Update on my over-rev'ed head...

[fspGTD]

Update: I got the bores deglazed:


There were some vertical scoring marks in the bores that woulnd't come out...  hope these vertical marks are OK.  If you look really close you can make some out in this close-up.  They are hard to see in this pic, but if you shine the light on them just right they really stand out.


Besides those vertical score marks, the honing seemed to have cleaned up all the other blemishes in the walls quite well.  I wonder how the vertical marks got there in the first place, and also if they are going to hurt the ring seal?

My rings are the "pre-gapped" variety.  I measured my ring clearances near the top of the bores just below the ridge, where in theory the bores will be most worn so gaps should be the largest.

Here is how the ring gaps measured out in that location:
* Top compression rings: .022"-.024" (new specs: .012"-.020", wear limit: .039", according to bentley)
* 2nd compression rings: .017"-.021" (new specs: .012"-.020", wear limit: .039")
* Oil scraper rings: .014"-.015" (new specs: .010-.016, wear limit: .039")

So generally measured at that location, the gaps are generally right on the loose border line of the "new" specs.

It would be interesting to see how much tighter the ring gap gets if I set the ring down near the bottom of the cylinders where the bore should be tightest.  Maybe I'll push one down there and see what happens.

[therabbittree]

looks good jake did you cover the crank and take out the oil squirter when you deglazed the block in car?..i've hit em trying that before and had to rebend them back to shape no fun.. the pistons you had beadblasted..you may want to watch that..i remeber in class they always taught us  to beadblast ont the top of the piston..never the sides or the ring land..because the glass bead and get impregnated into the aluminum...then it comes outlater ..kinda like a sand or galss bead injection to your piston skirts ..but a good idea..i remember reaming ie crosshatching skirts to get them to fit tighter but that was temporary..as they raised portion would wear down after a while... Im surprised your machinist beadblasted the pistons for you ..blakes machine shop  where he worked almost sh*t a brick when he mentioned it..and my machinist also said it will end up causing you problems later..
thanks...just a heads up
Deo
\x/ hillfolk!

[QuickTD]

I would worry a bit about glass retained in the skirt as well. A good wash in hot soapy water will help get the grit out. We always washed honed blocks with soap and water and a plastic scrub brush, solvent will not remove the honing grit. After soap and water washing we rub down the bores with a white rag wetted with engine oil, keep rubbing until the rag comes out clean. It's surprising how much crud comes out.

[fspGTD]

Thanks for the info guys... I read a bulletin by hastings (a ring maufacturer) warning about glass beads remaining in the ring lands, recommending to clean them out after bead blasting.  The glass beads if left in the ring lands can abraid the ring land surface and the rings.  The bulletin and other additional information are in these links:
http://www.hastingsmfg.com/Service%20Tips/enginering_bulletin_cleaning_pis.htm
http://www.hastingsmfg.com/Service%20Tips/pressure_cleaning_media_in_engin.htm
http://www.hastingsmfg.com/Service%20Tips/pressure_blast_cleaning_engine_p.htm

I wan planning on wiping/scouring the ring lands with brake cleaner and paper towels and maybe a brush to try and dislogde and flush away any glass beads that may be in there.

Deo - yes I removed my piston cooling oil jets... nearly had to remove the block and drop the crank after discovering a stripped oil jet screw, but I got the stripped bolt extracted successfully without having to drop the crank.  Here is the related thread:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=2307

[v8volvo]

My cylinders had those vertical streaks too after I honed them. I think it's no big deal. I couldn't feel them with a fingernail, so I figure they can't mean much. My car uses literally ZERO oil (like, not a single damn drop even during break-in), and has perfect compression and no smoke, so I have no complaints.

Thanks for the info about my con-rods and stuff. Man, do I ever feel like an idiot for not replacing that circlip. In fact, next time I think I might just replace all of them with new ones for good measure. I bent this replacement clip (which looked more like a cut-up key ring than a machine part like the rest of them) so that it fit in there very snug, but it was loose and rattling before, so maybe the heat got to it and it is back to jumping around in there. I'm not gonna think about it...I cannot afford to rip into that thing again for another few years. I can rarely hear it anyway, so I will just drive it till it blows then drop in a fully rebuilt one (I used sloppy old pistons and reused bearings on this one anyway).

[v8volvo]

Here's what my bores looked like. Similar deal.

[greggearhead]

Heh.  When I was in college I pieced together a 1.8 gasser from free, broken engines while I was working at a VW Porsche shop and going to school.  

THere was one bore where the block I had gotten for free had lost a head gasket where you could feel a 1" wide section where the coolant had washed away the oil and the bore was more worn.  The owner of the shop said not to worry about it for a decent motor.  

The engine turned out great, and I used to beat up on my GTI driving buddies and it didn't noticeably use oil or make smoke.

[v8volvo]

Just out of curiosity, were you at Colorado College? (Noticed Colorado Springs...)

[fspGTD]

Thanks for the info, v8volvo - it's great to know I needn't worry about the vertical streaks!

How did you prep your block deck?  I just scraped the surface of mine with a razor until nothing else would scrape up.  The resulting surface is nice and flat, but not very deeply-scoured like yours appears to be.  Did you sand it, or use some kind of metal scouring pad?

[v8volvo]

I didn't want to fool around with a crappy seal, so I just decided I would get all the right stuff and spend a couple hours cleaning up the head and block gasket surfaces. My arsenal, if I recall, consisted of a flexible razor scraper, a hard blade scraper (which I sharpened to a very fine point on a bench grinder), a roll of emory cloth, a few sheets of ScotchBrite material, and some fine-grit sandpaper.

I got the big stuff with the flexible razor scraper, then went after things with either the scotchbrite or the emory cloth, whichever seemed to work better. Finished with the sandpaper, and used the hard scraper when I needed to really dig tough stuff out. The iron block surface is hard to hurt but you have to be very careful with the aluminum on the head; the razor and the hard scraper will shave that stuff right off and screw everything up. Then I got out a bottle of brake cleaner and bought some lint-free polishing rags, and wiped everything down. (That was, of course, after I had popped the pistons in, since that job gets oil everywhere and that creates a crappy seal. The brake cleaner cuts through the oil and leaves the gasket surface clean and dry).

That was my trick, anyway. I used it both times I've had the head off and no problems. Also did it when I replaced the headgaskets on an old Ford 289 several years ago (when I was 14...jeezus), and I know that thing is still running fine. Hope to check your Rabbit out next time I'm in town!

[Black Smokin' Diesel]

I'm rebuilding an engine right now. I'd like to know how you guys deglazed the cylinders? I know it's a tool that is used on a drill but where you I get that tool? Is it a standard soft wire wheel? Is there a particular technique I need to use?

Thanks for the infos  

[v8volvo]

You need what's called a cylinder hone. I think the kind with the hundreds of gritty beads works better for the DIY mechanic's purposes than the 3-stone type, since the bead kind is more tolerant of angle changes (ie, not being completely straight down in the cylinder, which can easily happen if you are trying to hone it with the block in the car).

The hones cost about $80, so unless you think rebuilding engines will be an ongoing, frequent thing for you, you might be better off to rent (as I did, cost me $7 for a day and that's all I needed). Either way, make sure you get one that is designed to work in a bore the size of a VW diesel's--3.01 inches in diameter, if you didn't know.

Depending on how big the "ridge" is at the top of the cylinders, you will also want to buy/rent a "ridge reamer" that will cut the ridge off. Otherwise, when you put the new pistons and rings in, the rings may hit the ridges at the top of the pistons' travel and break, and then you are in trouble. If the ridge is very small (ie, hard to feel), you probably shouldn't worry. And, of course, if it is very very large, it probably means your cylinders are too worn to be re-ringed and you need get the block taken to a machine shop and bored out to the next size up.

George

[v8volvo]

And yes, there is a specific technique. Get the guys who rent or sell you the hone to walk you through it. Sounds complicated but actually it is hard to screw up too badly.

You need a pretty big, powerful drill, so if yours is just a little quarter-inch affair, you should get a bigger one of those too.

[Black Smokin' Diesel]

Thanks for the infos v8volvo. I think my drill will handle honing. I'll probably rent it, don't plan on rebuilding many engines. I'll be sure to ask them how to properly use it.

Thanks again!

[fspGTD]

Although the "econo" rering project for my GTD autocrosser project has been going a bit slow due to crappy weather and time taken away by the long runner intake manifold fabrication, I made a little progress late last week.  I was glad I took some extra time to scrub my beadblasted pistons with soap and water, because I discovered one of the rods had previously been assembled on the piston backwards!  I put them all back together correctly and with new circlips.

I found little grooves were worn in the pins where they rode on the edges of the rod bushing.  My engine builder said it should be OK though.  The pins slid in smoothly when the rod was held perfectly square, but I could feel the groove "catch" on the edge of the bushing when there was a little bending force on the rod.  I guess I'll just run with it on this block.  But it is definitely going to be nice to put in fresh, new pistons and piston pins when I eventually get to my future "dream" engine build.

I also got the block deck looking better than it used to using a rotary scotchbrite pad with my new die grinder toy.    I used WD-40 to lubricate it and a few times stopped and soaked the surface in it and blotted residue out with a paper towel, which helped keep the pad from from "loading up".  Photos below show the surface before the scotchbrite (but scraped as clean as a razor would allow), versus after scotchbriting.



Equipment used: