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I've been waiting, well, since last August to make a blog post about this topic with that title.
I had a long to-do list in the garage today. Among the items I was worrying about in my Beetle's engine that I'm putting back together were the rocker assembly studs in the new cylinder heads. I think the old ones weren't sealed right, and were contributing to general oil seepage. Here's the inside of the valve gallery on one of the new heads. I've circled the stud. Keep in mind that this area has oil splashing around in it when the engine runs.
What's interesting is those heads protrude out the back of the gallery, meaning that if oil goes around the threads, it will leak out of the engine.
The first piston/cylinder combination ready to go on the engine, early this afternoon
And on the engine
The right side cylinders are on...but what's missing?
Ah, the all-important air deflector
Which, because I don't like how mine fit, I wired on for double-safety.
And finally, after 8 months, the engine looks like an engine again
The pistons and cylinders are in, and the heads are on and torqued. Now I need to deal with the valve train, and getting new push rods.
[The process of torquing the heads on involves going back and forth across the engine multiple times increasing torque slowly, creating a web of tension that holds the whole engine together tightly; thus "cat's cradle".]
Ok, things moving forward on the beetle.
Air deflectors, which looked nasty
cleaned and painted with rust-eating flat black paint
Push rod tubes prepped
and painted with flat black radiator paint
Checked the chamber volume of the newer of the two new cylinder heads.
It checks out the same as the other head, so that's at least consistent.
The cylinders are cleaned, painted, oiled, and ready for installation
Oh, and I mocked up a cylinder and checked the deck height--it's the same as before, so the shims I have will be fine.
Going through the docket for today (yesterday, really), that leaves...the pushrods themselves. They're supposed to be very very straight. Using a marble tile as a reference surface, for most of the pushrods it was hard to tell that they were anything but dead straight.
Here's one that looks good
Still pretty good, although I might say that it's not quite straight
And then there was this one, definitely bent. Guess which valve this one is from?
For those of you keeping score at home, this is the right-front-most pushrod in the engine, that actuates our friend, the #1 exhaust valve that was stretching which is what started this mess in the first place. This is totally consistent from what's gone on before, I just wish I'd checked this earlier, because now I can't run the engine without a new set of pushrods.
This bent pushrod wasn't the cause of the valve problems. On its own, a bent pushrod would effectively shorten, meaning that valve clearance would get bigger, which is a normal wear pattern (the symptom was valve clearance getting smaller). However, it's perfectly consistent as a further symptom the valve clearance closing. When the valve clearance was tightened down, the camshaft was hammering on the now-constantly-too-tight valve train, and the pushrod is what gave first.
Oh, and three of the pushrods from the right side of the engine have significant scuff marks on them
which is further parallel corroboration that things were not well on the right side of the engine.
Now I need to finish cleaning the piston components, and then assemble them and stat installing stuff. Tomorrow I'd like to get the heads on and do a dry install of the valve train so I can check to make sure the geometry is right so that I can be sure to order the right length of push rod.
I balanced the new pistons for my VW yesterday. They came with a spread of a little over 3 grams across the set. I spent some time grinding and weighing yesterday, and reduced the spread to .4 grams, and it would have been better if I hadn't overshot on one of them. The VW factory tolerance for new pistons is 5 grams, so even the original set was within spec. My inspiration for doing more was this post by Bob Hoover.
Here's my setup, fairly shortly after noon, with my supervisor looking on
Here's what I was doing. Pistons are cast with "balancing pads"; sections of metal that are specifically designed to remove to reduce weight. Here's the piston that started out as the lightest; I haven't removed anything from its pads. They are marked with green dots so they're easy to see.
And here's what started out as the heaviest one, which I basically ground the pad down to the base metal. With the pads the size they are, I don't think you can safely remove much more than 3 grams to balance it.
To do the grinding, I went out and bought a bunch of the cylindrical grinding sleeves for my rotary grinder. I used up quite a few of them.
When you're sanding metal or wood, typically the coarser the sandpaper, the faster material is removed. This isn't necessarily the case with rotary grinding tools. I found that the 120 grid rotary sleeves were much better at removing Aluminum than the 60 grit. While the 60 is more abrasive than the 120, I guess the 120 has more material in contact with the target metal?
I took yesterday off work to get a running start on the weekend. It just turned 10 am here, and in many respects how I do today will be a measurement of how much I've actually gotten better at working on stuff this spring. I am a serial procrastinator, but I've gotten slowly better this spring. More instances of going on trips and unpacking immediately when I return, rather than unpacking a suitcase when it's time to pack in it again. More leaving for trips on time. The summer gets busy in not too many weeks, and this weekend will provide the best chance for me to work on this engine for the next couple of months.
I don't realistically think that I'll get it done and in the car this weekend (although that'd be great), but if I get it far enough along that I can just continue to work on it in the evenings, then that will be a great accomplishment. However, that's going to require me to dig in and really work on it today. None of this lounge around on vacation and sort of putter; I need to dig in and work. Yesterday was a good start, but I need to do 8 or 10 hours of good work today.
And I just realized that I never checked the head chamber volume on the second new head that I have. Argh.
I finally got to the step of prepping the cylinders for engine assembly for the Beetle.
VW cylinders are raw cast iron, which corrodes very easily. They come coated in "cosmoline" which is a thin wax that prevents the metal from rusting. I cleaned off the cosmoline with mineral spirits
and then dried them via compressed air and heat, and set them to finish drying in the sun.
The first cylinder I did this with, I tried to clean off the mineral spirits by scrubbing the cylinder with soapy water. The cleaning and rinsing took less than 2 minutes, but it ended up with some rust down in the crevices of the fins.
Here's one cylinder that hasn't been in water:
and here's the one that did go into water:
Before painting the cylinders, I needed to mask off the sealing surfaces, and to make sure that the interior doesn't get paint on it:
I did end up painting the cylinders, and they're drying in the garage
The painting is to improve the cylinder's heat transfer characteristics and prevent them from rusting. Here's what a cylinder looks like that came off the engine:
Tomorrow, hopefully I'll be balancing pistons.
The tops of the new cylinders I got for my Beetle's engine still had machining marks; since those form the all-important metal to metal cumbustion chamber seal, I decided to sand the surfaces smooth before proceeding with the assembly.
Here's my setup. A marble tile to provide a flat surface to sand on.
On the left is a cylinder as delivered, on the right after sanding it down to 600 grit sandpaper.
The next step will be to clean and dry the cylinders and paint them so they're ready for engine assembly over the weekend.
Back from Illinois. I had a big work presentation on Thursday. It was well received, I was asked for a follow-up in a couple of months. I got a great question in the Q&A about whether I could do something that I've already worked on in other contexts, so that should be easy to implement.
I'm back, and not without deadlines, necessarily, but without any looming ones. Today, I'm going to sit down and take some scrap paper and make out a calendar that goes from now through DragonCon in September so that I can lay out my schedule for the summer. It will include work stuff, Oshkosh, and possibly Convergence.
My other main task for the day is to get the Sirus radio set up in the Taurus in a more usable way. We picked up a car kit yesterday to this end.
The mid-term plan is that I hope to have the Beetle running by mid-June. Hopefully from now on the task will be preparation for assembly and then assembly, rather than fixing more stuff.
Now, I just need to get this cat off my lap (who apparently missed me).
No new Beetle stuff, argh.
On the above page, I do have a history and some writing about what I've done to my car, but it's terribly out of date. If you've read my blog, and are confused and want the back story of my vintage car, then this post is for you. This is a brief overview. I'm not mentioning various attempts to work on the carburetor and get the car running right, unless it pertains to a longer-term issue.
2003-2005: Got into my head that owning a vintage beetle would be a good way to learn to work on engines, particularly air-cool horizontally opposed ones (similar to airplane engines in man respects). Started looking at vintage beetle ads here and there; started running search on ebay.
July 2006: 1 week before major cross-country move for wife's new job, I see a vintage beetle ad in newspaper. We check it out. Has mechanical issues, but body is in amazingly non-rusted condition. Have it checked out my our mechanic, brings it up to snuff for major cross-country trip. Buy the car. Drive it around town for remaining 5 (very busy) days as primary car, everything goes fine.
In two car, two cat, road trip to new house, starter fails in beetle. Wife continues on, have beetle towed, get it "fixed". Drive another 200 miles, starter fails again, roll start, stay in hotel. I get to house half a day late.
Fall 2006: I drive the beetle as my primary car, without starter failure. After a while, it starts to fail occasionally. Late fall, it finally fails in the house where i can diagnose. Problem is the starter solenoid.
fall/winter/spring 2006/2007: take top part of engine apart, replace starter, put in breast tin (it was just left out in the last assembly). replace rubber seal around engine compartment.
spring/summer 2007: work on getting beetle to run right. I discover definite air leaks around carb throttle, possible ones on right side of intake manifold. Buy another carb on ebay; makes those leaks go away. In the process of re-tuning everything, discover that #1 exhaust valve is stretching/sinking. Crap. From now on car is driven limited milage only until I figure out why. #1 exhaust valve stretching .001 every 200 miles or so. Danger Wil Robinson!
Fall of 2007: Try to investigate valve issue. (possibly I discovered valve and the carb air leaks; don't remember). Driving frequently short distances. One day I discover that brake fluid is down all the way. Refill. Realize next day it's down all the way again. Refill and time. It takes less than 4 hours for entire reservoir to drain completely. Crap crap crap. Car up on blocks.
fall/winter/spring 2007/2008: Take entire brake system apart. Master cylinder was the culprit; leaking brake fluid into body. Discover all four brake drums machined badly past spec. Replace all four drums, all new brake system, relube wheel bearings. Having mistakenly decided that main front-to-back brake line was the culprit, run a new line in a custom location.
spring 2008: put car back on the road, get brakes adjusted right for the first time in ownership of car (adjusting stars had been frozen). Brakes really nice.
Summer 2008: work on stretching valve issue again. Still no real information. I decide that I need to see the valve to see what's going on.
August 2008: I pull the engine, hoist it up on work bench.
Fall/winter/spring 2008/2009: Dis-assemble engine down to long block. Remove heads. Problems: 1) loose head nuts. 2) possibly loose intake manifold on right side. 3) right head machined too far. 4) left side compression ratio is too high, right side is WAY too high. 5) oil pump way out of spec, and installed with wrong gasket, making the problem worse. WTF? Was this engine assembled by a squad of Shakespeare-typing monkeys?
Buy new cylinder head to replace right one, discover it's the wrong type. Buy another head, with unusual spark plug holes (seemed like a good idea at the time). Buy barrel shims to get compression ratio down to reasonable level. When weather is warm in spring, start the re-assembly process. Pull first cylinder to install barrel shim, realize massive crack in cylinder. Crap crap crap.
Order new piston/cylinder set, and as long as I'm replacing cylinder, I attempt to order another head just like the one I have. Discover that the new, good head I have is an extremely rare type and have the devil of a time ordering another one.
As of May 2008: Cylinders are here. Pistons are within 4 grams of each other, which isn't too bad. The next to-do list, which will happen after I get my big work presentation done next week:
- equalize piston weights. - sand clyinder sealing surfaces - paint cylinders - clean cylinders and pistons - do deck height re-evaluation - shim cylinders, install pistons and cylinders, install heads - assemble and install engine - replace all soft fuel lines (and possibly remove and seal tank)
and away we go!
Sorry no pictures, but there's nothing new. More in a couple of weeks, I hope!
I'm finally signed off in the Cessna-172. I can now take the wife unit flying and we can go on trips together. Whoo-hoo! This has been a very long time in coming. I have a book on becoming a pilot that my mom gave to me in 1987, so I've been working on this at least that long.
We may be going on a bigger cross-country flight, so today I ordered charts and facility directories
from mypilotstore.com.
A quick story: When we moved to Kentucky from Illinois a few years ago, I spent some time checking the local airports and looking for plane rentals and so on. One of the places I looked was at the Knoxville aiport. I remember going into Tac Air at Tyson/Mghee airport and asking things.
One of the coolest things I remember doing when I was learning to fly we landed at the Knoxville aiport as part of my cross-country training. Having been to the Tac Air building before, from the ground side, it was the coolest thing to come into the same building from the airplane side as a (training) pilot.
It didn't quite match, but it was fun the other day to stop by there again to pick up a chart for a cross country (that didn't work out, alas).
First of all, here's the stylin' entertainment system that I brought along to listen to in the 8 hour drive from Kentucky to Detroit:
I used my laptop as an mp3 player, and hooked the headphones to the rather old and well-used headphone-jack-casette-adapeter. The sound was nice. I listened to Wil Wheaton game with the folks at Penny Arcade, which was pretty cool.
There's a big cluster of hotels just north across the interstate from the main Detroit airport. Although I'm sure the hotels hate it, I thought it was pretty cool that we were right below the approach path to the airport:
Unfortunately, Wil ended up having a massive sinus infection (which would have been dangerous to fly with, frankly) and so didn't come to Penguicon. Wil was the main reason for my going. I decided that I had enough stuff to do at home, and that I'd be crabby the whole weekend, so I drive back to Kentucky starting Friday afternoon.
I would like to give a big shout out to the Fairfield Inn in Romulus, Michigan. It's in the chain of hotels just across from the airport. They had nice rooms, good internet as far as I could tell. When I decided to check out at about 14:15 on Friday afternoon, the manage who checked me out of my room was happy to only charge me one night. If you're staying in the area, I highly suggest this hotel. Oh, and one of the really big airport parking lots is immediately next door to the north.
Despite driving 1000 miles in two days and not ending up going to a conference I've really been looking forward to, the trip wasn't a total loss. I found a NAPA auto parts store fairly close to the hotel, and stopped by and got gear oil:
Materials like this conform to certain specifications for performance, which can include lubrication capability, temperature performance, and so on. There's an on-going debate about the correct gear oil to use in the manual transaxle of a vintage VW. The original VW transmissions called for "GL4" rated gear oil. Just about any gear oil you can buy in a modern store is rated GL5, a late and in some respects better rating. However, the skeptics point out that there are corrosion inhibiting properties that GL4 has that GL5 is not required to have. To add to the confusion, there are oils that are rated both G4 and G5.
I don't know what the answer is. I didn't know about this whole debate before I changed the transmission oil in my Beetle; last summer I think it was. Without knowing about the issue, I bought GL5 oil and put it in the tranny. One thing is, it's definitely louder when driving than before.
So the oil I bought is GL4 rated, and NOT GL5 rated, so it's the closest thing that I can buy to what was specified for the transmission. It'll be interesting to see how it goes when i change what's in there now for the GL4.