riredale

I'm a new owner of a gorgeous 2010 RX450h and have been reading many of these threads on CL to get a quick education about this sophisticated car. Everyone here seems pretty friendly and helpful, so I thought you all might enjoy a little story about my early education about engines:

Back in 1969 I was back home in Los Angeles for the summer from my freshman year at a college in Boston. Turned out the computer job I thought I had for the summer in Pasadena just vanished as part of a cutback that very week, so I busied myself with other things that summer. In August one morning my curiosity got the better of me and I began disassembling the two-barrel carb on my 1967 Mustang (289 V8). I've always been fascinated by mechanical things, so seeing how all the parts worked on that carb captured my imagination.

Okay, lesson done, everything went back together, and of course the trick was to see that there were no extra parts left over. There weren't, and I fired the engine up. Started quickly and ran perfectly--for about five seconds. Then a very loud metallic "ping" began, related to rpm.

So I borrowed my mom's car and drove to the local library to check out one of those car repair books that was about 4" thick. (Now, I'd just hop onto YouTube, but this was long before the internet). Once again I took my tools to the carburetor and did a second disassembly. By comparing what I saw with the diagrams in the book, I could account for each and every part. Except for one. I couldn't seem to find a tiny little steel ball, commonly known as the "accelerator pump check valve." The idea is that when you goose the throttle, it takes a half-second or so for the inertia of the normal fuel delivery channel to catch up with the sudden increase of air volume, so carburetors have a separate little plunger assembly that shoots a squirt of raw fuel into the manifold to cover the temporary lean condition. The little ball kept that pump chamber from emptying on the down stroke. That little ball must have accidentally squirted into the intake manifold.

Over the next week I learned how to take off the driver's side cylinder head. Sure enough, down in cylinder #6 (second from front on driver's side) a shiny little ball rested on the piston top. I smiled at my wise deductive skill and went about re-assembling the V8's head, manifolds, and carb.

Then the engine ran great--for about a week. I began to notice it seemed to have a lumpy idle. Out with the tools again. My nearly-new compression tester showed zero compression on cylinder #6. So the top of the engine came apart a second time. Nothing seemed out of the ordinary, so I took off the oil pan to get to the connecting-rod bolts for piston #6 and pulled it out the top. Whoa--one entire side of the piston looked like it had melted! And the piston no longer rocked freely on the connecting rod. What apparently had happened was that there was zero clearance between piston top and cylinder head in part of the combustion chamber, a design that intentionally made the gases swirl at TDC and promoted combustion. But that left no room for a little ball bearing, which as a result really hammered down hard on the piston, so hard in fact that the forces slightly bent the piston pin and prevented free rocking. So as the connecting rod came up and went back down the piston was forced to "scrape" against the cylinder walls, melting the aluminum piston's side and trashing the piston ring grooves. Result: no compression.

ANOTHER trip to the Ford dealer, who was happy to sell me a new piston and ring kit, and who pressed in the pin at no charge.

So to summarize, back into the engine the piston went, everything put back together (again), and not a moment to spare--I had to leave two days later to drive the car the 3,000 miles across country from LA to Boston. The engine ran fine.

One little postscript: I set out from Los Angeles in late August and by the next day I was passing through a small town in New Mexico (I was trying to stay on "Route 66" just to be able to say I had followed it the whole way to Chicago, with no Interstates). I was accelerating back up to highway speed when all of a sudden there was a very loud "bang" and once again the engine ran poorly. With a heavy heart I pulled over to the side of the two-lane road, left the engine running and opened the hood. Engine loping, and as I peered down I saw three little spark plugs gently rocking back and forth. Not four. In my haste to finish the engine I apparently had put in the plugs only finger-tight on the driver's side and had forgotten to torque them down. The #6 plug had gradually worked its way out while crossing all of California, Arizona, and half of New Mexico. I walked back down the highway a couple hundred yards and sure enough, there's the fourth spark plug, still too hot to hold with bare hands. Not believing my good fortune I eventually got the plug back in the hole, and at the next town I was able to borrow a surprised mechanic's torque wrench. After that, the little 289 Ford engine ran flawlessly for 100K+ miles until the Mustang was sold many years later.

So that's how I learned something about engines. Rule #1: NEVER WORK ON A CARBURETOR WITHOUT TAKING IT OFF THE ENGINE FIRST.

mmarshall

Thanks for the story, riredale. Although EFI is far superior to virtually ANY carburetor, you were fortunate enough to at least have a relatively simple 60s-era carb that didn't have a nightmare of vacuum-hoses/ports and electronic choke-adjusters on it. The later-vintage, late-70s/early-80s Chrysler Lean-Burn carbs, for example, were a true PITA to deal with....as were the POS carbs that GM stuck on early-model X-body compacts with the Iron Duke 4. But even some 60s-vintage carbs (particularly the 2-bbl Carter AFBs on Dodge/Plymouth/Chrysler V8s) were far from foolproof when it came to drivability, and produced marked cold-engine/warmup hesitation/stalling and carburetor icing. On some later 70's-vintage carbs, the conversion to lead-free gas in the early/mid-70s had a tendency for the gas, over time, to eat up the carb's accelerator-pump seals and cause the lean condition you describe on initial acceleration. They eventually had to change the seals to other materials.

A general rule of thumb, BTW, for tightening spark-plugs.....if available, use anti-seize compound on the threads, and, unless a specific torque-figure is given in the Repair Manual for tightening them, tighten them 3/4 of a full-turn past the initial contact of the base of the plug with the block.

(BTW, like you, I grew up in the Baby-Boomer Era with 60s-vintage cars).

riredale

Mmarshal, you are correct, now I can't recall if I used a torque wrench or just tightened them.

Looking back, I think that 289 was a good engine design and I learned a lot from my mistakes that summer. I can remember being surprised as how heavy those cast-iron heads were. Also, the v-belt driving the A/C compressor had a long section that was unsupported by an idler pulley, and at a certain rpm that belt would vibrate like the string on a cello. Could never get the belt tight enough to eliminate it.

mmarshall

Back then, Ford, like Chrysler, tended to use heavy-cast blocks and heads, which generally fit in with their philosophy of engine-design......narrower bores, long strokes, more metal between the cylinders, lower RPMs, and an emphasis on torque over HP. GM, on the other hand (and particularly Chevy), tended to use the opposite philosophy......wider bores, shorter strokes, less metal between the cylinders, and smaller, lighter-weight blocks/heads designed for higher RPMs and an emphasis on HP over torque.


BTW, until the special-production Shelby Mustangs debuted in the mid-late 60s (GT350, GT500, GT500KR), the run-of-the-mill production Mustangs used essentially the same in-line 6 and V8 engines and transmissions as their Ford Falcon stablemates. The 289/271 HP, with the 4-bbl carb and four-on-the-floor transmission, was the top drivetrain until the Shelbys came out....it was also used in Sport/Futura versions of the Falcon. The original 1964-66 Mustang itself (if you are not aware of it, which you probably are) was simply a re-skinned Falcon chassis/platform/drivetrain with a completely different (and far better-looking) body and interior. It got a mild restyling inside and out for 1967 (the year you had)....but more extensive changes (and the Mach 1/Boss/Cobra-Jet versions) did not arrive until 1969 and 1970.

Htony

Wonder OP became an engineer in some field? Regarding spark plugs cross threading is the worst thing can happen. Nowadays plugs last LONG time. I always use Iridium plugs.

mmarshall

Unfortunately, plugs last so long today (sometimes 100K miles or more) that the accumulated engine heat, over time, can cause the threads to essentially bind together (seize), and make the plugs very difficult to remove. Technicians have been known, in some cases, to actually have to drill them out and re-thread the holes (it is possible to successfully re-thread them, but I don't know much about the actual procedure). As I said above, that is why it is important to use anti-seize compound, if available, when screwing in the plugs.

bitkahuna

iTrader: (20)

we learn more from our mistakes than our successes. welcome!

oh and don't make a mistake with the hybrid... the 400+V can be deadly.

riredale

Fascinated by the changes in engine technology over the years, for example, the adoption of an Atkinson Cycle for the 3.5 V6 in my new/old 2010 RX450h.

As for plugs, the old 1997 Mercury Mountaineer that just went to Car Heaven when I bought the RX had 177,000 miles... and original plugs. Or at least I can vouch that I never changed them from the time we bought the car in 1999 with 33K miles on it. Car started and ran great to the end. I would have to assume that plug technology must have come a long way, or perhaps the spark was far hotter than before.

Couple of years ago the battery finally began failing. I was surprised to discover from the documentation on the battery top that it was slightly over 10 years old.

What a change from cars of the '60s, when one did points and plugs every few years, I seem to recall.

mmarshall

Actually, in the 60s, before the days of EFI and electronic ignition, a car's points, plugs, plug-wires, condenser, rotor, distributor-cap, and carb-adjustments (in other words, a tune-up), were routinely replaced about every 10,000 miles or so......sometimes a little more often with Chrysler products, which tended to eat up points. 10,000 miles, of course, could be anywhere from a few months to a few years, depending on how often you used your car and how many miles you put on it. Chrysler, however, to its credit, was also the first American company to drop the breaker-points and convert to electronic/solid-state distributors and ignition systems (first offering it as an option in 1972). This, of course, greatly simplified the tune-up process and extended its intervals. By the end of the 1970s, not only because of these advancements, but with unleaded fuel letting spark plugs run cleaner and lasting longer, frequent, traditional tune-ups were generally history. Some unscrupulous repair-shops, however, were still charging unsuspecting and uneducated car owners for traditional tune-ups that were clearly no longer necessary.....there's often crooks and dishonesty when there's money to be made.

Htony

I built a CD ignition box for my '70 Plymouth Fury with 383 cu. in. engine. Spark was much hotter. Started better in cold winter days. Today's cars seem to be more electronics than mechanics. Coming week end I am installing an after market remote starter on my '15 RX hybrid. Only problem for me is removing the dash panel
to access the wiring connection points. 13 wires altogether plus sticking new antenna on the windshield. And flashing the brain(module) Costs only ~200.00 saving almost
same amount doing it myself. My back is EE so most electrical/electronics problem is easy for me but not the mechanical side.

chuyrobles

I think the OP is an English teacher, or has a very good proof-reader. Nice job, that was an interesting and funny read.

As for torquing plugs, one must be careful using anti-seize. Any type of lube on threads decreases friction, increasing the clamping force on the head of the bolt, potentially snapping it. Since a spark plug does not really have a head that can snap off, the increased clamping pressure is placed on the threads, which can lead to strip threads. Moral: reduce the recommended torque by at least 10% when applying lube to threads.

Exactly how much to compensate is hard to say. It depends on type of lube; bolt size; metal type; etc... But, I do recommend lube as it helps prevent thread seizing. Just know you need to compensate the torque specs.

That being said, I have always used the feel method. I have never stripped threads nor had a plug come loose. It comes from decades of replacing plugs. Wouldn't recommend it for newbies.

http://www.globaldenso.com/en/produc...ion/index.html
https://www.ngksparkplugs.com/about-...ut-spark-plugs


NGK claims their plugs do not need anti-seize lube.
http://www.jagrepair.com/images/Auto...1antisieze.pdf

mmarshall

Not to take the thread too far off-topic, Htony, but did you have a lot of trouble on your '70 Plymouth with loosely-built and poorly-fitted parts? Quality control and fit/finish on late 60s/early 70s Chrysler products was so bad (by today's standards) that it is hard to imagine today. GM, Ford, and AMC also had some problems, but Chrysler products took the cake for poor assembly. However, to compensate somewhat, Chrysler engines and automatic (not manual) transmissions of that vintage WERE durable...especially the 225 Slant Six and 318 V8 engines. Slant Sixes would routinely run the better part of 200K miles in an era when most engines were junked or overhauled before 100K....that's why many taxicabs of the era used them.

Htony

It was Sports model. I was a second owner and previous owner took care of all the loose ends of this car. Only beef I had was engine only had 2 bbl carb. Those days I used to be on highway a lot running around here and there as systems tech. support guy for large scale system. Soon after company started providing company cars. Depending on one's rank within the organization, certain domestic cars were available. If one pays personally. any option could be added. After 40 years when I retired I am left without a car of my own. Bought a Honda CR-V and started saving extra money to get a nicer decent car. Moved upto MDX, BMW, Audi, etc. Ended up with RX hybrid for Toyota reliability. I am thinking about going back to BMW X5 again for it's handling characteristics. My wife used to drive British Sunbeam Tiger which I had to work on it almost every week, LOL. Now she drives Subaru. Since then anything British in cars never interests me. Getting old is no fun, even crawling under the dash is a big chore now. Installing remote starter, I think I twisted my neck, cracking noise every time I turn my head last few days.

mmarshall

Yes, the 1970 Sport Fury. I remember it well.





The two-barrel carburetors on the Chrysler V8s in the 60s and early 70s (usually Carter AFBs) tended to run lean and stumble/hesitate when cold (and sometimes suffer from carburetor icing during warmup in cold, wet conditions), but, otherwise, when warm, were usually fine.



Yes, the Lucas electrical systems and cork-derived gaskets in those old British cars could drive you nuts. The more you repaired them, the more they failed.


Hope your neck recovers. Best of luck.