4.0/4.6 heads - dropped guides?
I recently picked up a set of 4.0/4.6 heads. I didn't notice until I started removing the valves that all of the intake valve guides have dropped toward the chamber by about .150 -.200". Is this a common problem? Are the guides THAT loose from the factory? And on that note, I only removed one intake and one exhaust valve, but the intake guide appears to be bronze and the exhaust is cast iron? Are these the factory guides or did someone possibly replace the intakes this deep (these heads have been hot tanked and I cannot see any witness marks on the intake guides to validate that they have dropped). Also, the intake stem seals look to be identical to the exhaust, so that leads me to believe that the bronze guides are factory? Any insight here is appreciated.
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roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: 4.0/4.6 heads - dropped guides?
Perhaps "crafty" installer pushed in deeper to avoid cutting on top for higher valve lift ? I find no logic in bronze int. and iron exh.
Check how much effort to push bronze guide up to proper location. Art. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: 4.0/4.6 heads - dropped guides?
It might work well with teflon intake seals and umbrella seals on the exhaust. Less vacuum on the exhaust side to suck in oil. The cast iron being more porous could hold the oil better.
Jim |
Re: 4.0/4.6 heads - dropped guides?
Upon further inspection, they are not bronze and highly magnetic, sorry for the confusion. The end profile of the guide (slightly "chamfered" on the port end) is different from the exhausts and they are bronzey colored which is what threw me. But....they are definitely dropped. I pushed one of the guides back into approximate position on a 20 ton press and it took quite of bit of force. Stumped at how they could move so much given the apparent interference fit on the one I moved back up away from the port??
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minorv8 Jukka Harkola (268 posts) Registered: 04/08/2009 06:50AM Main British Car: Morris Minor Rover V8 |
Re: 4.0/4.6 heads - dropped guides?
They are not original so maybe whoever did the job simply installed them deeper in the head. Are they shorter than ex guides.
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