People who have lapped their blocks...

[satori]

Here is my block after about an hour.

Here's a closeup.

I figured since the block was machined flat, the machine marks should come up evenly. Obviously, they are not. But if you notice, there does seem to be a pattern to the machine marks still visible. This pattern repeats itself down the entire block. Does this look like a bad resurfacing. Bad lapping on my part? Both? Neither? Is this what it should look like halfway through lapping? Any advice here would be much appreciated.

Please ignore the my half attempt to block the various passages. At some point I figured it would just be easier to get the block cleaned again.

 

[IJ.]

Someones Milling machine needs the ways tightened.

 

[Neal]

sorry to get off topic how did you get those pins off...for lapping
cheers

 

[IJ.]

Neal: I use a pair of side cutters with a scrap of aluminium to protect the block and lever them out.

 

[Neal]

tried that but decided not to since i was sort of cutting in to it....but it wasnt in vain ill get them buggers out 2moro for sure. thanks Ian

 

[IJ.]

Neal: It will trash them but they're cheap from Toyota.

 

[supramaze]

this looks very rough and not good in my opinion

when I lapped my block it was so smooth as a glass surface, with perfect finish on it. took 8 hours to get it perfect. using a HKS 1.2 bead on that

 

[IJ.]

^ 8 hours!! :aigo:

This is mine after 20 minutes I did 2 in an hour heads included.

 

[jdub]

Diamond paste FTW!

 

[satori]

It's hard to tell but what's done on my block looks like IJ's. It's just that it isn't coming up evenly. Should I keep lapping or just go get this thing resurfaced and possibly start over with the lapping? As for the pins, one I carefully pulled out with a pair of vise grips. The other wouldn't come out so I gently knocked it down through the block and caught it with a magnet.

 

[Typhoon]

I'd get it resurfaced. You don't want to be reprofiling metal with lapping, just removing machine marks.
Those low spots you have remaining are just a litlle to unnerving for me, it would always be in teh back of my mind.
Oh, and use another machine shop. And tell them light skim and do it slowly!

Regards, Andrew.

 

[3p141592654]

I would start with a straight edge and measure the flatness. With a fresh cut it should be better than 15 microns (Toyota's spec is 50 microns).

How are you doing the lapping? What paste are you using? Personally, I would keep lapping for now. There isn't a whole lot of meat on the block to allow two cuts.

 

[satori]

I have the plate from McMaster, the one I think you, 3p141592654, recommended in another post. I using grade 6 diamond paste and just moving the plate in a figure 8 motion, trying not to apply pressure, just moving it around. I started with the smooth side because I just wanted to clean up the machine marks, which, despite the picture, really aren't that bad. Once I realized the pattern that was beginning to show, I moved to the grooved side for a bit and then figured I should get some opinions before I continued.

The shop took about .007" off the block and about .005" off the head so I have a bit of room to work with and still maintain a stock CR if I use a 2mm gasket. I'm kind of afraid the surface of the head is going to be the same, though, so if I can clean this up with lapping, I would prefer it.

I'm going to use a different shop. The strange thing is, this shop came recommended from another member that used them for machine work while building up a 400+hp 7m. I guess they just don't like me.

 

[3p141592654]

Keep going! You can get the bow out, if its less than 15 microns, but its not going to be an hour's job. You need to confirm flatness with a straight edge after you're done.

 

[Nick M]

Keep going! You can get the bow out, if its less than 15 microns, but its not going to be an hour's job. You need to confirm flatness with a straight edge after you're done.

This needs to be repeated a third time. MHG aside, the block must be flat, or any headgasket will have trouble sealing, and likely leak.

 

[suprarich]

There is a special tool to pull the pins that makes it a snap.