Engine won't turn ?

[Sboxin]

Edit: Problem Solved - hydrolock oil in #3 cylinder

Wow, how do I phrase this . . .
1. 964 3.8L 60 hour race engine ran great in last race (6-19-2016 Buttonwillow) and fine when loaded in trailer.
2. Car sat in enclosed trailer between race and now (9-15-2016)
3. Tried to start car to put in garage for check up - "thunk"- starter makes that sound and engine does not turn at all.
4. Checked battery and starter - all good
5. Took to shop - they can turn CCW hard and not CW at all. Both with clutch in and out. Car rolls fine to push in neutral. Brought car back to house.
6. Shop thinks maybe a collapsed chain tensioner.

We will wait for cooler temps to drop engine (DIY - done a few times) and start the search process for a cause.
While we wait I thought I would ask you all what you have experienced ??
Also posted in 911 Tech forum . . .

What say you?
Thanks in advance,
Regards,

[blue911rsr]

What do you have for fuel system carbs or fi have seen carb drain into cylinder and hydro lock and break cylinder and bend rod after sitting in trailer

[Sboxin]

Originally Posted by blue911rsr

What do you have for fuel system carbs or fi have seen carb drain into cylinder and hydro lock and break cylinder and bend rod after sitting in trailer

Stock 964 FI fuel system - don't smell fuel in the engine compartment . . . but will pull the plugs and scope the cylinders for fluid, etc.

Thanks,
Regards,

[Flat6pac]

Turning the motor backwards should empty any fuel in the cylinders into the exhaust.
Bruce

[Sboxin]

Originally Posted by Flat6pac

Turning the motor backwards should empty any fuel in the cylinders into the exhaust.
Bruce

Bruce,
Thanks for the tip - -

Today I removed the top set of plugs and rotated the engine CCW and == gurgle gurgle oil out of the #3 cylinder . . . it really did make that sound.

And when I drained the oil I found 2x 3/4" metal pieces on the magnet - most likely parts of #3 oil ring. Funny thing - engine was not smoking and ran fine on the track during last race.

I looked with a scope into the cylinder and only saw lots of oily carbon build up on the piston top.

It looks like the next step will be remove the engine/ heads/ cylinders and inspect/clean/recondition for another race season next year.

Does anyone think we need to open the case and make sure there are no metal pieces loose in the bottom end?? I know this decision depends on what we find in the cylinders.

A few pics to add to the "show and tell" . . .

Regards,

Oil from #3 cylinder - I know . . . need to turn your head to see correctly



Metal pieces from magnetic drain plug - - EDIT: these turned out to be rod small end bushing material broken off at rod surface -
replaced with Clevite rod bushings

[Flat6pac]

Probably more where that came from
You're going to be looking. I'll bet there is more behind the oil pump under #3, possibly a broken piston skirt.
I'm just being a stick in the mud...
Bruce

[Sboxin]

Originally Posted by Flat6pac

Probably more where that came from
You're going to be looking. I'll bet there is more behind the oil pump under #3, possibly a broken piston skirt.
I'm just being a stick in the mud...
Bruce

Thanks Bruce - not "a stick in the mud" - - you are always very helpful on this Forum !
We have plenty of time to work on this race engine - driver out till February - so we will most likely open the case and do a thorough cleaning -

I'll post again when we get the heads removed and see what we see, eh . . .

Regards,

[Sboxin]

.
.
.
Ah HA . . . engine autopsy . . . found little pieces of metal/brass are from rod bushing outside the rod edge - will remove rods and turn down to flush with rod edge . . . why - - because race engine.
Pistons and cylinders are great condition.


Edit: still don't know why the oil was in the #3 combustion chamber ? ? ? Cylinder was perfect and oil rings too . . .

Regards,

[Sboxin]

FYI - another photo of rod bushing chip (?)
Have any of you seen this exact failure in your experience with engine rebuilds?? TIA



Best guess - - JE piston nicked the bushing (stock 964 Porsche rods) causing the chip during a cold start (???)

The oil hydro lock in #3 cylinder - - because we routed the oil breather hose directly
back into the intake manifold with no catch can breather the engine running at high racing RPM
and higher compression - 12.5:1 - was sucking/vacuuming oil vapors/oil back into
the intake system. During the 3 months of not running this oil that accumulated on the intake
manifold drained into the #3 cylinder which may have been the one with the open intake valve.
The other cylinders also showed signed of oil in the cylinder combustion chamber but not enough
to hydro lock like the #3 (lots of oil pumped out when plugs were removed.

We will add back the breather catch can we previously used with the 3.2L engine.
This bushing will be replaced and all rod bushings will be machined to match rod width - no overhang.

Regards,

[DRACO A5OG]

Wow wow

[prschmn]

Would I be wrong to think those bushings were at some point redone? I'm thinking either
it-they was-were cracked when being pressed in or there was insufficient clearance between
them and the boss on the piston. And plumbing your vent entirely into the intake? Oh my-----
But you know that.
I'd also say if it were me I'd do a check to insure the rods are absolutely straight.
It's entirely possible to have bushings not quite square to the rod.
And good luck with it.

[Sboxin]

Originally Posted by prschmn

Would I be wrong to think those bushings were at some point redone? I'm thinking either
it-they was-were cracked when being pressed in or there was insufficient clearance between
them and the boss on the piston. And plumbing your vent entirely into the intake? Oh my-----
But you know that.
I'd also say if it were me I'd do a check to insure the rods are absolutely straight.
It's entirely possible to have bushings not quite square to the rod.
And good luck with it.

Thanks Mark,

Yes, the rods were reconditioned when we put the 3.8L together 4 years ago - balanced and new bushings pressed, etc ...
- - we will replace the one broken and recheck the rods at the machine shop for balance, etc...

I had a good talk with Don at EBS and Henry at Supertec - putting Supertec head studs and Clevite 77 rod bearings this time around - heads were a little leaky.

We rely on a local Porsche Indie shop - Don Jackson - for the engine build. Engine has run
strong so far - and my son was very quick at Buttonwillow back in June - our last race event.

This is the long story version of our engine build in 2012:
1992 964 Engine rebuild - reasonable approach?

Regards,

[Sboxin]

Update - -
Other rod bushings showed signs of failure - - rods at machine shop - new improved rod
bushings from EBS and will machine bushings flush with rod surface - machine shop will focus
on Porsche spec tolerances for bushing/wrist pin - - check big end roundness (?) and balance
Rod bearings were fine and maybe could have reused them, but decided to replace with
Clevite bearings (while you are in there . . . ) and new ARP rod bolts . . .

Heads need #3 cylinder surface smoothed and match all heads for cam carrier height

We have some cam/rocker surface pitting also - sending back to WebCams for evaluation/repair/replace
- - 63 hours on race engine - 4 years -12.5:1 CR 5-7K RPM . . . maybe just time for "heavy"
maintenance

I was able to take a look at the machine shop (Chuck's Speed and RV) here in Phoenix doing
our Porsche engine work - they have a terrific shop . . . just don't do a lot of volume
Porsche work --3 Porsche Indie shops here use them - - but, the Porsche machinist has
retired and has to be called in for our head work . . . a lot of experience years there . . . I
think they have been here for 40+ years . . . Chuck the owner and Don Jackson have worked
together on projects for 40+ years and Don worked for Carrol Shelby in CA building Cobras
"back in the day" - - - a lot of Porsche/car history . . .

Regards,

Originally Posted by Sboxin

FYI - another photo of rod bushing chip (?)
Have any of you seen this exact failure in your experience with engine rebuilds?? TIA



Best guess - - JE piston nicked the bushing (stock 964 Porsche rods) causing the chip during a cold start (???)

The oil hydro lock in #3 cylinder - - because we routed the oil breather hose directly
back into the intake manifold with no catch can breather the engine running at high racing RPM
and higher compression - 12.5:1 - was sucking/vacuuming oil vapors/oil back into
the intake system. During the 3 months of not running this oil that accumulated on the intake
manifold drained into the #3 cylinder which may have been the one with the open intake valve.
The other cylinders also showed signed of oil in the cylinder combustion chamber but not enough
to hydro lock like the #3 (lots of oil pumped out when plugs were removed.

We will add back the breather catch can we previously used with the 3.2L engine.
This bushing will be replaced and all rod bushings will be machined to match rod width - no overhang.

Regards,

[m42racer]

A couple of comments for you to consider.

Head studs are way over the top for an engine like this. Certainty wont hurt but you will never "use" them. Focus on making sure the cylinders are all the same height off the deck and the heads surfaces are flat and good. Make sure the threads in the block are good, chase them with a chase tap, NOT a cutting tap. Then check the platforms in the heads where the head washers go. Make sure they are flat and not tipping inwards towards the stud hole.

Consider a sealing system here too. If you need help here PM me and I'll tell you where to go. Once you have this sort of tech, you will never have a sealing problem again.

The pin bushing issue probably was not the result of the rod contacting the piston, unless the rods are top guided. Porsche rods are typically bottom guided and JE piston usually have very wide pin bosses. This could be the result of the pin bosses flexing and or the pin bending. I would hazard a guess and suggest the pin bosses are moving. Best to Zyglow the pistons for any possible cracks around the pin bosses. JE pistons with wide pin bosses typical of the early and common forging are not the strongest in this area. Top guided rods have very small clearances to the pistons and the early JE pistons do not lend themselves to this tech and would never have the bushings extend out from the rod pin end.

If the bushing was damaged in assembly, then I would expect the top half to have broken off first as this is the part that takes the most abuse at speed. Under compression you have an oil film somewhat helping here, even with any bending happening. In the opposite direction, where the piston is trying to pull itself out through the top of the engine, the pin is unloaded and the hammering effect is the greatest on the pin bushing.

[Sboxin]

Progress Report:

Rods and heads back from machine shop - new/better rod bushings, big end checked - OK -
heads smoothed and measured for same exact height - OK
New = Supertec head studs, Clevite rod bearings, ARP rod bolts , piston rings
( FYI will be selling steel head studs and nuts and used ARP rod bolts)
Rods, pistons, cylinders and heads assembled
Waiting on cams and rockers return from WebCams to finish assembly

Special Thanks to Don at EBS and Henry at Supertec for great technical advice over the phone
and of course Roland/DJ our engine builders at Jackson's
And - - thanks to all of you on the Pelican Forum whose input/postings are of great value !!

Happy New Year to you all,
Regards, Roy T

History:
1992 964 engine core rebuilt in 2012 by Don Jackson Ent. Porsche Indie shop in Phoenix
New valves/guides and EBS race springs, 3.8L JE pistons , cylinders refinished by EBS to 102mm 3.8L,
Rods checked and balanced, crank polished and with new Patrick flywheel balanced
WebCams 20/21 cams regrind and rockers reconditioned
65 hours on this engine over 4 years of racing
We had an oil cooling issue in the beginning and added a 3rd cooler in the drivers side to
reduce oil temps. On inspection of this disassembly there is some evidence of over heating
- probably during the first few track runs before the added oil cooler.
Engine dyno tuning by Steve Wong in CA November 2012 - 277 RWHP 255 RWFPT
conservative approach for durability (ie. don't blow the heads off . . )








Adding back the oil breather/catch can right side engine bay so engine intake doesn't suck oil back into the intake . .

[DRACO A5OG]

Good Job!

Have a Happy Healthy New Year Brother!

[Sboxin]

Happy ending . . .
Engine back in car - 20 minute fast idle run in with break in oil . . .
on the track tomorrow for further break in . . . smoke is from oil in headers . . . cleared up in 5 minutes . . .

Can't get the photo to come out upright . . .
Son is happy with his 911/964 3.8L race car ready for the track again

Thank you all for your input to our engine locking issue

Regards,

[Sboxin]

.
.
.
Video of refreshed engine 20 minute break in - added muffler so I could hear the engine sounds -

https://www.youtube.com/watch?v=3RZ7Oj_t9c0

https://www.youtube.com/watch?v=8GWrSAs37w8

Temp up to 180 and oil pressure at 4Bar - -

Regards,

[DRACO A5OG]

Woohoo!

Congratulations, how was the condition of the break in oil?

[Sboxin]

Originally Posted by DRACO A5OG

Woohoo!

Congratulations, how was the condition of the break in oil?

Break in oil came out dark - - because I wasn't able to get all of the old oil completely out of of the
lines and coolers (that oil had only been in the engine for one prior race weekend, about 3 hours
of run time and had it lab tested with excellent results) - - there were no shinny flakes in the
break in oil . . .

I had a long talk with our engine builder about cam wear/pitting - - he advised we get the
engine oil above 100 degrees F or preferably up to 180 before running the engine at high RPMs
and load. We have been doing this at the track . . . but when I start the engine at home
between track events I tend to idle the engine too much to warm it up and circulate the oil . . .
I will be doing a 1500 to 2000 RPM 15 minute warm up in the future . . . keeping the RPMs up during
warm up . . . some where along the way I seem to have missed this point = that cold start low
idle RPM causes cam wear.

Our weekend at the track went very well - ran the break in oil on Sat and changed to our
regular Amsoil 15-50 Race oil for Sun - used the warm up sessions to do the engine break in
procedure . . . accell/decell limit to 5000 RPM then increase RPMs each session . . . Sun was
full race mode . . . no problems, engine ran great . . .

Regards,