matthewsx Posted September 20 Report Share Posted September 20 Searching for a set, or maybe single 1 over piston for my A14 motor I just acquired. john Quote Link to comment
datzenmike Posted September 21 Report Share Posted September 21 I assume that one cylinder is scored? Not the best to do one cylinder. Do them all to 77mm. Rings and pistons from Australia 1mm oversize or 77mm. A14/15.... https://www.swmotorsport.com.au/store/Pistons-Rings-&-Bearings-c123061731 Quote Link to comment
matthewsx Posted September 21 Author Report Share Posted September 21 Thanks, yes minor scoring in the #1 cyl. Can’t catch a fingernail on it so thinking a very light hone will do. Will need to pull all the pistons and inspect but hopefully I don’t find any issues with rod bearings and I will be able to reuse them. Or should I…. I have an A12 motor that needs a crank and have thoughts of building that one up from scratch. Slippery slope. John Quote Link to comment
datzenmike Posted September 21 Report Share Posted September 21 If you pull all the pistons it's better to hone and replace all the rings. Best to measure the cylinders accurately at 6 places. 1/2" down and at 90 to that, then 1 1/2" down and 90 to that and last at 2 1/2 and 90 to that. Record the measurements. This will show if the cylinder is tapered or oval. Measure the piston for that cylinder and subtract and you have the piston/cylinder clearance. It's usually about 0.001" to 0.002" A machine shop has the tools and can do this. If worn but within spec honing and cheap cast iron rings are good for a quick break in. Special chrome rings work best on pristine bores and perfect hone. I don't expect there's that much wear so just hone and ring it. Rod and Main bearings are cheap and can be easily changed with the crank in the block. I would rather have the larger displacement A14 engine. Quote Link to comment
matthewsx Posted September 21 Author Report Share Posted September 21 Thanks for the tips, yes I agree doing all 4 is the way to go. I spent a few years building racing kart motors and did my own rebuilds on Triumph engines a while back so I still have a bunch of tools and measuring equipment. In case it wasn’t clear all cylinders are bored 1 over already. Someone built it up at one point since it has ARP head studs already. I haven’t dropped the oil pan yet so we’ll see what that looks like soon. Provided everything measures out good I’m tempted to just replace the number one piston and do new rings, etc. if I can find a single 1 over piston. But, prices aren’t too bad from the supplier you linked if shipping is reasonable. I should also profile the cam to see if it’s stock or not. Are the timing chains on these motors strong enough that I don’t have to replace if everything else looks good? I’ve got $500 into the motor and another $500 into the car, a ‘62 AH Sprite. I can do pretty much everything myself and would like to target ~$2500 getting it on the road. Don’t want to go down the road of building too much motor for what I want to be a fun town and country cruiser. John Quote Link to comment
datzenmike Posted September 21 Report Share Posted September 21 Piston may be fine. I guess you don't know if they are forged or not till you take them out. Then you would need a forged one to replace it. A series are out of my wheelhouse. Try http://datsun1200.com/modules/news/ Quote Link to comment
matthewsx Posted September 21 Author Report Share Posted September 21 Thanks, appreciate you😄 Quote Link to comment
Stoffregen Motorsports Posted September 21 Report Share Posted September 21 Hey John! The best A motor is an A12A, which uses an A14 bore and an A12 crank. I don't remember any of the piston or rod specs though. Nice to finally meet you and thanks for coming all the way up to Cool. 1 Quote Link to comment
matthewsx Posted September 22 Author Report Share Posted September 22 Have the piston out now, will need to build a pin puller but no big deal, have a lathe and mill here. It measures 76.89mm so definitely 1mm over. Would like to find a single but would take a set if available. Once I get this motor going I may build up the 1200 I have for a future project. John 1 Quote Link to comment
matthewsx Posted September 22 Author Report Share Posted September 22 I really enjoyed porting and all the other stuff I did to build the crazy kart motors I used to sell. I may even resurrect my old dyno some day, it would work with these engines with a few modifications. John 1 Quote Link to comment
datzenmike Posted September 23 Report Share Posted September 23 52 minutes ago, matthewsx said: Have the piston out now, will need to build a pin puller but no big deal, have a lathe and mill here. It measures 76.89mm so definitely 1mm over. I've pressed pins out before. 1,200-1,400 PSI did the trick. I was careful to support the piston properly. Maybe I should have heated the small rod end first to expand it. 76.89mm is curious. Can you measure the bore at the very top where there is no wear??? 2 Quote Link to comment
matthewsx Posted September 23 Author Report Share Posted September 23 Made a puller with my lathe & mill yesterday, will use all thread and yes, piston supported all the way around the pin. Shouldn’t need heat but have all forms of it if needed. Measurement was of the piston with digital caliper, biggest mic tops out at 3”. Hopefully I can get a single 1.00 over piston. Will just do a light hone of all cylinders and put in new rings and bearings. I do know how to check more throughly but will not be doing any machine work this time so knowing won’t change the planned process. John 1 Quote Link to comment
matthewsx Posted September 24 Author Report Share Posted September 24 Ordered a "forklift" piston yesterday, will see when it gets here. https://www.ebay.com/itm/374910058206 John 1 Quote Link to comment
Stoffregen Motorsports Posted September 24 Report Share Posted September 24 (edited) Nice score! But replacing one piston, hopefully it weighs the same as the others. Edited September 24 by Stoffregen Motorsports Quote Link to comment
datzenmike Posted September 24 Report Share Posted September 24 I'm concerned what the piston to bore clearance is. These might be forged pistons if used in competition and they require more clearance to allow for heat expansion when warmed up. A regular hypereutectic piston expands very little and will have too much bore clearance. Something to think about. Quote Link to comment
matthewsx Posted September 25 Author Report Share Posted September 25 6 hours ago, Stoffregen Motorsports said: Nice score! But replacing one piston, hopefully it weighs the same as the others. Will weigh and measure before using. Would weigh and balance all four if I bought a set anyway. Much remains to be seen, it was only $20 and bought through eBay so can probably send it back if it’s wrong. Otherwise a nice paperweight. John 1 Quote Link to comment
matthewsx Posted September 25 Author Report Share Posted September 25 6 hours ago, datzenmike said: I'm concerned what the piston to bore clearance is. These might be forged pistons if used in competition and they require more clearance to allow for heat expansion when warmed up. A regular hypereutectic piston expands very little and will have too much bore clearance. Something to think about. The one I removed appears to be a stock cast oversize piston. Will compare carefully before installing and if anything isn’t right I’ll probably have to bite the bullet and order a full set from OZ. They haven’t returned my message yet about shipping costs but I’d much rather replace one @ $20 than all four at ten times the cost. I’ve had the pleasure of speaking with several other enthusiasts trying to source pistons here in the US but have so far come up empty. Problem is the 1.00 over size. Fortunately this isn’t my first engine repair so I’m fairly confident I’ll be able to get it right. Of course if I have any questions I know exactly where to come ;^) john Quote Link to comment
matthewsx Posted Saturday at 10:38 PM Author Report Share Posted Saturday at 10:38 PM Well, It’s only about 11mm too big. 🙄 Ill be reaching out to the Aussies next to see about getting a set…. John Quote Link to comment
datzenmike Posted Saturday at 11:24 PM Report Share Posted Saturday at 11:24 PM So the one you bought on line is 87mm? How could they screw that up? VG30 and Z22 pistons are 87mm Quote Link to comment
matthewsx Posted Sunday at 12:03 AM Author Report Share Posted Sunday at 12:03 AM 36 minutes ago, datzenmike said: So the one you bought on line is 87mm? How could they screw that up? VG30 and Z22 pistons are 87mm Don't think I should blame them. The part number was really close so I took a chance... Have questions out to SW Motorsport and a couple of other eBay vendors. I'll get it eventually😁 John 1 Quote Link to comment
matthewsx Posted Tuesday at 04:38 AM Author Report Share Posted Tuesday at 04:38 AM Ordered this set. https://www.ebay.com/itm/175026755888?_skw=175026755888&itmmeta=01J935QJV0K4S03DG0SB63QE6K&hash=item28c0685930:i:175026755888&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKlDD0Fn9clw4QNLrLN7k9b28u2vev9xHlpBBOdVd1Xzv%2FGcNm1V5iiqJQdousX3D6v8SiXgu0HzqT1Kpvt5%2Fd49X8wy6Kz7w6HSULj3TKAd9lpfyf9XszW%2FEtOV0JyToZXMu1NbIaM6VXpbOC922L7wAFUHbrOnlLeUgKc%2BKFCeXQS3PhXPlSFCnV5%2BBWbitIOv42QzUJtJvPzwXMdSvENaF6I5qvSrrm%2FKOAHgDsMZx8Ax6fPBHXn0AtmdYYA6odHbskoQQpLJMgC2i2Ro2ljXubeazYpofnKOF3%2BVVhz8NQ%3D%3D|tkp%3ABk9SR8at3uXIZA john Quote Link to comment
datzenmike Posted Tuesday at 01:27 PM Report Share Posted Tuesday at 01:27 PM Nice video but doesn't show the pistons or rings. Good price though. Were the the 1 mm over that you wanted? Quote Link to comment
matthewsx Posted Tuesday at 05:16 PM Author Report Share Posted Tuesday at 05:16 PM Well, they said I ordered the wrong ones and cancelled my order. The ones I need are here. https://www.ebay.com/itm/134321831919?var=433775115710 Also no picture and $28 more but shipped from the US and should be here next week. At least with eBay if not as advertised I'll get my money back. John 1 Quote Link to comment
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