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Loctite 573 v 574 and application areas
Posted: Sat Mar 12, 2016 3:38 pm
by Gary71
Before starting the reassembly of my 2.4 mag case engine I'm reading up on sealants making sure I understand everything,
So quick questions:
Q1. Main case: Loctite 573 or 574?
573 (green) is the factory recommendation but everywhere else talks of using 574 (orange).
As far as I can tell from the data sheets 574 sets faster (45mins v many hours for 573) and has higher adhesive strength.
I'd rather use 573 (although I've already bought 574!) as I don't want to work under time pressure putting the case together. I'd hope the clamp load of the bolts hold it together so don't see the need for the additional adhesive properties.
Q2. Do you apply it on the main bearing joint faces?
The Dempsey book shows it everywhere, but you don't need to seal the main bearing faces for leaks and I'd rather make that critical joint clean rather than clamp up on sealant. The Porsche manual is not specific, but the little picture shows a roller being used around the edge only.
Q3. Any other sealants I need?
Dempsey stick silicone and 'curit T' in various places, but I know this is frowned on.
Any information or ideas?
Thanks
Re: Loctite 573 v 574 and application areas
Posted: Sat Mar 12, 2016 3:45 pm
by sladey
Speak to Miek Bainbridge on it. He doesn't use either - IIRC he used some japanese stuff that gives you longer to put it back together.
From what I remember he was saying that the Loctite stuff is great as long as you're all geared to have the whole thing buttoned up within 20 minutes and you've got exactly the right amount on. If you've got two guys doing it all day on a production line it's fine, but if you're on your own and you've got to take your time then the danger is that part of it sets (like rock) before it's all buttoned up - therefore it's like screwing it together with a stone in the way - leading to problems.
So whilst it's the original stuff and by implication it's the best, it's actually the best if you're on a porsch production line - maybe not so much if you're on you're own, doing it carefully as you've not done it much before
HTH
Re: Loctite 573 v 574 and application areas
Posted: Sat Mar 12, 2016 4:01 pm
by Gary71
Thanks Mark, ironically the factory recommendation is the slow setting stuff (573). It gives you a few hours, but maybe that's not enough for me!
I
Re: Loctite 573 v 574 and application areas
Posted: Sat Mar 12, 2016 6:20 pm
by DustyM
It also only sets by exclusion of air so won't go off until you start to bolt it up.
Re: Loctite 573 v 574 and application areas
Posted: Sat Mar 12, 2016 6:27 pm
by Gary71
Thanks Jon, Any thoughts on where it's applied? On the main bearing shoulders like this?
Re: Loctite 573 v 574 and application areas
Posted: Sat Mar 12, 2016 6:32 pm
by DustyM
Yep, like that. and also on the cam carrier to cylinder head mating surface. You don't need a massive amount but you do need even coverage, I put it on from the bottle and then use a fine brush to even it out.
FWIW I use 574
Re: Loctite 573 v 574 and application areas
Posted: Sat Mar 12, 2016 6:47 pm
by 911hillclimber
I've done 4 re0builds, all with 574 and all without the seal on the mains.
I have a steady hand so clean the faces of crud and then clean with cellulose thinners or alcohol, then I run a bead about 3mm wide and 1.5 ish high as it comes out of the bottle (with the concertina base.)
Cleanliness is Godlyness.
Get yourself prepared with tools and bolts and O rings etc and you will have all the time you need to do a steady job. Preset the torque wrench...
Worst is keeping the rods and chain in the air etc. as the top is lowered to the bottom on the stand.
Bit nervy at first, take you time but don't dilly-dally!
I have found I need more than one bottle to do the whole engine, but one bottle is more than enough to seal the cases.
None of my engines have leaked from this joint.
Re: Loctite 573 v 574 and application areas
Posted: Fri Mar 18, 2016 4:50 pm
by AndrewSlater
Gary,
When I did mine with Loctite 574 I was under the impression I had to rush.
As things went it took longer to get back together than I had planned but luckily it hadn't gone off.
When I used it on my cylinder gaskets I had a problem with one cylinder popping out of the piston rings. This meant I had to strip it all down.
When I went back to it the next day the 574 had hardened between the gasket and the cylinder, but on the other side where I had applied it ready for the cylinder to be fitted it was still as wet and fresh as when I prepped it.
Therefore as Jon says I'm pretty sure he is right that it only sets by exclusion of air.
If I had known that I would have taken more time putting the case halves together.
Possibly once the air is excluded the 574 sets faster than the 573 but I doubt you will be running your engine up within hours of putting the case halves together.
Re: Loctite 573 v 574 and application areas
Posted: Fri Mar 18, 2016 5:00 pm
by johnM
Gary71 wrote:Thanks Jon, Any thoughts on where it's applied? On the main bearing shoulders like this?
NO,
And are you sure you want to use loctite on the cases??
Re: Loctite 573 v 574 and application areas
Posted: Fri Mar 18, 2016 6:26 pm
by Gary71
Thanks John, If not Loctite then would it be the Japanese stuff Sladey mentioned?
What's the problem with Loctite 574? I'd have thought that a correctly prepared surface and correct application should work?
As to the main bearing cap question: I now have a two no's and a yes
I should have done a poll!
Re: Loctite 573 v 574 and application areas
Posted: Fri Mar 18, 2016 8:05 pm
by sladey
Just phone Mr B Gary - can't hurt
Re: Loctite 573 v 574 and application areas
Posted: Fri Mar 18, 2016 8:57 pm
by johnM
Hi Gary
The main bearing caps are machines to be round metal to metal, so putting a jointing compound makes the main bearing journals eccentric.
No expert just repeating what Mike Bainbridge has said, but although loctite was the best solution 40 years ago does not mean it still is. Its anorobic so starts to cure as soon as you pus the O2 out of it. This means you need to bolt the case up quickly. Mike uses a VW gearbox sealant which is not anorobic so gives you more time to get it right. My case was built with this and is still oil tight after 20,000 miles.
Give Mike a ring and I'm sure he will tell you the product name.
Kind Regards
Re: Loctite 573 v 574 and application areas
Posted: Fri Mar 18, 2016 9:22 pm
by Gary71
It will be the stuff I used on my gearbox rebuild on Mr B's advice a few years back, I've got the code somewhere on my thread. It's also the same stuff I stupidly used on my rockers covers and could never get them off again!
I agree on the main bearing caps hence I why I was asking the question.
Thanks
Re: Loctite 573 v 574 and application areas
Posted: Fri Mar 18, 2016 9:31 pm
by Gary71
Occasionally I should use the search function on this site before asking questions. Oddly enough this has come up before! This was Mikes answer then:
Certainly not 574 for the crankcases or the cam boxes, have tried all sorts of sealant, some work and some did not and some where really good, at the moment the ThreeBond 1194 liquid Gasket Gray/VW's AMV18820003 gearbox sealant I find the best, if applied correctly, the prob' with the 574 is as soon as you have the two mating faces together it starts to go off and it is then a matter of time before it is starting to go hard, I have taken a few engines apart with oil leaks and found 574 as the sealant and in some case's MORE is not always better, the 574 also is a hard sealer when set and if applied with to-much/lot will then come out between the joint to form excess which could then come off in time and then poss' go through the oil pump into the oil system, if not applied with to little there is poss of a oil leak and the sealer setting to soon to not let the cases close up, getting the correct amount to seal is a bit of a black art and I have not found my black art book yet after the move, so I use what is working for me, also found the a crystal ball or a magic wand always helps, but have found the temperature change affect both and the sealer.
regards mike
Re: Loctite 573 v 574 and application areas
Posted: Sat Mar 19, 2016 6:56 pm
by Nine One One
Not sure if it helps for any further discussion purposes, but others have recommended Ford’s Water Pump Sealer (B5A-19554-A)
Some listed on ebay
http://www.ebay.co.uk/itm/252299863005? ... EBIDX%3AIT
and others swear by Permatex® AVIATION FORM-A-GASKET SEALANT LIQUID again seems listed on ebay as everything is nowadays
http://www.ebay.co.uk/itm/380567967742? ... EBIDX%3AIT
Depends on what you use, what you know, and the results obtained in the past?