about ready to give up!!!

[mustang112]

i bought a new block not to long ago for $50 bucks because my old block had a spun cam bearing and wasnt salvageable. i pressed my new rods into my pistons tonight, only small problems with those but they turned out to be fine. then i honed my NEW block and at the top of every cylinder is and indention. its not like the ridge usually left by the rings its indented. so now my best bet is to bore it over 30.
anyways, the real reason for this post. anyone know the compression ratio of a 5.0 with explorer heads? i need to know what it is now so ill know what it will be if i bore it and then chose my new pistons. thanks, adam

[Black Horse]

Post up some pics of your block. You also might assemble one of the Pisotn/rods to the crank and see if the upper oil ring will be anywhere near the "indent" - you might not actually have an issue.

[Ryan218]

101.6 mm bore, 76.2 mm stroke, 9.0 compression ratio for GT40 heads

101.6 mm bore, 76.2 mm stroke, 9.1 compression ratio for GT40P heads

if there milled it would be slightly higher

[mustang112]

ok thanks ryan, and black horse, i will try that tonight but im almost positive its to low in the cylinder but ill give it a try

[BigBadStang]

101.6 mm bore, 76.2 mm stroke, 9.0 compression ratio for GT40 heads

101.6 mm bore, 76.2 mm stroke, 9.1 compression ratio for GT40P heads

if there milled it would be slightly higher


What the hell is it with 'dem young-uns and this metric crap? :lol:
Must be that there new fangled math theys a teachin 'em now-days...

**CONVERTED for all the non-metric folks... 4" bore...3" stroke.:D
:lol::lol::lol:

[Black Horse]

What the hell is it with 'dem young-uns and this metric crap? :lol:
Must be that there new fangled math theys a teachin 'em now-days...

**CONVERTED for all the non-metric folks... 4" bore...3" stroke.:D
:lol::lol::lol:

Metric makes you feel like it's bigger!

[Maximus]

What the hell is it with 'dem young-uns and this metric crap? :lol:
Must be that there new fangled math theys a teachin 'em now-days...

**CONVERTED for all the non-metric folks... 4" bore...3" stroke.:D
:lol::lol::lol:

I thought we were on CSS for a second, Metric??? :eek:

[mustang112]

lol yeah. the only good news i have about my block is that a guy i work withs dad has a boring machine at his house.... aparently he has a whole machine shop there so i might be able to get it done cheap!!!!!

[mustang112]

ok,the spot i was worried about is right at the top of where the piston ring will stop. i measured the piston bore and heres my measurements
bottom of the bore spec= 3.9972-3.9980 mine = 3.9960
middle of the bore spec= 3.9982-3.9992 mine= 3.9990
top of bore spec= 3.9996-4.0006 mine = 3.9990

where the piston rings end is 3.9955

i also measured it for out of round also and it checked out fine.

*note: this is all on one cylinder and i was using calipers and a telescopic gauge for my measuring

[mustang112]

so im out of spec at the bottom of my bore and the dents at the top too. should i just go ahead and bore it 30 over?

[Black Horse]

Think it might clean up with some honing?

[mustang112]

yeah thats what i thought at first but after trying 3 times and it only got better in a few areas i started to doubt it. good news is i was looking at pistons and i think i found a set i like. i wanted forged but those are to much for me right now..... what do you guys thing about these? or should i just go for the forged???

http://store.summitracing.com/partdetail.asp?part=STL-H273CP30

[mustang112]

heres the forged im looking at also are moly rings really worth it?
i think i might go with the forged pistons after all and just hope i get a good refund check lol

[mustang3091]

Is that the block i sold you!

[mustang112]

yeah lol but im thinking im just going to bore it out now. everything else on the block looks great so i dont wanna just let it go to waste.

[BigBadStang]

yeah lol but im thinking im just going to bore it out now. everything else on the block looks great so i dont wanna just let it go to waste.

In my opinion, if I had it down that far and had ANY doubt of how true the cylinder bores are, I would have it bored, and go with forged pistons. Keep in mind, you don't have to spend $500 and up to get a good quality forged piston either. Good luck and keep us posted! :bigthumb

If cost is a huge factor, and providing you will NOT use a power adder in the future or spin the thing more than 6,000 RPM, a quality name brand hypereutectic piston is a viable option.

[mustang112]

hmmmmm lol the ones im looking at are 600 for pistons, rings, and a new set of head gaskets. i have the money for them now but its really going to set my project back some. i had planed to have it on the road by summer but now im thinking fall and then next winter do the suspension and brakes

[BigBadStang]

You can get TRW/SpeedPro's for about $310 with iron/moly rings, or about $435 for the coated skirt versions (weight added is 4 grams per piston [608g vs. 612g] ).

[bestracing]

Do it right the first time and be done with it, I say bore it out. You'll have too muck side play if you just try to hone it out and the cylinder won't be even either. Also make sure you get some good ARP bolts to keep things together too!!

[BigBadStang]

...Also make sure you get some good ARP bolts to keep things together too!!

If you change the rod bolts, make sure to have the big ends of the rods resized. :)

[mustang112]

Ok thanks for the input. I'm going to see how much it is to have my block bored since the guy at work can't do it. Also gunna have it magnafluxed while I'm at it and idk about line honeing it cause I've heard its easy and can do it at home. What do you think and what should I bore it too? Suggestions?

[BigBadStang]

I would not go more than .030" overbore. Going more than that can, and will make the engine run quite warm, and those blocks just don't have enough material to safely go more than .030" with out sleeving. A good machinist can measure your cylinder bores and be able to tell how much to overbore to true up the cylinder. You need to have the pistons you plan to use before taking the block to the machine shop. The machinist needs to mic the pistons (because they all vary ever so slightly) to make sure they machine in the correct tolerance. I would not try to line hone the mains at home, premature bearing wear, and or a spun main bearing sucks.

[mustang112]

thanks, i just gotta get prices now
anyone know how much it is to bore a block and magnaflux it?