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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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Posted: Sat Apr 16, 2016 11:01 pm Post subject: seized engine |
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Recently acquired '87.
"Ran when parked" (I believed the guy, still do but doubt is growing.....)
Wouldn't turn over.
Pulled starter, tests "okay"
Breaker bar on crank, no movement. (even after I remembered to put in neutral
Pulled belts covers, belts look good to me.
I don't know what proper tension should be. I would think if it slipped and smashed valves there would be some evidence on the belt, and there could be, under the crank pulley, the only place I can't really see well.
Plugs out.
Oil looks clean.
So where to start? (no pun intended)
I shot some penetrating oil into the cylinders, not a ton, not enough if it's rust in bores.
I could really dose the cylinders with..(I'm not sure what's best to use) and wait and see.
I could start pulling the head off.
I could part it out.
 _________________ 87 924S project, '83 944 engine,
my son's first car. |
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Rasta Monsta

Joined: 12 Jul 2006 Posts: 11733 Location: PacNW
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Posted: Sun Apr 17, 2016 12:25 am Post subject: |
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Father/son project, right? Pull the motor and put it on a stand!
Best way to learn the 2.5 well. _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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Posted: Sun Apr 17, 2016 4:05 am Post subject: |
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Certainly an option if comes to that. Might try a rolling bump, can't really hurt anymore if the valves are trashed, right?
Or, and this might be more intelligent, start in for normal belt replacement and assess things as we go pulling head if needed down the road. _________________ 87 924S project, '83 944 engine,
my son's first car. |
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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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Posted: Mon Apr 18, 2016 11:39 am Post subject: |
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poked around a tad more, pulled the dizzy and the cam gear cover, belt looks good up there too, can move the cam until the belt stops it, seems like the crank is holding up the works and not because the pistons are smashed into valves, but I don't know of course.
I ordered a cheap borescope for fun, will poke it round in the bores. No rush. _________________ 87 924S project, '83 944 engine,
my son's first car. |
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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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edredas

Joined: 09 Dec 2004 Posts: 861 Location: Charlotte, NC
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Posted: Wed Apr 20, 2016 8:12 pm Post subject: |
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If the cam is moving then that might be good news! Perhaps there is just something lodged in the flywheel... although its not exactly an easy job to get in there.
As for your starter, it appears your missing the retainer on the bendix side of the tip. From what I can tell, that is what holds it in place. The tips of my starters look like yours, only yours is barreled out.
I hope that helps! _________________ '84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver |
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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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Posted: Mon Apr 25, 2016 11:11 pm Post subject: |
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did a little scoping, managed to feed the borescope into the bell housing, pretty interesting but inconclusive, no "smoking gun". Went in through the upper passenger side opening, and a little through the timing mark inspection hole from the top, camera doesn't fit too deep in there though. The camera head has a tendency to get stuck too.
Can't see anything in the bores, am going to try that again on Tuesday with yet another scope. But I highly doubt it's valves because all the pistons seem to be about mid stroke as I probe them from the spark plug holes with a stick.
I will continue probing.
What about an internal bearing failure? I suppose if a rod let loose and got wedged it'd lock things up. I tried to scope the oil pain through the drain hole but couldn't make out anything. Hopefully the next scope reveals more. _________________ 87 924S project, '83 944 engine,
my son's first car. |
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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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Posted: Tue Apr 26, 2016 1:35 pm Post subject: |
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So we were dinking around with it, scoping out the flywheel and oil pan and bores and I grabbed the breaker bar on the crank and my son watched the flywheel. It moved a fraction, back and forth about 6 times and bam, she was free!
So it's not siezed anymore, spun around many times and no drama.
Starting getting ready to light her off, fresh oil, spent a LONG time trying to clear the ATF/acetone out of the bores. Had to try and fire it off; pops and wants to go but didn't quite do it and didn't sound all that great trying to so prudence won out and we called it an evening.
Not saying we've got a runner quite yet but we're a lot closer than we were 6 hours ago! _________________ 87 924S project, '83 944 engine,
my son's first car. |
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Paul

Joined: 02 Nov 2002 Posts: 9491 Location: Southeast Wisconsin
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Posted: Thu Apr 28, 2016 9:33 am Post subject: |
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Bores and pistons can't rust, but rings can corrode and by doing so glue themselves to the bores. Hopefully no rings broke when you broke them loose. _________________ White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy. |
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TJC

Joined: 04 Apr 2010 Posts: 828 Location: Northwestern-ish Arizona, USA
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Posted: Fri Apr 29, 2016 1:18 am Post subject: |
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| Paul wrote: | | Bores and pistons can't rust, but rings can corrode and by doing so glue themselves to the bores. Hopefully no rings broke when you broke them loose. |
Yep! I'd be real careful from here on out and be more inclined to make sure nothing is scoring the cylinders before going much further. _________________ '95 BMW 318i/5 ..."Pearl"
'87 Porsche 944 NA... "Liebchen"
'02 Porsche Boxster..."Sunbeam"
'04 BMW X3..."Xander"
Still on the Prowl!
www.ttrs1.com |
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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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Posted: Mon May 02, 2016 1:34 pm Post subject: |
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I made a bushing for the starter nose and it's spinning the engine okay. With no plugs in in turns over nice, with plugs it make a a bit of disconcerting thud during cranking.
The speed and reference sensor ohm out okay.
I used one off my many LED cluster wedge bulbs with some wires soldered on as long leads, confirmed good pulses to injectors. Pulled injectors (took all of 5 minutes, WAY easier in that regard to our engines).
They look terrible and thats just the outside. Hunks of crud all over the tips, both ends, just nasty. I think I will send them off for cleaning, witchhunter if I can't find a local shop. I should go after the cold start one but it's pretty buried in there.
So this may be the smoking gun.
I did use a "good" scope to see what I could see of the bores, they look okay but I can't really see them entirely just too hard to manipulate the camera and focus it down there. The piston tops look pretty terrible, carbon I suspect, disturbed by the ATF/acetone, can't do much about that I guess besides let it all burn off.
We're hopeful. I don't like my low compression numbers on 1 and 2 but we'll see. Maybe just sticky rings? Could be head gasket between 1 and 2.
So, she is seized no more and we're just working on getting fire.
We did confirm the cam and crank are timed to each other, the inspection camera was awesome for finding the timing mark on the flywheel, no way I could have seen that with the naked eye. _________________ 87 924S project, '83 944 engine,
my son's first car. |
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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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Posted: Fri Aug 05, 2016 11:29 pm Post subject: |
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Update.
We had it running pretty well until an engine fire set us back. Still sure what was seized, piston in bore I suspect but at the moment, with the engine out and clutch apart I see some serious damage on the flywheel bolts so maybe it was something hung up in there.
Picture isn't so great but you can see gouges in each of the bolt heads.
The gouges are not lined up so I'd guess the flywheel was off since it happened (and thus bolts retightened to different line up) The release bearing is a SACHS so that was replaced once at least.
I've got the clutch disc relined and am going to clean up the PP and flywheel surface a little and call it good. _________________ 87 924S project, '83 944 engine,
my son's first car. |
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Fifty50Plus

Joined: 28 Feb 2008 Posts: 1423 Location: Washington DC area
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Posted: Sat Aug 06, 2016 3:32 am Post subject: |
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I suspect that the gouges in the flywheel bolts are from and air chisel used to either take off the bolts at some time or tighten the bolts on reassembly. Either way, not using the star socket for removal/assembly is a sure sign of a hack mechanic.  _________________ 1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA |
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jvandyke
Joined: 30 Mar 2016 Posts: 212 Location: Hudsonville, MI
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Posted: Sat Aug 06, 2016 12:47 pm Post subject: |
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| Fifty50Plus wrote: | I suspect that the gouges in the flywheel bolts are from and air chisel used to either take off the bolts at some time or tighten the bolts on reassembly. Either way, not using the star socket for removal/assembly is a sure sign of a hack mechanic.  |
That's not the only sign I can tell you that! _________________ 87 924S project, '83 944 engine,
my son's first car. |
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