2.3 N/A - how much to mill the head? what pistons to get?

[Ray III]

I started my car up one morning, and all a sudden it's making this loud ass hammering sound. It freaked my dad out but what was he gonna do about it lol. I put about 100 miles on the car like that then when I was putting on a Ranger header I stuck a die grinder in the exhaust ports (don't do this) and next morning POOF biggest cloud of smoke you ever see come out of a 4 banger. It went away but I wasn't looking forward to putting THAT much oil in the car and didn't want to ruin a brand new catalytic converter and what with the banging noise pissing me off I yanked the head off. I wanted to re-grind the valves and seats and install a roller cam anyways. But then dad says I have to take the whole damn thing out and prove to him there's no rod knock, and the bottom end is a bit worn anyways. Couple days later after excessive dicking around I finally have the head and block stripped for machining. Turns out I shattered one of those peice of crap cast pistons on an earth moving 90 horsepower

***THIS IS THE PART OF THE POST WHERE I GET TO THE POINT***

I am doing a 0.010" overbore on the block and need to replace the pistons. Obviously I am not sticking stock N/A trash back in there. The question is, will the forged turbo pistons fit on the same connecting rods with the same compression height? Do they use the same rods? If not, (or if I can't find any) I was thinking of going with TRW forged stock replacements. Sound good? I did a search and read something about higher compression pistons; how is that possible when the pistons already sit nearly flush with the deck? Domed pistons?

Also, I plan on having the head milled to increase compression for more power. The thing is, information on stangnet is kind of vague about precisely how much to take off. I saw alot of mention of 0.060", but I was told 0.010" on corral, though the fellow said I could probably go higher. This is the pre-91 engine. I want a compression ratio that 87 octane crap gas can handle, plus advanced timing. I'm not looking to go crazy here. What's the safe amount to take off, and what will be the resulting compression ratio?

Thanks fellas

 

[Dan P.]

Bhuff might be of some help on this. He had his head milled and replaced his pistons with forged pistons.

 

[bhuff30]

First of all, you need to figure out what caused the piston to shatter. When I went lean with my turbocharged NA engine, all I did was break the compression rings. They are suprisingly strong.
If you must go forged, you will find that the TWR's arn't avaible anymore, and havn't been for years. The most affordable forged piston right now will be the Diamond stock replacement (search on Turboford). Your rods will work. Without milling the head, your compression will drop to 8.3:1.
Unless you have a power adder in your eyes for that engine, I would stick with a hypereutectic. They can run a closer piston gap, and will never knock on startup.
As for milling the head... I went .090 with my dish pistons to get 9.7:1 compression. I have absolutly no trouble with running 87, and I would like to creep it up to 10-10.3:1 by milling another .020 or .030

 

[Ray III]

Thanks for the replies. Yeah I was thinking I should just get a good set of cast pistons, I doubt I am going over 150 horse with this one.

Just to clear up what I have read elsewhere, ALL 2.3 motors use the same cylinder head and bottom end, and the turbo just has dished pistons?

I've read .060" off the head, should I do that if I get stock spec replacement pistons? I tried doing all the calculations for how much to take off but I don't seem to have the combustion chamber volume figured out perfectly, I measured 58cc but it should be 62 from what I read?

need to get this thing together, I'm driving my dodge around and that thing is a terrible nuisance to keep running!!

oh yeah, it was excessive piston to wall that shattered the skirt. I have a pic maybe I will get it on here sometime. There was a big crack in my air cleaner that I think wore the engine out rapidly.

 

[Bearded Forever]

I put about 100 miles on the car like that then when I was putting on a Ranger header I stuck a die grinder in the exhaust ports (don't do this) and next morning POOF biggest cloud of smoke you ever see come out of a 4 banger.

Did you grind the exhaust with the head on?

 

[stackz]

Just to clear up what I have read elsewhere, ALL 2.3 motors use the same cylinder head and bottom end, and the turbo just has dished pistons?

you read wrong. the turbo heads are indeed different from the n/a heads though not by much. I found this out when my turbo engine's head had some radical cracks in the exhaust seats and I had to use my old n/a engine's head. The n/a heads have smaller combustion chambers due to a little triangle island coming out between the valves, the turbo head lacks this little formation and thus has that little bit extra combustion chamber volume.

also, most people say the exhaust valves are hardened on turbo heads but when I was swapping valvetrains between the two heads I honestly couldn't tell the difference in the n/a exhaust valves or the turbo exhaust valves, not in color, metal characteristics, shape, size, taste, blah blah blah but I used them non the less haha.

Turbo head springs (at least for 86+ turbo heads) are higher rate and wound oppositely as opposed to the n/a head springs. average seat pressure on my turbo head springs was about 40-50lb's higher per spring compared to the n/a ones, probably due to the higher lift from the turbo camshaft.

Thanks for the replies. Yeah I was thinking I should just get a good set of cast pistons, I doubt I am going over 150 horse with this one.

why don't you turbo it anyway since you're rebuilding it? There's a set of turbo pistons on ebay right now new in the box for $88....

http://cgi.ebay.com/ebaymotors/ws/e...tem=2480572332&category=33623&sspagename=WDVW

turbo is so much more fun than n/a anyway haha, I wouldn't mill that head down anymore than you positively have to. every bit you increase that c/r with means the less tolerant the engine will be to lower grade pump gases...

 

[Ray III]

well I don't want TOO much power out of this thing, just whatever natural aspiration can get me, I might eventually give this car to my little brother and god forbid he start out with too much torque. He isn't yet aware that there is life beyond an 88 Civic. Besides I already pissed away money on the entire exhaust.

I'm going to tell the jobber to take .060" off... I'll just dial in an appropriate amount of timing after that

Did you grind the exhaust with the head on?

Yea why? I just wanted to open the ports like 1/16" and get some of that soot out of there. No, I don't think you should try it lol.

 

[Red_LX]

One thing you guys are missing is that if he does a .010" overbore he won't be able to use stock turbo pistons.

why don't you turbo it anyway since you're rebuilding it? There's a set of turbo pistons on ebay right now new in the box for $88....

Didn't you notice that those were hypereutectics? You don't wanna run that junk with a turbo, they don't hold up at all.

Anyway the stock compression is 9:1...I figure you could PROBABLY get away with 10:1 on 87, but I don't really know for sure.

 

[Ray III]

but how much would I mill to get 10:1 is what I'm asking?

the overbore's going to .020" now cuz Perfect Circle don't make rings for .010"

 

[stackz]

Didn't you notice that those were hypereutectics? You don't wanna run that junk with a turbo, they don't hold up at all.

nope didn't notice that but then I didn't really look all that well at the listing