Machinist straight edge or Steel ruler ?

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Originally Posted By: Darwin1138
You can use a piece of float glass, you just need to put oil or some liquid between the head and the glass. If the surface is truly flat the film of oil would be equal in all the surface, bubbles tend to appear were there is an imperfection or when the surface is warped.

The glass needs to be fairly thick to prevent warping, about half an inch or more.

maybe that is how my Dad used to use glass to check cylinder heads for warpage, back in the day.

thanks for sharing. I appreciate it
 
Originally Posted By: andyd
I use a 3' level. If I can see day light underneath. I know there are issues. A feeler gauge could be used,I guess,to measure gap. The most recent head job was to replace 2 exhaust valves. Even though it is in side wise and runs backwards, the dual cam,16 valve Honda is a preety thing under the grimy cam cover. It may have been over kill, but I backed the head bolts out in three stages, just the opposite of the torque down. Anyway,put my 3' level on it and saw no light under it. The CRV has soldiered on 75 k miles so far.

cool...I have heard of some folks using a 3' level, and glad it worked out for you.

thanks for your input
 
Originally Posted By: Shannow
One of the cleverest I've seen is pressure sensitive paper.

The logic being that initial set-up, two flat surfaces are perfect fit, after service, if they are bowed, but matched, they are still OK.

To that end, some Prussian Blue can be used to check fit.

(Turbines, I've had casings that you can fit a 1/4" drill bit between pull down flat with enough boltage).

Wow! never heard of that method, wonder if I can find that on the web, should be interesting to see.

thanks for sharing
 
Originally Posted By: Vern_in_IL
use a precision machinist ruler, rigid, you can take the ruler out of a combination square and use it as your flat.

You would have the ruler upright, in a vertical position, and you would use flexible feeler gauges, to feel for the low spots as you check the ruler along the work piece.

You would know where your low/high spots are, and you would know your tolerances..... so you can decide based on the spec. tolerance if it needs reground, which is the WHOLE POINT OF CHECKING IT.

I am purchasing a Machinist Straight edge from Summit Racing, they are just up the street from me. I'll hopefully get one tomorrow:)
thanks for your input
 
Originally Posted By: clinebarger
My local Machine Shop charges $50 per head, Have the head surfaced.

Have it MagnaFluxed first, Could have some cracks between the Valve seats.

I have talked to my local machine shop about that, after I got my engine machine work done. If I feel like I need to take it to them, I'll do it without hesitation.

Thanks for your input.
 
this topic is interesting. I appreciate the continuing input, and suggestions. It's good to know all the different ways to do this procedure.

btw I have checked this topic to receive instant emails, but haven't gotten any yet, so wonder what is gong on? any suggestions

thanks!
 
Originally Posted By: Merkava_4
Is a 24'' carpenter square long enough? They're fairly cheap at about $7.00 at Sears.


Do you really trust a made in China $7.00 carpenter square from Sears to be true enough to make certain a head surface is flat? They're straight enough for woodworking, not for testing a machined surface for true.
 
Originally Posted By: buckz6319
Originally Posted By: Shannow
One of the cleverest I've seen is pressure sensitive paper.

The logic being that initial set-up, two flat surfaces are perfect fit, after service, if they are bowed, but matched, they are still OK.

To that end, some Prussian Blue can be used to check fit.

(Turbines, I've had casings that you can fit a 1/4" drill bit between pull down flat with enough boltage).

Wow! never heard of that method, wonder if I can find that on the web, should be interesting to see.

thanks for sharing


Note sure, but this place might have a "free" sample that suits your needs

http://www.sensorprod.com/pressurex-micro-green.php?app=Bolted Joint
 
got my Machinist straight edge from Summit Raching
smile.gif
 
The 'redneck' head resurfacing works for aluminum but not so good with the old cast iron. No mention of grade of paper, but after determining how much needs to come off, I've used around a 100 to start and 300 for finish. This isn't really redneck-that's when I've dragged warped exhaust manifolds around my concrete driveway to true-=has worked just fine!
 
Even if you resurface the head sucessfully, how may times is a head with over 150k good without a valve job( grinding)? It still will need to go the the machine shop.
 
I'll be checking the head with my new Straight Edge, soon....can't wait. I'll post the results when I know, got grand kids coming for a few days, so I know I'll be busy with them
 
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