Topic Dead Center/Bottom Dead Center ?

[55 Fargo]

I have an engine on the garage floor, its seized, in process of dismantling it.

If 2 pistons are bottom dead center, should 2 be absolutely top dead center?

I have 2 about 3/4 of an inch from the top, and 2 at 4 1/2 inches from the top, what displacement is it? 250 or 265?

[casper50]

Can't tell you the displacement without more info.

[Plymouthy Adams]

if on the floor in on-op status it is displacing concrete storage space ,,contact Archimedes for the answer...

 

not enough info at all...

[55 Fargo]

Can't tell you the displacement without more info.

Its a long block 6, made in around 1960, but was rebuilt at a massproduction place no doubt.

There is no rebuilders tag.

My ? is this, if 2 pistons are right at the top, are 2 right at bottom dead center? Which I think it is, then it would appear it is a 4 3/4 inch stroke, which would make it a 265 with .040 over pistons. 

[55 Fargo]

if on the floor in on-op status it is displacing concrete storage space ,,contact Archimedes for the answer...

 

not enough info at all...

Now Tim, here is the ? when 2 pistons are at top dead center are 2 at bottom dead center nothing else.

[Plymouthy Adams]

now I get what you are driving at...the TDC is at zero next closes to top is 120 degrees and the third is at 240 slightly out from  the 180 ou will need for a BTC reading  the sister slug will be on exhaust while the other is on compression..

Edited September 29, 2015 by Plymouthy Adams

[55 Fargo]

now I get what you are driving at...the TDC is at zero next closes to top is 120 degrees and the third is at 240 slightly out from  the 180 ou will need for a BTC reading  the sister slug will be on exhaust while the other is on compression..

Yup, see if I can get this crank to spin, without hammering out pistons, its an odd number on the block P6D1, prefix, and it aint a P6 Plym engine, its possibly  1960 Dodge truck engine...

[TodFitch]

Riffing on Plymouthy's comment: There are basically three throws on the crankshaft at 120° apart. Each throw has two pistons. The pairs of pistons are 1&6, 2&5, and 3&4. So if two of the pistons are at bottom dead center then none of the pistons are at top dead center.

[55 Fargo]

Okay I get it now.

Looks like it's a 250 engine after all.

[suntennis]

You can figure out the cubic inches yourself. Measure diameter of the bore and find the area of the bore. The area is 3.1416 times the bore diameter multiplied by itself then divide all this by 4. Multiply this by the distance from block surface to the piston at bottom center and that gives the cylinder volume. Multiply the cylinder volume by 6 and you get engine size.

[Plymouthy Adams]

I believe the question is at this time with the stuck block...ARE  the two deepest pistons in the bores truly at BTC without the ability to say for sure what are you going to use for an exact stroke?

[55 Fargo]

I believe the question is at this time with the stuck block...ARE  the two deepest pistons in the bores truly at BTC without the ability to say for sure what are you going to use for an exact stroke?

Yup, time will tell, will have to wait till get this engine apart, thanx for helping me figure this out