Help with Vortec/E-Street Head and Cam built

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Jan 31, 2012 | 09:22 AM

#21

ezobens

Drifting

Joined: Aug 2005

Posts: 1,443

Likes: 65

From: Wauconda IL

Quote:

Originally Posted by Xterrable

I must be doing the math wrong then.

Enter Cylinder Bore Size 4.030
Enter Piston Stroke Length 3.48
Enter Head Gasket Bore Diameter 4.10
Enter Compressed Head Gasket Thickness 0.015
Enter Combustion Chamber Volume In CCs 70
Enter Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') 6 cc
Enter Piston Deck Clearance Negative If ABOVE Deck (Use '-') : 0.040

When I use those numbers, the calculator says 10.6:1 ratio. What number am I doing wrong?

Your Piston volume (6cc) is being entered wrong.
If I enter it as a domed piston, I get your 10.6, if I enter it as dished, it's 9.3
Elm

Jan 31, 2012 | 09:32 AM

#22

ezobens

Drifting

Joined: Aug 2005

Posts: 1,443

Likes: 65

From: Wauconda IL

Quote:

Originally Posted by Xterrable

No, I have not checked the deck for its flatness. I dont think that the tools I have will provide me with accurate numbers..

You guys are really a buzz kill today....

Trying not to be a buzz kill but I am trying to make sure you only have to do this once.

I've run into things over the years when assembling motors and it always boils down to the details- If you don't check everything, then you've really not checked anything because it's what you DIDN'T check that will bite you in the end.
I can understand and appreciate being on a budget (4 kids in college here!) but the piece of mind knowing your bottom end is in good shape for the price of an oil pan gasket is priceless.

I just put my 409 SBC together less than 1000 miles ago and I am now swapping heads (ports were WAY too big for my application) but I still dropped the pan to double check the condition of my bearings and my side clearances- Maybe I'm a bit **** but I can now rest easier knowing they are perfect!

Elm

Jan 31, 2012 | 09:33 AM

#23

jackson

Le Mans Master

Joined: Sep 2001

Posts: 7,739

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From: Unreconstructed, South Carolina

fyi 1094 gasket volume is 3.2cc

enter neg 6 (-6) for your flattop w/ 4 eyebrows ... 12cc swing ... makes about 9.3:1

Jan 31, 2012 | 10:43 AM

#24

billla

Le Mans Master

Joined: Jun 2004

Posts: 6,231

Likes: 65

From: Seattle WA

St. Jude Donor '14

Quote:

Originally Posted by Xterrable

So what is the downside to just doing the top end with the issues known. Loss of performance? Engine is going to break?

The risk is that some bad machine work generally means more bad machine work. The downside is a pile of scrap...potentially taking your new heads with it. How likely that risk is to occur is impossible to say...

This is one of those things where you may want to post in your regional forum to get another pair of eyes on the engine. It's just a tough call for anyone to make by remote control. No one here can accurately assess the risk level and help you make the right decision.

Jan 31, 2012 | 11:33 AM

#25

Xterrable

Thread Starter

Racer

Joined: Oct 2011

Posts: 294

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From: Easton pennsylvania

Oh believe me, I do not dispute what you are all saying. And inside I know it is the right answer, despite what I want to hear..

If I this was 5 year ago and I was not married, the block would be down to the shop already. But its hard to explain my reason for someone who see's this as a money pit and not a hobby. But nothing another trip to Iraq of Afghanistan wont fix.

So on the piston volume, any dish or valve relief on the piston is considered a negative number?

Jan 31, 2012 | 12:04 PM

#26

billla

Le Mans Master

Joined: Jun 2004

Posts: 6,231

Likes: 65

From: Seattle WA

St. Jude Donor '14

I hear you

I don't know why my wife tolerates my hobbies...but she does.

My stepson comes home from Afganistan in April...and he's buying an S2000. Bleh

Yep, reliefs or dish is a negative number.

Jan 31, 2012 | 01:22 PM

#27

scottyp99

Le Mans Master

Joined: Mar 2008

Posts: 5,948

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From: Oxford MA-----You just lost the game!!!!

Quote:

Originally Posted by Xterrable

Well, using a dial indicator, I rechecked everything. And I confirmed that the pistons are anywhere from 0.040 to 0.060 down in the block. We checked each and every piston, which is where the variance comes from.

Now my neighbor also noticed that the babbitt on the cam bearings are wearing on the low side.

So I am wondering if it is worth rebuilding at this point.. I dont need a precision motor but I dont want to dump 1500 into a top end and have it grenade in a little while... But to be honest, I dont have cash to do a full tear down and rebuild.

Thoughts??

This is really going out on a limb, but please just humor me, OK?
Are some of the pistons .040" in the hole, and others .060" in the hole? Or are they all over the place between .040" and .060"? I'm asking because if some are .040", and some are .060", you may have pistons with 2 different compression heights. I know it sounds crazy, but stranger things have happened. Also, have you got the deck nice and clean? Any crap left from the old head gasket will affect measurements. Not trying to question your intelligence, just being thorough.

Scott

Jan 31, 2012 | 01:34 PM

#28

Xterrable

Thread Starter

Racer

Joined: Oct 2011

Posts: 294

Likes: 0

From: Easton pennsylvania

Yep, my first your afford me the opportunity to build the 30x30 garage and get the car. Rebuilding it was not in the plan. But I can leave well enough alone, and that is one thing my wife did predict.

As for the measurements, they seem to be all around. Passenger side seem to higher than the passenger side though. 0.040 to 0.050 and the drivers side seems to be 0.050 to 0.060. Plus the measurement around each piston yeilded slight variations as well.

As far as cleaning the block off, I have done all that a razor is going to do. It looks clean, but as I am finding out, an imperection the size of a human hair can change a meansurement significantly. When I did take a measurement, I made sure that the area was as clean as possible..

Can anyone guess what a shop would charge to deck the block and put new cam bearings in it? Keep in mind that my pistons are in right now so there would need to be some tear down and reinstall time added as well. And on top of that, might as well do new pistons as well? My fear is doing all this work to a 40 year old engine might not be worth it.