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Sealing Case "Experiment" (so YOU don't have to!)
I suppose the best way to see how our various sealant methods for the case look "from the inside" would be to do an assembly with the sealant, and then let the case cure for a month - then take it apart again. Well, that is just what I did. More detail later, but here are the pics:
http://forums.pelicanparts.com/uploa...1157329616.jpg http://forums.pelicanparts.com/uploa...1157329641.jpg http://forums.pelicanparts.com/uploa...1157329667.jpg http://forums.pelicanparts.com/uploa...1157329684.jpg http://forums.pelicanparts.com/uploa...1157329707.jpg http://forums.pelicanparts.com/uploa...1157329723.jpg |
Only comment is on the 2nd picture from the top... The oil relief cut around the 2nd hole from the bottom on the left seems to be full of sealant. I always put sealer on the outer side of it to make sure it does not clog up. If the factory put it there, I would make sure it is clear. How critical is it? Comments from the pros? Lou
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More experienced hands than I are always great to hear from! |
There is way too much sealant used on this case and in places it doesn't belong. It needs to be kept away from the oil relief areas and o-rings. There should be no sealant "inside" of the O-ring on the number 8 main bearing. You want oil inside of the O-ring to be able to get back into the case not be trapped trying to get out past the O-ring. Also there is sealant in areas that are oil galleries, this can break loose and clog up the engine.
Many more engines have been ruined by too much sealant than have leaked due to too little. All you need is a small bead around the perimeter or a thin coat of 574 if you use that. Keep it away from the oil galleries and relief areas. -Andy |
Sealant placement and type is exactly how we have been sealing 911 cases for 7 years. I see no areas of concern here, although I would not glue the oil cooler seals. Previously we used Loctite 574 exclusively and we were experiencing unsatisfactory results as did the Porsche factory around that same time frame.
After hearing that new, factory built engine were failing at a rate of 4% before they ever left the dyno (new parts, factory techniques), we decided that new techniques were required. Gluing the #8 main bearing was something we resisted for the longest time. When we rebuilt a few engines (even aluminum cases) with #8 main bearing leaks, we started measuring the journal. We discovered that most #8 main bearing journals were not round. O-ring function best in round cylinders. We have seen journals that measure .015" out of round. Because most companies don't aline bore the #8 bearing journal, most #8 journal won't seal properly without glue. Trust the o-ring if you like but we don't. As for 574 clogging engine parts, I have never seen that. The sealant that is notorious for clogging oil passages is silicone. (RTV). 574 is anaerobic so it only hardens in the absents of air so it is soft until then. We have never seen an engine damaged by too much 574. I have seen some engine build with huge amounts (MM) and still seen no negative effect from it. |
This engine was sealed using the methods that Henry suggests in terms of the sealant for each area. However, Henry was not involved with the engine sealing process, nor did I speak to him personally about any of the procedures. Instead, I started a thread to collect the "consensus" on the sealants used to try and find the best solution for me. See http://forums.pelicanparts.com/911-engine-rebuilding-forum/284737-complete-engine-sealant-thread.html
I have quite a few questions and observations from this process. The first was noted by len911 - what is that relief there for? I do not get the purpose... Second (observation) - I seemed to be partially blocking the oil feed thru the forward studs around the #1 bearing. I will take more care in this area upon reassembly. Third (observation) - I seemed to use a bit too much ThreeBond on the case perimeter. Less would have done just as good of a job. |
The relief is there because the throughbolt holes are used as part of the oil distribution system and therefore under pressure. All the others are isolated so a bit of oil weeping simply dribbles harmlessly into the crankcase. A leak from this particular hole could find it's way to the outside of the engine if not for the relief.
regards, Phil |
The last engine I bought was a 3 litre that had been rebuilt with 574. The builder used too much and some of it went into the oil system clogging 3 cam spraybar holes. The resulting cam/rocker wear caused a poor running condition and made a good deal for me to buy and fix.
-Andy |
Just so I'm clear.
Where would you put 574 so it would do what you are suggesting? I assume it would have to be up stream of the spray bars. I believe you but, I just can't figure out where. |
I assume you mean upstream of the spraybars. The sealant was inside the spray bars and blocking the holes. I don't know the area that the 574 came from. The case had excess 574 in all the through bolt holes and in the pressure relief "ring" around the through bolt on top of number 7 bearing. The case also had some dried 574 in the bottom of the case. The case had 574 in the area where the pump o-rings are but don't know if any got inside the o-rings.
I'd say if the sealant gets into the through bolt holes it could get into the squirters too but that didn't seem to happen in the engine I bought. -Andy |
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As for 574 clogging the oil squirters, I have never seen that either. Sometimes theory doesn't match reality. |
You edited out my comments on where the sealant was. My speculation is that the 574 in the oil galley's (through bolt holes and around the oil pump o-rings) made it's way downstream into the cam spray bars. The cam oil lines come from the number 8 bearing area of the case which is fed oil from the main galley that is connected to the through bolt holes, etc. I don't think it's much of a stretch to think that 574 in the oil galleys could make it to the cam spray bars. If you have other ideas of what caused the 574 in the spraybars I'm open to them.
-Andy |
I was wondering about the curing time of the threebond. I smeared it on very thin (with my finger) and it seems to set really quick. It took me about 5 minutes between the last smear and bolting down the case. I have very little squeeze out and now am wondering if this is caused by the fact I only used a very thin coat, or because it already cured before torquing the case.
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Very good thread. I recently discovered that number six cylinder spray bar hole(s) clogged starved my oil head for adequate oil. Did the rebuild on my engine 2 1/2 years ago. I am curious to see what will be found in spray bar.
Can the dried sealants we have been talking about break off from the edges of the surfaces where they are squished and travel through the oil circuit causing these types of failures? |
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That is my theory anyway :) |
Chris,
I think that's part of the problem. The 574 stays liquid until it gets in an airless environment. Once you first start the engine the 574 can travel in the oil but it will harden at some point because it's surrounded by oil and will cure. -Andy |
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Using the data offered by Loctite, I begin to wonder how 574 could clog a cam oiling tube.
574 does not form a breakaway bead. The break away bead is the portion of the glue that squeezes out and forms on the inside of the two joined parts. When hardened the 574 forms a bead that must be scraped off (you almost need a chisel). For those of us who have rebuilt engines that used 574 you know what I mean. Next: If the product is not dry, when the engine is started the product will take at least 1 hour to cure at temperature. That means, any 574 that the oil system ingests will travel though the oiling system for at least hour hour before it can clog any oil hole. The engine oil should circulate through the oil filter at lease 20 times in that hour. Final issue, according to Loctite, 574 will only hold pressurized fluid (read oil) in a gap of .010". It is rated @.020" for seepage but only .010" @ pressure. Here the point, the oil spray bar holes are .034". How can 574 seal a hole that size ? Inquiring minds want to know? Only the oil in the case bolt above the #7 main bearing is upstream of the cam feed line that feeds #1-3 cam housing. . #8 main bearing feeds the crank. All other case through bolts feed main bearings and squirters. |
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I didn't add my experience on here of clogged spraybars by sealant to get into a debate about how it can happen. I added the information so that others could avoid a problem that the engine I bought had.
I'll throw one last shot at an explaination. All the through bolt holes are upstream of the pulley end of the case. Any liquid sealant can run down the holes into the main galley when the engine is on it's side. The cam lines are the last stop in the oil system. The locktite goes through a hardening process just like any liquid that turns to a solid. During that time the viscosity increases. It's entirely possible that It could get stuck in a hole either while it's drying or after it dries if it breaks off of somewhere. The sealant that was in my spray bars was dark brown and looked like 574 but I don't know that it was for a fact. The clogs were "glued" and hard to remove idicating to me that the sealant was at least partially liquid when it clogged the holes. I didn't imagine this problem. I'm not looking for anyone to agree or disagree with what happened or how. I'm only providing information that might or might not help other engine builders. Please use this information or not. I'm sure it's possible that it was some other substance that clogged my spraybars but the sealant seems to be the most likely based on what I saw and the amount of sealant that was in the case including the through bolt holes. -Andy |
Accurate information is the best way to guaranty success.
Avoiding a potential problem without accurately identifying what really happened is tantamount to impossible. Your story really tells us that excess is generally an error not that 574 is the culprit. 574 is bright orange, even after curing. My experience says that the viscosity of 574 is so high that it is very unlikely that it would wick more than an inch or so. That says that it probably wouldn't run from the case seem all the way to the main oil galley. My guess is that your spray bar was clogged by something other than 574. |
From my vast experience of tearing down one engine, which had never been rebuilt, the loctite (I assume) was brownish and not orange.
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Having just spent lots of elbow grease cleaning my case (3.0 '82) I can definately say it was black/drk brown and hard as hell to get off... It was very similar to a resin and chipped off on the edge of the sealing surfaces. Case had never been split.
Is it possible that the factory ran out one day and used something else? Or that the formula for 574 canged over the 20+ years? Or maybe, after 20 years of oil it finally got stained black? Was 574 even around in '82? Just curious and enjoying this thread very much! -Michael :) |
I don't have any more info to add, I just want to 2nd, 3rd, 4th that this is a great thread, and the main players are very civil gentlemen involved in an excellent debate that we all stand to learn from.
Thank you all. |
I don't build my own engine, but knowing all the thought that goes into a proper rebuild is encouraging.
Someone suggested that reasoning why/what causes problems isn't important. That seems naive. How could anyone know all this without years of experience? We are all lucky that Henry has chosen to participate on this forum. Many people offer impressions but he is giving us true knowledge and reason to boot. |
HI the black/dark brown sealant is Curil K2 made by Elring the gasket people, (part No 534.501 ) and still available, you will also find it on heads/cambox's and the bottom of valve springs by over zealous German engine assembler at the factory.
regards mike |
hI,
First, I agree with and support all the postings on this issue by Mr. Schmidt of SUPERTEC. To the disgrundled member with the unexplained, clogged-up piston spray nozzle - just get over it. Sorry about a clogged oil passage and the damage which resulted, but I doubt in the extreme that it was ever caused by any of the loctite anaerobic products. I remember a clogged up spray hole on number six intake rocker some thirty years ago, which I expected was caused by new sealants (back then we were just moving on from aviation permatex to the "new marvel sealants", the RTV products). The clogged orifice (which ruined the rocker arm, and damaged the cam sufficient that I had to take a knife-sharpening stone to it.........times were tighter in those days for me), also was suspected of being caused by the recently introduced RTV products. I had never/ever heard of permatex finding its way into a spray jet, so the new RTV must be the cause of all this disaster. On much closer inspection though, the tiny, offensive, plug of material, resembled a plant product more than any smooth new space-age plastics?? It looked like cellulose in structure as if somehow a plant form had been introduced to the oil system of that specimen. It was a complete mystery to me until I happened to learn form a third party, several years later, that the first owner of the car had actually violated his warrenty on this 1967 model, by installing and using for about a year, an aftermarket gismo which rested its unfounded claim upon the ability to replace the "expensive" and "inefficient" German oil filter, with a new "Common-Sense alternative" to the BIG-OIL RIPP-OFF of the common man..........an earth-filter using what we already have in abundance", which in addition to saving you money will also double the efficiency of your automotive oil filtration performance and greatly extend the engine life of any car. What was it? what was the miricle product - and where can I get one?? It was an empty aluminum canaster which fit up to the stock filter base on the 911 and any number of other cars. How did it filter the oil? Wait, because you may be too young for this. What one did ....to feed the filter...........was unroll just enough paper from a standard, Mark I, Mod 0, roll of toilet paper, so that it just fit the canaster. I do not suggest that toilet paper would have been the cause of the piston spray clog which has taken this thread so far from its original subject, but I do suggest to all of us, that unless you drove it away from the factory yourself, you cannot possibly know what your Porsche has actually been through. My son was a dealer teck...........You would not be happy to know the truth about Porsche Dealership maintenance. Let's not go there. Secondly, on the subject of the 574 sealant, or any of the anaerobec products...........it seems to me (from reading the responses) that, at least one property of these sealants has not been fully explained. Maybe, of course, I don't understand it (not unusual, but please set me straight). Excepting that, I have found that these wonderful sealants (the loctite anaerobics I consider to be excellent by any defination) will stay "as new" for long (years) periods of time after opening the tube. Yes, you may say, of course, for they will only ever begin to set up in the presence of metal (steel is best - Aluminum not so good) and the absence of oxygen. OK, I expect we can all agree with this, but please note there is no mention of pressure. In other words, the general feeling that one can simply spread on a coating of loctite 574 and not worry much about the passage of time.......untol aht parts are joined....is untrue. Underline it............FALSE!! The very second that 574 materal comes in contact with a metal surface we have met ALL requirements for setup, AND THE CLOCK IS RUNNING! The glue is in contact with metal and there is no oxygen present. Reaction starts - no pressure was ever necessary. The 574 will therefore begin to set up, on that surface alone. Note that the tube instructions call for final clamping of the parts within 10 minutes. This is the reason for the time limt. The time allowed is generous compared to some of the other products.........but one does not have a second to spare, whatever the glue. Dally too long, any you will create, with 574, the thick sealant problems which Mr. Schmidt has noted . Dally too long with other sealants and the results will be also poor. From what I have seen, 574 still offers the longest time............oh, but it is not easy......that 10 minutes starts when the first glue contacts the first metal surface. How many guys do you think can really meet the Loctite 574 time limit? 10 Minutes from the first drop on the case until the two cases are tight. One in a hundred perhaps. No wonder Mr. Schmidt has noted high buildup of 574 on cases he has split. The GM Corp. have a product which is getting rave reviews from the VW group, and I personally wonder whether it might work well for us, but it has only five minutes. Honestly, most of us cannot handle ten on a Porsche 911, so, for my money, loctite 574 is the choice product. Not because it is the Porsche recommendation, but because in my experience, it has never failed to provide a leak-free case joint of sufficient duration to far exceed all the other trouble spots (say, front shaft seal, rear shaft seal, power steering cam take-off shaft seal, and etc.). The case joint has never been an oil leak problem on any engine I have rebuilt. Oil leaks on the 911 engine are, in my view, a part of the design. Don't like it? Then go for a Jap car. Otherwise, accept, as I have, that these engines have a lot of exposure (holes) and should be expected to leak oil if allowed to do so. Maintain them, as you would an aircraft engine or a race engine, and you will never see a drop on the floor. Never. But my brothers, whether you use permatex aviation type II, or type III, or RTV, or Loctite 574, or Three Bond motorcycle sealant, or the new GM Aluminum Engine sealant , or whatever appears next year, my advice is the same...Seal to clean surfaces....Expect to do it again, for nothing last forever, and the leaks will rarely be at the case joint.......the valve cover leaks, the shaft exits, both drive and cam, and the upper engine breather leaks will overshower anything likely to be seeping though the engine case seal.................in my experiene. Finally, be glad that you have an object in your life, which you consider to be worth all this effort, ......Then, GRAB IT - AND GO !!! Regards to all, James |
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Sorry for posting a question-----I misunderstood the purpose of this forum. Didn't realize the forum is for people who are writing their memoirs! I asked the question because if I had made a mistake of using the wrong materials, I want to know about it. |
I say send in the offending chunk to a lab for some testing :D
I got pretty worried when after the first break-in, I saw about a 8 inch long but very narrow strip/bead of Threebond 1104 come slithering out the case oil drain hole. Obviously I used a little too much, but someone on this thread mentioned case oil going directly to the filter, but is that really the case? No pun intended. I thought it was possible that case sump oil could bypass the filter. Someone tell me it can't and I'll feel much better! |
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I guess I must be the "disgruntled" member. I didn't know I was disgruntled but now I know. Just for the record I didn't have any of these problems on any engine I've built or car I've bought. The damage was on an engine that I subsequently rebuilt and knew of the damage before I bought it. I, like James thought it was the sealant. Unlike James however I still think it was the sealant.
I'm hoping we can have a difference of opinion without denegrating each other on this forum. -Andy |
Gentlemen,
I seem to have inadvertently rattled the cages of at least two members by my recent posting, and I deeply regret having done so. I just now went back and read over the wording of that post and honestly, I feel a little like the Pope must do. What I wrote there was just what came to mind on the general subjects of this interesting thread. It was never my intent to denigrate the efforts of any member on this forum. No, I do not feel that it is unreasonable to conclude that one would be disgruntled at the necessity of pulling an otherwise fine engine apart just to clear a tiny oil orifice, which never should have been clogged in the first instance. I certainly was quite disgruntled when I did the same exercise. Nevertheless, I note that we do have a spell checker feature on this site, and I shall try and remember to use it in future. James |
James, good on you!
Cheers |
JW Pate, I've done what you just apologized for, and for me it felt good to say I was wrong. I hope that you derived some satisfaction from it as well. I'm sure the wounded party or parties will forgive you for any percieved transgression, and all will be well.
If this was real world rather than virtual, we could gather for a beer, but unfortunately we're too far apart. Cheers from a distance. |
Why is sealant used on the main webs anyway? I don't recall Porsche recommending this in their manuals. Too much sealant there could definitely cause clogged squirters or spray bars. I have built a few 911 engines and only used sealant on the case perimeter. The last 88 3.2 I built failed at the case perimeter using the Loctite 574. Fortunately it was just a short block sitting on the engine stand when I noticed a drip under the engine! So I switched to an RTV with no problems. I am curious about the Dirko.
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Just thought id post my findings here, ive just stripped a 3.2 that was rebuilt with 574 a little over a year ago. It was my first engine rebuild and undoubtedly over did the sealent. When I stripped it las week I found lumps of solid 574 on the mesh of the oil pump and also this in the through bolt hole.
http://forums.pelicanparts.com/uploa...1172947776.jpg http://forums.pelicanparts.com/uploa...1172947820.jpg This is definatly locktite 574 and its very solid If this did come lose im sure it could block larger holes than a cam spray bar. My only thought on why it may have solidified is that I filled the engine with oil a few weeks before it actually ran maybe this caused it to soildify rather than been washed away by the oil? Steve |
The factory used a roller to apply the Loctite very sparingly to the case outer perimeter only, not the through-bolt areas. The last 3.6 I took apart showed signs of shuffling at the through-bolt holes so sealer would not work there anyway. Porsche used a silk screen to apply 574 to the 928 and 944 bottom ends.
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I agree with rs-vic
I took apart my 3.2, it had never been opened since Porsche made it, there is no sign of any sealant near the through-bolt holes. |
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I just checked my 3.0 and there are no sealant present from the factory. |
Now I get it. We should never do anything that the factory didn't because they always know best?
Dilivar studs? Shuffle pins ? DC Cams ? My engine building would grind to a halt without them. The factory never used case savers so all you purest stay away from that! Please try to remember that when the factory built their engines they were working with new parts and making a specific horse power.Their processes are quite often dictated by cost not effectiveness. We're required to recondition parts and use those parts to make much more horse power. Our goal is more reliabilty and enchanced performance. BTW: in the early 90s at the beginning of the 964 engine runs, Porsche with new parts and factory trained techs produced a 4% leak average on the dyno. That means 4% of their engines leaked before the engine even made it to the car. No, you won't find that stat in print, but people working in the factory can verify this claim. We are constantly enspired to find ways to improve on the original design and that includes assembly procedures. This process (gluing the webs and using multiple glues) was originally shown to me by Bernard Grundl. Bernard was building 934/935s for Vasic Polack back in the day and he has been working for me some 15 years now. Over the years we have improved on the process. The factory only uses one kind of glue to assemble their engines and we use 5. Do you need five? probably not. But I'll match my assembly process with the factory anytime and we back ours with a two year/unlimited mile warranty that even includes leaking. I have rebuilt or overseen 400+ engine rebuilds and with each engine we look for ways to improve our process. I would like to believe that the last engine is better than the one before and the next one will be better the this one. I refuse to stick my head in the sand and stagnate the process. If you do a servey of the top flight professional engine builders (Steve, Ralph, MB and more) on this forum, I would bet all of them use a process that varies from the factory. Glue or don't, it is ultimately the builders call. In my shop it's my call. Good luck with your project. |
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