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Valve seals

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Head-on Refresh, valve seals or no? No smoking

1K views 6 replies 3 participants last post by  Mr_Random 
#1 ·
I've got an 83 5MGE with the timing belt and everything removed. I have valve seals in hand but know it's kind of a chore to pull the cam towers and springs with the head on. The car was sitting for ten years - no compression problems or tail pipe smoke, but is it still somewhat of a time bomb for valve seals? Don't want to slap it back together and have to dig back in right away.

160k Miles and I've gotten it heat cycled a few times - was parked due to bad ignition switch and lots of other maintenance the old lady didn't want to pay for. Intend to keep the car forever, which means a full rebuild down the road regardless, just weighing priorities right now as I have a whole car to throw parts (and time) at. I have pulled cam/valve covers and there is no obvious signs of leakage - everything is the beautiful gold stain I am familiar with seeing in old engines.

Thanks!
 
#3 ·
Off to search for my spring compressor now!

I found out in my searching that the keepers are shared with the ford FE big block and happen to have a bag of spares just in case, additionally the spring retainers are the same diameter (on paper) and I bought an extra while working on a 390 recently. While it is in pieces I will get comparison pictures - if the retainer dimensions are similar enough, I may have found an avenue for new (performance) parts and an ample supply chain.
 
#4 ·
Can actually replace valve-stem seals without removing head...

If you remove head, might as well do full valve-job with back-cut valves and fully-radiused seats.
 
#6 ·
Well... grinding angles with stones is like hunting with stones and spears. Machining technology has improved hugely in past couple decades. Perfectly smooth curved valve-seats flow. way, way better than 5 or 7-angle "competition" grinds.

The actual radius of curve can actually vary depending upon whether flow is moving towards spark-plug or towards cylinder wall. Here's one I did while back.

Copper-beryllium seats also conducts heat significantly quicker than steel.

 
#7 ·
Well that didn't go as planned...

Got all the valve seals done, started replacing rear cam retaining plate seals when one of the tiny 10mm bolts snapped in the cam tower. After drilling clean through it I tried an extractor bit and instead of pulling the remaining bolt, it somehow cracked the aluminum. It should be repairable, didn't crack through any oil passages or cam bearing surfaces, just munched what remained of the hole and made a hairline crack through to the outside of the tower. I guess I will see what a machine shop can do for me tomorrow. Not a very fun development.
 
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