Serious press fit

Moving from boats to cars, one of the very few things I don't like about modern Chrysler engines is the use of a press-fit for the crankshaft pulley. Keyed pulleys are just incredibly easier to work with....

Just in time!

The stupidity of this design is mind-boggling. Import engines, especially Toyota, all have slip-on dampeners, with a couple 10's clearance. There is absolutely no need to have a press fit, except to demonstrate their inability to machine the crank and dampener to such close tolerance. JR Dweller in the cellar

How do Toyota and others fix those dampeners to their shafts?

One advantage of a press fit, especially for such heavily loaded joints as those between a flywheel and the shaft of a piston engine, is that there is no keyway to weaken the shaft and to produce a stress raiser in both mating parts. It's frustrating for those of us who like to repair things, but the big issue today, as we've all noticed, is not ease of repair. I wanted to strangle the nearest Korean last week when I had to replace a headlamp in my Hyundai, in a place that looked like it was intentionally designed to tear up your knuckles and to give you cramps in your fingers.

Sadly, my 2007 (2007 classic, really a 2006) Chevy truck is like that, also. (my Dodge was much better). Ease of repair is no longer a priority.

This could be a really good group rant. I'll bet everyone here has some stories like this. I have at least a half-dozen, but having to lower the engine in my Caravan (said the manual) to replace the serpentine belt is my personal best.

I fixed that particular problem permanently, BTW. One time when I had the engine all unbolted and hanging down, I took a 3-pound maul, aimed it carefully at the offending bulge in the right-side strut tower, and, swinging it with two hands, gave the bulge one hell of a whack. I only needed an extra 1/2" or so of clearance to begin with -- one would think that Chrysler could have done something about that themselves.

Hoping that I hadn't bound up the suspension so that the wheel wouldn't move up or down, I bolted the engine back in place and drove happily away. Problem solved.

lol. i had to replace the battery in my mother's saturn, the acid leaked and corroded the underlying metal structure, i wanted to do a GOOD job (instead of just slapping another battery back in) so i took out the steel battery tray. holy s*it i was like "this m'f'er must've been designed by a computer!" i had to take apart like the entire corner of the car to get the battery tray out and clean and paint it and the parts under it. everything was attached/bolted/clipped/overlaid/underlaid on top of/etc. everything else.

b.w.

Press fits require pretty much the same tolerances, just on the negative clearance side. I'd say it has a lot more to do with eliminating the cost of milling a key slot, broaching a pulley, and providing a key.... But otherwise I totally agree.

Jon

I had to replace the input flange on a German 10,000 rpm 500 hp AC dynamometer. The flange mounted on the slightly tapered stator shaft, about 65 mm in diameter. Same deal, pump up to 2000 bar and pull off with a slight push. Replacing was the reverse, a small bolt in the end of the shaft with a washer to bear on the flange, and crank up the pressure. The flange just glides into place. Very neat, but one small scratch in the near mirror finished shaft surface and I'd guess your screwed. A lot nicer than some other dynos I've worked on with shrink fit straight shafts with keys.

Late 80's Honda Accord. If you don't have a rack or means to get the car off the ground a ways, and have to remove the lower center intake manifold bolts from the top, well, it just ain't no fun...

My brother offered me a Maverick once dirt cheap. It had been our grandmother's car and had been driven seldom and lightly. Had the 302. I'd driven one of these before, they will get up and go. For the money, I was about to jump, until Dad told me you have to undo engine mounts and jack the engine up to get at one (or more?) of the spark plugs.

Years ago a friend had a nice clean Fiat X19 I admired. She offered to let me take it out for a good spin, if I gave it a tune up, as her boyfriend wouldn't touch it. Well after that disaster, neither would I. Several very oddly bent wrenches are required just to access needed fasteners on the distributor. But the best, though I certainly didn't do it, was the water pump on that car. Now, being a dingy blonde, maybe she got ripped off. But her car had air conditioning, something apparently quite rare for that model. The stock water pump bearings would not take the additional stress added by the compressor so it took a special pump with a shaft extending out the back of the pump and alongside the block to a support bearing. This made it impossible to remove the pump in the car. So the entire engine had to be pulled out the bottom. $1400 for a water pump, IIRC and 4 weeks waiting for it to come from Italy. I did btw, enjoy the hell out of flogging it (the car) on some twisty roads. Handles great. But I lost any interest I ever had in owning one...

Best vehicle I ever owned, from a maintenance point of view, was a 1964 Chevy 3/4 ton truck. I could open the hood and sit on the fender while working on the engine...

Jon

Yeah, that's a pretty good collection you have there. IIRC, there was a small Chevy (Monza?) of about the same size, and the same time, as the Maverick. With the optional small-block, it had the same problem: you had to partially lower the engine from the tranny end to get to the rear spark plugs.

Regarding your truck, those were the days. Working on those cars was actually fun. Sometimes they handed us too much fun.

Oldjag could tell us about working on the two-stage chain drive for the overhead cams on a Jaguar XK engine. He's probably worked on the older ones, which had no automatic take-up for chain wear. I used to have to take all that stuff off my friend's XK-120 to adjust that sucker every month. Of course, the carbs on my MG required adjustment about every other week, so there was plenty of that stuff to go around.

So it's a tradeoff. Which would you prefer? A car that you had to work on every two weeks, but which was easy to work on, or one that's a b**ch but almost never has to be touched until it gets old? If I can keep affording new cars every once in a while, maybe I'll stick with the latter. Otherwise, I'm going to find something old and cheap to fix, and call it my "hobby."

Did you replace the timing belt every 20K miles?

Wes

There is always one part the is installed first. Sadly, it seems like that is the part you often want to replace first. I encountered this often when I moonlighted in a major company's lawnmower service center. Often, when you do it more than once or twice, you can figure out the direct path, that helps speed things up a little.

By the end of that spring, I could do short blocks or swap transmissions in about 1/2 hour. Total time from putting it on the bench to test running the repaired machine.

Sadly, I can do a clutch replacement in a Ford tractor with the same speed. I can even lay out all the wrenches I need in the correct order. No small job, this involves splitting the tractor. Poorly designed PTO clutch in an application that stresses the s#$t out of it. And I got four Ford tractors

Karl

Your hands are too big, I bet.

War story: In the early 1970s, a penurious friend asked me to repair the lightmeter on her old Nikon (F1?). The repair was easy - just solder the wire back onto the meter, and lace the wire down with waxed dental floss so it wouldn't flop and break.

Then I tried to put the camera back together. No dice - fingers too large. This brought to mind those advertising shots of the assembly area, with ranks of benches each with a five-foot-nothing woman at work. Their thumbs might be the size of my pinky. Laughed, took camera back apart, lengthened the wires, and then was able to reassemble the camera.

Joe Gwinn

The weird thing there is that while Toyota gets the pulley right, in general the 3.0 Toyota engine and the 1990 pickup it's installed in is the miserable vehicle to work on that I've ever owned. My 2000 Intrepid and 2007 Dakota are immeasurably better.

Could you tell me a little more about WHERE the pressure was applied? I could see simply pumping oil in between the shaft and the plate to get it off, but that wouldn't work to get it back on.

Pete Stanaitis

---------------------- Karl Townsend wrote:

For the daily driver, reliability hands down. Got enough other 'stuff' that needs doing. For a fun vehicle, being it a hot rod or 4x4, working on it is just part of the game. Yeah, calling that a hobby works for me.

Jon

After helping with the 'tuneup' and taking it for a spin, I never touched it again... Fool me once, shame on me. Fool me twice...

Jon