Re-hone or New Rings?

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T56MaxTorq

T56MaxTorq

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Need to put a new crank in my 318 turbo mag. I had a hone job on the original bore and put 10 hours on the engine before the thrust bearing ate ****. Bores and pistons (stock cast) look good and my ring gaps were large for boost (.032"). I did notice a good amount of vapor coming out of my crank breathers (I'm running e85 if that matters)

Wondering if I should prep the bores with a hone and get new rings (I used cast rings) or just put it all back together after a good cleaning?
 
Wouldn't hurt to hone it. Also the vapor from your breathers could have been blow by. Maybe caused by bad rings.
 
Transmission install we think, from the converter being misaligned. But I haven't ruled out the converter itself (it was torn open, fins bent over, re-welded) and the flex plate (non oem neutral balance) dimensions
 
Were all your ring gaps wide or just the top ring.
If you hone it you have to put in new rings.
Convertor case ballooned?
 
I believe just the top ring was wide. The second ring was fairly wide out of the box, but not .032 like the top. Pistons are removed so I can measure to verify. The vapor from the breather was that of a hot cup of coffees steam, when engine is hot or cold. Engine is the one in my avatar. Both valve covers run a 10 an line to the breather/separator.

Haven't snooped around the trans yet, wanted to get this short block to the machinist. I have some time to look this weekend
 
Glaze? Probably not.... Do you see Crosshatch? If so Beady Ball that sucker and put it together.... Unless junk went through the motor and scarred up the Cylinders the only thing you will achieve out of Honing is time served at Machine Shop Prison lol....

JW
 
I'm of the opinion that if you're not going to bore/hone and replace the pistons then keep it simple. I use green scotchbrite wrapped around my rigid stone hone and WD40 rather than a dingle ball or having the shop hone it. Then run moly coated rings. Plain iron rings will need a rougher finish to seat to. The piston ring lands are also worn, and the seal against them is as or more important than the wall finish, so you're already limiting yourself running those. Especially with a turbo I'd expect to see a bit of blow by. You might help yourself by adding .003-.004" more on the 2nd ring gap given the top ring isn't going to seal as well.
On the thrust - depending what the package makes for power, that factory convertor is probably ballooning. You need a better convertor.
 
Crosshatch looks nice, no wall or piston damage

Moper - I want to avoid an overbore with new pistons. So rehoning and using moly rings is better than cast irons? Somehow I was under the impression that cast rings would seal up better on a used, honed bore. As for the 2nd ring, you're saying add .003-4 more gap to the stock, oem limitation?

Ballooning is a concern, I'll have to inspect the converter and look for signs. I'm running about 400-450 torque I'd estimate. Boost begins at 2500 rpm. Max rpm is 6000

73 Duster, 318 turbo mag
9.1:1 compression
EQ 1.92 heads, roller 1.65 lifters
Fuel injection
218/218 .500/.500 115LSA
Stock rotating assembly
904 trans, 3.55 gears
13 lbs boost on E85 (which is 10 lbs boost if I were at sealevel)
 
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I never over bore (sort of) This is how I build a engine, most people argue with me about it.
I have a Sunnen hone, I hone all cyls only till there straight, then I measure them. I bring the smaller 7 cyl out to the largest size which is usually only a couple tenths, once they are all the same I call Ross and order pistons. I a little more $ this way but you keep the cyls as thick as possible. In your case you could just finish hone then with a Sunnen hone put in new moly rings keep the same pistons, you need the gap for the boost any way, and your done.
 
Still want to run a dingle berry hone through it to give the rings something to break in on,,smooth bore won't seat ring even if cross hatch is showing...Hell I've torn down 150,000 mile engines and still see hatch marks
 
T56MaxTorq said:
Moper - I want to avoid an overbore with new pistons. So rehoning and using moly rings is better than cast irons? Somehow I was under the impression that cast rings would seal up better on a used, honed bore. As for the 2nd ring, you're saying add .003-4 more gap to the stock, oem limitation?
Click to expand...

If you hone it with anything (dingle ball, a pro shop's equipment, whatever) run iron faced rings and expect they will need time to seat (400-500 miles). because the surface will be left very rough - rougher than moly rings should have. If you use my Scotchbrite deal, I would not use plain iron face because IMO, they may not ever seat. The moly top ring will help them seat on the lightly finished cylinder walls. I'll add I've done this on 5-6 engines over the years with no issues whatsoever.
 
"if you hone it with anything other than my Scotchbrite deal the surface will be rougher than moly rings should have? I don't think so
 
moper said:
I'm of the opinion that if you're not going to bore/hone and replace the pistons then keep it simple. I use green scotchbrite wrapped around my rigid stone hone and WD40 rather than a dingle ball or having the shop hone it.
Click to expand...

Interesting concept of using a green Scotchbrite for cylinder wall conditioning.......where/how did you come up with that?
 
Actually it was something a machinist I worked for told me about. It's not for engines with high mileage whose bores are shot. It's for engines that were rebuilt and maybe are being freshened, or who's bores are in decent shape already. Light abrasive, light oil. It basically cleans out the low spots of the earlier hone without adding to the piston to wall clearance. The last step of a modern fresh hone is a brush to create the plateau finish for the moly-faced rings. Scotchbrite simply does a milder version on the existing plateau surface. If you're not going to address any out of round or taper there's not much of a reason to do much else. A dingle ball leaves a rough surface and the finers stones will not contact the worn wall surface well anyway which is why I'd advise just to use iron faced rings on that. So this is a "cheap and charming" deal. It works great. It's better IMO than honing the **** out of a trashed bore and making it more uneven and so rough the moly will just get torn off anyway.
If someone thinks otherwise that's cool. It's still a free country.
 
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