TheSamba.com :: View topic - Where to use Loctite on New Engine Build?

Sat Mar 27, 2021 12:27 am

Can you please tell me where to use or not use loctite (red or blue) on new 2161 engine build? Thanks!

Sat Mar 27, 2021 5:24 am

Loctite any studs except for the head studs. A medium strength threadlocker will suffice. I use Grade A if I never want them to move again.

Loctite teflon paste for tapered thread plugs, or pipe dope for extra insurance

You can use the 6 series Loctites for pressing in a sand seal

Oil for gland nut threads.

Can't remember the number, but there's this red anaerobic gel that often gets used on case halves. I prefer to use it on the lower four head washers for oil sealing.

Sat Mar 27, 2021 8:41 am

I've built engines and never used a single drop of loctite on anything.

Sat Mar 27, 2021 8:51 am

You will not get a straight answer. Some use it, some don't. Both sides claim success....

I use it on studs and bolts that I don't plan to remove any time soon. Even case hardware. Rocker studs, gland nut, big fan nut, engine tins especially down low. Most nuts and bolts for attaching the other parts to the case. High strength type on cam gear bolts/screws, w/ NO star washer. The star type washers dig into the soft metal which isn't great, but many cam or gear hardwate kits come with them for some reason. Throw them out or save for another project.

I find it's still easy to disassemble everything later, some people claim using loctite makes this impossible but I disagree. Even the red can be removed easily with a little bit of heat. The way I see it the loctite prevents the threads from corroding, lubricates during install, and helps prevent lossening from vibration. All things a motor is subject to.

The anaerobic gel bugguy1967 is talking about is the 518. The anaerobic comes in a few flavors but the 518 is the most popular. This is not a thread locker but rather a flange sealant. It can also be used as a gasket dressing for paper gaskets and even flexible seals like o-rings, pushrod tubes seals, oil cooler, main seal, etc.

Sat Mar 27, 2021 9:49 am

518 gell seal for the case halvs.it is lock tight just thicker.so it will lock threads if you get it on them. also be sure you are ready for final assy & total toruqeing. do not do a partial torque then come back and frinsh as that will throw off the case bearing bore sizes as the gell seal will harden . so be sure to torque all studs&bolts in both sequences one right after then other. dont answer the phone, do go pee, dont eat a slice of pizza ot a taco.finish the torquing. then pee on the phone while eatinga pizza taco having a drink
if for any reason you have to stop and take it appart :shock: you will need to use a razor blade and remove every bit of gelseal and start over when ready.

Sat Mar 27, 2021 11:04 am

I have the Red, Blue, 518 gasket sealant and 592 thread sealant on hand.

Thinking on using the 518 gasket sealant on the case halves, 592 thread sealant for taper plugs and red on the cam gear (without lock washers).

Can't think of anything else to use loctite on.

This is my first build in 40 years so i appreciate all of your opinions on doing my last engine build to the best of my abilities.

Thanks!

Sat Mar 27, 2021 11:56 am

Yep 518 is the red gel, there is a spray primer you can use before applying it. If used on the case halves it will work well, but in the future it’s a bitch to remove.

Red on cam bolts, green sleeve retainer on pulley to crank shaft...not the pulley bolt.

Blue loctite on the end bolts of rocker shafts.

Sat Mar 27, 2021 12:33 pm

Since the question is asking about red or blue thread lock, then I can say same as Dave, never needed to use it on anything. I prefer to choose better hardware if needed, then rely on glueing threads.

Loctite brand in general has lots of great products for things other then thread locking, so thats a different subject.

Sat Mar 27, 2021 4:36 pm

If you’ve taken very many engines you’d have your answer. To compound the problem people don’t just use a tiny drop, more often than not more is better.

Until you are the poor sap trying to tear it down. I’ve seen gland nuts ruined using this shit. Way back when dinosaurs roamed earth Gene Berg used only a tiny amount of green. I don’t use it and have never had a fastener back off.

Sat Mar 27, 2021 4:52 pm

txoval wrote: Yep 518 is the red gel, there is a spray primer you can use before applying it. If used on the case halves it will work well, but in the future it’s a bitch to remove.

Red on cam bolts, green sleeve retainer on pulley to crank shaft...not the pulley bolt.

Blue loctite on the end bolts of rocker shafts.

518 is easier to get off than many other things, like the hardening Curil, I find. Scrapes right off. Boy that stuff smells like candy. Kinda looks the part, too. Mmmmmm.....

Sat Mar 27, 2021 6:24 pm

I used it one time, had to scrape it off slowly with a razor blade...this was quite a few years ago though. I’m sure there are cleaners now to make it easier.

But...gaska-cinch and aviation both work well and come off easy with brake cleaner

Sat Mar 27, 2021 8:08 pm

Ya, I would say its not neccesary to use, but in my experience it doesn't hurt. Doesn't make much difference really, it's not like it's JB-weld or something. The goal is still to have proper torque holding fasners in place, but it serves as extra insurance against vibration and heat cycling IMO. I find it especially helpful on engine tins and especially when threads are not in perfect shape anymore which is often the case after 50+ years. They might look perfect but they are slightly worn down and aren't as tight fitting as they were when new.

I use the new orange colored one. It holds like red, but can be removed like blue. At least that's what it says on the bottle :lol:

Sun Mar 28, 2021 1:12 pm

the 592/ 565 is good for... Rocker studs, lower head stud nuts, oil valve plugs, maybe the oil pump nuts.
Why loctite...is because, Threads don't seal. people don't get that. you know...the only reason pipe plugs work at all is because... sealant.

VW had special nuts for the oil pump, and o-rings to seal the rocker studs (which didn't work great), but the head stud nuts apparently.... they just let leak. Or maybe they used some kind of invisible german sealant which evaporated leaving no trace. They could have used sealing nuts but they did not, probably the more accurate washers needed were deemed an unacceptable cost.

You may as well do the top head studs/nuts also, so the torque is the same. Drop the torque 5% at least due to the very slick lubricating qualities of the ptfe thread sealant. It should not be necessary to seal between the washer and head, if the washers are flat and sitting on a flat surface they don't leak.... but the head washers are often poor quality or old and bent so fix that or.... do what you have to do, so maybe do.

Tho some have a justifiable fear of.... the full wrath of Red loctite,
BUT, keep in mind... bolts coated in red still come apart easier than 100% rusted solid. Blind holes do not "need" sealing to prevent leaks, but, still be nice touch so they don't rust solid. It will seal out the moisture.

the oil pump hardware needs sealant too, those stud holes go all the way through, and the nuts too if nuts are used. Many studs go all the way through and they all need sealant.
I don't really care which one you choose but they do need a sealant. You just get to choose in each case if it's semi-permanent (red), weakly locked (blue), or sealed TIGHT but easy to remove (592/565)

The engine was DESIGNED to use virtually no sealant besides the case halves. O-rings on the main studs, rocker studs, and sealing nuts ect...
Some OCD guy is going to freak out at the thought of NOT putting an o-ring in an o-ring groove. so I'm not going to push that as being the right way, but you can at least consider the option.
565 sealant, if applied correctly, is a lot more reliable than o-rings in my experience.

Sun Mar 28, 2021 1:43 pm

vwracerdave wrote: I've built engines and never used a single drop of loctite on anything.
VW never did either in over 40 years of producing millions of these engines.

I have done it both ways, with and without on con rod nuts and have seen no difference either way. I use it on aftermarket cams and cam gears because VW used rivets (read permanently attached) and occasionally on a loose, worn out stud hole. Everything else gets oiled, anti seize or in the case of oil pump and head studs and nuts, high temp engine grade RTV sealant.

Never ever on the gland nut, pulley bolt or fan nut! Those are parts that I want to keep and re-use. Crankshafts are too expensive to sacrifice to the God of ruined threads.

Sun Mar 28, 2021 10:29 pm

Gland nut is a very odd design, I'm not totally sure, so I'll say it's plausible.
But personally, heck no.
Better living though chemistry.... supposed to be a tool to make things easier or work better, if it isn't then don't bother.

VW cases probably DO use loctite on the studs and oil plugs, because, why the heck not?
Do you really think the plugs and studs all fit PERFECTLY metal to metal with no clearance?
maybe they were, but they aren't anymore.
Only in old germany would they have the patience to do that CORRECTLY, meaning, a terrible waste of time. Just because the studs are all stuck in it now doesn't mean that's how it was built, that's just what happens over time.

I had to take all the studs out of a mexi case and re-do it, because they were loctited in crooked. It was overpowering the dowels and the case halves would not align right.
Loctite on the studs is a great idea for lots of reasons.....but you don't just stick each stud in there and bottom it out, do you that they all end up crooked. You have to put the two parts together and tighten the fasteners before it cures, & run each stud in the right depth, if it hits bottoms then back up a half turn. Most people would not understand this problem.... including myself in the past, but I noticed it right away from having the same problem before in other machines. Sure enough, after that the alignment was perfect.

Sun Mar 28, 2021 11:42 pm

The “vw didn’t use sealant or loctite” is stupid. They also didn’t put a big old stroker in either so we shouldn’t do that?

Loctite was invented by an American in 1956 btw.. why would a German use a American invention? Think they cared if it leaked a little oil? It’s a cheap motor, we can do better.

Vw also recommended 30w oil. Should we use that too?

Truth is a lot has changed in the past decades. No issues using modern stuff to make a motor less prone to leak.

I loctite (blue) any studs that go through the case. Keeps it from rusting too as modok mentioned.

I put sealant behind the washers and on top that are near the rockers for the head studs.

Better to use common sense sometimes than ask IMO.

If a guy can’t remove loctite then they might consider another hobby OR as vw did they don’t care what the end user has to deal with.

Building a motor to come apart easy is silly as well. Build it to last.

That’s mu .02 cents. Take it or leave it.

Oh I don’t use loctite on rod bolts. I don’t use cheap bolts so I can use a stretch gauge.

No loctite on the bolts for the mains either. Just a little sealant on both sides of the washers. My case is shuffle pinned so no o rings and I did once use sealant on them and didn’t notice a leak without sealant.

So what makes you sleep better at night..

Mon Mar 29, 2021 7:21 am

Loctite was bought out by Henkel, a German corporation. I used to work for a sister corporation.

Very high quality products, but so are Permatex.

Yes, I use the blue thread lockers, RARELY use the stronger red.