Dayz Posted October 1, 2008 Share Posted October 1, 2008 As the title says, I am rebuilding my engine and see very little detonation. What is your advice? I could dismantle another engine to steal its piston, but that would be a lot of work. Everything else look very good, I just want to make sure. Here is the piston with markings and another one that look like the five others. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted October 2, 2008 Share Posted October 2, 2008 It's the damage along the edge I'd be concerned with. I had forged pistons one time with det damage, and the top edge was distorted downward and pinched the ring land to where the rings did not have the proper clearances... Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 2, 2008 Share Posted October 2, 2008 I'd not reuse them... but who is saying the other pistons you get will be any better? You may end up weight matching with a set of drug scales (er...postage scales) and using POTL (Pick of the Litter) between the 12 you have to choose from...if I were using used parts, that would be where I'd tend to lean. But only after very careful measuring of everything! Ring side clearance is like JS said, hare to 'eyeball' but once you stick a ring yer screwed! Quote Link to comment Share on other sites More sharing options...
woldson Posted October 2, 2008 Share Posted October 2, 2008 I'd not reuse them... but who is saying the other pistons you get will be any better? You may end up weight matching with a set of drug scales (er...postage scales) and using POTL (Pick of the Litter) between the 12 you have to choose from...if I were using used parts, that would be where I'd tend to lean. But only after very careful measuring of everything! Ring side clearance is like JS said, hare to 'eyeball' but once you stick a ring yer screwed! LOL, I was thinking ash trays. Quote Link to comment Share on other sites More sharing options...
Clifton Posted October 2, 2008 Share Posted October 2, 2008 I wouldn't use them either. Det will/can crack ring lands and stack them tight on the ring or snap them off. Even if they aren't visibly cracked I would be concerned knowing the crown is showing signs. Quote Link to comment Share on other sites More sharing options...
Dayz Posted October 2, 2008 Author Share Posted October 2, 2008 I guess I will dismantle the other engine and POLT (see tony's post) It is a very stock 240z rebuilt, as a present for my father...so no real performance is in the future. If on this piston, my ring clearances are fine, is it usable or I will have a nice paperweight either way? What impact does it have on the rebuilt engine? This camera is awesome, I can see a lot more detail on this pics than by looking at it. Thanks guys, Dayz Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted October 2, 2008 Share Posted October 2, 2008 Why don't you ask around for another piston? Someone here must have a piston or two laying around..or an ashtray. Anyone? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted October 2, 2008 Administrators Share Posted October 2, 2008 As mentioned already, scrutinize for broken/collapsed ring lands AND collapsed/cracked/broken piston skirts, as well as galling in the piston pin bores and out-of-round pin bores. If all is good, those pistons would be fine for a typical "stock" overhaul, otherwise they make for "ok" ashtrays or hardware containers. Quote Link to comment Share on other sites More sharing options...
ozconnection Posted October 3, 2008 Share Posted October 3, 2008 This camera is awesome, I can see a lot more detail on this pics than by looking at it. One of the many reasons people get into photography A lot has to do with light casting and camera settings!! Enjoy. Quote Link to comment Share on other sites More sharing options...
Dayz Posted October 3, 2008 Author Share Posted October 3, 2008 I will go and do it right with a good set of pistons. Anyone have a good set STD size? I am sure they could work, but why not doing it right the first time. Thanks for your help guys, Dayz Quote Link to comment Share on other sites More sharing options...
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