GlenL

I'll contribute to the mayhem with my own approach:

Lightly use a scotchbrite pad and lacquer thinner to remove old sealant and clean surface. Finish with cotton towel and lacquer thinner. Roll the 574 on nice and thin. Doesn't take long. Never a problem.

AO

My experience with 574 suggests it does not dissolve previous applications. Pass the grape jelly...

jeff spahn

[QUOTE=FBIII;10835851]
Yeah, there is NO WAY Rob would take an engine apart and then not have it look brand new before reassembly. I mean have you seen the underside of his car!

harveyf

Speaking with regard to my 944 engine rebuilds, I clean the contact surfaces with a Roloc disk (think stiff Scotch Bright in a round circle on a shaft) mounted on a die grinder. I don't believe Roloc can remove metal but it sure will remove the gunk left over from the previous Locktite installation. I too could never bring myself to leave the surface as found.

I apply the Locktite with my finger on both mating surfaces. Shame on me, there are mini rollers for sale at Home Depot that look like they would do the job!

My track record is mixed. First engine rebuild also involve dressing the block surface with a file to repair a damaged area using JBWeld (see my Orange Track Car rebuild articles for more detail). Bad idea. The Locktite would not fill the area with file marks. I was dumbfounded but when disassembled I could see where the oil was oozing through that spot. Could not get a prime on the pump.

2nd time cleaned and used finger. That engine has 100+ hard track hours on it.

3rd time was with the Silver car. Same approach. Could not get a prime on the oil pump. Pulled it apart and could see no obvious problem. Cleaned it up again and put a heavier coat on with my finger. Sealed it up and had no trouble getting a prime.

So I would say it is definitely necessary to apply the Locktite. I will use a mini paint roller from now on, and I will continue to lay it on a little thick. I am glad to learn that it dissolves in the presence of oil. I did not know that but makes sense. I think putting it on thin enough to keep it from oozing out the sides would be impossible to attain without risking a gap in the sealant. Any gap means your oil pump will suck air and not prime. (See article on my website about 944 Oil gallery configuration. I'm sure 928 is very similar)

Jetdriver69

The block and girdle were boiled and thoroughly cleaned. No problem with any residual locktite in the oil gallery or the mating surface. However I did notice the coolant expansion tank was looking a little brittle so another $150 to Roger. But it is much easier to replace the tank when the engine is out, so one less thing to worry about for a while..

Mike Simard

I've tested 574 by applying it to test blocks to measure the minimal thickness. It was about .0001-.0002" which means it's not going to act as a shim if too much is applied. It will also fill in larger gaps.
I use a plastic roller.

About "rolocs". These are hideous and a sign of a careless, lazy mechanic. They remove too much material from corners and sling crap.

Mrmerlin

Speaking with regard to my 944 engine rebuilds, I clean the contact surfaces with a Roloc disk (think stiff Scotch Bright in a round circle on a shaft) mounted on a die grinder. I don't believe Roloc can remove metal but it sure will remove the gunk left over from the previous Locktite installation. I too could never bring myself to leave the surface as found.\

This device^^^^ would work well to clear the gasket off a ford or chevy oil pan

BUT

I would suggest to use the razor blade method previously suggested,
when working with precision machined surfaces.
This disc will cause permanent damage to those surfaces

harveyf

Well, 2 strong votes against using Rolocs. Since I don't think of myself as a careless or lazy mechanic, I'll take a 2nd look at this issue. Maybe I'm using the wrong term because as far as I can tell the device I use won't remove metal. Yes, it does sling material around, can't argue with that. Razor blades make me very nervous.

marine928

Hey Jet, I have been following your progress what is your eta to have the shark on the road? Can't wait to see the finished product.

Jetdriver69

Well we are installing the pistons/heads on Monday. Had to order a new coolant tank, it was looking very brittle and it is a pain to replace when the engine is installed. Roger sent that Friday, so that should be in Monday or Tuesday. Hopefully all installed, broke in and checked by Friday.

Anything going on Porsche-wise in Houston next weekend, the car needs driven!

This shark has evolved from a low dollar 16 year old kid's cool high school car into the frankenstein project from hell. We have been working non stop on this since April and needless to say, our budget has been blown Hiroshima style. But it will be an almost brand new car, there isn't much left to replace or refurb!!!

Fresh engine and heads with new WP/TB, bearing/rings, etc., complete intake refresh with WitchHunter injector work, electrical panel refresh, alternator, rebuilt Greg Brown 5 speed, new steering, clutch, AC compressor and most components, all new fuel/vacuum/brakes/coolant, PS lines, fuel pump/tank/sender/filters, plug wires, rotor, cap and green wire, re dyed interior with DynaMat insulation, custom stereo, wheels, tires, brakes, rotors, bushings, shocks, tie rods, custom electric fan, air pump/clutch fan/aux electric fan, cat delete, paint less than 3 years old and lots of engine aluminum polishing. I'm sure I have forgotten a few things. Good thing I don't have a 9-5 job or the car would be sitting for years! Some of the work was done by the PO, but i had to do all the big/expensive stuff except the paint.

Hopefully we can get another 31 years and 85K out of her, but by that time I won't be able to get in the driver's seat, LOL!

My wife has decided that I should give car restoring a miss for a while....Maybe a motorcycle next?

GregBBRD

OMG......threads like this are dangerous.

A Rolex disc is absolutely the worst think you could ever use on two surfaces that need to seal against each other.....even if there is a gasket between them. A Rolex disc is the equivalent of an "axe" out in the garden....shouldn't be taken out of the garage very often and should only be used for the proper task. I will not assemble an engine, cylinder head, or cam carrier than has been "attacked" with a Rolex disc. Scrap metal. Find me different parts that have not been attacked with an axe.

Remove all previous Loctite 574 with a razor blade, as Stan says. While the "proper" amount of Loctite may be able to soften and reseal, I do not trust this....and very seldom is the "proper" amount of Loctite used.....unless the engine is "factory original....virtually everyone uses too much product.

Apply very thin, with a suitable roller. The "caulking gun" approach does not work.....which is why Porsche takes the time to tell people how to use the product! If a "finger" worked.....they would have not spent an entire page of the Workshop Manual telling people how to do it correctly! The cradle/case halves can be held apart with Loctite. I can't even to begin to estimate how many 928 engines and 911 engines I've taken apart with a very thick layer of Loctite holding the two surfaces apart.....which had terrible main bearing wear, as a result. This is such a huge problem, that I use a completely different torque order and pattern than the "Workshop Manual" calls for....on 928 engines, 944 engines, and 911 engines.

Loctite 574 has a "shelf" life. I throw away any tube that has been opened for more than 6 months....and I only purchase my Loctite from dealers that have large "turn-over" of product. A good indication if your "tube" of Loctite is too old to use can be determined after your are done torquing and wipe the excess off. If the excess can not be wiped off completely and there is a "pink" hardened fillet of Loctite left after you wipe.....your Loctite was to old and you need to disassemble and start over.

GlenL

That's a great point: the thickness of the sealant affects bearing tolerance.

danglerb

I am beginning to question the value of the quart or so of date expired 574 I bought on ebay last year.

GregBBRD

Old 574 works great, in place of Teflon tape, to seal pipe threads.

I wouldn't use it for sealing water pipes going into my home....but for air lines, oil fittings, things like this, there is nothing better....and you never have to worry about Teflon tape getting into an oil galley or plugging up an injector.

atb

Here's a test I did with some expired loctite 574 a few years ago. It was about 18 months beyond its expire date. Was opened before then, then just sat on the shelf. I didn't end up using it, but was surprised by the result.