How can you actually measure a blocks flatness when..

Datsrboi

Datsrboi

Loud pipes Save Lives
Jul 31, 2007
797
0
0
Haltom Texas
www.cardomain.com
I have been running around all day looking for a straight FLAT bar or anything to check my block to see if its straight, flat and warp free with the feeler gauge but I am being told at ever store I go to there is no such thing as 100% flat tools you can just buy if its over 2 feet long. Yet every shop the bars they use to measure the block are over 2 feet long. Even my dad who works at a restrictive company says they use machines to accurately measure their products rather a bar and feeler tools (And I trust him because I was an intern engineer there over the summer and their machines spins at 15,oooRPM with pipes pushing 40-90,000 psi equivalent so no room for error).............. Sooo.... what to do? I know on a machine you can get accurate reading but I am not in the mood to pulling a whole short block out to find out I did not really have to resurface.
 
Datsrboi

Datsrboi

Loud pipes Save Lives
Jul 31, 2007
797
0
0
Haltom Texas
www.cardomain.com
jetjock said:
While a CMM is nice to have most people don't own one. That said precision straight edges in the length you need are readily available from any machine tool supplier. They aren't cheap though.
Click to expand...


Yeah and I will only need it for just this one check up...
 
Clip

Clip

The Magnificent Seven
Oct 16, 2005
2,738
9
38
35
Virginia
would a brand new level from lowes not be accurate enough? i know that empire was advertising one that shoulda been accurate to .0005" inch level.
 
jetjock

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
Lets not get confused here. Prepping isn't the same as measuring. My two cents is it's not the block he needs to worry about unless it's getting a MHG. It's the aluminum stuff that needs checking and it can be taken to any shop for that. If the OP is not going to use a MG he can pretty much forget about the block other than clean up. If he is going with a MG the block should come out anyway.
 
Datsrboi

Datsrboi

Loud pipes Save Lives
Jul 31, 2007
797
0
0
Haltom Texas
www.cardomain.com
Yeah people will complain about what I am about to say but eh I am ready...

I would pull the block out but first of all this car was just a project at first but since I am giving my dad my daily car this car will need to run soon. Because of that funds are a bit short to where I can't afford a motor lift at this point and to rebuilt (I am told if your going to resurface the block most likely you want to rebuilt the entire thing).....

with that said yes I do want to run a MHG but with my timing cut short do not know. My head is resurfaced and all though. I had a ruler on the block a few days back and ran a feeler gauge on it at .003 and it did fine, did not get to try the .002 like the tsrm said but it did good at .003 at least.
 
p5150

p5150

ASE and FAA A&P Certified
Mar 31, 2005
1,176
0
36
Central Idaho
If you dont have a machinist straight edge you can probably get by with a nice clean metal straight edge of a common tool. No, its not ideal, but it will let you know if you have bigger problems...

The block must be clean before you start. I prefer to use the generic "lubricant" from wal-mart because it breaks up gunk and carbon pretty well. The "surface prep" discs from harbor freight work well to clean off the old gasket and junk. Be sure to get the highest grit they offer because it doesnt bite into the iron. A drill at low rpms and very light pressure will clean it up very fast.

Dont use this on your head.

Just be sure that the straightedge is of reasonable length and measure it in a few different directions. If you get some measurements that indicate warpage, filp it over, move it around and even try a different edge to see if your discrepancy is consistent with the block or the edge.
 
MmmBoost

MmmBoost

DDS Performance
Nov 4, 2006
182
0
0
Las Vegas, NV
www.ddsperformance.com
i measured mine with a level. keep in mind that the max warpage number of .003" is only good if the straightedge is touching the block corner to corner, front to back. the main places you will be concerned with is in between cylinders, and towards the front of the block at the oil pressure hole, and also at the place where the front cover meets the block.

fwiw, mine was cleaned very well, more than twice now with no resurfacing and mhg was no problem with a properly surfaced head.

p5150: 90 degree die grinder w/ green roloc disc ftmfw :)
 
J

JAB89

Supramania Contributor
Mar 2, 2006
68
0
6
Atlanta, GA
Datsrboi said:
Yeah people will complain about what I am about to say but eh I am ready...

I would pull the block out but first of all this car was just a project at first but since I am giving my dad my daily car this car will need to run soon. Because of that funds are a bit short to where I can't afford a motor lift at this point and to rebuilt (I am told if your going to resurface the block most likely you want to rebuilt the entire thing).....

with that said yes I do want to run a MHG but with my timing cut short do not know. My head is resurfaced and all though. I had a ruler on the block a few days back and ran a feeler gauge on it at .003 and it did fine, did not get to try the .002 like the tsrm said but it did good at .003 at least.
Click to expand...
First, given your time and money constraints I would go with the stock HG for the time being.

Now, This is an idea that will probably get me flamed but here goes:

You have cleaned and checked the surface as best you can, right? Now, You might try using your freshly resurfaced head as a straight edge. That's right, set it in place without the gasket (use a friend and be very careful). First, see if the head rocks at all. Second, use a feeler gauge along each side to check as best you can. Third, hold a light along each side and see if it shines through to a piece of paper on the other side and how much. Maybe use a mirror to look on the opposite side. This is very subjective and not precise I know, but it might give you a better feel for what shape the deck is in and it is free. Also, as JJ mentioned, you are probbably OK for an OEM HG anyway.
 
Datsrboi

Datsrboi

Loud pipes Save Lives
Jul 31, 2007
797
0
0
Haltom Texas
www.cardomain.com
^^^ yeah 74 bucks really is not what my credit card can handle right now. Thats almost the same price as renting or buying a engine hoist :(

Guess I have to end up running a none mhg then :(
 
cuel

cuel

Supramania Contributor
Jan 8, 2007
1,536
0
0
Baytown, Texas
A level from the hardware store can have a .045" bow over 4 ft., and still be level. It sure would throw off trying to measure the block, though.
 
suprabad

suprabad

Coitus Non Circum
Jul 12, 2005
1,796
0
0
Down Like A Clown Charley Brown
p5150 said:
level and straight are two different things - what are we talking about here?
Click to expand...

For what he's trying to find out we're talking about straight.

FWIW, a machinists straight-edge is worth it's weight in gold and I'm always surprised how handy the thing is, and how often I use it (avoid dropping).

If you can find anyway to measure or get the top of the block measured to find out if it's flat enough for MHG, it's totally worth it. But flatness is not the major thing you're fighting when installing a MHG.

I have come to find through trial and error, (and I know some of you are going to gasp and reach for the flamethrowers), that the ra (smootheness) is a more critical factor than warpage in terms of getting the MHG to adequately seal.

Simply stated, a little warpage can be dealt with (arp studs and lots of ft lbs of torque), but if the mating areas on the block or the cyl head are not mirror smooth, it's going to leak compression.

The first one I did for my bud's supra wouldn't seal even though it was just machined and as flat as a good machinist could get it. We disassembled it, polished it ourselves and got a good seal. Still running strong almost 3 years later. However, that's the tough way to do it. If you can afford to send it in and get it polished to the correct RA, do it. I've done a few MHG conversions now and this seems to be the rule.

I'd rather work with a little warpage anytime, then try to get a rough surface to seal (impossible from my experiences) with a MHG.

Hope that helps.:icon_bigg
 
You must log in or register to reply here.
Top Bottom