Is there a year to year difference in the "down in the hole" distance for 225 blocks? What is a typical number? What is the largest and what is th e smallest number anyone has seen on a stock block?

The reason why I ask, is I am measuring 0.129 ('72) on a stock block. The others I have seen are much larger than that.

Thanks

bwhitejr

_________________
'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
CompCams 252S, Holley 390cfm, Offy manifold
Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

Bob
Ive seen .1 to .2 I would say about .180 is average. Most of the block I have are .180-.187.
Hope this helps,
Frank

_________________
Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

Sounds like that block was milled. The least I have measured is about 0.170".

Lou

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Home of Slant6-powered fun machines since 1988

The block in Ryan's Dart (1972 block) was -140 before we milled it.

Rick

Tore down a 300 mile professionally rebuilt motor cause it sat for five years,front cyl was .170 down,rear was .145 ,,deck had a slant to it.My machinest couldnt belive how bad it was,had to be prior work,got them all straight now,Mark

I have seen that before. Certain mills will not accept a Slant block in a way that the deck comes out flat.

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Official Cookie and Mater Tormentor.

Explain? Kind of odd to say that. Gonna have to be flat and parallel WITH crankshaft bore line or the machine shop is fired.

Cheers, Wizard

Mike ran into it with a shop he used for decking a block. The fixture the machine had for mounting the block held one end slightly higher than the other. You could not tell with the naked eye, but Mike caught it when checking deck height on the pistons before final assembly.

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Official Cookie and Mater Tormentor.

My machinist actually put a piece of paper under the front of the block after he got it real close to get it perfect,he is a friend and let me watch,was off a little sideways also,mark

I cant find my notes for the measurements, but my #6 piston is down more than my #1...also the head I have from a completely different engine- the #6 chamber cc's less than the #1 chamber, oddly, the difference in the combined volumes equals out. Hehe, a slant-slant six....go figure

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<img src="http://farm4.static.flickr.com/3173/2992308402_5481afb26e_t.jpg">

So does the fixtures is slightly worn on one side or the engine block is springy on one end? What about the "bed" that everything are mounted to?

Machining the diesel block is more critical as deck had to be absolutely parallel with the crankshaft center, even I had a note asking to check the rebuilt head deck for parallel-ness with the camshaft bore if head is for diesel also.

Cheers, Wizard

I am curious now.
When checking to see if #1 cylinder is down in the hole the same as #6 cylinder, do you use a different piston/rod combination to check each or use the same piston and rod?

If there is a slant to the decking is it always #1 to #6 or #6 to #1 sloped (most depth to least depth)?

bwhitejr

_________________
'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
CompCams 252S, Holley 390cfm, Offy manifold
Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

Bob
I use the same piston to mock it all up. Most people check the deck before they disassemble the engine. That tells them how much to take off.
As for 1-6 or 6-1 I guess it would depend on which end they put where on the machine and how off the table is.
Frank

_________________
Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

Well, I finally got a depth micrometer and measured my block. I was getting different readings depending on where I measured.

225 Rod with stock piston (no rings)
Driver Side of block 0.172
Rear of cylinder 0.17075
Passenger side of block 0.16875
Front of cylinder 0.17025
Dead center of cylinder 0.17925

198 Rod with stock piston (no rings)
Driver side of block 0.1385
Rear of cylinder 0.1395
Passenger side of block 0.1450
Front of cylinder 0.1435

Both pistons were pitted somewhat, so that accounts for the center being lower.

The good news is the sum of the 225 down in the hole measurement and the 198 above deck measurement comes out very close to the difference in the rod length if you average the measurements for both cases.

So, which measrement would be the more accurate one? It seems the one at the rear of the cylinder should be the most accurate, since there are no rings on the piston.

Thoughts?

bwhitejr

_________________
'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
CompCams 252S, Holley 390cfm, Offy manifold
Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

Bob
Depends on what you are trying to do. If you are going for Zero deck height then use the smallest number. If calc. the volume for compression then the average. Remember it may change by .005 or so when it get machined.
Frank

_________________
Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered