clay mold results / quench question

Posted By: newbee69

clay mold results / quench question - 06/12/09 12:48 AM

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.

Posted By: Supercuda

Re: clay mold results / quench question - 06/12/09 12:51 AM

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.

Posted By: newbee69

Re: clay mold results / quench question - 06/12/09 12:57 AM

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).

Posted By: Supercuda

Re: clay mold results / quench question - 06/12/09 01:09 AM

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.

Posted By: patrick

Re: clay mold results / quench question - 06/12/09 01:29 AM

pit each piston at TDC, run a straightedge across the bore and measure the clearance with feeler gages...

Posted By: newbee69

Re: clay mold results / quench question - 06/12/09 01:33 AM

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.

Posted By: RapidRobert

Re: clay mold results / quench question - 06/12/09 01:40 AM

Quote:

Did that first, before the clay. Deeper in the hole in the rear.

need to take the block in to your machine shop & have them check the block height in all 4 corners

Posted By: dOc !

Re: clay mold results / quench question - 06/12/09 01:40 AM

That deck is waaay off .. but 020 is not that bad. I have heard of guys having to deal with as much as 110.

Posted By: newbee69

Re: clay mold results / quench question - 06/12/09 01:59 AM

110!! Yikes!! Well this is what I was afraid of, but if I gotta get it checked then I gotta get it checked.
So once they check it and see that its off, can they true it up as an assembled short block or do they have to do it as a bare block?
Also, what kind of intake fitment issues am I going to run into?

Or should I just forget it, run the .020 steel shims giving me .040 quench in #1,2 and getting higher to .060 in #7,8?
Obviously, this option is NOT the right way to go about this problem, but I would like to hear your opinions anyways.

Posted By: dOc !

Re: clay mold results / quench question - 06/12/09 02:04 AM

How about taking ONE rod and piston combo and throwing IT in the 1 and 2 ... and 7 & 8 holes to check. This will check front-to-back slope. The other will have to be checked when jigged up at the machine shop.

Posted By: justinp61

Re: clay mold results / quench question - 06/12/09 02:07 AM

If it were mine I'd tear it down and have it square decked. It will have to be torn down to be fixed.

Posted By: Crizila

Re: clay mold results / quench question - 06/12/09 02:33 AM

Quote:

How about taking ONE rod and piston combo and throwing IT in the 1 and 2 ... and 7 & 8 holes to check. This will check front-to-back slope. The other will have to be checked when jigged up at the machine shop.

This is the way to do it to verify you have a problem. If in fact you do, It's off to the machine shop ( block must be bare ). They will verify the problem using the crank centerline as a reference. Make sure when you get your block back from the machine shop that they put a chamfer back on the bore holes. Without it you could / will have problems sliding the pistons back in the holes with the rings on them.

Posted By: Stanton

Re: clay mold results / quench question - 06/12/09 02:42 AM

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

Posted By: newbee69

Re: clay mold results / quench question - 06/12/09 02:55 AM

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.

Posted By: HotRodDave

Re: clay mold results / quench question - 06/12/09 05:06 AM

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.

Posted By: Bill MeLater

Re: clay mold results / quench question - 06/12/09 12:42 PM

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...

Posted By: Bill MeLater

Re: clay mold results / quench question - 06/12/09 12:48 PM

I'm running 10.3 to 1 w/iron heads.Had .016 dif in deck heights. Runs great on the local BP 93...NO ping, pulls like mad to 7k, no problem. We're at the same elevation, what's ACTUAL intake close on your cam choice?

Posted By: JohnRR

Re: clay mold results / quench question - 06/12/09 01:01 PM

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 ?

Posted By: moper

Re: clay mold results / quench question - 06/12/09 04:10 PM

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.

Posted By: newbee69

Re: clay mold results / quench question - 06/13/09 01:19 AM

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.

Posted By: 383man

Re: clay mold results / quench question - 06/13/09 02:45 AM

My 440 in my 63 is a 10.0 comp 906 headed quench eng. I had my blocked square decked and when I check it I use the same piston and rod in all 4 corners. That way you dont have to worry about difference in lenth from recontioned rods. I had my rods bushed for floating pins and they can be off a tad also so you have to use the same rod and piston in all 4 corner's. Now my chamber depth varied a good bit and that was alot of work getting them close. Mine were as much as .010 difference so I had to work them to get as close as I could. I got all my quench readings between .040 to .046 and I went with that. So with the 906 iron heads and 10.0 comp using the MP .557 cam and 37 total timing I have no ping at all and run fine on 92 pump. I know how it is on a tight budget. If you run it like it is let us know how you make out. Sure it will run and you may not have any ping but it could. If it does ping then back the timing up a few degrees and hope that works.

Good luck , Ron

Posted By: RapidRobert

Re: clay mold results / quench question - 06/13/09 04:50 AM

I would suggest that you spend the time/money to get quench and balanced etc that way your short block is right w nothing left on the table and any further upgrade/addition ie heads/intake carb etc will only compliment your solid foundation & you'll sleep better knowing that it is right & you will not have to open it up again.

Posted By: JohnRR

Re: clay mold results / quench question - 06/13/09 11:22 AM

Quote:

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.

your pretty much wasting your time at this point , you can't even remotely setup a quench using the parts you have in the condition they are in ... as cast and a block that has settled .
I question your .020 difference front to back considering the tools you are using to measure things , my question , even though its a moot point , is how are you measuring the clay , straight edge and feeler blades ??

Posted By: newbee69

Re: clay mold results / quench question - 06/13/09 05:35 PM

Quote:

your pretty much wasting your time at this point , you can't even remotely setup a quench using the parts you have in the condition they are in ... as cast and a block that has settled .
I question your .020 difference front to back considering the tools you are using to measure things , my question , even though its a moot point , is how are you measuring the clay , straight edge and feeler blades ??

My buddy let me borrow his dial caliper to measure the clay.
I really dont think its the block, but more the rods and crank.
So am I screwed here, or am I gonna be okay runing it as is on 93?