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Rb25 Cam Cap Buggered

SYK-200

By SYK-200,
in Engines & Forced Induction

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SYK-200 Enthusiast

SYK-200

Posted
Posted

Hello everyone...again! a few months ago i built a rb25, and ever since it was running their was a really high pitch squeal coming from the engine and i had no clue wat it was until yesturday i took off the cam covers and found metal shavings at the first cam cap, so i took it off, and what do i find? the cam cap and camshaft have been worn VERY badly, wat can cause this? no oil getting to it? over tightening the bolts? i didnt install the cams, we sent it to our local machine shop and got the block/head cleaned up, also installed tomei valve springs. ill post up a picture so you can all see how bad it is...

post-74114-0-58401200-1329458772_thumb.jpg

post-74114-0-89122200-1329458800_thumb.jpg

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https://www.sau.com.au/forums/topic/392073-rb25-cam-cap-buggered/
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rob82 Mentor

rob82

Posted
Posted (edited)

From those phots it appears to be Abrasive wear which is probably due to lack of sufficient lubrication. It seams weird that it etched the middle of the cam bearing surface away. My guess is they possibly tunnel bored the cam bore and forgot to debur the oil feed cause both a blockage of the oil passage and significantly higher loading on the middle section of the cam journal. Really hard to tell just from those photos.

Edited by rob82
JonnoHR31 Grand Master

JonnoHR31

Posted
Posted

did they do any machining? was it the original cap from that engine installed on the correct side? if so lack of oil is the only reason for that to happen, but to get that bad it must have been getting no oil whatsoever. what does the oil feed look like?

The Dan Grand Master

The Dan

Posted
Posted

If you put the cap on the wrong side and the top half overlaps the bottom half on the leading side, it will start removing material from the cap as it rotates. The removed material will just stay there, stuck in the middle and continuing to wear the cam away like a big clump of camf*ck

SYK-200 Enthusiast

SYK-200

Posted
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Posted

at JONNOHR31, i dont exactly know what they machined, my brother got the machining work, the engine was my school project for HSC, i built most of it, brother payed for it all...

at abr33, we first started the engine in around july 2011, and since 16th feb, it probably has only been started ~15 times.

is this at all repairable, or a new head is needed now? definately a new cam is needed lol, on the positive side, at least i found this problem before something worse happened!

abr33 Proficient

abr33

Posted
Posted

Repairable? maybe, get a competent shop to weld your busted journal and tunnel bore it back out.

Or if its easier get a new head, your lucky you didnt break your cam and eat your engine worship.gif

Would be a tricky one to repair

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