Today i was putting my motor back together after changing the head gasket and this guy who lives around the corner was walking by stopped to bs for awhile.While he was their he was looking at my motor and asked for a tape measure. He measured my bore dia and said i dont have a 2.8. He said 2.8 bore dia's are like 3.1/2 and my bore dia is more like 3 3/4.Another guy told me 2.8's are near 3 3/4, WTF did the prev owner do? does anyone have any ideas as to what is going on with my motor?
PS tomorrow im going to finish putting all the crap back in, i have the fuel rail, plenum, alt, and the spark plugs, cap to put back yet.

 

The best thing I can tell you here is: You don't measure cylinder bores with a tape measure. You'll never get a true reading for the most part.

 

Ugh, a tape measure, yeah real accurate.

Stock bore is:
3.503" for the 2.8/3.1
3.622" for the 3.4

 

thats what i was thinking, and before i knew it i had these two guys fighting over what a 2.8's bore dia was while i was trying to get my motor back together. All i wanted was a little peace while i froze my *** off putting the motor back together. I know the prev owner had the motor apart before because like every bolt was loose. the smog pump is gone. etc. This is one of the bad points on buying used cars.

 

You'll need a set of telescoping gauges (well in reality, just one, but it'll be cheaper now to buy a set) and a micrometer to find that out.

 

do the pistons have anything stamped on top of them?

 

Thanks for the correct method Tom p but i already have the head on and im not in a hurry to take that off. lol. Am91 i didnt see anything on the piston but the guy who said it wasnt a 2.8 said 2.8's have a small hole indented into the piston and a pizza slice like mark by the front part of the enine on the piston(if this makes any sense?)Mine didnt have any of these marks. Just flat. I know a tape measure isnt exactly the right way to check, but i know how to read a tape and it wasnt near 3.5.I was in too much of a rush to get the motor together to wait and check the correct way. The weather here in Philly hasnt been the kind you want to be outside working on cars in. . Now its snowing AGAIN!

 

According to Chilton's, the 2.8 has a bore X stroke of 3.5039 X 2.9921 inches (89.0 X 76.0 mm), while the 3.1 has 3.5030 X 3.3122 inches (88.9 X 84.1 mm). The 3.4 has a bore X stroke of 3.6220 X 3.3221 inches (91.9 X 84.1 mm).

Pete