deanfun Posted January 20, 2015 Share Posted January 20, 2015 Hey from Canada! This place seems like the internet-nexus for 60/70-series crowns, and I would love to see if someone can help me with my problem. I currently have three Crowns - two MS65's and an MS75. I'm doing a cheap-ish rebuild on one of my 4M's simply to get one of the cars running and have encountered a weird problem. This is what my current pistons look like. Note they are raised, not flat. Finding replacements for the 4M is not a walk in the park, especially not in North America. Nothing is simple. Look at the two standard size piston options I have: Crappy looking no name set without rings, but has a raised top: http://www.ebay.com/itm/Toyota-Crown-2600cc-4M-Corona-MK2-2600cc-4M-New-Standard-Size-Engine-Pistons-/311218945353?pt=Motors_Car_Truck_Parts_Accessories&hash=item4876183d49&vxp=mtr Great looking TRW's with rings... but they are flat tops, with a valve relief I don't need. http://www.ebay.com/itm/NOS-TRW-TOYOTA-4M-80mm-Engine-Pistons-Rings-Pins-2-6L-Supra-Cressida-/220988219773 I've googled far and wide, and as you might imagine, there isn't a whole lot of 4M information or pictures out there. I have found ONE reference to 4M's with different compression ratios, here in an old build thread: //oldschool.co.nz/index.php?/topic/39462-julwers-ms65-crown/#entry1134029 I'm tempted to go with the TRW's because they are cheaper, "look" better, and include rings... and I'll just deal with what will certainly be a decrease in power relative to whatever stock was 40 years ago. However, it's not like the 4M has much power to spare. The crappy castings on the set with the raised domes are making me wary. I would appreciate any help, info or comments. Cheers! For your troubles, this is what I'm working with... and my 1JZ MA67... 3 Quote Link to comment Share on other sites More sharing options...
sheepers Posted January 20, 2015 Share Posted January 20, 2015 hey man. off the top of my head the only thing i can think of is that there was two different heads used on the 4M. one looks like a 2M and one looks like a 5M-U. i have no idea if there were different pistons used in the two variants but ill have a look in my manuals tonight and see if i can find anything that shows the pistons. nice 75 by the way. oh, and do a build thread for your MA67 Quote Link to comment Share on other sites More sharing options...
igor Posted January 20, 2015 Share Posted January 20, 2015 If you were here in New Zealand I'd suggest dumping the 4M and repowering with something like a Falcon or Holden six that you can get parts for easily. Must be something available in your part of the world that would be an easy swap if you really can't get the 4M fixed. Quote Link to comment Share on other sites More sharing options...
deanfun Posted January 20, 2015 Author Share Posted January 20, 2015 hey man. off the top of my head the only thing i can think of is that there was two different heads used on the 4M. one looks like a 2M and one looks like a 5M-U. i have no idea if there were different pistons used in the two variants but ill have a look in my manuals tonight and see if i can find anything that shows the pistons. nice 75 by the way. oh, and do a build thread for your MA67 Way ahead of you... http://www.celicasupra.com/forums/showthread.php?54173-Let-s-do-this-slowly-(Canadian-85P-restore) Are there any visible differences between the heads? I bought the 75 about 4 years ago. It's unfortunate that this one is in such poor shape body wise. They are incredibly rare in north america, but also worth just about nothing. It's not worth the effort to restore - I've already done that to my MA67 which serves the same purpose. The sedans I bought as a pair - one was supposed to be a runner, the other a parts car. Both are in great shape and come with a bunch of spares. The "runner" lost compression on two cylinders on it's maiden voyage home, hence the rebuild. I have no aspirations of performance with these cars - hence the straight up 4M rebuild. Quote Link to comment Share on other sites More sharing options...
deanfun Posted January 20, 2015 Author Share Posted January 20, 2015 If you were here in New Zealand I'd suggest dumping the 4M and repowering with something like a Falcon or Holden six that you can get parts for easily. Must be something available in your part of the world that would be an easy swap if you really can't get the 4M fixed. The idea of a 3B has already been discussed... but this is about getting it on the road, running ASAP. I bought it to enjoy and drive, not build. And yet, somehow I'm here building again. Quote Link to comment Share on other sites More sharing options...
h4nd Posted January 21, 2015 Share Posted January 21, 2015 Odd, that web address looks a lot like irex-jp.com, who I've had good results from via Alex / moonlight. Lot's of crown bits here http://www.irex-jp.com/catalog/default.php/cPath/100_91?PHPSESSID=11227db7b81edddedae67628e3c0a155 (use google chrome to translate, or translate.google.com) but no pistons, sorry. None of those lovely Jun kits fit? http://www.junauto.co.jp/products/customkit/lineup.en.html These guys list em, none in stock? http://www.supertoyotaparts.com/oe-toyota/1310145011?search_str=13101-45011 http://toyotaparts.bochtoyotasouth.com/oe-toyota/1310145011 http://oemparter.com/oem-parts/1310145011.html ...or add big head gasket for lower compression and add turbocharger? Quote Link to comment Share on other sites More sharing options...
deanfun Posted January 23, 2015 Author Share Posted January 23, 2015 I ended up pulling the trigger on the higher compression pistons. We'll see how it goes when they get here. Thanks for the replies! Quote Link to comment Share on other sites More sharing options...
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