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Ron Earp Member 
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As eluded to in this post: http://www.jensenhealey.com/forums/view_topic.php?id=234&forum_id=10 We'll go on with the restof the story. Well (all good stories start like that), we got the motor out and the pan off. Lo and behold, lots of metal bits in the pickup screen and in the oil pan. Lots of little blue/black ribbons of metal that used to be a bearing shell. Now, which one? Didn't take long to figure out. Judson suggested go for number three since it fails quickly. Nada, nice and clean bearings. Number two? Nope, not behind door number two. Use a little light and viola - look, number four is oozing metal out around the con rod! Pop the cap and all was revealed. Number four spun and coughed bits in the pan. Bearing was still all there though and the crank is not heinously scored. It has some roughness compared to #1 and #3 which are smooth, but not so much to catch a fingernail or measure. I think it might polish up with cloth, or at least we'll try. Some pictures below, looks like fun times ahead!       Last edited on 06-07-2006 03:13 pm by Ron Earp |
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Judson Manning Member 
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Ron, Trust me I feel the pain....been there done that...I DID write the book on 907 disasters! In realative terms this is actually good news. The mains may have a little wear, but all you should have to do is polish the crank and install a new set of rod bearings. If I remember correctly those bearings are 0.010" undersized. Check the p/n on the back of the shells. Then get yourself some 1000 and 2000 grit sandpaper, polish up each journal plastigauge the assembly, and you should be back on the track in no time. Judson |
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Ron Earp Member
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We're on it. I'll make measurements and talk to you about it. I think it can be polished and servicable. Some heat discoloration, some roughness, but in general I think it can be done up right without machining. R |
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Ron Earp Member
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The motor spun the bearing but there is no damage to the rod big end, and, the material on the crank basically polished off with 1500 grit paper. Specs on the big end and the crank seem to be where they were when the thing was put together. All the other bearings look perfect, and I do mean perfect. I'm replacing them though since we're in there. I don't think it spun the bearing when I lost oil pressure. I think it spun the bearing when we tried to crank it in the paddock after getting the oiling system back together. When I hit the starter for just a second it made a strange "clunk" noise and didn't start. Jeff heard it too. Then, we hit the starter again and it fired up and ran at idle. I could hear a ticking though, and it got louder. We only ran it for maybe a minute before we decided that was definitely rod knock and we were done. RPM was never over 2000 or so during this period. Before it goes out to a track event, and oils down another venue, plus costing me a lot of time in towing and gas, we're going to take it to a local asphalt roundy round track and run it for a few hours. They rent out for about $150-$200 for four hours, all you and only you, so it'll be worth it to run the car in. |
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Jensenman Member
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Ummm, I don't recommend reusing that rod without having it checked and resized. I reused a spun rod many years ago on a Chevy Vega motor against my better judgement; the rod looked good and the owner didn't want to cough up to pull the head etc to replace the rod. Two weeks later, the same bearing spun again. What happens: the rod big end gets worn by the spun bearing, this makes the bearing hole odd shaped and a bit oversize, then the bearing 'crush' is wrong and you are back to square 1. |
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Ron Earp Member
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It's all done now - rod big end was out of size, that was easily checked. Motor is being rebuilt now. I forgot to update the post, under close inspection it didn't work out at all. R |
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