Source for 30 oversize Total Seal rings and pistons?

[nelstomlinson]

The machine shop called. They say the 7.3 block will need to go to 30 thousandths over to clean up the pitting. They can't get Total Seal rings or pistons, so I need to find a source. R&D only has 20 thousandths oversize, so can't go there.

So, where is a source for the oversized Total Seal rings? Will they fit stock pistons? Or will they require something special? Rock Auto has Sealed Power pistons for $73 each.

From the Total Seal website, it looks like the part number for gapless rings is s1474. Can't find any evidence that they make pistons.

 

[aggiediesel01]

Are all the holes that bad? .020" over is usually the conservative limit on cutting these. Much more and the chance of cavitation goes up and the cylinder walls are pretty thin at that point. What is the goal of your rebuild? Total Seal rings are a pretty premium product, if your goal for this motor is long life and high HP then I think I'd be investigating other options than boring .030". Down here in Houston, sleeves are about ~$100 a hole. Are your existing pistons good? By the time you spend $73 on pistons and whatnot to get them in the engine I'd bet your at nearly breakeven for sleeves per hole and you're back to stock size not ever having to worry about cylinder wall flex or cavitation. Other option is to look for a better block, for the money spent on boring and pistons a better block could likely be had and once again your ahead on quality of your bottom end.

 

[nelstomlinson]

I will ask the shop on Monday about sleeving. I would rather go that route, if the stock pistons are OK and if it's affordable up here. On the other hand, I'm consistent about keeping the nitrate levels up, so there shouldn't be cavitation problems.

Not finding anyone who stocks these in any size except R&D. I'll try calling Total Seal on Monday.

Edited to add: The last of these blocks rolled off the line 26 years ago. I haven't opened any of my other engines, but I suspect this one is better than most of them.

 

[nelstomlinson]

WHat makes a piston unusable? Looking over the existing ones, there are faint scuff marks on the skirts, and a bit of carbon, but otherwise no obvious problems - no signs of cracking or melting on the tops. I guess I need to measure the ring lands. If the lands aren't wallered out too big, are they good to go?

 

[IDIBRONCO]

You also need to check the skirts to make sure that one hasn't collapsed for some reason. Faint scuffing won't hurt anything. The thinner cylinder walls make them more likely to have cavitation issues at .030" over. The machine shop that we used when I was in the IDI business wouldn't bore to .030". It was either .020" or sleeved to standard. They felt that .030" left the cylinder walls too thin.

 

[aggiediesel01]

Roundness, Ring lands, wrist pin wear, skirt wear, cracks or overheating damage to the crown/top. There are allowable dimensions for each, probably listed somewhere on here but I don't remember them off the top of my head. If they pass they're useable

 

[IDIBRONCO]

Roundness, Ring lands, wrist pin wear, skirt wear, cracks or overheating damage to the crown/top. There are allowable dimensions for each, probably listed somewhere on here but I don't remember them off the top of my head. If they pass they're useable

Better than what I came up with.

 

[nelstomlinson]

There are folks up here getting away with running 'em 30 thousandths over without any nitrites in the coolant. I might get lucky, too. I'd rather spend a little extra and get a better engine, if I can afford the extra cost. I'll talk to the shop on Monday.

 

[IDIBRONCO]

Nobody said that you can't do it. It's just more of a risk to do than keeping the bore smaller.

 

[nelstomlinson]

Nobody said that you can't do it. It's just more of a risk to do than keeping the bore smaller.

Like I say, I know folks who are doing it, and so far so good. The machine shop doesn't see a problem with it.
I'll find out later this morning what it will cost to not take the risk. Saving the cost of 8 pistons is going to go a long way to pay for the cost of 8 sleeves.
The shop is saying that the iron in these blocks was soft. Putting in a harder sleeve might make the engine last longer, so that would be an extra bonus.

 

[nelstomlinson]

I talked to the machine shop this morning. We were at $2400 for everything if we were going 30 thousandths over, and he can sleeve all eight for $2750 for everything. $350 extra to get it back to stock is worth it.

 

[Shadetreemechanic]

Good call.