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clay mold results / quench question
#344338
06/11/09 08:48 PM
06/11/09 08:48 PM
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Joined: Feb 2007
Posts: 908
North Chicagoland
newbee69
OP
super stock
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OP
super stock
Joined: Feb 2007
Posts: 908
North Chicagoland
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After mocking up my heads to the block and putting .039 feeler gauges in b/w as a mock gasket. I have some disappointing results. From front(#1,2) to rear(#7,8) the molds get thicker. .060 front to .080 rear. So what do I need to do now? Have it block decked or heads milled at an angle to "true" it up so I can get the same clearance everywhere? Is it possible the deck is sloped? Im confused.  Thanks.
Last edited by newbee69; 06/11/09 08:50 PM.
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Re: clay mold results / quench question
[Re: newbee69]
#344339
06/11/09 08:51 PM
06/11/09 08:51 PM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
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About to go away
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Posts: 14,889
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Only one way to know for sure.
CC the chambers ans see if the volume gets greater across the head.
It is entirely possible the deck is "sloped" or the heads, or both for that matter.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: clay mold results / quench question
[Re: Supercuda]
#344340
06/11/09 08:57 PM
06/11/09 08:57 PM
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Joined: Feb 2007
Posts: 908
North Chicagoland
newbee69
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North Chicagoland
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I dont think its the heads as I made some molds, took those out and measured them. Then swapped the heads from side to side, made more molds, measured them, and got the same results. If it was the heads, I would think the 2 sets of molds would be different (or reversed actually).
Last edited by newbee69; 06/11/09 08:58 PM.
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Re: clay mold results / quench question
[Re: newbee69]
#344341
06/11/09 09:09 PM
06/11/09 09:09 PM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
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About to go away
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Posts: 14,889
up yours
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Makes sense. Then it's likely the block. There are ways to accurately measure the deck height to be sure but most guys don't have it lying about.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: clay mold results / quench question
[Re: Supercuda]
#344342
06/11/09 09:29 PM
06/11/09 09:29 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
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Grand Haven, MI
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pit each piston at TDC, run a straightedge across the bore and measure the clearance with feeler gages...
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Re: clay mold results / quench question
[Re: patrick]
#344343
06/11/09 09:33 PM
06/11/09 09:33 PM
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Joined: Feb 2007
Posts: 908
North Chicagoland
newbee69
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OP
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North Chicagoland
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Quote:
pit each piston at TDC, run a straightedge across the bore and measure the clearance with feeler gages...
Did that first, before the clay. Deeper in the hole in the rear.
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Re: clay mold results / quench question
[Re: Stanton]
#344351
06/11/09 10:55 PM
06/11/09 10:55 PM
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Joined: Feb 2007
Posts: 908
North Chicagoland
newbee69
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North Chicagoland
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Quote:
Who's to say all your rods are the same length ???
I don't know how you did it but I would do this...
1) assemble the short block
2) clean the piston tops in the quench area and put a dollop of putty on each
3) spray wd40 on the heads so the putty won't stick
4) install the heads WITHOUT shims or gaskets (you know the pistons are not going to hit so why do you need shims ???)
4) crank the motor over slowly ONCE
5) take the heads off and check the putty
Yeah, I did it once without shims. There was still a .020 difference b/w front and rear.
Good point about the rods, didnt think about that.
My whole concern here is to get the proper quench because I am running iron heads with about 10:1 CR and probly a smaller type cam (Engle k56/58 or Voodoo 60303). So I want to try to get rid of any ping that might occur. I want to be able to run pump gas. We do have 93 octane here.
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Re: clay mold results / quench question
[Re: newbee69]
#344352
06/12/09 01:06 AM
06/12/09 01:06 AM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
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I Live Here
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Kalispell Mt.
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Checking quench with clay is not going to give you a safe acurate reading. The quench pads are on the out sides of the piston, off center from the pin. With clay on the piston between the quench pad and the edge of the piston it will cause the piston to rock and lean over on that side and the clay will measure thicker than what your actual quench distance is.
On my zero deck 318 with tight fitting KB hypers I could push up on one side of the piston from underneath the block and the piston would come up slightly above deck and if you pushed down on the side of the piston from the top it would go slightly below deck about the same amount. I asked several engine builders the proper way to measure quench and the pretty much all said to measure the stroke, rod length, pin height and deck height and do the math. Only one said to use the clay method and he said tighter than .050 and the piston will hit the head, the others generally said they would run as tight as .030 to .035 on a tight, roughly 4 inch bore motor. Bigger bores need more clearance because the piston can rock more, also short pistons need more clearance as they are prone to rock more and loose fitting forged pistons need more clearance and aluminum rod motors need more clearance. My motor is .040 and runs smooth as glass.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: clay mold results / quench question
[Re: newbee69]
#344353
06/12/09 08:42 AM
06/12/09 08:42 AM
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Joined: Nov 2008
Posts: 671
Wisconsin USA
Bill MeLater
mopar
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mopar
Joined: Nov 2008
Posts: 671
Wisconsin USA
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Quote:
Quote:
Who's to say all your rods are the same length ???
I don't know how you did it but I would do this...
1) assemble the short block
2) clean the piston tops in the quench area and put a dollop of putty on each
3) spray wd40 on the heads so the putty won't stick
4) install the heads WITHOUT shims or gaskets (you know the pistons are not going to hit so why do you need shims ???)
4) crank the motor over slowly ONCE
5) take the heads off and check the putty
Yeah, I did it once without shims. There was still a .020 difference b/w front and rear.
Good point about the rods, didnt think about that.
My whole concern here is to get the proper quench because I am running iron heads with about 10:1 CR and probly a smaller type cam (Engle k56/58 or Voodoo 60303). So I want to try to get rid of any ping that might occur. I want to be able to run pump gas. We do have 93 octane here.
Put it together and run it, You can easily destroy your budget chasing perfection that you'll never notice in a street driven car. Unless you have very deep pockets that is...
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Re: clay mold results / quench question
[Re: newbee69]
#344355
06/12/09 09:01 AM
06/12/09 09:01 AM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
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What heads are you running ? Have you MACHINED the open parts of the chambers to EQUALIZE THE DEPTHS from one end of the head to the other ? Measure the depths of the open part of the chambers , but you need to do it with the PROPER TOOLS , NOT a ruler and feeler blades . Has the block been DECKED to SQUARE IT ? .020 is A LOT , the block isn't that far out , the pistons aren't rocking that much , if they are you have too much piston to wall clearance . What rods are you using ? Has the crank been cut ? Isn't setting the quench distance FUN ? 
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Re: clay mold results / quench question
[Re: JohnRR]
#344356
06/12/09 12:10 PM
06/12/09 12:10 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
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Posts: 12,675
Columbia, CT
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Like John says, you either build knowing you need to set a certain distance or you dont. I do on all my engines. As a result, a typical rebuild gets align honed(the other machining operations use the cam and crank bores as indeces to set up the machine), then bored and square decked to square everything up. There's a HUGE difference in quality between a typical horizontal miller and a CNC type block machining center. And a price difference in the work. Avoiding issues like this is why some pay more. Then theres the rod lengths (and differences between stock and aftermarket replacement and good aftermarket replacement), and crank stroke length and indexing. WHen all that is accounted for in the machining, you can set a real distance. Otherwise you're just making a half-behind effort and living with the result. AS Bill said, now that things are at this point, it could get expensive to fix. But it throws off everything if the deck is angled. Cylinder pressures, pushrod length, intake fitment, quench distance, cam lift, not to mention gasket integrity and sealing capacity. There's three ways to get machining done: Right; functional; and not functional. Sounds like you got functional which is probably fine for your use at this point. Teh fix would be to take the stripped bare block (cam bearings have to come out for the fixture) to a shop that can square deck (decking as I said, is NOT the same as square decking, and old school millers do not have teh capability to do it) and have them correct it for you. Then reassemble and the differences will only be from rods and crank issues and only effect the cylinder pressures.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: clay mold results / quench question
[Re: JohnRR]
#344357
06/12/09 09:19 PM
06/12/09 09:19 PM
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Joined: Feb 2007
Posts: 908
North Chicagoland
newbee69
OP
super stock
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OP
super stock
Joined: Feb 2007
Posts: 908
North Chicagoland
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Quote:
What heads are you running ?
Have you MACHINED the open parts of the chambers to EQUALIZE THE DEPTHS from one end of the head to the other ? Measure the depths of the open part of the chambers , but you need to do it with the PROPER TOOLS , NOT a ruler and feeler blades .
Has the block been DECKED to SQUARE IT ?
.020 is A LOT , the block isn't that far out , the pistons aren't rocking that much , if they are you have too much piston to wall clearance .
What rods are you using ?
Has the crank been cut ?
Isn't setting the quench distance FUN ?
First off, thanks for the replies.
Now to answer John in order.
213's
No. Tried to measure, but used the straight edge/feeler method. Obviously not accurate.
No square decking.
reconditioned BB rods.
Yes.
And finally, This is my first engine build adventure, so I expected there to be some pitfalls. I think that it is all part of the learning curve, and now I will know for next time. But actually, even though its frustrating, its still fun. 
Moper, I think you hit the nail on the head with the word "functional".
I hate to say this, as I wanted everything to turn out perfect, but I think Im gonna have to take Bills advice and just run it and go from there. I am not in the position $$$$$$ to go for perfection. Disappointing, but reality.
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