hi_im_sean

iTrader: (3)

it would just be a good idea to re ring while doing all this, and hone to go with it. but if you are going to reuse your rings, sure.

aidandj

iTrader: (5)

<p>Realize that this isn't going to grow into a do **** while I'm in there build. That will happen on the next motor. This is a keep the motor alive while Aidan thrashes it for a bit longer build.</p><p>Can I not slide the piston almost all the way out, pull the wrist pin, new rod, slide it back up?</p>

hi_im_sean

iTrader: (3)

nope

the main bearing and its supporting structure is thicker than the bore spacing

patsmx5

iTrader: (16)

Because you can not reuse rings. See below.


Never reuse rings. Ever.


No, you can't slide the pistons down enough to be able to swap rods. You also need to check the fit between the pin and small end of the rod too.

I've tried rebuilding a BP by reusing rings/not honing the motor. Burned a quart ever 100-200 miles. Had fantastic compression, mainly because of all the oil it was burning.

You can do rods-only cheap, and I recommend it.

Nice set of rings
Good hone, correct grit
Reuse bearings
New ebay h-beam rods
ebay gaskets
fel pro head gasket
oil/rtv/coolant/distilled water, etc

It's about 500 bucks and I've done it in a day before, but I'm on motor 7 so I'm getting good with BPs.

hi_im_sean

iTrader: (3)

i agree with you, that while im there i would never not do rings. but there is no reason he couldnt just because he is swapping rods. they would seal the same they do now.

and what is the correct grit?

patsmx5

iTrader: (16)

I tried doing this on a 40k mile motor and it was a complete fail, they did NOT seal the same, they burned a qt of oil in 100 miles! Have you done this before?

hi_im_sean

iTrader: (3)

many times, in various half assed rebuilds on different engines. cant say ever on a bp though.

maybe you were just unlucky with that particular one?

aidandj

iTrader: (5)

Damn. You guys suck. I had grand plans.

patsmx5

iTrader: (16)

All 4 cylinders looked perfect, rings looked perfect, so I put my rods on and threw it together. All 4 oiled the same. pulled it apart, rings looked "fine", didn't damage anything on installation.

For me it was a big fail. Same motor i honed it, put new rings, and then it worked. Ran 28 PSI for 2 years till I turned up the boost and broke a piston in half.

hi_im_sean

iTrader: (3)

seriously though aidan, your rings are the gods of power that say: no bitch, you push this piston down! to the explosions.

for like $70 you should just do it. i cant find any info on the proper grit though.
pat?

patsmx5

iTrader: (16)

Roll the dice or drop 500. 500 including cost of rods isn't that bad! There's a lot of guys here running 3000+ dollar motors that are scared to crank the boost or up the rev limit.

hi_im_sean

iTrader: (3)

in either case, the end result is, i agree. i think it is ill advised to have an engine that far apart, with miles, and not do rings. rings are low hanging fruit.

patsmx5

iTrader: (16)

I can tell you 240 grit is not the right grit, it's wayyyy too rough.

I don't know 100% what is correct, but for chrome rings at least a 400+ grit hone would be my guess. The motor in my car now, a machine shop build this bottom end and they honed it slick compared to anything I've done in the past. I looked into it and chrome rings use a finer finish than iron rings.

Sorry don't wanna give a firm answer as I'm not 100% sure but it's not 240 grit, more like 400-600 probably with chrome rings.

aidandj

iTrader: (5)

I'll think about it. For a bit more I could do a rods only on the VVT, but not what I want.

patsmx5

iTrader: (16)

In the interest of cheap and fast, I've honed a motor twice with the crank still in the block. Literally took 3 hours to take a stock shortblock and turn it into a rods-only shortblock. Pull stock rods/pistons, clean pistons, install rods to pistons, put old bearings on old rods. Have them all ready to go in. Hone motor till cylinders looked pretty, clean with brake parts cleaner, assume they are clean but then tested this by scurbbing one with hot soapy water and a sponge, found out they were not clean, scrubbed with sponge, rinsed it out with a rag and water, then oiled the holes very lightly so they wouldn't rust, installed piston/rod assemblies, overtorqued the rod bolts. Bam. Run on but oh well, that's how you do it.

patsmx5

iTrader: (16)

I've done rods only VVT, stock pistons break around 350whp FYI. If you can keep it around 300 or so I'd rock it. I rev'd the **** out of it to (8,800) and it stayed together.

aidandj

iTrader: (5)

Tempting. With e85 I bet the piston would hold up to more. But for the VVT I also need stuff like an oil pump, water pump, new manifold, new downpipe, new motor mounts, new etc etc etc.

patsmx5

iTrader: (16)

I don't think it would make them last. I've twice broke a stock piston in half. Not melted it, not cracked a ring land. Straight up broke in in half.

I think this is from too much power/pressure. Both times were right around 350whp (estimate). Once with 31 PSI on pump gas with a GT3271, once with 20 PSI with WI with 12.8:1 indicated* AFRs with the whipple and 21* of timing. With E85 you'll start throwing timing at it and peak pressures will shoot up (as will power).

*WI skews AFR reading, it was actually leaner than 12.8....

Just do rods-only on the 1.6 and be done. You'll be happy with it and be able to beat on it and not worry about it, rods are the weak link.

aidandj

iTrader: (5)

This won't be happening till after track season either way. So just speculation.

18psi

iTrader: (76)

I would never build a 1.6
ever

I've also pushed 18psi on a gt3076 which I would also estimate at 350whp, on stock pistons, on e85, and it didn't even flinch.

Opinions....

*edit: aidan, I've skimmed your posts about doing the rods only 1.6, don't be that guy, don't be a retarded hack with a terrible build just to save 2 pennies. if you can't do it right, don't do it. what makes you think you'll eject rods on your engine as is?
We laugh at people that do this or talk about this all the time. Their cars suck, always broken, always down, always something wrong. Never consistent or reliable. Always losing $100 to save $1