what happened to my hone???

[1fast97gsx]

last year ( 4000 miles ago ) I had my block bored .020 and honed. I installed ross pistons and eagle rods. At about the 3500 mile mark the car started to blow blue smoke and run low on oil. I pulled the head and saw a lot of oil on the pistons. Compression was 165 across .. anyways .. I was going to swap on a built head I had anyways so I just pulled the head off and looked inside the bores. To my suprise the crosshatch from the honing was totally gone. In cylinder 3 I could see it if I tried really hard .. but in the others it was gone. There's a bunch of verticle lines in all the bores but none of them are really scratches. I tried taking my fingernail to see if I'd feel any resistance on any of these but there was none. Would the cross hatches be gone from the rings not seating properly? Maybe the end gaps were wrong? Can I just rehone the block and get new rings and pay extra close attention when setting the end gaps? This just really suprises me because when I originally took the engine apart for the first time the crosshatches ( factory ones ) were perfectly visable with 59000 miles on the engine ... now after 4000 the new ones aren't visible anymore. Something is not right ...

 

[tsi20gawd]

forged pistons for ya.
they just run a little loose thats why the cross hatching is gone.

 

[IMMORTALSPYDER]

The cross hatch usually goes away as the piston rings seat themselves.

 

[1fast97gsx]

I thought it wasn't supposed to go away ( hence why I got worried because my stock crosshatch was still there ) ... anyways you guys think it's nothing to worry about? I still don't know how to explain all the oil on the top of the pistons but maybe it was leaking out through the valves since that head wasn't in the best shape anymore.

 

[tsi20gawd]

forged pistons tend to "slap" the cylinder wall in turn causing the cross hatching to wear away quickly.
As far as the oil, if the valve guids are worn or the valve stem seals old you usually pull oil during decel conditions. Ring's usually cause oil use during boost or hard driving.
Did you notice any smoking or excess oil consumption?

 

[1fast97gsx]

yea it was loosing oil ... about a quart every couple of days ( but it also had a good leak from the return line ). It would smoke under hard acceleration ... not deacceleration. It would usually just smoke once when I floor it and then stop ... then after my driving it around for a while and flooring it again it would smoke again and stop after that.

 

[kpt4321]

What was the compression ratio on that motor supposed to be? 165 is pretty low compression, I think that the bottom end parts were chosen incorrectly, or it was machined and/or assembled wrong.

 

[1fast97gsx]

What was the compression ratio on that motor supposed to be? 165 is pretty low compression, I think that the bottom end parts were chosen incorrectly, or it was machined and/or assembled wrong.

8.5:1 pistons and MLS gasket was used. I thought it seemed low as well. Block was bored .020 and I used ross .020 over pistons. Only thing I think could have been wrong is ring end gaps. What do you think? Would my best bet be to just have it rehoned and pick up a new set of rings and pay extra attention to endgap this time? ( machine shop set gap last time )

 

[tsi20gawd]

yeah something's wrong. Thats alot of oil consumtion leak or not.
Was a torque plate used while being honed? Double check all your clearances and use NEW rings at least. Your compresson does sound a little low I would think 170+ even with a mls gasket.
Smoking under boost is typically a ring sealing issue.

 

[bastarddsm]

you guys need to stop worring about using a torque plate when honing. they are not that important.

 

[tsi20gawd]

YES THEY ARE! If you are running a cast piston you can get away without it, but forged pistons require the use of a torque plate to prevent scuffing and other cyliner wall damage caused by an incorectly shaped cylinder.
If you want it to last use a torque plate plain and simple.

 

[1fast97gsx]

A torque plate was used, however the girdle for the crank was not bolted on for the honing process. If I have it rehoned should this be bolted on this time? Is it fine for me to get another set of .020 rings and just rehone and install the new rings or do I actually have to enlarge the bore and get different pistons and rings again??

 

[tsi20gawd]

Just double check everything It's better to do that now than have a problem again later.
Without the girddle installed the bore will only slightly be out of round and will be deep in the bore anyways.
You could probably get away with just rehoning and a new set of ring's but check everything out first just to be safe.
Be sure to check piston to wall clearance's these are most crutial when running a forged piston.
hope all go's well.

 

[NitrousBob]

did you have the block machined before you bought the pistons? I would just rehone and re ring. Are you using a "harder than stock ring".

 

[Strm Trpr]

What was the compression ratio on that motor supposed to be? 165 is pretty low compression, I think that the bottom end parts were chosen incorrectly, or it was machined and/or assembled wrong.

I thought 165psi in a 2g Turbo was actually pretty good compression being that stock ceiling is 178psi and service limit is 133

 

[tsi20gawd]

I could be wrong but I thought 165 was spec on a 7.8.1 motor, and 185ish was standard on a 8.5.1 setup?
like I said could be wrong so dont kill me

 

[Strm Trpr]

Sorry dude, I'm gonna have to break out the big guns....
No hard feelings, I'm just trying to give out accurate info, you know how people don't like hear say, so I figured documented info would be best...

 

[Strm Trpr]

A torque plate was used, however the girdle for the crank was not bolted on for the honing process. If I have it rehoned should this be bolted on this time? Is it fine for me to get another set of .020 rings and just rehone and install the new rings or do I actually have to enlarge the bore and get different pistons and rings again??

Read this if you haven't already.....
<a href = http://www.dsmtuners.com/forums/showthread.php?t=8817&highlight=crankwalk+theory>NosLaser's Crankwalk Theory</a>
You think losing you're hone marks are bad..... imagine losing your thrust bearing because the shop you used skipped a step....
This is the best theory I've read yet, and it all makes perfect sense to me....
If my 7-bolt walks, I'm going to search for a machine shop that will do the same process mentioned in that long azz post...

 

[tsi20gawd]

178psi on 2g's got it.
Someone need's to come up with away to eliminate c-walk completly. My friend's talon had the wierdest tuning problem's ever! The damn crank was walking and registering knock, it was so bad we could slide quarter between the block and the thrust bearing! I feel for you 2G guy's that just sux no other way to descibe it...just sux.
good luck on the re-ring
late.

 

[bastarddsm]

YES THEY ARE! If you are running a cast piston you can get away without it, but forged pistons require the use of a torque plate to prevent scuffing and other cyliner wall damage caused by an incorectly shaped cylinder.
If you want it to last use a torque plate plain and simple.

Think about it. is a 1.25inch think steel plate going to flew the block in anyway close to the way that the aluminum cylinder head does. I think not. Maybee on an iron headed motor it might makle a difference, but not on an aluminum headed motor.

 

[bastarddsm]

if you really would have wanted to know what was going on then you would have done a leakdown test, and found out if it was going by the rings or not

 

[1fast97gsx]

I could be wrong but I thought 165 was spec on a 7.8.1 motor, and 185ish was standard on a 8.5.1 setup?
like I said could be wrong so dont kill me

yes but I am using an mls headgasket which is thicker so I figured itd be lower than 178. I was expecting 170 or so compression.

 

[Strm Trpr]

Hey bastarddsm, I'm sure you know this, but if not, here goes....

A torque plate is used to simulate the stresses that are induced into the block when the head is torqued on.
This pulls and stetches the block as if the head is on, so then align honing with a torque plate would be... ummmm... a good idea...

I'm willing to bet that most 2gs out there that got crankwalk, have a factory built bottom end, but they chose to install ARP headstuds when they reinstalled their heads.

If you over torque your head, you are going to pull and stretch the block so far as to knock your crankshaft thrust bearing out of alignment.
Then you add a heavy clutch, and wahla instant crankwalk....

Not using a torque plate to align hone the bores is F***ing retarded....
Align honing without the girdle or main caps on is also F***ing retarded....

Here's a link to a poor 7-bolter that unfortunately was a victim of crankwalk....
<a href = http://www.dsmtuners.com/forums/showthread.php?t=9703&highlight=%247500>Poor Soul</a>

 

[bastarddsm]

we were talking about the bores. not the main berings. and ya the torque plate may stretch the block but it ain't gonna be anywhere close to where the head would

 

[tsi20gawd]

Actually it is. It is used to pre distort the cylinder so when the the head is torqued down the cylinder wall's are true and round.
look let's not hijack this guy's thread over who's right or wrong you build your engines your way we will do our's our way.
Maybe you should talk to a few dsm shop's on there opinion's on using torque plate's they dont all use them for no reason
later and good luck with your rebuild man!

p.s. 1fastgsx sorry about the thread turning into a pissing contest this happens all too often on this forum again sorry.