Hey Rexcat, thanks for the ideas! Sorry for the delay in replying, my fingers were bleeding for a while... Okay, so I have two surface plates: 1. Starrett Tool Room surface plate - Grade B - accurate to .0002" / .005mm 2. Woodcraft / Wood River (for sharpening planes, chisels, etc) - Grade A - accurate to .000025" / aka ~ 1/2 micron The Grade A plate is brand new. I had originally purchased it to scrape in the bed of my milling machine, but never used it. The Starrett was owned by an electrical engineer friend and has always been cared for and taken super good care of. Both are always cleaned prior to use, yes. I try to use them around 68 degrees if possible. In a perfect world, I'd pull the block out and sweep it with a tram gauge or a dial test indicator or something and get everything zeroed in, etc. However, since I'm just doing this with the block in the truck, I have to get a little more "ghetto fabulous" about it. Also, we are moving and selling the house soon, so my workshop goes with it. So I'm just rushing here to try and get the pickup truck as reliable as I can, short of doing some long drawn out pull-the-motor rebuild. I'm actually a lot further in now than I had anticipated, but there's no turning back at this stage haha. I spent all of last night learning about hand scraping - largely by just diving in and trial/error. I'm starting to get the hang of it. After about 6 or 7 passes, I realized I was doing something wrong, however. I was rocking the cylinder head on the block (only about .001", but still) and that was giving me a false touch point, which I was then scraping. I've since corrected that mistake and now my fitment pattern with the Prussian blue is looking better each time. Given that I don't have a mill right now, I am going to have to get a bit more creative. I think what I am going to do is use my little vintage height gauge and place it on top of each piston (with the motor at TDC - such that piston #1 and #4 are at TDC). This will allow me to sweep the 4 corners of the block using my height gauge (sitting on top of the pistons front and rear) and perhaps I can ascertain if one or more of the corners are low, relative to the piston tops and/or each other. Assuming the crank, rods and pistons are all in good condition, then I think that should give me a reference point (e.g. the center line of the crankshaft basically) from which to work my way outwards. Once I figure out where I am in space, then I can make adjustments to how I'm scraping the deck surface and pull everything back to being not only flat, but also level (or horizontally plumb I guess you could say). So yeah, the fun continues over here Here is what I can say, when I bolt the head down, it's going to be touching as much of that head gasket as humanly possible. Ray
Piston method was a failure. The surface of the block is flat to within about .002 (which is within Toyota factory specs), but I'm going to try to get things near perfect. I'll try setting up something later which I can use to measure multiple points, but working from the tops of the pistons doesn't seem to cut it. My guess is the pistons aren't perfectly level relative to the deck block and there is also some compliance due to the rings. Ray
So in thinking about how to check the deck for straightness, I decided that I'm going to do is setup a machinist rule or 123 block across the center of the block (horizontal) and then put a height gauge on top of that. Then that little cross section will be my flat starting point and I will measure height out to the four corners and along different areas. That should provide some insight into high or low spots. With a long machinists rule across the deck (from cylinder 1 to 4) it seems to be quite flat. So I think using the cross section in the middle as my reference plane and then checking height out to the edges is going to be about as good as it gets, short of pulling the block out and setting it up on a milling machine bed or something - or like a large surface plate with a fixture. I'll report back if that works... Ray
Ray. Quit making this hard or complex. You are being led down a stupid road. Use a straight edge. Put it length wise. Check for gaps more than .1.5 - 2 thousadths. Put it crosswise at 5 places down the block and measure it the same way. Do the same to the head. If they both pass move on. To be honest here without subjecting the gasket itself to scrutiny to determine : A. If it blew B Where it blew C. How it blew this is just a big jerk off.
I've used exactly the method you describe above and checked at multiple points using my feeler gauges between .001, .0015 and .002 and it's pretty good. The Toyota factory specs are .002 limit on deck warp and that's about where I'm at currently. The issue I am working on now is going one step beyond that, as it relates to surface scraping. Using Prussian blue and fitting the head to the block, I want to improve the sealing clamping load across the center webs. Right now the marking with the blue shows up at the corners, with only light touching on the center webs. So that's bugging me. I want the majority of the clamping force going to the center (between the cylinders), not at the four outer edges. That's why I was going to use a surface plate height gauge to measure the four corners next. When I put the head on the block, there is maybe about .001 or .002 "wobble" where the front right corner of the cylinder head sits (I can get a .002 feeler gauge between the head and block in that corner). I realize that's within Toyota factory limits (see attached) and I'm sure it wouldn't pose any major issues once the head is torqued down. However, I still want to get it as close to zero as humanly possible. That's just the machinist in me, for better or for worse. If I put the head on the block and tap the head bolt bosses with a rubber mallet, I want to hear a solid tap rebounding back on every hole. As it is now, the forward 2 holes on the right side of the cylinder head sound a touch hollow, so that - combined with how the Prussian blue marks are not making solid contact on the webs between the cylinders - is what's bugging me. I'm on a quest to have an better contact patch, come hell or high water - or Rifledriver Ray Image Unavailable, Please Login
Machinists Rock Ray! You da Man brah!!! Machinists care about the little things like 100ths, 1000ths, 10,000ths, 100,000ths and yes even 1,000,000ths of an inch! We are dedicated to precision metrology... It is hardwired into our DNA and we eat, sleep and drink it everyday! You rock Ray! Good luck and best wishes to you! Cheers!
Thanks Here are a few pictures from just now. Using the .0001 dial test indicator was a bit unruly. But using the surface plate needle one was helpful. Everything seems to be pretty flat when tested off the center section of the block. So that is heading in the right direction. I found a few mildly high patches that need knocking down and also a couple of uneven areas (only maybe .0005"). The little setup with the large machinists rules (which are accurate/flat to about .0002") worked pretty well - all things considered. Brian's recommendation to measure the block front to back and in 4 or 5 sections across actually worked really well. Using that approach, a machinists rule and feeler gauges, I am some place around .0015" from what I can see. In some "problem areas" I can run a .001" and .0015" feeler under the rule, but not a .002". I also double checked the feeler gauges using my Mitutoyo digital calipers and they are on the mark at .04mm for .001" I'm going to attach my .001 dial test indicator and recheck the block later. I think the Prussian blue is really what is going to tell the real story. A little more scraping and I think the little rocking I'm feeling in the head to the block at the front right should go away. When the sections between the cylinders mark in blue, that's when I will call it good. Ray Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
That's for sure. The head is already surfaced (it's brand new). I was just going to swap cylinder heads, but then realized the previous failure was from a head gasket. So then started checking. I'm trying to avoid pulling the short block apart, since the bores look pretty decent. Ray
MLS require particular surface finishing. Or they will leak. I have copper head gaskets in an Australian GMH V8. Highly modified. Surfaced decks on block and heads, O ringed. I use a product called 3 Bond as a sealer. Never had an issue. Remember the 3 P's Piss Poor Prep= Piss Poor Performance. Nothing more to add.
I would need to verify the box No but yes I'm pretty sure it is 1184. I will add Using MLS gaskets requires pretty precise machining. I personally have never had an issue with copper head gaskets using 3 bond. O Ring pertrusion is important also. I'm sure there will be people that disagree but I comment on my own experience.
I've also read good things about Aviation cement. So are you using 3 Bond all across the entire surface of the copper head gasket on both sides? Or only in smaller areas around the coolant and oil passages? Ray
Yeah, that should do it So with the compression chambers, you are O-ringing both the head and the block or just the block? I was reading about using O-rings and how the size presses out the copper into the grove and that allows the head to move, but provides a nice sealing groove I guess. Do you put any of the 3 Bond in the O-ring area as well, in order to help seal in there as well or do you let the wire and groove handle all that? Also, what boost pressures are you running? Ray
BTW, for anyone coming along later (who might be interested in hand scraping) here are two excellent videos from a guy I follow on YouTube and Instagram who does machining: Ray
Just block O rings. My engine is 11.3 comp N/A no boost. I have built quite a few with boost. No problems at 15psi. Timing and tune have a lot to do with regarding boost pressure. No seal under the O ring. Just tapped into groove with a nylon hammer.
See the posts by RW Tech in this thread. This may help your situation. https://www.speed-talk.com/forum/viewtopic.php?f=1&t=15654
So I've been working on the Toyota block in my free time over here. I've also been reading a lot about how hand scraping was done back in the 1940's for machine surfaces and whatnot. It's a super fascinating subject, which seems to largely be a lost art these days. I'm going to make myself a carbide hand scraper soon, but for now I'm just using what I have on hand. I made a video the other night, which shows how flat I've gotten the deck. From what I can measure, it's sub .001" and probably sub .0001" (or very close to it) and I would say based on how it's marking using the Prussian blue and my surface plate, it's got to be about 85% to being perfectly flat to darn near .000025" (the surface plate specification). Here's a picture showing the current point I'm at. I'm going to scrape it a few more times, then turn my attention to the cylinder head. I had to knock off the other night just because my back was starting to hurt: Image Unavailable, Please Login Laugh all you want, but when the block marks off totally blue against a surface plate that's flat to 25 one millionths of an inch, there's not a lot of arguing that the deck is flat - and frankly, I'm having a hard time thinking of something more important than having the head gasket on my motor sealing perfectly against two flat surfaces. Here's a brief video clip showing how things are coming along: I'm tempted to use a copper head gasket with some of that 3 Bond stuff. However, for now, I think I'm going to stick with the Fel-Pro PermaTorque and call it good. Anyway, sealing between the cylinder bores will clearly be improved; prior to scraping the block, the surface plate wasn't touching at all in the areas between the cylinder bores, which was personally keeping me up at night. I have a few more passes to do, then going to check the head against the block and start bolting the motor back up. Ray
Oh and here's a before pic - from when I first started and marked the deck initially using the surface plate. So you can see how far things have progressed: Image Unavailable, Please Login and after: Image Unavailable, Please Login
Okay... I'm stopping here. I think having some mildly low spots around the outside edges might help improve clamping loads near the center. From what I can tell, the block surface has to be over 90% flat to within around .00005" so something. Next up is the cylinder head. It's brand new and has been fly cut, but it's only flat to about .001" from what I can tell. I'm going to knock it down a tiny bit and then see how the head marks off against the block and then start reassembly on the motor. Very tempted to use a copper gasket from SCE, but given this is a stock motor, I don't think it's needed. This has definitely been a learning experience. Thanks to everyone who provided their insights. Ray Image Unavailable, Please Login
