Unknown engine not fully rotating
 

I have an 83 SC engine on a stand. I pulled all the plugs, looked ok. I put in MMO into each plug port. I went to rotate the engine and it went about 180 and was met with a hard stop. I reversed the direction and was met with another hard stop. The only time I felt something like this on an engine was when my 914 dropped a valve. I inspected all intake and exhaust ports and it looks like all is good regarding them. Will scoping the cylinders tell me anything? Where would I look at next for a non fully rotating engine? For that 180 degree turn its relatively smooth. Broken rod?

well? i would guess we need more info..why do you have it in the stand to start with? are you rebuilding it was it running prior removing from the car and e.t.c.

ivan

On the stand to look it over. Was told it was running before pulled from a wrecked car. Seller claimed it turned over on engine stand before shipping. I'm not planning to rebuild. I was planning to perform a health check, clean up, address any oil leaks, throw on an intake and install it. Assume anything prior to me getting it is hearsay.

My thought is you have jumped time so you’re hitting a valve or there is something in the cylinder keeping the piston from cycling.
Bruce

Something in one cylinder. A washer, nut, maybe a carbon chunk. Got a bore scope handy? Figure out which two cylinders are approaching the heads and scope those.

I love how the experts immediately have good ideas :)

I do have a scope.

The lock is between 4-3-5-1 per the distro rotor. I have not yet removed the chain covers to inspect there.

Not completely getting to 4 and not completely getting to 1

Does this mean to check 1 and 4?

I think Bruce gets the trophy.

Looks like when I approach cyl 1 the exhaust valve is still open. When I approach cyl 4 that exhaust valve is still open. All cyl move when checked with the scope. Now the question is did the transport of the engine cause the jump or was it already like this and what catastrophic damage would have been caused. When the timing jumps it makes the valve touch the piston correct? It didn't look like there was an impact on the piston top via the scope. Are bent valves hard to determine from outside? I guess a leakdown would tell if the valve is bent/not seated.

How can I test the theory that it is the timing that jumped? I guess removing the rocker on # 1 or #4 would be a test. If it gets further than that point from removing the lower rocker than it would be in fact the timing until the next interference touch. Although why wouldn't 3 and 5 be affected? Would timing be off on all cylinders?

1 6 2
4 3 5

running mates are 1/4, 6/3, 2/5.
These pistons come up together, one on compression, one on exhaust stroke.
Sounds like you are 120 degrees away from #1 TDC from our convo, so 2 and 5 are suspect.

John - great talk, excuse my horse voice, its leaving me lol.

Anyway, you get the trophy. A washer is in there. I need to figure out out to get it out. Hopefully it is not wedge in. Looks like it contacted the top of the piston. This is cylinder 5.

http://live.staticflickr.com/65535/5...2891b78f_c.jpg

This tool might work:

https://www.amazon.com/dp/B000GTIJOY/ref=cm_sw_em_r_mt_dp_31G3N1MSY1QFTFTKG3GV?_encodin g=UTF8&psc=1

Thanks Scott, just bought the last one.

Very educational read on a Friday night! I lost the metal cylindrical piece from a pencil head while trying to find TDC on a Bug engine years ago. Caused interference for a while then went bye bye. That washer ain't goin anywhere!

Cool. William Knight turned me on to that tool. That tool saved me from having to tear my engine apart to find a broken rocker tip that made its way through the oil return tube into the depths o the engine....

One time, when I was a young kid working at a tuner shop, we dropped a washer in the fuel injector port on the head while upgrading the fueling on my fast audi.

Do not do what we did: we pulled the spark plug and the fuel pump relay, my coworker and I got into my car and rolled up the windows and hit the starter. That washer blasted out of the spark plug hole and careened off the wall. I’ll never understand how that worked but I’m grateful it did!

Great news! I managed to get it dislodged from its resting place. It definitely was once round and is now an oval. I will need to fish it out through the intake as the spark plug hole is just a bit too small. I'll keep at it. I'm just happy it didn't need a tear down to break it free.

I was fixing a high pressure oil leak on my 6.0 power stroke the other day. As I was pulling the last oil rail bolt I managed to drop my 30mm torx bit into the open head. After hours of searching with a flashlight and mirror with no joy I looked around with my Milwaukee camera. Still no joy. Finally I pulled out two injectors in order to gain more access for my flexible magnet. I fished around for awhile without success (I thought)
After reading similar stories online it seams, most times the offending piece makes it to the bottom of the oil pan (which is a nightmare to remove)
So, I decided to carefully turn the motor by hand an see if there was any interference. None felt so I cleaned up my tools and found the Torx bit on the end of my magnet. Best feeling ever!
Glad you found the washer. Let us know how it goes

Success! Full rotations once again. Thanks all for the quick thinking and where to look.

http://live.staticflickr.com/65535/5...b7e756cc_c.jpg

http://live.staticflickr.com/65535/5...3fc69028_c.jpg

Super cool thread, community and experience at work with an awesome outcome.

So how did the washer get in there? And if it is physically compressed like that to change its shape, would you find damages to the cylinder or piston? I would not assume that everything is fine now that the washer is out.

Its easier to drop something into an engine than you might think... It seams like its easier to miss a 200 sq ft floor than a 1 sq inch of open engine orifice..