 Head quality |
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| gman3850 |
 Feb 3 2020, 05:17 PM
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#1
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Newbie  Group: Members Posts: 9 Joined: 23-February 16 From: gilbert az Member No.: 19,699 Region Association: None  |
Found a set of 914 heads that had been rebuilt and rewelded for 12mm spark plugs. Looked great in the photos. Got them today and had a few questions.
In one of the exhaust ports there seems to be a void in it. Also there seems to be a void on the outside of seats. Are these good to go or should I be worried Attached image(s)   
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| Stuckon914 |
Feb 3 2020, 06:29 PM
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#2
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Member Group: Members Posts: 132 Joined: 25-December 18 From: East coast Member No.: 22,747 Region Association: MidAtlantic Region |
Never mind- you meant cylinder heads.
(IMG:style_emoticons/default/smile.gif) |
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| Mark Henry |
Feb 3 2020, 09:03 PM
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#3
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Welding aluminium with any kind of impurities will cause porosity, hard to get an old casting to weld up without a slight amount of porosity. If the void is superficial and it sealed the seat to head it shouldn't hurt anything.
The one inside the head port looks like a casting flaw, I see small flaws, bubbles, dirt and flashing all the time. Again as long as it doesn't hurt the integrity it should be OK. But disclaimer it's not in my hands, so it's hard to pass judgment with just pics. I'd do a time test, level the head chamber up fill with a thin liquid like alcohol, time it 5 minutes and see if you have any leakage pass the valves. I'd also remove the valves and see what kind of job they did cleaning out the ports. When you weld up the seat bores and re-cut for new seats a lot of weld is left in the port that has to be cleaned up. |
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| Mark Henry |
Feb 3 2020, 09:18 PM
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#4
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
This pic of my 2.6L heads you can see some of the impurities (small dark specks) in my freshly cut seat bores.
BTW your valves are stainless steel, likely SSI brand and your exhaust valve will have a 8mm stem and guides, not 9mm like stock. Attached image(s) 
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| porschetub |
Feb 4 2020, 10:24 PM
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#5
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Advanced Member Group: Members Posts: 4,754 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
Looked @ the pics and as Mark mentioned it could be porosity in the casting or it has had welding done ??,in general those heads look pretty sound IMO.
x2 on removing the valves to check the ports and also see what the valve guides are like for stem to bore clearance which is really important with the exhaust valves on a T4. Good luck. |
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| gman3850 |
Feb 8 2020, 08:39 PM
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#6
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Newbie Group: Members Posts: 9 Joined: 23-February 16 From: gilbert az Member No.: 19,699 Region Association: None |
Well the porting looks fine but one of the valves was coming out fine Than completely stopped. Couldn’t go up or down. Valve had a bur on it where I’m guessing was clamped to do lapping. So now I have a scored guide. Am I fucked or can I send it. I just can’t catch a break today. My top tool box drawer died today and fell on my foot.
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