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YOUR RESEARCHNew 99 996 owner. Spun rod bearing next day.
Leading reported evidence
Replace piston rings
Performed · outcome unconfirmed
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Performed · outcome unconfirmed
I see in your rebuild list that you replaced the piston rings.
Leading evidence: 'Replace piston rings' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Clean engine build room' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion · Original poster
Also, we're not doing the engine build outside, we have a clean engine build room.
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Suggestion · Original poster
We have been doing repair for quite a few years but this is our first flat motor rebuild.
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Just purchased a black on black 99 c4 6 speed. Very good condition inside and out. 75k miles. Day after I buy it hear some engine noise. Used a stethoscope and sounded internal. Buddy and I took yesterday to pull engine and trans. Everything came out fine. Removed exhaust and all items on top. Today we were back at it. Huge pita. Tore the whole engine down to examine crank and found spun cylinder 6 rod bearing. We measured the crank journals that rods rotate around and found the damaged one to be only 2 thousandths less than the rest. Tom. We are taking the crank to a machine shop to see if they can refinish the crank. Ordered a new connecting rod. My question is does anyone have or know where to buy oversized bearings? I know they are out there but don't know where.
There are NO undersize bearings period. You should measure the cylinders for wear & roundness also. If you deciede to sell the car as is I am interested as I am almost finished rebuilding a 2001 engine.
Too bad about the timing of your problem, but I have to say, you apparently have a very healthy proactive attitude regarding what happened so soon after your purchase.GL with the fix.
I do not have the bearing clearances/dimensions but that 0.002" may not be that bad. If the bearing clearance is still within spec (though of course on the high side) and if the journal is ok and so on you could just replace the spun bearing, freshen up anything else in the engine 'while you are there' and have a perfectly good engine.
In fact freshen up all bearings. While they are not worn out (assuming they are not worn out) this will bring the clearances down some and help reduce the engine's oil budget and thus free some of that oil for the one bearing that has some extra clearance.
Instead of running say Mobil 1 0w-40 or 5w-40 you might want to switch to Mobil 1 5w-50 oil. And if you are going to drive the car on the track, or even hard on the street, give the engine a bit of extra oil insurance with a deeper oil sump and even fit an Accusump.
Sincerely,
Macster
Well the rebuild is going good so far. New crank, connecting rod, and bearings. PITA. Never thought it was possible to install wrist pins with pistons installed. Taking a lot more time and patience than expected. So far block is together with heads bolted on and oil and water pumps installed. Next is the cams and timing. Not looking forward to it.
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I'll keep you updated with the progress. FYI for you all we do have the weird expensive tools to rebuild these motors if anyone is in need. If you have questions feel free to ask. We have a repair shop called world class auto. We have been doing repair for quite a few years but this is our first flat motor rebuild. Trying to branch out and try new things. Originally we purchased this car to put our logo on the side for advertisement. And it turns into this Haha. If anyone is taking there motor apart or putting it back together feel free to chime in.
Subscribed.
Good luck getting her back on the road.
BTW, is that your 199X RX-7? I've always liked/wanted one that type. How does it perform? Sorry to hijack.
Yeah I currently have 2 94 rx7s. They are both r models one red and one black. Imo 3rd gen rx7 is one of the most amazing cars. You can make a 9 sec. Drag car, a great car for the turns, and a great drift car on a budget. You can pick one up for 10k if you look in the right places. And yes an outdoor 996 motor rebuild not recommended Hahaha.
hi spyder348
I am working with the same problem with my car. Only diffrence is that my engine spun rodbearing 5...
I'll get the parts next week and start putting the engine back together then.
I allso had JDM fd for 5 years, I used it to compete in Finnis Pro Drift Series. Nice car and intresting engine. The sound that the 13brew makes, is just
Sorry to hear that. If you have any problems or learn any tricks with the rebuild please post. Maybe this thread can provide help to the people who have been told these motors can't be fixed, you have to throw them away as I have seen in previous threads. After this project I'm going shopping for a balanced bridgeport rotary engine to acompany a t88, lots of fuel, and standalone.
Great work. Love to see all those internal bits strewn across such a different rebuild environment than I think most would be used to seeing.
Not really as difficult as it sounds if you have the cam timing tool.
Here's a shadetree mechanics method to timing the M96, but you can adapt it to use your cam timing tool assuming you have one.
http://986forum.com/forums/showthread.php?t=26418
We hear though from F6I to truly get the timing 100% dead on you need a degree wheel and split overlap method.
I have been into supra 2jz rebuilds. The rotary is my new project. I got whooped in my 800 whp supra by a 550 whp rx7. Within 1 month I buy 2 fd's. Thanks logray for the advice. Weather is the only bad thing about the outside work but on a nice sunny day there's nothing better. Tkrtape12 the rug was my 87 porsche 930 oil leak collector. Lol
Any chance you're an Army Field Mechanic? That looks like some of the best combat repairs I have ever seen! Already impressed but will be really amazed if that engine is till purring in 5000 miles.
We finally got the repair info about the timing and everything is going together perfectly. Also, we're not doing the engine build outside, we have a clean engine build room. All we did was remove the engine outside so no contamination should occur.
Trans bolted back up, whole assembly is back up in the car. Just a few things to button up and its all done. I hate the anticipation of starting this thing up...should be running monday!
Funny you say monday. Just wrapped up the whole project. Threw a new clutch in as well. Removed fuel pump fuse and relay. Cranked engine for 3 10 sec. intervals to build oil pressure. Put the fuse and relay in waalaa smooth as glass. No leaks No smoke No noise. Oh and i threw in all new lifters. Held engine at 2k rpms for a few minutes and took the car out for a 10 mile road test. Its good to go. No leaks no smoke no noise and no overheating. Was a very fun project now its time for a new owner. One last piece of advice i can ask from you guys. What price range can i list this car at? Black on Black c4 6 speed with rebuild new ims and new clutch along with speedline corse wheels. Im thinking somewhere around 25k????
A few more to give you all more info on what im working with here. I dont want to sell myself short but i dont want to price it so high that no one is interested.
My carbon fiber wheel and shift **** would be a fine addition to that interior, if you are interested in buying them - they are packed and ready to go.
If they were in bad condition id take you up on the offer but looking to sell and get a GT2 or 3 with bad engine. This rebuild was not bad at all. What took time is the learning part. First flat six rebuild I have ever done. Next one will be wrapped up in a week. If any of you guys have a flat six porsche with a bad engine and want to sell let me know.
Hi spyder348,
Good to hear that you got the engine ready.
It seem's that the interior is the same colour as my car, space gray not black.
Good looking car, good luck with the sell
No interior is black. Pictures are from my phone so they are not that accurate. I have had a space grey leather porsche. I sourced the lifters from world pac. 30 a pop.
Nice job again on the rebuild!
I see in your rebuild list that you replaced the piston rings.
Did you do anything to the pistons or cylinder walls? Did you measure the cylinders for oval and/or wear?
Any chance you would have pre/post rebuild compression and/or leak down numbers to share?
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