Anyone know what goes into a commercial oilway gasket (the thin, papery kind, not metallic head gaskets, thick waterway gaskets etc.)? Are they simply paper cut to shape, or are they treated with something to make the fibres stay together better under heat / vibration / oil attack vs. ordinary paper stock?
cheers
Jules
Snips, snails, puppy dog tails, asbestos fibres and a subscription to uk.rec.engines.stationary
Otherwise most "thin" gaskets (i.e. not thick and conformable) can be ignored these days and replaced by a liquid gasket compound instead. Hylomar for choice, not Hermetite.
WE used to cut em out of cornflake packets and soak em in some gunk or other. Probably gasket compound.
I do like to use them even with hermetite, because the last bit of tightening of a steel bolt into an aluminium housing can strip without a little 'give' in the assembly.
:-)
I should actually get back on there... I think I unsubscribed during some Great Usenet Reorganisation a year or two ago and never quite got around to signing back up...
'these days' because the gasket compound's better, or do you mean 'only on modern stuff', because the tolerances are a bit tighter so the gasket has less of a job to do?
The existing lower crankcase gasket on the mower's (4-stroke) engine leaks like a leaky thing, and I'm in a "mucking around with engines" kind of mood today :-) Easy job to pull the engine and strip the bottom end, so I was wondering whether to just make a gasket out of thick paper / cardstock
- or just lump it and wait for a week for a genuine one to arrive (doubtless along with paying ridiculous S&H, it'll arrive mangled, the lawn will need mowing again by then etc.!)
My motivation says to just make one (because thin gaskets never look particularly different to thick paper anyway), but OTOH the geniune thing might be treated (and I'd rather not end up with paper fibres from a homebrew clogging bearing oilways etc.). I doubt any homebrew would leak any less than the current gasket on there.
I used to have a stash of 'gasket paper', but I'm on the wrong side of t'pond for that now...
cheers
Jules
Jules explained :
Just paper ready cut to shape. I use brown paper for the thin gaskets and cornflake packet for the thicker ones. Make some initial bolt holes with a hot soldering iron, drop bolts through to keep the gasket in place, then tap gently along the edges to mark then on the new gasket. Remove and cut along the edges with scissors.
I remember doing that in student days, but student cars never lasted long enough to reach any conclusion as to whether it was a long term solution ;-)
I did use a bit of cardboard for the carb gasket on the lawn trimmer the other day, which so far is holding up - but time will tell.
Never did that, though. At one point in time I got used to using a bit of hylomar with gaskets, but I'm not sure it's absolutely necessary, and just seems like extra clean-up if the gasket's ever replaced. I've not bothered with it in recent years, and not had any problems so far.
Is that the stuff that's a bit like clear caulking? Some oik had used that on one Stag engine I had, but they used too much - some of it eventually broke away inside, clogged a waterway, and overheated the head (always was a sod sealing the intake mainfold on those engines, but it's still no excuse!)
cheers
Jules
Flatter seal surfaces, partly from machining, partly from better distribution of clamping forces. Engine cylinder blocks and heads these days are even FE-modelled and their internal stiffness adjusted so that the clamping bolt forces don't warp them any more.
Banknotes are very strong, why not use one of those? Probably cheaper than the proper gasket anyway :)
Red rubbery sort of goo, or did it dry hard..
Hermetic compound I suppose it stands for, and a trade name.
I haven't rebuilt an engine since student days back in the 70's, but then it was common to use Hermetite on all 'wet' gaskets, barring the metal head gasket. As I recall, it came in three basic varieties - red, green, and gold - each of which had its own setting and sealing characteristics for different gaskets. I think that the red was the general stuff, and that
*did* dry semi-hard, and was a mother to get off later. I seem to recall that green was for oily gaskets, but I wouldn't swear to that - it's been a long time ago ! :-)As to what gold was for, I really don't remember at all, but I do seem to recall that it was a lot more expensive, so got 'shared around' ...
Arfa
Hylomar dissolves in cellulose thinners - which is also a good final wipe for most mating surfaces too. A 5 litre tin of 'gun' cleaning thinners isn't expensive but can be hard to find these days.
Hermetite came in two versions - brown which set hard and red which didn't. But there are better modern products.
Usually because a head has been planed after a gasket failure which alters the 'V' the inlet manifold sits in. I ended up with a paper gasket on one side and an extra thick one on the other to help square it up - and had to helicoil most of the threads into the heads too. Overheating on those is caused by poor water circulation - although the pump was modified on later cars. But still isn't great. I added an electric pump.
Ah - don't think I ever saw gold. Just one which set hard - to a dark brown colour which came in a green tube, and red which was nominally non setting. But neither really worked on the motorbikes I had then - but that wasn't the fault of the sealer. ;-)
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jules saying something like:
Of course you're not - plenty of home engine builder in Septicland and they get their gasket sheets somewhere. Try McMaster Carr or Frost's.
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Strangely, paper gaskets were usually coated with ordinary grease and it was quite effective as a sealant after the initial bleeding out caused by heat.
If you're stuck for material you might try heavy duty lining paper (wall-papering type). I haven't tried it but a single roll would provide plenty to experiment with. I usually used the covers off notepads/ exercise books if they were big enough.
Cic.
You need something with long fibres. So good quality paper is good, newsprint is bad. Wallpaper is likely to be at the poorer end of the scale.
A workable gasket compound can be made from elephant dung, which has sufficient fibre content (these were eating acacia). It also makes really good paper, although the colour is a little "rustic".
Oh, I mean I'm sure I can get it easily here - I just know I have a pile already, but that doesn't help when it's 4000 miles away :-)
Well I've got some pretty heavy duty cartridge paper, which I think is the right kind of 'consistency' - just not sure how well it'd hold up in a hot / oily environment. Sounds like it's worth a shot (I got sidetracked building some benches yesterday, so never did get a chance to play with the engine)
Interesting. No elephants here, but plenty of deer. Maybe I'll give the kids a job and see what they think ;)
cheers
J.
Yep. I ended up sourcing another pair of heads and then getting the inlet manifold machined to suit, which took care of all the problems - just frustrating that someone had tried to bodge it rather than doing something like what you did.
Heh, sure - BTDT. I've seen quite a few engines where they've been stripped. Don't talk to me about seized head studs, either :-)
Both of mine were always OK apart from that drama with the sealant - but I put a new pump in one engine and made sure I'd flushed all the casting sand out (another major cause of overheat) and it had a decent radiator. The other engine was a complete ground-up rebuild, and probably ran better than it had when it left the factory.
Maybe I'll pick one up this side of the Pond sometime, although it's really hard to find a good one here that still has the original engine.
cheers
Jules
It's my brothers' car - and I really didn't see the point of that engine. I'm a Rover V-8 fan. ;-) There were so many basic mistakes in the engineering to make it pretty pointless when the company had a better one readily available.
Heh - one of the best exhaust notes out there, though. I liked the fact it was OHC, but it certainly was a bit of an oddball design - not very well thought through, and then with sloppy production when it came to actually building the thing.
I think I read somewhere (don't have my reference books with me, sadly) that it was intended to be a stopgap prior to bigger things though, so maybe 'v2' would have been considerably better (but doubtless still with crappy quality control :-) Something without bloody head studs and a coolant pump that was low enough to actually pump coolant would have worked wonders...
I've done quite a bit of stuff with the ol' Rover V8, too, so have a bit of a soft-spot for those as well - good, strong engines. Back when I first got into classics it was really hard to choose between a P6 and a Stag.
cheers
J.
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