PDA

View Full Version : evidence of a nice tram



A.K. Boomer
03-21-2017, 12:37 PM
You should see this pattern every time you mill a cylinder head - if you don't then don't bolt it together,

This is not evidence of a "perfect tram" because fore and aft tilt of the head could still be way off, although that you will notice in your first "skin cut" and it's also no where near as critical and really means nothing for sealing capabilities,,,

However the crosshatch pattern does, the side to side crosshatch is evidence of a very good tram and you should see this pattern every time, very critical esp. with todays very unforgiving three piece steel head gaskets,

if you do not see crosshatch it means only one thing - that you have dished the center of the head length wise, so the extra critical bridge area of the head gasket that does double duty for sealing off combustion gasses/pressure is far more apt to fail.

I know for many all the above is quite obvious but thought id post for the ones who have not been around engines much and such...

Too achieve good results always tram your Mill with a wider swath then the actual part you want good results with...

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC04273_zpsj991jpx4.jpg (http://s146.photobucket.com/user/AK_Boomer/media/DSC04273_zpsj991jpx4.jpg.html)

The Artful Bodger
03-21-2017, 02:58 PM
I thought you meant one of these...

http://www.myweb.net.au/mottram/trams/nzpres/nzpres7%20no%202.jpg

Doozer
03-21-2017, 03:08 PM
Could be just built-up-edge.
Not impressed.

-D

A.K. Boomer
03-21-2017, 04:11 PM
its an insert cutter with a nice radius, no built up edge on anything

and yeah iv seem prettier done by auto-feeds but the principal stands, this is one smooth flat head and there will be no wimpers on it's end of the bargain...

now the block on the other hand is another story --- another one of those yee-ha hacks went wild with a power disc on an aluminum block --- all to remove that thin membrane material that comes right off with a scraper,,, definitely not impressed...

two hours of precision hand stoning and with the perfect head mill :p I believe im within allowable tolerance...

AB is that one a wood burner?

BCRider
03-21-2017, 04:20 PM
I totally agree with what you posted AK. But the picture is too fuzzy to see the pattern properly.

To me it's just fuzzy enough that I'm only seeing the arcs running in one direction without any reversed hatching. But it's pretty fuzzy as I said. Or I wonder if it was posted as an example of what NOT to see?

J Tiers
03-21-2017, 04:33 PM
I totally agree with what you posted AK. But the picture is too fuzzy to see the pattern properly.

To me it's just fuzzy enough that I'm only seeing the arcs running in one direction without any reversed hatching. But it's pretty fuzzy as I said. Or I wonder if it was posted as an example of what NOT to see?

Yep, looks way off tram and dished in the pic.

Paul Alciatore
03-21-2017, 05:43 PM
That's funny because, although it is somewhat fuzzy, I do see the cross hatch. It looks like a good tram to me. At lease in the X axis. Can't say anything about the Y without more testing.




I totally agree with what you posted AK. But the picture is too fuzzy to see the pattern properly.

To me it's just fuzzy enough that I'm only seeing the arcs running in one direction without any reversed hatching. But it's pretty fuzzy as I said. Or I wonder if it was posted as an example of what NOT to see?

A.K. Boomer
03-21-2017, 05:59 PM
It is a fuzzy pic but if you look between the two coolant ports at the bottom of the pic you can see the hatch pretty good,

I think it took the camera being directly above the head to see it best as it does not have much effect off to the sides.

boslab
03-21-2017, 07:52 PM
I watched a vidio yesterday from the Russian guy that goes as factory dragon, he was grinding the dace of the block on a big old stankoimport surface grinder (nice machine from memory), I was told this wasn't a good idea because of sealing, it's too smooth, even though the job looks really nice, not being a car guy apart from the basics does this hold up in practice?
It has to be said that stanko machines are built like bloody tanks, stick a gun and tracks on one and you can invade harbour freight single handed
Mark

John Stevenson
03-21-2017, 07:55 PM
That's nothing. You only need a 50c off coupon to invade Harbor Freight.

BCRider
03-21-2017, 07:57 PM
Oddly enough if I squint a bit to fuzz it out even more and to make the bright areas darken a little the fairly broad cross pattern does come through. More between the lower coolant ports as you say.

It's the sort of thing where if we saw it in person it would be obvious. But with the lighting in the picture it doesn't really leap out at one.

wierdscience
03-21-2017, 08:55 PM
Looks good to me-RUN IT!

Arcane
03-21-2017, 09:45 PM
I watched a vidio yesterday from the Russian guy that goes as factory dragon, he was grinding the dace of the block on a big old stankoimport surface grinder (nice machine from memory), I was told this wasn't a good idea because of sealing, it's too smooth, even though the job looks really nice, not being a car guy apart from the basics does this hold up in practice?
It has to be said that stanko machines are built like bloody tanks, stick a gun and tracks on one and you can invade harbour freight single handed
Mark


http://www.felpro-only.com/blog/gasket-sealing-surface-finish/

J Tiers
03-21-2017, 10:40 PM
I saw those, but they looked straight, where the others looked curved as you would expect.... maybe an illusion on my part, I see one just inboard of the RH triangular port that is curved as I expected. OK.

boslab
03-22-2017, 03:38 AM
Arcane, thank you, not only do I now know the surface texture to aim for but also the block flatness, a very useful thing, more so once I get a new straight edge, or surface plate and make one.
Seems grinding a head is quite ok, possibly better than fly cutting, I've seen quite few blocks whose surface after machining exceeds r50/60, no suprise of the gasket failing , usual thing, damn these cheap Chinese gaskets, last time I heard that was on an Audi I had done, the part was OEM from Germany, but it explains a lot.
I still have my old Taylor Hobson tallyvel roughness comparator from work, needs new battery pack though, we used to check the surface of steel coils, having one you could put in your pocket was easier than cutting a sample and carting it back to the lab every time there was a problem, though one was later on when doing the tensile strength tests etc.
Mark

vpt
03-22-2017, 08:27 AM
Is that a D-series head? Is this the one you just did some work to last winter or fall?

A.K. Boomer
03-22-2017, 10:18 AM
no it's a 2 liter CRV

I do allot of honda's but way more subaru's when it comes to head gaskets due to them always popping a cork on the 2.5 liters,

one thing I can say about the 3 piece steel is the heads don't go as warp crazy when someone has a serious overheat,

and also when the gaskets do fail they tend to give allot more early warning signs, sometimes even allowing someone to finish their vacation trip if they know what to watch for or nurse it around town for awhile till they get some funds together, not so with the old style, was like a damn letting go in short order...

tomato coupe
03-22-2017, 11:10 AM
How flat do the mating surfaces have to be? .0001? .001? .005?

johnd
03-22-2017, 11:25 AM
I won't disagree with the basic idea of what you are saying. However, if you have a head resurfaced at your local automotive machine shop you will most likely NOT see a crosshatch pattern. Ignore for now those platen / belt sander type machines. Millions of heads have been resurfaced on the 570 Van Norman Rotary Broach or many brands of surface grinders. Common wheel diameters 15" to 18". These machines are all set up with just enough tilt so that the cutters or grinding wheel DO NOT drag on the back side so that they DO NOT leave crosshatch. The reason being that the machines would have to be much longer and heavier to allow full coverage of wheel to sweep entire length of head / block. Think of a 6-71 Detroit head or maybe an old straight 8 engine. In the case of surface grinders-- you may sometimes see traces of crosshatch showing up when the front of wheel comes off the head under heavy grinding. This means you are forcing the process and the grinding head is riding up and dropping back down when the front cutting edge travels off the cylinder head. If this is allowed the head will not be flat! Many of the grinding machines rely only on the weight of grinding head and gravity to keep it running true on the ways.
I'm not going to do the geometry and math to say just how many "tenths" dish shape these machines leave across the width of head but it's of no consequence.

A.K. Boomer
03-22-2017, 11:29 AM
This is for full length - it's .002" sounds like ample le-way till you consider if it's width its much less and also the compound errors of the block come into play, that's my main concern as like stated some hack took an abrasive wheel to it, some of these errors can be within less then an inch so even more critical than width...


" If warpage is less than 0.05 mm (0.002 in) cylinder head resurfacing is not required.
If warpage is between 0.05 mm (0.002 in) and 0.2 mm (0.008 in), resurface cylinder head.
Maximum resurface limit is 0.2 mm (0.008 in) based on a height of 132.0 mm (5.20 in). "



If you see any "mechanic" using an abrasive wheel on an engine block and esp. an aluminum engine block do me a favor and biatch slap him right on the spot...
so much quicker to remove the easily removable thin membrane material with a good well tuned scraper and you don't ruin somebodies entire engine... arms still sore from stoning that block in...

A.K. Boomer
03-22-2017, 11:56 AM
This is why im so P.Offed

I see this all the time, this is after stoning my arss off - you can see dug in evidence on the engine block at the lower bridge section,,, there are tons of "mechanics" still using this "practice"

they should all be rounded up and quarantined from society in a special little place --- kept far far away from anything mechanical - no real chance for re-hab but maybe start introducing them to simple things like wheel barrows and such so that they may become more self sufficient, I don't think they should technically even be allowed to use a typical shopping cart as the rear swiveling wheels are far too complicated for them to comprehend the effects of steering, better to have one foreword wheel as it's of far more simpler design...

Iv matched up the gaskets critical sealing area's to the lower bridge and have total contact in the crucial area's

please don't tell me I should "do it right" and pull the engine and tear it all down and put it on the mill because it would then be worth more than the vehicle is...

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC04271_zpskdvzm7aw.jpg (http://s146.photobucket.com/user/AK_Boomer/media/DSC04271_zpskdvzm7aw.jpg.html)

vpt
03-22-2017, 07:26 PM
Wipe on a very thin coat of hondabond around the water and oil ports, both sides of the gasket. Copper spray around the cylinders again both sides of the gasket. She'll seal up good.

A.K. Boomer
03-24-2017, 10:16 AM
I know you've probably had good luck with that Andy but I try to get within specs and then leave the rest up to Fel-Pro,
I remember warnings at least by them not to jack with using additional sealants on their membrane material, they do claim even with their three piece steel gaskets that they are designed to cover your butt should there be "imperfections" in the mating surfaces, have had good luck with them for many a decade, additional sealants may or may not help with holding back the fluids like oil and coolant - but when it comes to combustion pressures the rest is up to the gasket itself,

some pics of my precision valve spring compressor :p

Mills are so dang versatile, usually just do the little 1600 cc heads pushing by hand with a T-handle but these two liters have a little more spring.

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC04286_zpsbsghfy13.jpg (http://s146.photobucket.com/user/AK_Boomer/media/DSC04286_zpsbsghfy13.jpg.html)

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC04284_zpsm6hw7ipp.jpg (http://s146.photobucket.com/user/AK_Boomer/media/DSC04284_zpsm6hw7ipp.jpg.html)

this is not my best mounting effort but it sure was fast, going to end up with a huge dummy mark on my table one of these days...

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC04285_zpsztv8y0wl.jpg (http://s146.photobucket.com/user/AK_Boomer/media/DSC04285_zpsztv8y0wl.jpg.html)

Paul Alciatore
03-24-2017, 02:11 PM
OT: I would suggest that if you can not see the cross hatch pattern in the photo in the first post, then your computer's monitor may need some adjustment.




You should see this pattern every time you mill a cylinder head - if you don't then don't bolt it together,

This is not evidence of a "perfect tram" because fore and aft tilt of the head could still be way off, although that you will notice in your first "skin cut" and it's also no where near as critical and really means nothing for sealing capabilities,,,

However the crosshatch pattern does, the side to side crosshatch is evidence of a very good tram and you should see this pattern every time, very critical esp. with todays very unforgiving three piece steel head gaskets,

if you do not see crosshatch it means only one thing - that you have dished the center of the head length wise, so the extra critical bridge area of the head gasket that does double duty for sealing off combustion gasses/pressure is far more apt to fail.

I know for many all the above is quite obvious but thought id post for the ones who have not been around engines much and such...

Too achieve good results always tram your Mill with a wider swath then the actual part you want good results with...

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC04273_zpsj991jpx4.jpg (http://s146.photobucket.com/user/AK_Boomer/media/DSC04273_zpsj991jpx4.jpg.html)

wombat2go
03-24-2017, 07:23 PM
Memories, Sometimes that was my job after school in early 1960's.
The heads of the Diesel tractors and cars went away for a head job, and the block stayed in situ
with its studs sticking up.
The job was to clean up the block surface, and also the piston tops,
with an old file hand ground with a curved end.
Removing metal was strictly prohibited. The clean up was done with a compressed air spray gun
with a mix of kerosene and gasoline.
I recall sitting for too long up on top of a stinking old tractor outside of the shop,
on a hot afternoon in the sun, thirsty, with a sore back and too hot.
Imagine today's kids doing that?

A.K. Boomer
03-25-2017, 09:52 AM
On diesels to boot - I bet ole Ma told you more than once "I thought I told you to go wash your hands before coming to the dinner table" lol
that was way before the days when nitrile or latex mechanics gloves were worn,

Be proud of yourself - at least you didn't go around scrapping peoples engine blocks to clean them up...

vpt
03-25-2017, 09:05 PM
There are times I will still scrape an aluminum block but I do it very methodically as to not dig in, scratch, or gouge the metal.

For omc outboards they use a spray on acid to eat the gasket off the aluminum parts.

I know the copper spray doesn't do anything for the combustion chamber sealing. I use it for pretty much all "hard" gaskets I install to help seal up the fluids. I have had very good success with it and will always use it when I can. Yes the stock type (bare) gasket does seal fine, but getting seepage because of some very slight imperfection (tooling mark, fine scratch, etc.) drives me crazy, I like to see pepper dry engines/gaskets.

A.K. Boomer
03-26-2017, 09:39 AM
There are times I will still scrape an aluminum block but I do it very methodically as to not dig in, scratch, or gouge the metal.



Absolutely - I never have a problem with "dig ins" even though my scraper is razor sharp - just using the proper angle and only applying so much pressure,

the thin membrane material on these newer gaskets comes off so easy,
there's no need for abrasive discs or other methods, scrape once, use some hand held scotch bright everywhere and I try to use a strategic pattern when using it that "dams" the fluids,
then it's brake clean the surface about three times applying it to a terry cloth rag first two times then a regular rag last time,
even fibers from the terry cloth rag for the last run might cause seepage if trapped.

anyways - beast it running and is out the door - onto the next bucket of fun...

oxford
03-26-2017, 07:13 PM
Ak, I have one of these I use for valve springs, makes fast work of removal and installing.

http://www.mactools.co.uk/rate-mac-tools-products/content/images/thumbs/0001641_valve-keeper-remover-and-installer_300.jpeg

vpt
03-26-2017, 08:21 PM
Absolutely - I never have a problem with "dig ins" even though my scraper is razor sharp - just using the proper angle and only applying so much pressure,

the thin membrane material on these newer gaskets comes off so easy,
there's no need for abrasive discs or other methods, scrape once, use some hand held scotch bright everywhere and I try to use a strategic pattern when using it that "dams" the fluids,
then it's brake clean the surface about three times applying it to a terry cloth rag first two times then a regular rag last time,
even fibers from the terry cloth rag for the last run might cause seepage if trapped.

anyways - beast it running and is out the door - onto the next bucket of fun...



I like to do a wipe with a very clean hand after all the rags and towels. Every towel I have ever tried always leaves some sort of fiber or pieces behind. Brand new towel, shake it out, blow it out with the hose, shake again, wipe, stuff left behind. lol

A.K. Boomer
03-27-2017, 10:20 AM
Ak, I have one of these I use for valve springs, makes fast work of removal and installing.

http://www.mactools.co.uk/rate-mac-tools-products/content/images/thumbs/0001641_valve-keeper-remover-and-installer_300.jpeg

Oxford thanks for that - never seen this kind and had to find some u-tube vids to see how they work and how well they work,

https://youtu.be/b1DmJQ4Fods

I like this second one because it explains more how it functions and shows the parts better, plus it's nice to see them using it without the sledge hammer and the gal is pretty and entertaining lol

https://youtu.be/VIwmf0nhljU