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-   -   rear rotar lost partial compression (https://www.rx7club.com/new-member-rx-7-technical-256/rear-rotar-lost-partial-compression-995807/)

IdioticMoney 04-22-12 08:44 AM

rear rotar lost partial compression
 
i just purchased a 89 turbo 2 that has 100 compression in the front and 30 in the rear. the guy i purchased it from said i just needed to replace the seals but he didn't tell me what seals that would be and now i can't get hold of him to ask. im going to have a shop pull the motor for me and another guy coming up from san Marcos to Georgetown tx to replace the seals for me but i need tp know which ones to get. are there any other problems i should be looking for or does what the owner said sound like its possible. let me know please cause im gonna tow it to the shop Monday so i can have it running by next week. thanks

Aaron Cake 04-22-12 10:21 AM

"Just replacing seals" means the engine needs to be rebuilt. He likely blew it up by jacking up the boost without appropriate fuel mods.

Just to give you an idea of what the process is to rebuild a 13B:

These videos will help you in the process of rebuild a 13B or 12A engine. While they deal with an older 13B from an RX-5 Cosmo, the engine internals are basically the same for any 12A or 13B. The only real difference is that on engines newer than '85, the coolant o-rings are in the irons instead of the housings as shown in this video.

The first video is engine removal. While it is an RX-5 Cosmo, an car that few will ever see let alone work on, the process will give you the general idea of an engine removal. Steps are similar for most rotary vehicles, it's the details that differ.

http://www.youtube.com/watch?v=zgsbVp22pOE

The next video is engine disassembly and some cleaning. This is an old carbureted 13B so the accessories bolted to the engine are different than newer engines. However the process of externally disassembling any rotary is about the same. Covered here is also flywheel removal (same for any rotary) and engine parts cleaning.

http://www.youtube.com/watch?v=W1MXfs_Srs4

Cleaning of all engine parts continues in this video. Provided here are examples of how this is accomplished with a minimum of tools and supplies. It's a lot of labor to clean old parts until they are looking new again. At the same time, parts should be inspected.

http://www.youtube.com/watch?v=U5A5q61bzRI

Finally, here is the engine assembly. This video includes clearancing side seals, assembling all the seals onto the rotor, then assembling all the parts into a 13B short block.

http://www.youtube.com/watch?v=ijJeUk_GqiI

The seals he is referring to are the "apex seals". You will likely need a new rear rotor housing and rotor, possibly turbine wheel as well because the bits of apex seal tend to destroy things as they come out.

I hope you didn't pay much for the car. Plus the previous owner sounds like a dishonest douche.

IdioticMoney 04-22-12 12:37 PM

i traded my 94 ls integra which needed a new transmission for it and also a new passeanger door. the rx7 has a large street port. upgraded top mount, turbo. lot of suspension work and a custom lsd. body is in great shape too so my car was work like 2k. would it be more cost effective for me to just get a new warranted motor for 1k from a motor import company?

misterstyx69 04-22-12 06:02 PM


Originally Posted by IdioticMoney (Post 11064471)
i traded my 94 ls integra which needed a new transmission for it and also a new passeanger door. the rx7 has a large street port. upgraded top mount, turbo. lot of suspension work and a custom lsd. body is in great shape too so my car was work like 2k. would it be more cost effective for me to just get a new warranted motor for 1k from a motor import company?

Warrantied from an Import company?...
Ya right!..every time I hear that word I smell Bovine Fecal matter!
..not New,used with about 40km and pressure-washed..with water left inside,rusting the guts out of it.

They let you take it out the door,then if it has anything wrong,they say YOU did it..
Contact Japan2LA on forum for any engine needs.He is tops on here.Mark it in the PM as : "Urgent" as he is often stacked up(busy guy).

Manny_Apex 04-22-12 09:51 PM

Good luck man. Its sucks that the previous owner was such a douche. I had one myself, but luckily nothing major was wrong with the car.

IdioticMoney 04-23-12 04:29 AM

well im still happy to own it. i m just going to have the motor sent off to a shop in Dallas i guess am have them fix it. hopefully it doesn't cost more then a grand cause that'd what a new motor will run me...

Aaron Cake 04-23-12 09:05 AM


Originally Posted by IdioticMoney (Post 11064471)
i traded my 94 ls integra which needed a new transmission for it and also a new passeanger door. the rx7 has a large street port. upgraded top mount, turbo. lot of suspension work and a custom lsd. body is in great shape too so my car was work like 2k. would it be more cost effective for me to just get a new warranted motor for 1k from a motor import company?

It might be a better idea time and effort wise to just get a J-spec. But keep in mind they are junkyard engines, and often the "warranty" is so easily voided that it might as well not exist. I'd suggest if you go that route, buy from a reputable supplier like Japan2LA on this forum.

And then figure out why it blew up. If the upgrades are exactly as you listed without any fuel modifications, then that's why it blew up. There are few top mount upgrades out there so it would be curious as to what it actually is. Also, specs on the turbo would help. No sense bolting in a new engine only to have it blow up again.


Originally Posted by IdioticMoney (Post 11065163)
well im still happy to own it. i m just going to have the motor sent off to a shop in Dallas i guess am have them fix it. hopefully it doesn't cost more then a grand cause that'd what a new motor will run me...

It will absolutely cost more than a grand to have it rebuilt. No question. Any less and be very concerned about the quality of work.

IdioticMoney 05-11-12 03:45 PM

sorry i haven't reported. i was going to just give up on the 7 and go a different route cause i don't want to dump more then 2k to get it running. but I've decided to just get a new motor from above mentioned japan2la. just need to pm him and get a price..


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