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So I've been lurking for a year or two and particiapated in a few discussions and well, I finally can say I have a reason to be here. I purchased a 2002 C4S that was two previous member's car. The first member had experiences an engine failure at 70K via a dropped valve seat on cylinder 5. Subsequently, he had TuneRS out of FL build him a 3.8L using LN Engineering "Nickies" plus JE pistons. A few other goodies inlcuded a .5 deep sump, ARP rod bolts, low temp thermostat, billet chain tensioner paddle, Fabspeed 200cel X-pipe, and triple-row IMS bearing (yes, LN offered this at one point). The final build made 325 RWHP. He sold the car at 107K to another member who drove it for a few years up to about 114K. Some of you followed the sale of the car here on Rennlist and then saw it was put on hold and eventually sold as a roller to me. The last owner was taking the car to get it's final safety inspection from the DMV when it stalled and CEL appeared. He had it towed to his mechanic who declared the engine a catastrophic failure. The mechanic thought it might be a rod or main bearing based on the noise and codes.
Fast forward to me still wanting to buy the car as a roller and taking possesion of it last Tuesday. Just a note of caution. I used Nationwide Auto Transport who had a competitive proce for a cross country closed trailer transport. However, upon recieving the car, I just found that one of the rear control arms was bent (I had specifically asked the to tell the driver NOT to strap the car by the control arm) and I learned from the previous owner's mechanic that the truck driver had started the car even though I had told th ecompany NOT to start the car - UGH....
So here goes my build thread. I'll start with the tear down and what we found.
I'm working on this project with a friend who's specialty is high-performance Subarus (as in he builds 700HP turbo motors) who also worked at a Porsche indy for a while. The first thing we did was pull the filter and cut it open. It honestly looked pretty clean. There weren't any chunks but there was just barely a bit of gold colored glitter, but you really had to look for it. Next we pulled the sump plate and there was more metallic glitter, a mixture of gold and silver, but you really had to look for it. BTW - no big chunks at all.
Once we got a bunch of the accessories and the intake off things began to come clear. It looks like the engine dropped a valve seat on cylinder #5 (how ironic). The seat was partially smashed up and there were bits of sand sized metal in the intake manifold and just a few pieces also in the intake of #6. Here is a photo of the intake. Sorry for th epoor quality, my iphone wouldn't focus down into the hole. You can obviously see the sad-sized debris, but if you look close at the second photo you can see the void on the bottom of the seat where it meets the valve.
Next up was the piston and cylinder damage. It appears that there was only damage to the one cylinder and piston (#5). All the other cylinders all looked good - they still had their crosshatching marks and none appear to have any sort of scoring or scratches from the other debris. What do you think?
Assuming it was bought on the basis that the engine was potentially a total write off and priced accordingly, I'd be thinking I'd bought a bargain. I think I'd still be inclined to pull the engine down entirely to check everythng thoroughly, but be hoping that all it really required was one piston and perhaps a new nickie for that cylinder, and fix up the head.
Why did it drop a valve seat? Is that another M96 character trait? Of all the M96 maladies I've read about since buying my car, dropped valve seats did not figure highly. And an inlet seat at that?
Anyway, could have been far worse, I reckon you've had a win!
A couple things, even though it's water under the bridge... 1) The guy who started the car is clearly an idiot, but...it would have been a simple task for the shop to disconnect or even remove the battery before the transporter picked the car up... could have saved big potential trouble. 2) As noted by Uber666 it seems you may be looking at an easier fix than you originally thought. 3) Considering the motor already dropped one valve seat, I'd have both heads thoroughly checked by Hoffman (www.hamheads.com) to be sure none of the others are loose/ready to drop. 4) I'm sure LN engineering can give you good advice on the damage to the #5 liner and what to do about it (and how it should be done). Good luck - I hope you get it sorted out soon and for a reasonable amount of $
Assuming it was bought on the basis that the engine was potentially a total write off and priced accordingly, I'd be thinking I'd bought a bargain. I think I'd still be inclined to pull the engine down entirely to check everythng thoroughly, but be hoping that all it really required was one piston and perhaps a new nickie for that cylinder, and fix up the head.
Why did it drop a valve seat? Is that another M96 character trait? Of all the M96 maladies I've read about since buying my car, dropped valve seats did not figure highly. And an inlet seat at that?
Anyway, could have been far worse, I reckon you've had a win!
Hi Uber -
Yes, it was purchased as a roller at the appropriate value. I'm hoping that the damage you mentioned is all that happened, but I went into this prepared for it to be a total loss.
As to the dropped seat being common, I'm not sure where it ends up on Jake's list of known failures, but it is something you see fromm time to time on the forums.
A couple things, even though it's water under the bridge... 1) The guy who started the car is clearly an idiot, but...it would have been a simple task for the shop to disconnect or even remove the battery before the transporter picked the car up... could have saved big potential trouble. 2) As noted by Uber666 it seems you may be looking at an easier fix than you originally thought. 3) Considering the motor already dropped one valve seat, I'd have both heads thoroughly checked by Hoffman (www.hamheads.com) to be sure none of the others are loose/ready to drop. 4) I'm sure LN engineering can give you good advice on the damage to the #5 liner and what to do about it (and how it should be done). Good luck - I hope you get it sorted out soon and for a reasonable amount of $
Thanks dporto - man, you are so right about disconnecting the battery. I should have thought about that. I was so caught up in getting my dream car out here I lost sight of that precaution. Regardig the heads, Hoffman was the first place I considered, but being I'm on the West coast, does anyone know of any other reputatble shops out here?
Thanks dporto - man, you are so right about disconnecting the battery. I should have thought about that. I was so caught up in getting my dream car out here I lost sight of that precaution. Regardig the heads, Hoffman was the first place I considered, but being I'm on the West coast, does anyone know of any other reputatble shops out here?
Len will get your heads shipped, out and back, at a very reasonable rate. Their expertise is with these type of heads and he knows all of the issues and the corrective actions that need to be taken. And you wont have to worry about turn around time, the nikasil cylinder repair will take much more time. If you want the motor to work for a long time do what everyone here is suggesting with regard to the heads and get Jake's rebuild video series (and do everything he says)
I know we all sound like a$$holes, telling you to do this and that. But we all want to see you have a successful build and there are very few, proven, routes to follow. Its fun to debate the merits of various approaches and technologies but in the end go with what works.
Assuming it was bought on the basis that the engine was potentially a total write off and priced accordingly, I'd be thinking I'd bought a bargain. I think I'd still be inclined to pull the engine down entirely to check everythng thoroughly, but be hoping that all it really required was one piston and perhaps a new nickie for that cylinder, and fix up the head. Why did it drop a valve seat? Is that another M96 character trait? Of all the M96 maladies I've read about since buying my car, dropped valve seats did not figure highly. And an inlet seat at that?
Anyway, could have been far worse, I reckon you've had a win!
2002-2003 996 heads are the worst for loose valve seats.
Assuming it was bought on the basis that the engine was potentially a total write off and priced accordingly, I'd be thinking I'd bought a bargain. I think I'd still be inclined to pull the engine down entirely to check everythng thoroughly, but be hoping that all it really required was one piston and perhaps a new nickie for that cylinder, and fix up the head.
Why did it drop a valve seat? Is that another M96 character trait? Of all the M96 maladies I've read about since buying my car, dropped valve seats did not figure highly. And an inlet seat at that?
Anyway, could have been far worse, I reckon you've had a win!
Uber - since you last asked I learned a bit more about dropped seats. Here's a link to an article from Len Hoffman wrote that speaks a bit about it. On a similar note, I was talking with my neighbor who owned his own shop for years and holds multiple SCCA AutoX records in Datsun 510s and he said it's usually from not cooling the car down adequately (especially after track runs) and can also be caused by bad injectors where the mix gets too lean.
06-14-2020, 01:01 AM
3.8L Engine Rebuild
I think I'd still be inclined to pull the engine down entirely to check everythng thoroughly, but be hoping that all it really required was one piston and perhaps a new nickie for that cylinder, and fix up the head.
