240Z, 260Z, 280Z Performance / Technical Discussions related to performance motor enhancements, upgrades.

Engine Rebuild Suggestions

Old 11-20-2005, 10:48 AM
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Engine Rebuild Suggestions

My block is in need of a rebuild. My piston rings are bad, which is burning oil inside of the combustion chamber, making the car like a rolling smoke bomb upon acceleration. I know it's nothing related to the valves, because the head is fully rebuilt with new seats, seals, everything. So, I figure that while I'm changing the piston rings, I might as well get new rod and main crankshaft bearings, get the crank micropolished if it needs it, and get a new rear crankshaft oil seal.

I looked into Victoria British for my rebuild needs, and their prices are as follows:
  1. Piston Ring Set: $39.95
  2. Main Bearing Set: $49.95
  3. Rod Bearing Set: $29.95
  4. Rear Crankshaft Seal: $8.95
So, what kind of quality can I expect from the rings and bearings from VB? Are one type of ring better than the other for a mostly stock setup? Will I need to hone my cylinders, and how can I tell if I need to? How can I also tell if the crankshaft needs to be micropolished?
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Old 11-20-2005, 12:22 PM
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I did some more research into cost of engine rebuild parts from Autozone and Kragen's, and so far, I've come out with these prices:

1. Premium Ring Set (Chrome top ring): $66.99 (A/E Clevite, Kragen's)
-or-
2. Regular Ring Set (Cast Iron top ring) $40.99 (Beck/Arnley, Kragen's)
3. Main Bearing Set: $30.59 (A/E Clevite, Autozone)
4. Rod Bearing Set: $32.94 (Autozone)

My total with tax for the premium rings and other bearings would be $140.63, and the price for the regular rings and other bearings would be $112.62.

I did some research into the difference between Chrome top ring and Cast Iron top ring, and this site came up http://www.hastingsmfg.com/Service%2...ecommendat.htm. They state that cast iron rings are good for an every day engine, but chrome rings are good for enviroments where the engine may be driven hard, or dusty enviroments and that of the like. I'd like to be able to take my car down to the track and not have to worry about hurting the engine, so would chrome be a better way to go?
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Old 11-21-2005, 01:24 PM
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I'm tearing down my motor now, and have been looking at the exact same issues. I currently leaning towards the iron rings, based on the following:
My own experiences over the years
Knowing how I'll build and use the car
Having read Wick's How To Restore Your Z book, as well as the two Nissan OHC books from Fisher publishing (how to rebuild, and how to modify). Also, check out this guy's site: http://www.geocities.com/zgarage2001/z.html

That's mostly due to my intended use, which is fun twisty roads on nice sunny days, long highway trips, mountain passes, fun hot lap days at the track or Solo2 events. Mine won't be heavily modded just a little more aggressive cam, a header, and a little head/intake polishing. In other words, some more power, but not ridiculous, and fun/spirited driving, but not crazy. That combined with what I was reading and seeing made me decide on the iron. Hell, the original ones lasted 27 years and were in good shape. The only reason they're getting replaced is I'm rebuilding the entire car from the unibody up.

The one thing that's making me think chrome is the purported durability of it, and the stock chrome rings I've had in my 22R Toyota (well loved, but much abused) truck since 1989 (180k mileage).

Don't forget that there are other bits and pieces you'll have to get. There'll be lots of random gaskets (timing cover, maybe water pump, etc.), various materials like cleaners and solvents, new oil and filter. Maybe a new bolt set, hot tanking the block, a set of freeze plugs and some engine paint, too. Having read in other threads here about the other work you've already done, my guess is you're pretty well set-up on a lot of materials and tools, but it just wouldn't be a project without a new tool (how about some ring pliers, or some telescoping gauges and micrometer set? Perfect for Christmas!). Given the nice work you already did on your head, I'm guessing you already have the really expensive tools: an engine stand, a crane, and some nice torque wrenches.

Don't forget that the cost could potentially get pretty nasty. The worst case scenario is that your bores are too tapered and you'll have to bore it out enough that you need new pistons, and maybe you have to deck the block enough that now you need to shim your cam towers (really unlikely, but...). If you haven't already, check out the How To Rebuild Your Datsun / Nissan OHC Engine book. A lot of libraries have it, so you could check it out for free and decide if you like it or not. The section on deciding how much work your engine needs is priceless, and could save you from putting new rings in to a too-tapered bore and having to do this all over again in 10,000 miles.
good luck!
Dave

Last edited by BoulderZ; 11-21-2005 at 01:29 PM.
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Old 11-21-2005, 06:32 PM
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Good advice from Dave. One question Jeremy, did your engine smoke that bad before you got head?
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Old 11-21-2005, 10:31 PM
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Thanks for the feedback Dave! Yeah, I have an ok set of tools, enough to get me by. I've got a good Stanley socket set (my dad's), an engine lift, and a $30 torque wrench from Harbor Freight. I know I have to get gaskets and everything else, but I had discounted that out of the main parts necessary for the rebuild. The Geocities site you listed above is a good site, I read it when I've got questions just to check to see if he touched on it already. As for measuring taper and whatnot, I think I might take it to the local machine shop to get checked out, because I'm unsure as to what to look for. I did have to take the block down to the machine shop to get a broken off head bolt out, and the guy who got the bolt out also took a look at the ridges in the cylinders, and he said that the motor looked in pretty good condition. I figure my worst case scenario would be putting rods on my old pistons in my old block, dropping the crankshaft from the 'newer' block into the older block, and rebuild that engine. My original/older block spun a rod bearing, but never burned oil. It didn't even smoke on startup! It only had 120k miles on it when it died. But it did have a cracked head. I figure that if it didn't smoke, then the rings and bore in the cylinder should be pretty good, so I could always go that route. I did notice that there was more of a ridge on the older/original block than the 'newer' one.

Tom, I think the engine smoked before I got head too. I did notice on the last build with the original head (before I tried the one you hooked me up with) it went through a quart of oil in the 3 days I had it running, and I noticed water in the oil at the gas station. I had chocked it up to the water being in it and displacing the oil, but now that I think about it, it was burning oil back then.

If the crankcase had oil in it, what are the chances that I have gouges in the crankshaft from the water getting in there? I'm worried about having to get my crankshaft reground...I've already spent over a grand on the motor trying to get in the right direction, and now I've got a brand new head with a half *** block. It even ate the Lucas I put in the motor. Damned motors.
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