NorthWet

Addendum to above: Oh! An hour after I went to bed (why sleep when you can dream?), I remembered one of the "h) Other" ways to mitigate detonation. Reduce peak combustion temperatures. This is actually what EGR is used to do, but EGR is intended to reduce NOx formation. I am curious to find our whether EGR could be turned into our friend. Like, What happens to flame propogation rate and combustion efficiency at high power settings when charge is diluted with relatively large quantities of cooled exhaust? With forced induction, you wouldn't have to worry so much about lower max power... Also, another 2am musing: With proper charge cooling, there should be little difference in chance of detonation between an engine running "X"-psi with 7.7CR vs same boost with 10CR. If charge temp at time of ignition is equivalent, then both should have similar end-gas conditions.

All_talk: I did get your PM earlier, along with one from another person whom my swiss-cheese memory fails to recall (and I am too tired/lazy to look up). Long day, started yesterday. It sounds like I may have come across as knowing more than I really know. I definitely do not know all of the answers; and I am positive that many of you folk have far more practical knowledge, especially with soob motors, than do I. But I have messed with cars for a few decades and learned a few of the right questions. After reading through a lot of the threads having to do with power, tuning. detonation et al, I have decided that not many people understand what effects detonation. In the end, almost everybody seems to want to know how much timing advance they can get away with running, like lots of advance is a de facto great thing. AAAGGGHHH! Timing advance is a bandaid, a compromise, and the last item in the string of conditions leading to or effecting proper combustion or detonation. At the risk of sounding like I am lecturing: Every degree of advance that an engine requires subtracts from the power that the engine potentially could generate; every degree of advance causes some amount of combustion pressure against the rising piston. The slower the speed of flame propagation in the combustion chamber, the more advance is needed to cause peak pressures after TDC. Lean mixtures, a given fuel's combustion characteristics, lack of combustion chamber turbulence and low compression pressure contribute to slow flame propagation. Large distances from flame initiation (spark) and far side of combustion chamber contribute to total time to burn the entire charge. Detonation (as distinct from pre-ignition) is caused by spontaneous ignition of end-gas in the combustion chamber. (End-gas is whatever fuel/air mixture has not yet been involved in the flame front.) The spontaneous ignition is caused be the temperature of the A/F mixture reaching its flash point (I believe that is the correct term; I had only a little Organic Chem... and that was a couple decades ago), the temperature coming from original charge temp, heat radiated from the piston/cylinder/combustion chamber, heat caused by compressing the gasses, and heat radiated form the approaching flame front; it is reduced by any quenching during combustion by the relatively cool piston/cylinder/combustion chamber. In addition, the flash point of the end-gas is lowered because the heat "cooks" the complex hydrocarbons and breaks many of them into molecules with a lower flash point. The longer the end-gas is exposed to heat, and the higher the heat, the more the flash point is lowered. So, for a given hydrocarbon, the higher the heat and the longer the end-gas is exposed to the heat, the more likely that some of the charge will detonate. "Hi-Octane" gas is just a mix of hydrocabon molecules (and some additives) that have a higher flash point, lower breakdown rate from "cooking", or both. But usually to achieve this, the blend of hydrocarbons makes hi-octane gas burns slower, requiring more timing advance in order to get the most power. At low power settings, H-O gasoline is not just a monetary waste but actually could produce a little less power than cheap stuff. So, in the end, hi-octane gasoline is not the best thing since sliced bread, but just a compromise that forestalls detonation a little bit. Timing advance added on to all of this effects when peak pressure is reached and how big the peak is. Ok, so much for the technical crap. If you understand the causes of detonation, you can work to mitigate it. a) Lower the intake charge temperature. Run an A/F mixture that has optimum burn rate. c) Induce combustion chamber turbulence. d) Shorten distance flame front has to travel. e) Cool the end-gas. f) Use a fuel with high flame propagation rate, lower breakdown, higher flash point. g) Raise the engine speed. h) Other??? I don't think many people think past a), if they think about it at all. They (those THEY people!) reach for premium and their timing light. Maybe they try to use extra gasoline for charge cooling effect (though overly rich mixtures burn slower than a slightly-richer-than-stoichiometric mixtures). So, ideally what I would want to do is lower the intake charge temperature to around 35degreesF. If the final cooling occurred near the intake port I imagine the charge temp could go lower without fear of icing. This should be possible with liquid propane. It might even be possible to allow it to enter the combustion chamber as a liquid to achieve an even greater volumetric efficiency and additional in-cylinder charge cooling. Since the propane would only be added at high power situations, there should be plenty of heat within the cylinder to vaporize the liquid propane. In addition, propane has a rather high "octane" rating, if I remember right somewhere around 110. (Natural gas is even higher, but less available in any usable form for a car.) It is a mix of simpler hydrocarbons that I believe are less susceptible to breakdown by "cooking". (Commercial "propane" is not technically really propane, which is a specific organic molecule. The stuff we buy is more accurately LPG, liquid petroleum gas.) I can not remember if I have seen any figures for its flame propagation rate. Running straight LPG is kind of a waste (unless you run a very high compression). It is also harder to ignite (higher flash point) than gasoline, doesn't vaporize well when everything is cold, requires a heavy pressure vessel for a fuel tank, and has a lower specific BTU. I would use an air-to-liquid intercooler (can be smaller than an air-to-air for similar BTU rating), plus use chilled-water to further improve the BTU rating. I have seen discussions on using A/C to cool charge air; some think it might be worth it and others disagree. I am inclined to think (haven't thought about it enough to run any numbers) that it would work, especially if cooling a supply tank instead of being sized to cool "on demand". I have only recently learned (from you folks at USMB!!!) about MegaSquirt. I am very interested in it, being an incurable dreamer. EDIS also interests me, but seems like there should be an easier way of mounting a tooth-ring/sensor. I would be tempted to just use a sensor to detect flywheel teeth; more accurate crank-angle measurements could be possible. Except that a one-sensor solution would require me to remove one of the flywheel teeth... One last thought before my screen runs our of ink: Has anybody thought of doing a timing-CHAIN conversion for EA82? Just a thought. Could be made more durable than the Gilmer belts, though introduces chance of chain stretch. It might also make interesting sounds! Hope this post is not too long. Also hope that I don't come off as a bigger jerk than I really am.

Funny... I had thought of starting a thread like this just yesterday! I have a couple Loyale-type wagons, and my wife really wants rear shoulder belts. I noticed that a coworker had a '92(?) Loyale with the rear shoulder belts, so I looked at it. The mount point is some 10-12 inches behind the b-pillar along roof-line, with a belt stiffener used to bring the belt forward to the seatback area. Looked like it shouldn't be too hard to replicate if I got the right belts. So SOA might have a conversion kit? If they do and if it is reasonable then I would definitely be interested. Some of you may say "so what" if a car does not have rear shoulder belts, since driver never sits back there, right? But many of the new child car seats, especially boosters, pretty much require shoulder belts.

No, I did not know that the dealer sold these only as control arm assemblies. Its that Oracle thing again. (Tangent: Local dealer Parts dept. acted ignorant of 3AT governor problems; I was ignorant too, but we all were at one time. I tried to get a replacement for an apple-cored governor driven-gear, and they had no idea what it was. It took me an hour to get it ordered and to find out if they thought that the drive-gear also needed inspection. They charged me $75 for new steel gear. Later, I found that another dealer in region only charged $30 for same steel gear.) As stated earlier, I have spent ca. 10 hrs at my press trying to change these bushings. I have used lube, heat, and just plain brute force. (A shipyard guy suggested that I use KY, says that it works wonders. Still haven't tried it yet.) What I ended up with were bushings pushed out of containment tube, but usually without the center bolt-tube, or one of the bulges of rubber, or both (neither?). I have shredded 5 of these bushngs so far. So... any idea what the dealer charges for the control arm assembly? I would ask mine, but I am not sure that I would get an answer.... Pat

My underlying goal is to get the better thermal-efficiency (gas mileage and low-end power) that the higher CR can give, while still having the punch and altitude-mitigation of the turbo. Although it would be fun to talk about boosting to 20PSI, my daily driving doesn't need it (.... yet, my precioussss...). So I am willing to trade a little brag-boost for better everyday power. I also don't want the drawbacks of running hi-octane gas when it is unneeded for 90+% of my driving. I think this is doable with proper charge-cooling, combustion chamber shape, mixture control, spark control... and maybe imaginative use of some EGR. So, SPFI has the highest standard CR? Any idea if combustion chamber shape is pretty standard for all EA82s?

All_talk: I have one of the two commodities that you wished for... two guesses which one!!! Actually, its all about management of endgas. I have read a lot of c**p about what causes detonation, and how much advance you should run, and what high octane fuel does. Although the real world makes a mockery of laboratory "facts", if you don't understand the fundamentals you end up chasing your tail. Anyway, how about an air-to-chilled-water IC and supplemental fuel coming from liquid propane injection rather than larger/more standard injectors? If done right, intake charge temp could be brought down to just above intake icing temp. Add some way to induce a little more combustion chamber turbulence...

I really did type "compression-ratio", not "-ration"! I am not ig-no-rant, just have a nasty papercut on my typing finger. TTFN!

Anybody have suggestions/experience building an EA82T with higher compression-ration pistons than stock? I remember seeing someone that had around a 9.5CR. I am not asking for info on pros/cons of N/A-level CRs with Turbos. I have a decent book-lernin' background. I am wanting to know whether starting with EA82T block and using N/A pistons (and maybe crank/rod assembly) works. Can an EA82 N/A shortblock be used, or does it lack essential passages and/or mounting bosses? I have plenty of EA82T shortblocks to look at (and cracked heads!!!), but no N/A block to compare with them. Also, someone had mentioned a possible source of studs to convert from headbolts. I think it was ARP, but they didn't have the exact size replacement. Any contact info? Thanks for any wisdom that you can pass along! Pat

I am asuming that you are undoing flywheel to crank bolts... I simply use a length of chain (like the one I used to lift engine), run a bolt through a link and into a bolthole in block used for engine to trans bolt-up, and another bolt (from pressure-plate-to-flywheel) through appropriate link and into its bolt-hole in flywheel. (So you now have a short length or chain bolted at one end to block and the other end to flywheel.) A little trial and error (or just thinking about it... I will try that someday!) will get you what length to use and which bolt holes. Tightening the bolts is done the same way, except chain goes clockwise from Block-bolt to PPlate-bolt. Hope that helps.

I have been trying to replace the lower control arm bushings on our '85 TWagon for longer than I am willing to admit. NAPA does not show part numbers at all for these bushings, and Checker/Schucks/Kragen shows part#s for just about every vehicle EXCEPT TWagons... (The Subaru dealer here is next to hopeless for getting parts: You have to speak with a Service person, who walks back to the Parts guy, who looks stuff up, but isn't sure what was originally asked for, so Service guy comes back and asks you... reminds me of the mythology of the Oracle: Speak into a hole, wait a day or so and get a cryptic answer back!) I digress... So, I order from CSK parts that are listed for all the other EA82's in the world, and they are a B**** to press in! They are metal bolt-tube bonded (kinda) to rubber, with a metal casing around the outside which I PRESUME the bushing is pressed out of and into the lower control arm. But the rubber bulges out each end of the metal casing. I have spent around 10 hours at my press trying to change these bushings, and only ended up frustrated, covered in rubber lubricant, and with several shredded bushings. Now, a smart man (or any woman, by default smarter than me!) would just take the control arms to a machine shop and let THEM do the deed. I am neither smart nor willing to give up, no matter how many years it may take!!! Sooooo... Q#1: Am I using the wrong part? Q#2: Any idea how to make pressing these bushings easier? Thanks for any ideas.

Thanks for all of the input! Far easier than my tried-and-true method of banging my head until I reinvent the wheel. Since I found USMB, I have gleaned a lot of info from you guys/gals. It is amazing how much knowledge is floating around. (However, in general, posts about detonation/IG-timing and thermostats tend to be just voodoo!) Ta Ta For Now!!!

My first clutch job on a Subaru was on our '82 4WD. I didn't even think about pulling the engine and pulled the tranny instead. (It is what I had always done on my RWD Datsun.) MISTAKE!!! The thing weighs half-a-ton (especially sitting on your chest!), and I forgot to deal with the gear oil first. Second time (same car: parts man gave me wrong clutch!, plus machining problem, see below), yanked engine and it was SOOOOO much easier! Same with our EA82T, which has gone through a couple of clutches (my wife needed an AT...badly!). Just flop the A/C aside like previous post said, and the rest is pretty easy. I haven't tried scooting engine or tranny away from each other and doing it in situ. I have fat hands and fat head, so like my room to work. Also, as previously said, with the engine out it is a great time to fix leaks and stuff. (And don't forget timing belts on EA82s!) And for all of you that are not blessed with a cherry picker but have friends, it is possible for two people to lift the engine out "by hand". I have installed an EA81 by myself, using a lift chain over a length of 4x4 wood. Definitely NOT recommended, but it can be done! One final word... use a good machine shop for flywheel resurfacing. My first EA81 job the machinist didn't notice that his cutter needed dressing, so instead of a flat surface I got a dished one. Enjoy!

Checking into a 92 Legacy that sounds like it has a timing belt issue... don't know which engine at the moment. Do the EJ-series engines have an "interference"-style head (valve/piston contact if belt breaks)? I am (very!!!) familiar the EA82T engines (which don't bend valves), but not the EJs. Anybody know? Thanks in advance. Pat

I've had trouble with the GROUND battery cable on both our '83 and '87. Tried jumping them and nothing happened. Moved ground jumper cable back to the starter mount and VRROOM!!! Ended up replacing both battery cables with upgraded units. No trouble since.

Our '87 Turbo GLWagon's engine has been very reliable, but I agree that cooling is a big issue. Early on we toasted the turbo coolant outlet hose, which quickly dumped the coolant, and cracked the heads. The hose literally crumbled when I tried to remove its remnants; there wasn't even enough for me to guess the hose diameter. An expensive lesson... By the way, what are GenIII heads, and how can you tell which ones are GenIII?