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Rebuilt SR20 red top issues


Chriswaggs

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So heres what I got. 76 280z with an sr20det swap done by vildini motorsport. Awesome swap, but i spun a rod bearing a while ago and rebuilt the motor. Whats in it- 87mm CP pistons, ARP head/main/rod bolts, Eagle forged rods, new oil pump/pick up and oil pickup gasket, new timing chain tensioner,ACL duraglide main and rod bearings, Apexi 1.1mm head gasket, the head was cleaned and resurfaced, new HLA's (bled them correctly), megan exhaust manifold. So after the rebuild (my buddy's buddy did it, im handy with a wrench, just never rebuilt a motor and "he has built SR's before"...) i crank it over, idle sounds great, oil pressure looks good, let it warm up a lil, rev it to around 2500RPM and i hear a noise and a little vibration. The noise sounds identical to timing chain slap, not rod knock since i had that when i spun the bearing. i know that the oil pressure isnt what it should be and thats causing the chain tensioner to lossen a little allowing the chain to slap. Ive searched and everyone also says rod bearings. I plastic Guaged the rod bearings and eagle rods says the tolerance they want is between 2-3 thous. of an inch and im 2.5 thous of an inch so i dont think im loosing pressure there. ANY ideas on what else it could be!!!!?? if i cant figure it out, ima going to have to take it back to Vildini and see if Alex can rebuild it using my parts already since the literally have 0 miles on them. Thanks for your responses and time!!

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When they installed the oil pump/ timing cover, did they install that little o-ring that goes between the cover and the block? if that spot doesn't have a seal there, you could have an issue with oil pressure, also double check to make sure that the tensioner is not faulty, if its acting up it could cause problems too.

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yeah, he said he installed the o-ring and the tensioner is literally the second brand new one i put on. I put a new one on a while ago and it worked perfectly and had less than 5000 miles on it. I bought another one thinking maybe some metal shavings got into the one i had from the spun rod bearing and it didnt change anything.

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After listening better, I dont think its related to the timing chain.

 

Try this,

 

while your friend hold the throttle slightly open to amplify the noise, start pulling one coil pack off at a time. And see if the noise follows a cylinder.

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i did the unpluggin of the coil packs and didnt hear a change at all, or it follow a cylinder. I'll have to try to rev it with the clutch pedal down. Thanks for all the help guys, I appreciate it. Talked to Alex over at Vildini and im taking th car in on monday to see if they can help me out. I still want to try to figure it out though, but if its going to be over there i figure i might as well throw on the greddy intake manifold and some minor upgrades.

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  • 4 weeks later...

so i took it over to Vildini Motorsports and tehy took care of it. Ended up being the Main bearings were undersized so the crank was slapping around. They fixed it and installed a new intake for me. all thats left is to get it registered and go back down there and have them tune it for me. then off to paint.

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