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| Northstar rebuild: Will style (Page 20/119) |
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ryan.hess
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NOV 08, 05:09 PM
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| quote | Originally posted by Will:
There are no longer aluminum threads to worry about.
Is the sealant still necessary?
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I have no idea. Everyone I've talked to has said to get the headgasket/bolt set from GM, no matter what... And (of course) to use timeserts. In summary, I have no idea what the f*** I'm talking about... but if I were rebuilding it, I'd use the new bolts that come in the GM kit.
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Will
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NOV 08, 05:27 PM
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Since I asked that, I've been in touch with Allen Cline, and he says that the sealer is a Loctite product with two purposes... high pressure lubricant to lubricate threads as the bolt is being torqued and thread locker to prevent the bolts from backing out. Apparently aluminum blocks (or maybe just threads, don't know which) can spontaneously back out, which is why the lube/locker stuff is there. The head bolt cavities are sealed by the head gasket, so there shouldn't be any coolant in them anyway.
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Nashco
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NOV 16, 08:30 PM
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Any luck finding a competent machine shop? (read: bump) Bryce
88 GT
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Will
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NOV 24, 06:45 PM
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Honing stones got here the other day... possible issues with the profilometer not giving consistent readings
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Nashco
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DEC 13, 01:47 PM
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Any progress Will? I imagine things are slow around the holidays, just curious. Bryce
88 GT
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Will
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DEC 13, 06:03 PM
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Will
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DEC 19, 12:24 AM
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Finally made sense of something I had been noticing every now and then... shoulda looked harder at it a long time ago. My bores are patchy. I had been dismissing it as a trick of the light until recently.
Anyway, the bores have bright and dark patches. The dark patches are were the cylinders have been burnished... that's partially burnished... So the shop that honed it really screwed the pooch, only I didn't know what to look for until some time later.
Upon closer inspection, catching the light on the bores showed me that the dark patches are much smoother/shinier than the bright patches. Now that I have a concrete image of what's wrong, fixing it is much easier.
This is why the profilometer was giving inconsistent results. The surface finish actually is that inconsistent. Also put in a drawing for a torque plate. That should be lasered out next week, after which I'll have to drill the head bolt holes and surface grind it flat. This particular laser is somewhat old and can't do a good job cutting a hole smaller than the thickness of the material it's cutting, which will be 3/4" in this case. So once the torque plate is done, I'll take it to a shop that's been recommended to me by multiple friends and get them to hone it with the stones I bought. Once that's done, the block will have enough clearance for forged pistons, so I'll have to make a decision. That decision will be partially based on the outcome of my interview with Sunoco next week.
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ryan.hess
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DEC 19, 02:19 PM
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| quote | Originally posted by Will:
Once that's done, the block will have enough clearance for forged pistons, so I'll have to make a decision.
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Uh oh!  
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That decision will be partially based on the outcome of my interview with Sunoco next week. |
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Double uh oh! Good luck!
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aaron88
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DEC 19, 08:06 PM
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| quote | | Originally posted by Will: Progress (I think)... When warm the car doesn't smoke on heavy throttle, smokes somewhat on coast down/high vacuum conditions and blows LOTS of smoke at light throttle/tip in from coast down/blipping throttle from idle... Allen Cline thinks that the oil rings are not working correctly. He says that there's enough reversion in the intake port at light throttle to throw oil up into the intake runners where it flows back down and pools on the intake valves after I shut the engine down...
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I’ve heard of something like this before. I remember reading about Corvette owners that were complaining of high oil consumption. After some investigation it was found that at high rpm under light throttle conditions oil was seeping past the rings and getting burned. If I recall correctly there was a replacement ring designed (or found) to fix the problem.
From reading your posts it doesn’t seem likely that this was exclusively your problem but it may be something to double check. I can’t remember where I read the article, but I did find this, that collaborates my story. http://forums.corvetteforum.com/showthread.php?t=960313 Aaron .
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Will
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DEC 19, 11:18 PM
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Yes, I remember that. Under conditions of high ring loading (heavy throttle or engine braking), the rings were fine, but at high RPM, light load conditions when there wasn't much ring loading, the rings would flutter and allow oil past. GM didn't pick that up because no sane person drives in such a way as to spend a lot of time at high RPM light load conditions... I'm pretty sure my problem was all in my bores. I'll try to get a picture of what I am talking about later this week. It may not show up well in a picture, though.
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