worth rebuilding my engine?

Silver86 · 09-06-2009, 05:47 PM

is it even worth the effort? it runs like garbage... not entirely sure whats wrong with the engine, i know theres either a stuck or blown side seal in one of the rotors... NoDOHC came out the other day to give me a hand and he said it almost sounds like it is running on 1 rotor. maybe hell chime in and give me some professional advice.

saving up for this 20b N/a project is gonna take forever and i would like to at least drive and enjoy the car before i put her under the knife...

looking at this beautiful paperweight i have sitting in my driveway makes me all emo...

JShiz · 09-06-2009, 09:12 PM

Open it up and see the damage so you can make a good call.

Max777 · 09-06-2009, 10:15 PM

Dude, mine ran kinda crappy, the compression was low, it was only pulling about 12" of vaccum at idle, and the transmission had about 140K on it. I priced out a rebuild, and all the work/tools/time involved, and decided that unless there is some concrete reason you want to keep the N/A powerplant, a TII swap just makes more sense. Also, if a TII engine blows, there is more reason to rebuild IT, rather than the crap N/A.

Silver86 · 09-06-2009, 10:45 PM

Quote:

Originally Posted by Max777

Dude, mine ran kinda crappy, the compression was low, it was only pulling about 12" of vaccum at idle, and the transmission had about 140K on it. I priced out a rebuild, and all the work/tools/time involved, and decided that unless there is some concrete reason you want to keep the N/A powerplant, a TII swap just makes more sense. Also, if a TII engine blows, there is more reason to rebuild IT, rather than the crap N/A.

good reasoning, but a TII swap is not something i want... i would rather rip out my N/a powerplant, rebuild it and re-install... thus getting a chance to enjoy the car (even if its slow) while i buy/build/prep for the 20b swap.

need RX7 · 09-06-2009, 10:52 PM

Since you're trying to save for the swap, I'd look for a known-running, low-ish mile engine and throw it in for the time being. It won't cost as much as a rebuild and it'll get you back on the road. Of course, there's always the chance that there will be something wrong with it and it will put you even deeper in the hole...

RETed · 09-07-2009, 02:05 AM

Did anyone mention doing a COMPRESSION TEST before opening the engine up???

-Ted

Phoenix7 · 09-07-2009, 02:13 AM

Do a compression check first and then just stare at it as you gather the 3-rotor stuff (or you buy it all at once, dunno your situation).

Honestly, I wouldn't rebuild an NA but that's just me. I currently have a blown FC that I haven't touched because it's not worth my time or money to rebuild it (also have very little time) but I'm looking into a drop-in spare motor for it to get it on the road by spring..... If it was a 13BT then I'd have it apart and trying to rebuild it as we speak.

If it IS blown then look for a spare, decent running motor and drive it till it blows again.

need RX7 · 09-07-2009, 03:04 AM

Quote:

Originally Posted by RETed

Did anyone mention doing a COMPRESSION TEST before opening the engine up???

-Ted

Yes, do this if you haven't already. I assumed it was always a given.

Phoenix7 · 09-07-2009, 03:42 AM

Quote:

Originally Posted by need RX7

Yes, do this if you haven't already. I assumed it was always a given.

me too, blown motor = compression test showed 0 psi on 1 or more rotors.

Silver86 · 09-07-2009, 02:23 PM

Quote:

Originally Posted by RETed

Did anyone mention doing a COMPRESSION TEST before opening the engine up???

-Ted

lol... im no noob Ted... of course if did a compression test. it was the first thing i did after i got the car home after buying it. its been a few years... so i might as well try it again, just to see if anythings changed. the last i did check it though... i do remember now... i did get 3 decent pulses on the front rotor... and only 2 on the rear... that was also 3 years ago.

***TitaniumTT*** · 09-07-2009, 07:03 PM

Rebuild it. If you've got good comp in the front rotor and only one low pulse in the rear, it's definately worth rebuilding rather than let it sit for 2+ years

If you don't expect the motor to last forever pull it apart, clean everything up really well and reuse most of the seals. Buy new oil control o-rings, dowel rings, fire/coolant seals and just do the bare minimum. Even if a housing is chunked a decent N/A housing should be able to ba had for a bill or two. At that point you're looking at your time. Total time to do that should be in the 30-40 hour range. So wake up saturday morning and work until Sunday night and you'll be 90% of the way there.

Seems like a no brainer to me.

RETed · 09-07-2009, 11:52 PM

Quote:

Originally Posted by Silver86

i did get 3 decent pulses on the front rotor... and only 2 on the rear... that was also 3 years ago.

Only 2 on the rear might mean just a stuck side seal.
Try soaking the rear rotor in ATF or MMO or whatever your fav is.
1 good and 2 bad / no pulses is indicative of a bad apex seal and guarantee a rebuild.

If it's a stuck side seal, there's a chance you could resurrect the engine without opening it up...

-Ted

Silver86 · 09-08-2009, 03:16 AM

Quote:

Originally Posted by RETed

Only 2 on the rear might mean just a stuck side seal.
Try soaking the rear rotor in ATF or MMO or whatever your fav is.
1 good and 2 bad / no pulses is indicative of a bad apex seal and guarantee a rebuild.

If it's a stuck side seal, there's a chance you could resurrect the engine without opening it up...

-Ted

how would i go about positioning that side of the rotor down so itll soak? crank the engine by hand?

err i worder that wrong... how would you do it Ted?

RETed · 09-08-2009, 01:32 PM

Yeah, crank by hand.
I typically use the 19mm bolt in the center of the main pulley.
I'll pour the liquid via a hose and funnel through the leading spark plug hole(s).
Crank just enough just to get the liquid to go through.
Don't crank it too many times, and it starts to get spit out the exhaust.
Allow to soak 24 hours or overnight.
With ATF, it should fire up.
Just be warned that ATF burning causes a HUGE SMOKE CLOUD.
It'll take a few minutes to burn off.

-Ted

Silver86 · 09-08-2009, 02:09 PM

Quote:

Originally Posted by RETed

Yeah, crank by hand.
I typically use the 19mm bolt in the center of the main pulley.
I'll pour the liquid via a hose and funnel through the leading spark plug hole(s).
Crank just enough just to get the liquid to go through.
Don't crank it too many times, and it starts to get spit out the exhaust.
Allow to soak 24 hours or overnight.
With ATF, it should fire up.
Just be warned that ATF burning causes a HUGE SMOKE CLOUD.
It'll take a few minutes to burn off.

-Ted

easy enough... any particular brand of ATF? not sure if i can find MMO in my area.

09-06-2009, 05:47 PM	#1
Silver86 now what? Join Date: Jul 2009 Location: SE Wisconsin iTrader: (0) Posts: 178 Rep Power: 16	worth rebuilding my engine? is it even worth the effort? it runs like garbage... not entirely sure whats wrong with the engine, i know theres either a stuck or blown side seal in one of the rotors... NoDOHC came out the other day to give me a hand and he said it almost sounds like it is running on 1 rotor. maybe hell chime in and give me some professional advice. saving up for this 20b N/a project is gonna take forever and i would like to at least drive and enjoy the car before i put her under the knife... looking at this beautiful paperweight i have sitting in my driveway makes me all emo... __________________ 1986 Rx7 coupe - arctic silver - sold aka - 20bforme

09-06-2009, 10:15 PM	#3
Max777 Pirate Join Date: Mar 2008 Location: Central IL iTrader: (5) Posts: 1,323 Rep Power: 18	Dude, mine ran kinda crappy, the compression was low, it was only pulling about 12" of vaccum at idle, and the transmission had about 140K on it. I priced out a rebuild, and all the work/tools/time involved, and decided that unless there is some concrete reason you want to keep the N/A powerplant, a TII swap just makes more sense. Also, if a TII engine blows, there is more reason to rebuild IT, rather than the crap N/A. __________________ Rotaries:They are NOT that complicated!

09-06-2009, 10:52 PM	#5
need RX7 Clean S4 Nutswinger Join Date: Mar 2008 Location: Sterling Heights, MI iTrader: (0) Posts: 485 Rep Power: 17	Since you're trying to save for the swap, I'd look for a known-running, low-ish mile engine and throw it in for the time being. It won't cost as much as a rebuild and it'll get you back on the road. Of course, there's always the chance that there will be something wrong with it and it will put you even deeper in the hole... __________________ -Ted -1986 Mazda RX7 Sport [DD/beater]: engine finally let go at 205k. parts car status. -1986 Mazda RX7 base [resto-mod project]: S5 n/a swap in progress.

09-07-2009, 07:03 PM	#11
*TitaniumTT* Test Whore - Admin Join Date: Mar 2008 Location: Right Behind you son iTrader: (4) Posts: 4,581 Rep Power: 10	Rebuild it. If you've got good comp in the front rotor and only one low pulse in the rear, it's definately worth rebuilding rather than let it sit for 2+ years If you don't expect the motor to last forever pull it apart, clean everything up really well and reuse most of the seals. Buy new oil control o-rings, dowel rings, fire/coolant seals and just do the bare minimum. Even if a housing is chunked a decent N/A housing should be able to ba had for a bill or two. At that point you're looking at your time. Total time to do that should be in the 30-40 hour range. So wake up saturday morning and work until Sunday night and you'll be 90% of the way there. Seems like a no brainer to me. __________________ -The Angry Stig- DGRR 2009, 2011, 2012 & 2013 - Best FC DEALS GAP!! WOOHOOOO!!!!! 2015 Audi S4 - Samantha - Zero Brap S4 2004 RX8 - Jocelyn - 196rwhp, 19mpg fuel to noise converter 2000 Jeep Cherokee Sport - Wifey mobile - Now with 2.5" OME lift and 30" BFG AT KO's! So it begins 1998 Jeep Cherokee - 5 spd, 4" lift, 33" BFG's - Rotary Tow Vehicle 1988 'Vert - In progress 1988 FC Coupe - Gretchen -The attention whore BEAST! I'm a sick individual, what's wrong with you? I'm pure Evil I'm still insane, in the best possible way. I think Brian's idea of romance is using lube. Your rage caused the meteor strike in Russia. The Antichrist would be proud of his minion. You win with your thread. Most everything It's a truck with a steel gate on the back. Just a statement of fact Motec M820, AIM dash, ported 13B-RE Cosmo, 6-spd trans, 4.3 Torsen, custom twin wg fully divided mani, Custom 4" split into 2x 3" exhaust, Custom HMIC, Custom custom custom custom I like to welder stuff.... No Bolt-ons allowed. Dyno'ed @ Speed1 Tuned by me - 405rwhp on WG.... WM50 cuming soon. *-Angry Motherfcker Mode ENGAGED-**

09-06-2009, 09:12 PM	#2
JShiz ZOMG WTF BBQ!!! Join Date: Mar 2008 Location: Mobile, Al iTrader: (0) Posts: 280 Rep Power: 17	Open it up and see the damage so you can make a good call.