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Just what the Doctor ordered. 1977 280z


grannyknot

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14 hours ago, grannyknot said:

LOL I like that.  With the  M6x1 bolts I just put the flame on them from the side and got them glowing and quenched them with WD40, and did that a couple of times then did a double nut on each one and they came right out.  The head bolts I dropped the pistons as low as possible and slowly heated a six inch area around the bolts then after a minute put the flame right on the bolt until red then WD40 and repeat.  Welded on the nuts let it cool right down and they came out with no effort,  I was concerned about the thermal expansion of cast iron vs the steel bolt so went slow with heat.  That is a complicated area with water jackets (air gaps in this case) on either side of the head bolts and a steel cylinder sleeve on the inside.

Thanks for the details! Is your acetyl rig little bottles or full size bottles? I would have to lease full sized bottles but I wasn't sure how long little bottles would last

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My set up is one I bought at a garage sale years ago, 3ft Acetylene tank, 3 1/2Ft Oxygen tank.  Considering all I use it for is burning out rubber bushing and heating stubborn bolts they should last forever.

Tore down the rest of the engine today,  valve seats and guides are in good shape and so are the conrod and main bearings, only have to clean things up paint the block and reassembleIMG_0953.JPGIMG_0954.JPGIMG_0952.JPGIMG_0955.JPG

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1 minute ago, Zed Head said:

Are the E and the I really necessary?  :ermm:

No not on this engine but it's a habit I picked up on other engines where the valves are the same size.

 

6 minutes ago, Zed Head said:

Don't think I've seen anyone tear an engine down and put it right back together before, resisting the urge to put new parts in.

But it doesn't need new parts, everything is within spec, besides if I install new bearings that means I have to take the crank in to be polished which means I don't get the crank back for 3 months with un assembled engine parts all over the place. No thanks.

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Get yourself some 800 grit valve lapping compound and give the valve surfaces a quick refresh? I've used the oil based stuff with great success.

And I wouldn't use the Permatex stuff available at all the auto parts stores. Water based, and too coarse. Especially for a simple clean up job.

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20 hours ago, Captain Obvious said:

Get yourself some 800 grit valve lapping compound and give the valve surfaces a quick refresh?

Good call,  I will do them all but really there are only 3 exhaust valve seats that could use some dressing. These are 2 random valves, hard to believe they have 106,000 miles. This engine is such a cream puff, the timing chain hasn't even stretched, with #1 on TDC I think that is showing a bit of cam advance and the sprocket is still at the first setting. The chain guides hardly have any wear, I don't think the PO's ever put their foot into it much.

IMG_0966.JPGIMG_0968.JPGIMG_0724.JPGIMG_0965.JPGIMG_0972.JPG

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Well if that's just a random sample of a valve, then they look great. A quick wipe with the lapping compound and you're done. I don't know the grit coarseness of the two ends of your cup there, but the double ended container I have (green container by Clover) is 120 on the coarse end and 280 on the fine end. I'm no expert, but I tried a bunch of different grits and found that I like something way finer than even the fine side. I ended up with 800 grit.  And in my mind... The closer you are to "done" the finer you want.

But regardless, they look great for the mileage! So do you have a pic of the worst of the seats?

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