s2kbrit

Hello all, I am having my block Darton sleeved and I am looking for some insight on whether I can run stock pistons still. I don't see why not but I can't find anyone with a definite answer.

I was planning to install new rings on all 4, replace my one damaged piston and put it all back together without spending another $700 on 4 new ones.

All help greatly appreciated!

AZfury

If the size to the sleeves are the same size for the stock pistons I don't see why not but just make sure with whoever is sleeving it-they will know the answer for that, make sure wrist pins aren't worn either I would replace those along with new rod bearings, your already in there mines-well do those too.

boltonblue

Speaking strictly for myself but I've never been one to skimp on parts when going though the effort of a rebuild.
The labor effort and $$$ of pulling the motor etc etc etc easily out weigh the costs doing it right.

blueosprey90

Sounds like you might be going where no man has gone before.

This is purely a guess on my part, but based on everything I have learned about building an old MGA cast iron engine.

The pistons themselves should not be wear items, and so long as the sleeves are bored to the correct size for the pistons, and you get proper rings for the piston lays, you should be able to reuse the pistons. For boring out the sleeves, the machine shop will need the pistons in hand. This is true even if you get new pistons.

I'm not sure what the wrist pins look like, but get the micrometer out and carefully check for wear. I would replace all rod bolts and bearings. I would check the weights and balance both the pistons and rods.

But care must be taken to correctly analyze why you had a piston failure in the first instance. And then the question is whether it is better to replace the whole set rather than just the one piston. My limited experience is that manufacturers of replacement pistons usually won't sell a single piston.

AZfury

Through honda you can buy just one piston if you wanted to, sounds like that's what they want to do

Legal Bill

If you have to ask here, your engine is at the wrong machine shop. I would not have the work done by someone who does not know the answer to this question. Here is a link to someone who claims to be an expert in Darton sleeve installation in Honda motors. Give them a call.

http://www.rlengines.com/Web_Pages/D...tallation.html

As to your original question, the block came with composite cylinder liners described thusly:

"The S2000 engine block is a one-piece, open-deck aluminum-alloy die casting. Of special note are the block's FRM (Fiber-Reinforced Metal) cylinder liners cast integral with the block. FRM is a composite material consisting of carbon fibers embedded in an aluminum oxide matrix (aluminum oxide is a ceramic material used for spark-plug insulators). As a cylinder lining, FRM offers several advantages over conventional ferrous-metal liners, including lower weight, faster heat transfer and a greater resistance to wear. Additionally, "dummy head honing," a process where the engine block cylinders are honed with a "dummy" cylinder head tightened to the block, improves machining accuracy for stability of piston movement."

So your stock pistons and rings were designed to interface with the FRM cylinder. But that does not mean the pistons won't work with cast iron. The stock pistons are forged aluminum. Forged aluminum can run in cast iron just fine. But I do not know if the stock pistons themselves have any sort of coating over the forged aluminum that may be a problem with cast iron. I tend to doubt it as the coating usually goes on one surface (the liner), but I sure don't know.

Also, keep in mind that aluminum and cast iron expand at different rates when heated. So you need to make sure you bore the new liners to an opening that can accommodate the expansion of the aluminum pistons without allowing oil blow-by. In other words, the stock bore size which was determined for use with FRM liners may be slightly tighter than what you need with cast iron liners. The sleeve manufacturer should know the answer to this question.

I have no idea what the stock rings are made from. I would research that a bit. Maybe they will work fine, but you may need to look for rings that will fit the stock pistons, but were designed to run in cast iron rather than FRM. Try talking to the good folks at Summit Racing.

http://www.summitracing.com/search/p...oview=SKU&ar=1

And now my unasked-for advice.

Your sig line shows an '00 AP1.
How many miles are on the engine? How was the car driven? A moderate or high mile car that frequently visited 9000 rpm might benefit from new pistons. What did your machine shop say about piston wear? They can usually tell just by looking. What is the size of the ring gap on the used pistons and how does it compare to the specifications in the book? Has this been measured yet? What do the used pistons weigh and is the weight of the single new piston different? You may need to have these pistons balanced. Bottom line; You are spending big money on machine shop work and high priced liners. I would not cheap out on the pistons and rings.

This engine came with the old, inadequate oil jets. Do you know if they were upgraded in the past? If so, when? (I don't mean to be preachy, but you should upgrade them now if you have not done so already)

I don't mean to spend your money for you, just telling you what I would do.