I like the permatex red "high temp" thread locker, is good for 450F... cylinder casting temps under normal operating conditions shouldn't reach anywhere near 400F... I would be surprised to see an air cooled model 4 stroke go above 300-350F... VW engines, #3 cylinder would reach 380F, and if the oil cooler was blocked with caked on oil&dirt could go above 400F, but those are very different running conditions in comparison, with shrouded cylinders and poor air flow around the engine.

The time-serts have a serrated edge that gets swaged into the base metal to prevent the insert from backing out, but they are also set in red loc-tite as well... I wouldn't be too concerned, just clean / decrease both the cylinder, and insert threads, and then when you assemble it, tighten the insert firmly, and then let the thread locker setup at least 48 hours before you run the engine. You can also take a fine point center punch and peen the edge of the brass insert into the base metal in 3 locations, to capture the insert.


https://www.permatex.com/products/th...cker-red-6-ml/

Never tried this stuff, suppose to be good to 2000F for exhaust fittings... ceramic based translucent compound... they make the claims, not I

https://www.vibra-tite.com/threadloc...-threadlocker/

lol, I saw that one too. Dismissed it as bunk. Sure, most ceramics have a melting point of >/=2000°f, but what about the adhesive/carrier?

After reading Bert's post about erosive corrosion in high pressure/high velocity environments I wouldn't want loosening ceramic particles dropping into the combustion chamber anyway.

It wouldn't get into the combustion side, as it would be confined / trapped in the thread clearances only, unless you over apply it... but you're doing the repair cylinder off the crankcase, so there wouldn't be any residue to flake away. It was designed for firearm use mostly, it works in a similar way as gulling, but the ceramic has a breaking / shear point when removing the fastener. Any of the high temp red thread locker will be more than adequate

It doesn't exhibit much if any real locking properties... red locker properly applied, would be more difficult to remove without heat applied... if the rifle barrel gets well above 450F then the red locker will fail obviously, hence the use of ceramic particulates, and water based mind you... which may pose an issue from combustion moister working its way past voids in the ceramic. Not truly impressed with it, but it has its applications.

Lonnie, I see "John_M" has already informed you that 5/16 -32 is a standard thread.

Still, you may want to consider having a good lathe operator single point cut the threads.
Due to the root to crest diameter differences it may be beneficial to index the threads to one another to maximize potential wall thickness.

Note that Genuine Timeserts use indexed threads. , if the inserts in your engine were not indexed, this could result in a wall as thin as 1/64".
May have contributed to the fracture.

Silly busy week but a couple quick updates...

The Boxer 160 arrived and looks great. Can't wait to get started on this conversion. Ignition parts have been ordered- The TBI carb is going to be a easy conversion I think and the mounting will work out - Going to try a "plastic" body on this one.

Bert - what does the "rocker oiling" mod encompass on the ASP 160?

Lonnie - I have not forgot about you - Will give you a call and discuss the inserts as soon as I can. I have studied up the "indexed" insert idea and think I can make that cut being careful with the setup. Will need to 5/16-32 tap just to make a hole for sizing the external threads to get a "Snug Fit" and I think I can mimic the Timesert lock mechanism by "short tapping" the internal threads.

Can you confirm the bore is indeed 5/16-32 - a bit concerned if its home made it might just be 5/16-24

skip the rocker oiling mod for now. both of my twins have valves that are extremely wet with 10:1 fuel mixture. you probably won't need it.

Its cold in here, someone left the door open!

With the boxer, and 10:1 fuel oil mix, surprising how much oil gets past the followers and valve guide clearances... I think bert does the oil mode to renew the oil through the rocker chests by rerouting the crankcase breather through the rocker chests and then vents the rocker covers, one or both, depends on how you route the breather tubing... I still run my boxer on glow fuel, so no real need to make that mod... but I have had a look see, and the way I usually do it on the gas 4 strokes is, I create a few thou flat down the cam followers using a honing stone, to give a bit of passage for blowby to work its way up the pushrod tubes, and then just vent the rocker covers... it gets rid of the external tubing, and tidies up the appearance... but basically it keeps a small amount of oil moving through the rockers... Gas engines running with the leaner oil mix ratios, it can be beneficial... but with a 20% oil content, the oil will find its way into every nook and cranny.

aside from the solenoid and cdi, my boxers are stock and they have zero issues with lubrication. i would run your new (to you) engine a few hours before deciding to do mods of that type.

Maybe it is in the oil I am using, r in the fact that all my engines were new when converted, but they all remained scaringly dry on top, and for me that never was a point of worry since ASP in their manual recommend that the owner lubricates the rockers manually every 2 hrs or so.
Since I don't like manual lubrication, I did the crankcase drain mod.

It works well, I see zero change in valve lash.

I bet, same running the boxer on the glow fuel with the 14% lite-techniplate oil mix... But the gas F-50 4 stroke was surprisingly dry as well with 5% oil mix... upper lube relies on the follower & guide clearances, their bronze, but the rocker shafts and pushrod ends receive very little oil residue.

Why not take advantage of the oil blowby from the crankcase breather and pass it through the rocker chest, if oiling is required.

Do you have the ability to single-point cut the threads?
With a little bit of calculation, could make indexing reasonably accurate.

BTW, I can loan you 5/16-32 taps in both plug and bottom forms.

I have 7/16" C360 H02 brass, 5/16-32 plug tap and die on order. Should be here by week's end. I don't have a way to accurately synchronize/index the threads other than by trial and error, using an index mark on the tap. With a little luck I should be able to get them sync'd In a couple of tries and I do intend on short tapping the threads, a little more at a time, until the Timesert insertion tool swages the last couple of threads without excessive pressure.

The broken piece of insert I removed from the cylinder has a 32 thread pitch and the int/ext threads are not synchronized. My thread pitch gauge is barely visable once inserted into the insert bore but it appears to be 32.

Cleaned up thread, removed some snarky comments, keep it respectful and about engines.

Any more personal shots will be dealt with administratively.

Oh one more thing, i dont factor issues you have on other boards into moderation here, if you're banned on RCG and you behave here, then knock yourself out. Though I do often find that if someone gets banned at other forums they often can't suppress their tongue long enough to hang around here but you have a clean slate.

Thanks

You'll be ok with a reference mark... you said the 1/4-32 time-sert OD is too small for the existing 5/16-32 threaded hole correct.

You can use the 5/16-32 die as a guide to help you index the 1/4-32 tap.

Correct.

Yes, an index mark on the tap and a light tap or two to set the tap so it bites straight away upon rotation should get the job done. May take a couple of attempts.

I found a club member with a 4" or 5" benchtop lathe. I'm sure it's good enough for this type of light work. I'd have one myself but need one so infrequently I can't justify the cost. I suppose if I had one I could create projects but have little interest in metal working. I do enjoy woodworking however and have a nice cabinet shop.

Oh wait, I missed this edit:

"You can use the 5/16-32 die as a guide to help you index the 1/4-32 tap."

Edit: Won't work I'm afraid. The insert is shouldered/flanged on top. The tap has to enter from the top to short tap the hole for swaging.

Thanks Jesse,

Yes I can cut single point threads and would only need the tap to create a go/no go gauge to get the outer threads right... I have a trick VFD drive on my old lathe and it makes treading a much easier task as i have the ability to drive very slowly and stop instantly.

Here is how I would proceed - rough finish the insert and "short tap" it. Then using the tap as as a guide the setup can be made of the carriage to thread the OD . Because of the "flange" the setup would be a bit tricky and would have to be cut "upside down" and "backwards".

This type of repair is better done with all parts on hand to get the fits correct - if you can find a "local" with the right equipment it might be easier - I am willing to give it a try though Lonnie but it might take me a while as I have a pile of work stacked up here..

I understand why you would need the tap. Yessir, we are on the same page.
Especially the "backwards" part, perhaps doing the 1/4" female thread from top side, flip part in collet and cut the 5/16" up to the shoulder then part off.

With you as well regarding the variable freq drive; Lathe here as well as Bridgeport got the conversions long ago. Really sweetens up operation.Forward/braked stop/reverse, half nuts engaged , very helpful. Almost like having a Monarch 10EE!

Yes, you would certainly want everything on hand before starting. Several possible techniques .
Too bad the previous owner didn't simply use Time-Serts, perhaps unaware they existed. The lack of indexing or "nesting" of the threads probably led to the failure. Not a lot of wall thickness to spare.

Anyhow, tap is here, USA made. Yours if you can use it.

Thanks, here's my plan based on my limited tooling:

Rough the part, thread the OD and place a reference mark on the insert flange and the die, part it off, thread the tap into the die to tranfer the reference mark, install the insert into the cylinder and begin tapping the ID using reference marks. If the threading is syncronized I'll JB Weld the top couple of threads and let it cure overnight, then short tap the ID and swage the insert using the Timesert installation tool. If the threads are out of sync when I begin tapping the ID, it's a do over.

Am I on crack?

I have no idea about your substance abuse habits, but I would say you're on track...

Hey John,
I had an opportunity to do a rather small print yesterday evening with the layer set to 0.12 mm thickness. Printing is fairly slow at this resolution but the output quality is excellent. I'll try to get some better photos for you. For reference, the open circle which clips around the lens on my web camera is 14.7 mm in diameter to the inside.

Lonnie,
Cut and try is fine but how do you plan to check the results?

I would have to agree... There are 1000 ways to skin this cat and some might even be helped out with some chemical enhancement !!!

Might take a couple of tries to get the indexing right this way but I think that would be the case in most setups - Even in a lathe the "backlash" would come into play and would probably take a couple of attempts to get it right... Brass (especially the free machining type your getting) will be easy to work with in this instance.

Dave,
looks like the printing is progressing quickly.... making small parts is a setup and method onto itself..

Hope your not sitting there watching the machine print. I wasted about a year of my life on this endeavour Its strangely addicting.