and tapped

RATS

[Guest]

40 minutes ago, cliffy said:

It was used mainly in the military and on high power large radial engines

I used to pump some of it.

Ya I'm older than dirt

How about brown av gas? :-)

We learned about it in school, but never saw any of it.  I was around for the end of 100/130.  Brown av-gas is a new one.

Clarence

[EricJ]

5 hours ago, M20Doc said:

If you’ve ever seen this stuff, you must be older than you let on.

Clarence

115/145 was still being used by the military in at least the middle 1970s.   It's what we were putting in out flying club airplanes in southern Germany at the time when I was a teenager line boy, we bought it from the US Army for about $0.25/gallon at the time.    It was a very beautiful purple and evaporated *right now* if you spilled any. 

BTW, our O-200s and O-300s ran fine on it.   We had zero fuel-related issues.   Another US flying club at an AF base blamed their constantly-cracking heads on it, but in retrospect I suspect they had a mechanic that was over-torqueing spark plugs.  Pretty much all the US flying clubs in Europe at the time burned the stuff and that AF club was the only one that seemed to blame it for problems.

 

[cliffy]

IIRC brown was 91/96. Never pumped any of it but you still see can see it referred to in some old engine operation manuals and some TCDS. 

Edited March 26, 2021 by cliffy