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Engine out reseal

 
Old 02-17-2019, 12:02 PM
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968to986
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Default Engine out reseal

Hi everyone, I have finally bit the bullet and pulled the engine on my 87 951 because of substantial leaks. A little background first, for what it's worth. I've had the car for about five years now and have done quite a bit of work to it, including suspension and brake upgrades, rebuilt ECUs, rebuilt K26-6 turbo, Tial wastegate, Lindsey chips, gutted cat (that sounds gross). A lot of this was done with an eye toward having a fun street car that I could also use for track days and autocrosses. But, the leaks that were there when I bought the car were just getting to be too much. After researching the best the way to fix them, I felt like an engine-out approach would be best. I'll try to document the work here, and would welcome any commentary and suggestions as I go along.

The car:


Engine on it's way out from the bottom. The cat in this photo is not gutted:



Removing clutch and flywheel in preparation to bolt to the engine stand. I know for sure I'll be replacing the pressure plate and clutch, but does this flywheel look like it can be resurfaced?:




And on the engine stand. The real work can begin:



More to come...
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Old 02-17-2019, 01:56 PM
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Good idea.
So much nicer to work on an engine while sitting on a chair rather than on the floor with grease falling in your eyes.

Check the workshop manual or search for flywheel thickness spec, but I'd bet yours could be resurfaced OK.
Machine shop might be able to just check it for flatness (warpage), if it's OK they can just clean it up rather than cutting any meat off.
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Old 02-17-2019, 02:05 PM
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Dan Martinic
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You're a brave man doing all that engine-pulling work without any covers on the surrounding outer body panels

Question: how high off the ground is your front end? I'm curious if I have the means to pull the engine if required.

Nice garage floor
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Old 02-17-2019, 02:11 PM
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Originally Posted by V2Rocket View Post
Good idea.
So much nicer to work on an engine while sitting on a chair rather than on the floor with grease falling in your eyes.

Check the workshop manual or search for flywheel thickness spec, but I'd bet yours could be resurfaced OK.
Machine shop might be able to just check it for flatness (warpage), if it's OK they can just clean it up rather than cutting any meat off.
Thanks. I love working on engines on a stand. Hopefully the flywheel can be cleaned up. This is going to add up fast!

Next question: can I just remove the timing and balance belts and reset later to the timing marks on the crank, cam, and balance shafts? Obviously the flywheel is off now so I donít have that reference point.
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Old 02-17-2019, 02:16 PM
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Originally Posted by Dan Martinic View Post
You're a brave man doing all that engine-pulling work without any covers on the surrounding outer body panels

Question: how high off the ground is your front end? I'm curious if I have the means to pull the engine if required.

Nice garage floor
Yeah, looking at my own photos, I was like, WTF was I thinking? Worked out fine, but Iíll be a bit more diligent on the reinstall.

I think the height is about 23 inches, still a pain to slide it out from underneath.

Amorpoxy floor, holding up pretty well to some offensive abuse.
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Old 02-17-2019, 02:19 PM
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Originally Posted by 968to986 View Post


Yeah, looking at my own photos, I was like, WTF was I thinking? Worked out fine, but Iíll be a bit more diligent on the reinstall.

I think the height is about 23 inches, still a pain to slide it out from underneath.

Amorpoxy floor, holding up pretty well to some offensive abuse.
Cool.. thanks
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Old 02-17-2019, 02:47 PM
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Originally Posted by 968to986 View Post
Next question: can I just remove the timing and balance belts and reset later to the timing marks on the crank, cam, and balance shafts? Obviously the flywheel is off now so I donít have that reference point.
as long as the crank doesn't move.
can be verified with a wood dowel in a spark plug hole, or if the engine is at TDC now without the flywheel just make a sharpie line from crank flange-> block.
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Old 02-17-2019, 05:02 PM
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You could line up the timing mark on the cam gear, then put the lock on the flywheel.
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Old 02-17-2019, 05:44 PM
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Yeah this is probably my first mistake, because I removed the flywheel for access to the rear main seal, but I didnít set TDC first. I think Iíll just use the dowel trick on the number one piston to get TDC, confirmed by the cam mark, then remove the belt. The cam tower is coming off anyway, so Iím going to have set all this correctly when it goes back together. Probably rod bearings too, and I donít know if the crank has to rotate to do that (probably).

I appreciate the input!
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Old 02-18-2019, 12:43 PM
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Made a little progress thanks to a 3-day weekend. Front of engine torn down, now I have to start ordering parts!





It's a disgusting mess, that's for sure!
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Old 02-18-2019, 12:54 PM
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I think that's pretty clean compared to the many I've seen. How many miles? Original head gasket? You know where i'm going with this line of questioning right?
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Old 02-18-2019, 01:26 PM
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Originally Posted by Gage View Post
I think that's pretty clean compared to the many I've seen. How many miles? Original head gasket? You know where i'm going with this line of questioning right?
Well, it is true that it could be worse. About 130k on the motor. Probably original head gasket, and this will be one of the big questions. Do I preemptively replace it? I donít mind the labor, but at some point Iíll have to wave the white flag in terms of dollars.
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Old 02-18-2019, 01:45 PM
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Originally Posted by 968to986 View Post
...I donít mind the labor, but at some point Iíll have to wave the white flag in terms of dollars.
Lol my last engine out ďresealĒ set me back over $4k, itís easy to get carried away with wyit jobs. Clutch, plate, flywheel skim, head skim and refresh, rod bearings, rings, baffle plate, scraper, mounts, water pump, foes, belts, bearings, gaskets, seals and sealants.

A head is relatively easy to do with the engine back in, though if itís the original gasket Iíd be tempted to give the head a skim and fit a new gasket. Doing anything else would depend on what your compression and leak down numbers were like.
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Old 02-18-2019, 02:36 PM
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The head gasket is no longer a question for me. At 130k I go right down to the short block, remove one piston, inspect rod bearing and journal, measure rod bearing clearance, remove rings, inspect carbon build up in piston oil return passages, measure ring end gap with old ring and new ring, I try to leave the crank in, measure crank end play and compare measurements with the WSM specs. For the head, measure valve guide clearance, at least lap valves, new seals, surfacing is usually a good idea. Surfacing the flywheel is essential. I also try to not spend money on "performance enhancements". That's the slipperiest of all the slopes!
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Old 02-18-2019, 03:37 PM
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Last year, around 150k miles, I failed emissions. I replaced the CAT with a NOS one.. no change. Did all the regular tune-up things; no change. Opened up the engine and cleaned out all the carbon, obviously installing a new HG (though the old one didn't show any obvious problems).

Passed with numbers I have never seen so good in the ten years I've had this car. Anyway, I bet your pistons have this crap on them too!

BEFORE




AFTER




I would imagine this is a much nicer job--esp cleaning the mating surfaces of head + engine block--now that it's out
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