All_talk

Adjusting a carb is a long process, especially an automatic choke as it can only be evaluated on cold start which usually means you make an adjustment and see how it works tomorrow morning. I’ve been through this on many carbs including the Hitachi on my ’87 GL Wagon. When I rebuilt it I took the time to check and set all adjustments as detail in the manual and it was very close right off the bat. The rate that the choke opens is not adjustable (well not easily), it is a function of the supplied voltage and the resistance of the heating coil. What you adjust is the start position, “just closed” when dead cold is a good start. With the Hitachi I found that if you set closed enough for it to run smooth for the first few seconds on a cold morning it was a little to rich after the first 30 sec or so. I backed it off to run well in the middle of the choke cycle, a little lean at first start and ending up a bit rich just be for it full opened, a good compromise for most conditions. The idle up speed is independently adjustable, again can be a bit of a compromise between blubbery the beginning and screaming at the end. There is a separate screw for it and its timing can be adjusted by bending the cam connecting link. And remember that taping the throttle while warming up will move the idle cam down to the next step as the spring lets it move. Gary

Hey guys, thought some of you might be interested in what I found. I set up a couple of thermocouples on my ’87 RX (bone stock) to get some base line numbers to work from. I’m hoping to start on some mods soon (after new rings, bearings and a reseal) and its always good to know where you started so you can gauge how much you’ve gained. Anyway here’s the set up: ’87 EA82T, 252,000 miles, all stock systems intact and functional (weak compression on #1 cyl). Point #1 (T1) located just behind the MAF mounted at “duct B” (appendix like chamber), thermocouple in airflow about ¾” off the intake boot wall. Point #2 (T2) located just before the TB mounted through the connecting hose, thermocouple in airflow about ½” off the tube wall. Readings taken with a Fluke digital thermometer. Data as of this mornings ride to work: Ambient air temp about (T1) = 45 F (would rise some at idle, steady at road speeds) Max boost temp (T2) = 155 F (full and part throttle pulls in all gears show similar temps) Max deferential (T2-T1) = 110 F Cruse boost temp (T2) = 100 F (70 – 75 MPH, 5th gear, just below 0 psi manifold pressure) Note: temps under sustained full throttle seem to be slightly less than at part throttle, by about 10 F. I suspect that even though the boost level is the same, the less restricted intake path and higher flow move the compressor into a more efficient region. Or perhaps the higher flow reduces the transferred heating effects. Given this data it appears that even the stock system could benefit from an intercooler as the temps are high enough above ambient to see some cooling from an air-to-air IC. Its suppose to be near 80 F by this afternoon so the ride home should be good to show the effects of ambient temp changes, I’ll post those numbers soon. Gary

On my '87 RX they are mounted in a aluminum heat shield on the front of the pass side strut tower. Gary

I wonder if we had all the parts in hand if we could find a way to put the LSD parts (not the whole diff) in the front diff, will the side gears and clutch packs from the rear fit in the front carrier? With mods to one part or the other? Also, Adam, can you confirm the power flow of the full time trans with the diff lock engaged, does it lock front shaft to rear and bypass the diff gears? Gary

As the bearing gets worse it will be less willing to roll and it will impart more load on the outer race, at some point it will spin the outer race in the hub... the hub will then be junk (well there is a shadetree trick if its not to bad). In fact if you have noticeable play it may have already done this. 800 miles is a long way to go waiting for the other shoe to drop. Gary

If you guys are there on the weekend I might make it up, I live in Thorp (between Cle Elum and Ellensburg), so I’m close, keep us posted on the dates. Gary BTW, it doesn’t sound like you guy are going to be thrashing your rigs, but if you find yourselves in need of some shop space/tools, I might be able to help out. I don’t have a stockpile of parts (yet) but I have just about any tool you might need including a torch set and welder. I can give you a couple phone numbers.

Like you said, running it a bit with the knock would give me less concern than what caused the bearing to spin in the first place. I say tear it down, it will only cost you a few hours of your time and will tell you all you need to know. You never know what you’re gonna get with a JY engine, I’ve had pretty good luck in the past but it’s a bit of a crapshoot. Yeah, the rebuild will cost you more but at least you know what you got. Gary

My manual says the oil pressure spec for the EA82 is 43lb @ 5000rpm, so apparently the EA82 is a fairly low pressure engine. Gary

If you wanted to go with the more traditional engine in the rear the VW vanagon had an auto, and I believe you can get an adapter plate to mount up a Subie motor (I know you can for the older manual units). If you’re looking for a mid engine with a short driveline and a rear diff, any smaller pickup drive train should work. And yes, you could use a Subaru 4WD tranny (locked in 4WD) with the front diff removed, I’m sure you could fab up some plugs for the output seals, or just leave the diff in and let them spin. The trouble with the Subie auto trans is gonna be that the rear drive is NOT a positive gear drive, it’s a clutch pack, and I believe it reduces clutch pressure based on engine vacuum. You might be able to get full time clutch pack pressure if you disconnect the vac source, but you will still be driving through the clutch, not gears. Gary P.S. if you want to build a 3-wheeled vehicle that really handles well you need to put the two wheels in the front.

If you wanted to go with the more traditional engine in the rear the VW vanagon had an auto, and I believe you can get an adapter plate to mount up a Subie motor (I know you can for the older manual units). If you’re looking for a mid engine with a short driveline and a rear diff, any smaller pickup drive train should work. And yes, you could use a Subaru 4WD tranny (locked in 4WD) with the front diff removed, I’m sure you could fab up some plugs for the output seals, or just leave the diff in and let them spin. The trouble with the Subie auto trans is gonna be that the rear drive is NOT a positive gear drive, it’s a clutch pack, and I believe it reduces clutch pressure based on engine vacuum. You might be able to get full time clutch pack pressure if you disconnect the vac source, but you will still be driving through the clutch, not gears. Gary P.S. if you want to build a 3-wheeled vehicle that really handles well you need to put the two wheels in the front.

I'm with GD on this one, you need to undersrand the system before you go changing it. The truth is that if its all in good order it wont hurt performance, I understand about simplifying and troubleshooting, but if done wrong it could cause more trouble than it fixes. When I stripped it all out of my ’87 wagon it was early fall… later that winter I found that the warm air intake was important to keep the carb from icing. Gary

Sorry GD, I saw the year of the rig and assumed EA82, of course if I was on the ball I would have realized that no ’90 EA82s in the US were carbed. In my defense I did say that the proper connection depended on which system/distributor you had. I have seen a lot of miss information and confusion on this general issue and thought I would try to provide some info, in this case, due to my assumption I may have just furthered the confusion, again sorry about that. Gary

I own a bone stock 1965 Pontiac Catalina and it has NO ported Vac on the carb (in fact there are no vac connections on the carb at all), the distributor is connected directly to the manifold.I’m not one to be augmentative and I don’t like to talk out off my rump roast so I did a little research and found a very informative article on the subject written by former GM engineer (see below, warring: its quite long). As for the EA-82 (engine in question), as I said be for, it has a connection above and below the throttle plate. I’m not certain if the upper connection is “ported” (at the venture point) or just in the intake horn. Never the less, the way its plumbed its designed to accept the highest vac source which ever it is at the time. If you tee a vac gauge in to the distributor line I’m sure you will see vac at idle, my system is not stock so I can’t do the test myself. As many of you are aware, timing and vacuum advance is one of my favorite subjects, as I was involved in the development of some of those systems in my GM days and I understand it. Many people don't, as there has been very little written about it anywhere that makes sense, and as a result, a lot of folks are under the misunderstanding that vacuum advance somehow compromises performance. Nothing could be further from the truth. I finally sat down the other day and wrote up a primer on the subject, with the objective of helping more folks to understand vacuum advance and how it works together with initial timing and centrifugal advance to optimize all-around operation and performance. I have this as a Word document if anyone wants it sent to them - I've cut and-pasted it here; it's long, but hopefully it's also informative. TIMING AND VACUUM ADVANCE 101 The most important concept to understand is that lean mixtures, such as at idle and steady highway cruise, take longer to burn than rich mixtures; idle in particular, as idle mixture is affected by exhaust gas dilution. This requires that lean mixtures have "the fire lit" earlier in the compression cycle (spark timing advanced), allowing more burn time so that peak cylinder pressure is reached just after TDC for peak efficiency and reduced exhaust gas temperature (wasted combustion energy). Rich mixtures, on the other hand, burn faster than lean mixtures, so they need to have "the fire lit" later in the compression cycle (spark timing retarded slightly) so maximum cylinder pressure is still achieved at the same point after TDC as with the lean mixture, for maximum efficiency. The centrifugal advance system in a distributor advances spark timing purely as a function of engine rpm (irrespective of engine load or operating conditions), with the amount of advance and the rate at which it comes in determined by the weights and springs on top of the autocam mechanism. The amount of advance added by the distributor, combined with initial static timing, is "total timing" (i.e., the 34-36 degrees at high rpm that most SBC's like). Vacuum advance has absolutely nothing to do with total timing or performance, as when the throttle is opened, manifold vacuum drops essentially to zero, and the vacuum advance drops out entirely; it has no part in the "total timing" equation. At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15 degrees of spark advance, on top of the initial static timing setting (i.e., if your static timing is at 10 degrees, at idle it's actually around 25 degrees with the vacuum advance connected). The same thing occurs at steady-state highway cruise; the mixture is lean, takes longer to burn, the load on the engine is low, the manifold vacuum is high, so the vacuum advance is again deployed, and if you had a timing light set up so you could see the balancer as you were going down the highway, you'd see about 50 degrees advance (10 degrees initial, 20-25 degrees from the centrifugal advance, and 15 degrees from the vacuum advance) at steady-state cruise (it only takes about 40 horsepower to cruise at 50mph). When you accelerate, the mixture is instantly enriched (by the accelerator pump, power valve, etc.), burns faster, doesn't need the additional spark advance, and when the throttle plates open, manifold vacuum drops, and the vacuum advance can returns to zero, retarding the spark timing back to what is provided by the initial static timing plus the centrifugal advance provided by the distributor at that engine rpm; the vacuum advance doesn't come back into play until you back off the gas and manifold vacuum increases again as you return to steady-state cruise, when the mixture again becomes lean. The key difference is that centrifugal advance (in the distributor autocam via weights and springs) is purely rpm-sensitive; nothing changes it except changes in rpm. Vacuum advance, on the other hand, responds to engine load and rapidly-changing operating conditions, providing the correct degree of spark advance at any point in time based on engine load, to deal with both lean and rich mixture conditions. By today's terms, this was a relatively crude mechanical system, but it did a good job of optimizing engine efficiency, throttle response, fuel economy, and idle cooling, with absolutely ZERO effect on wide-open throttle performance, as vacuum advance is inoperative under wide-open throttle conditions. In modern cars with computerized engine controllers, all those sensors and the controller change both mixture and spark timing 50 to 100 times per second, and we don't even HAVE a distributor any more - it's all electronic. Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it. If you look at the centrifugal advance calibrations for these "ported spark, late-timed" engines, you'll see that instead of having 20 degrees of advance, they had up to 34 degrees of advance in the distributor, in order to get back to the 34-36 degrees "total timing" at high rpm wide-open throttle to get some of the performance back. The vacuum advance still worked at steady-state highway cruise (lean mixture = low emissions), but it was inoperative at idle, which caused all manner of problems - "ported vacuum" was strictly an early, pre-converter crude emissions strategy, and nothing more. What about the Harry high-school non-vacuum advance polished billet "whizbang" distributors you see in the Summit and Jeg's catalogs? They're JUNK on a street-driven car, but some people keep buying them because they're "race car" parts, so they must be "good for my car" - they're NOT. "Race cars" run at wide-open throttle, rich mixture, full load, and high rpm all the time, so they don't need a system (vacuum advance) to deal with the full range of driving conditions encountered in street operation. Anyone driving a street-driven car without manifold-connected vacuum advance is sacrificing idle cooling, throttle response, engine efficiency, and fuel economy, probably because they don't understand what vacuum advance is, how it works, and what it's for - there are lots of long-time experienced "mechanics" who don't understand the principles and operation of vacuum advance either, so they're not alone. Vacuum advance calibrations are different between stock engines and modified engines, especially if you have a lot of cam and have relatively low manifold vacuum at idle. Most stock vacuum advance cans aren’t fully-deployed until they see about 15” Hg. Manifold vacuum, so those cans don’t work very well on a modified engine; with less than 15” Hg. at a rough idle, the stock can will “dither” in and out in response to the rapidly-changing manifold vacuum, constantly varying the amount of vacuum advance, which creates an unstable idle. Modified engines with more cam that generate less than 15” Hg. of vacuum at idle need a vacuum advance can that’s fully-deployed at least 1”, preferably 2” of vacuum less than idle vacuum level so idle advance is solid and stable; the Echlin #VC-1810 advance can (about $10 at NAPA) provides the same amount of advance as the stock can (15 degrees), but is fully-deployed at only 8” of vacuum, so there is no variation in idle timing even with a stout cam. For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum. Absolutely. Positively. Don't ask Summit or Jeg's about it – they don’t understand it, they're on commission, and they want to sell "race car" parts.

Like you said yourself… its about balance. My wife isn’t particularly interested in any of my hobbies but she enjoys seeing me happy, so she pretty supportive. If you know your girl well you’ll know when you’ve been spending to much time under the soob and you’ll have to give a little. My general advice on marriage (I’ve been happily married for 15 years), if its important to you it should be important to her, and the other way around too. And be careful of little things you “think you can live with”, don’t expect people to change, if you have a problem with it now, chances are it will be a bigger problem down the road. Be honest with yourself and with her. If you think time/money management is tough now just wait tell you have kids. Gary

It sounds like you have a real tranny problem (not the easy fix type like the governor), you could try a filter/fluid change and maybe add one of the “trans fix” snake oils. I asked around and was told the Lucas stuff was the best, I had good luck with it in a K-car 904 auto (worst AT ever made), though I think the filter change did the most good. Rebuilding your tranny will be expensive, it may be time to find a good used one. Gary

Oil in the breather normally comes from blow by or a problem with the PCV system, check compression and PCV valve and hoses. Power loss is normal if the engine is overheating, did you notices and pigging/detonation? Gary

This is exactly what its suppose to do, retard the advance under high load, this way you can run a higher initial advance and avoid detonation at higher cylinder pressures. I’ve seen the debate on where the vac advance hooks up time and time again, the answer is… it depends on how the distributor/system is designed. Manifold pressure is a measure of engine load, the perssure goes up (less vac) as the load goes up. On almost all older engines (pre ‘70s) the advance works from straight manifold vacuum. Once emissions became a concern thing got complicated. If you want to know if your system is running with advance at idle (most have some), disconnect the line to the distributor and plug the line to the vac source. If the idle speed drops its because you have removed advance (this can be confirmed with a timing light). On the Subaru engine specifically the stock system connects both above and below the throttle plate with metering orifices and a check valve (check the emissions diagram in the manual). My Chilton manual also indicates some models use a coolant temp or module controlled vac source valve but I don’t have an early FSM to confirm. For what its worth, on my de-emmissioned ’87 carb wagon I have the vac connect to the manifold and it works quite well. Gary

hey eqvance When you loose a lot of water in a hurry (like a blown top hose), the coolant temp sensor can go dry before it registers the high temp. I suspect that it may have gotten quite hot and you may have cooked the piston rings, if you get them to hot they loose there strength and stop sealing, then you get major blow by (oil in the breather). A compression check will tell the story, if any of the cylinders show low then run them again with a squirt or two of oil in them, if they come up considerably you’ve got bad rings, if not its valves or a head gasket. Speaking of head gaskets, if it got that hot I bet they’re shot (maybe even a cracked head, sorry)… any water in the oil, bubbles in the radiator/pushing out coolant? The stock gauge isn’t all that accurate, maybe its reading low, temporarily mount up a mechanical gauge or check it with a good thermometer. Gary

Well, I did a bit of web searching, apparently the compressor map for the RHB5 is non-insistent, as the manufacturer has never released one. I guess its not that important, I just like to know as much as possible about a system and how it works before I start changing things (byproduct of being an engineer ). Gary

What’s the manufacturer, model, trim? Anybody have a compressor map for it? Gary

Shadow, great info, I read through a lot of info on that site and they seem to be coming from a very intelligent and informed point of view. The consensus, apparently backed up with dyno results, is that for low octane fuels (below 100 or so), you can make more power with low compression and high boost than the other way around. So the 7.7 will stay, I was hoping to use the higher compression to increase the low RPM pre-boost power but free flowing intake and exhaust will help with that and also bring the boost in sooner. Gary

Both switches are on the front of the passenger side strut post, I did some digging and found the “boost switch” on the wiring diagram but no positive ID on the fuel cut switch yet, but I’ll check wire colors when I get home and maybe I can figure it out. I downloaded a partial version of the ’89 FSM (PDF file) last week, its in section 2-7, page 80. This section describes the function of all the MPFI components, full of useful bits like… the fuel pressure regulator has a 1:1 ratio set at 36.3psi above manifold pressure and… there is a duty solenoid in the waste gate circuit to compensate for low air pressure at high altitude. Gary

Good point about the compressor, you’ll need a decent one. If it’s a bit small it will still work but you will have to slow down and wait for it to build pressure.

I think a sand blaster in the number one specialty tool for restoring old cars, I have access to an industrial cabinet blaster at work but a gun and bucket/tank type is on my list for home. Jamie, I think the one you’re looking at should be great for the occasional use you’re going to need. P.S. My daughter should be sending you some questions for her school project soon. Soobme, along the lines of what northguy said, I’ve seen guys make cabinets from plywood with a glass top or even a large plastic storage tub, then all you need is the gloves, or just cut the holes close to arm size and you wont loose to much sand. Gary

I was reading through the ’89 FSM (is it normal to use a FSM for pleasure reading?) and found this bit of info (see pic). Looks like the fuel cut is suppose to come in at 9psi and if we determine the switches normal position (closed or open) we should be able to bypass it and defeat the cutoff. Or maybe we could find a way to adjust/replace it to work at a higher pressure. My RX is not ready for extra boost so I cant test it yet but looks promising. Maybe use it for fuel enrichment or water injection. Another note, the oxygen sensor is not used under boost and the computer is running on a preset program, I wonder if this fact could be exploited and modify the pulse width of the injectors to enrich the mixture. Just some thoughts Gary