Argh- I rebuilt a 2.7l this winter. Everything went very well with no obvious problems. I installed my engine, hooked up all the hoses, filled with oil and hooked up the starter. I had problems with the starter wiring however I finally got them resolved. I was getting 12.6v at the starter. I cranked the starter and the engine turned a couple of times then stopped. When I would crank the starter again, it would just sound like a starter with too low of voltage- the solenoid would shoot out but the starter wouldn't turn. I checked voltage and it was 12.5v. If I look at the fan blade when I crank the starter, I do not see it move even slightly.

What are my options of what could be wrong? I see it as a starter problem or the engine is somehow seized. I do not have the axels hooked up so I cannot see if the engine turns by pushing the car in gear. I have a small window cut in the firewall so I wiggled a 19mm box wrench onto the timing pulley nut. I tried to see if I could turn the engine even slightly and I could not. I couldn't put much force into it however I would have thought it would have moved to some extent.

I think I will remove the starter and see if it cranks off of the car. If it functions properly, how can I check to see if the engine is seized without installing the axles. Is there anything common that could cause this issue? I would really prefer not to remove the engine. I am getting somewhat sick of working on it.

Any ideas?

Pull the spark plugs and try turning the fan by hand. If it doesn't turn easily, pull the engine and get help.

Mark nailed it first reply.

Is there a chance that some of your fasteners in your clutch/pressure plate/flywheel might be standing off and interfering somewhat ; not allowing free movement. Any metallic , or clicking noises while it turns over?
If it is just a weak battery, try putting a fully charged jump-box on the battery while cranking.
This happened to me with a g50 installation, some of the bolt heads were a bit too tall (in the clutch assy.)and whipped against the pressure plate. There was some noise and it was not cranking at speed. I slipped the trans from the engine, removed the clutch assembly, fixed the problem with shorter profile bolts, and that solved it.
If your 2.7 turned freely with a wrench on the stand, it should still turn freely with a starter.
Marty

How about the classic ground strap at the tranny problem? That will make for a slow cranking.

I checked several things and didn't have any luck. I removed the starter to see if I could turn the engine without it installed- didn't work. I checked the wiring again and all was ok. Removed spark plugs and no change. Of coarse the transmission is ini neutral.

It is strange cause the engine will not turn at all- even slightly either direction. When I first turned on the starter, it cranked 1-2 revolutions.

I did a partial rebuild. I did everything from the cylinders/pistons out. I did not have any binding issues at all during the rebuild. I could easily turn it by hand.

One of the last things that I did that moved the crank was when I mounted the flywheel. I everything turned without difficulty. After than I mounted the clutch, pressure plate then the transmission. I didn't try to see if it turned ok once the transmission was installed.

So unless there is something that I am not thinking of, there has to be something wrong around the flywheel. Another thing that I thought of was what if bolt or something fell into one of the intakes? First, I looked into the bores with a borescope and didn't see anything. Also, if something were stuck in a cylinder, the engine just shouldn't turn one direction. I should be able to back it up without difficulty.

Has anyone else had an issue with something binding around the flywheel? I saw Marty's post which may possibly be my problem.

Yes pull the plugs and report back

Plugs are pulled. Previous tests were all done without plugs. Engine still won't move.

sorry about this...

pull the trans and see if the motor is free
then pull the motor and start tearing it down until you find the offensive part.

Process of elimination. Likely you have a flywheel interference issue, cause you said the motor turned over fine after the rebuild.

I think I just needed someone else to tell me that. Looks like the tranny is coming out tonight.

I went out and removed the transmission only from eh car. The transmission turned without difficulty. I tried to turn the engine and it still would not turn so I removed the pressure plate and clutch. Still the engine wouldn't turn. I decided to remove the flywheel. I figured a flywheel lock wasn't needed since the engine wouldn't turn. I put some muscle into removing the flywheel bolts. Before the first one started to turn, it felt like something broke free and now the engine turns like it previously did.

Now what? Was it bound to something that broke free? Something related to the flywheel that I can't see? Did something break (didn't sound like it)? Where should I go from here?

Check cams are still rotating and in time?

I just checked and cams are moving normally however once I completely turned about one revolution- it got jammed again. I was able to unlodge it if I turned the engine the other way. Clearly I am hanging up on something.

ARGH- I found my problem. 13mm nut in cylinder 5.

I had previously checked each cylinder with a borescope however this time I saw a slight glimmer. I was able to twist the borescope and see a nut close to the exhaust valve on cylinder 5.

I do not know how the nut got in there. My kids were playing around my engine one day. It may have occurred then or at some other unknown time.

I haven't been able to fish it out yet however I think I can get it out. I can clearly see the Pistons head which looks ok except a slight indent in the valve pocket. I can see the cylinder bore which also looks good. I cannot see the valves or combustion chamber. I assume there is a big indent in the compression chamber cause I can see that there is damage to the nut. I do not know the condition of the valve.

What would you do?

Get the nut out, bolt up the transmission, compression test and if the number are ok then run it? (I plan on re-rebuilding the engine next winter)

Or

Tear the engine down and assess the damage.

Get out the nut, bolt her up and proceed.

Ouch. Get it out and run a leak down.

Hopefully ....
Or rebuild one head if necessary

Wow, man. That is some shit luck. Never force a stuck engine. I hope nothing got broken.

I would pull the head. Better to fix something while the cars in your garage than see smoke out the back of your car when your far from home. Just the piece of mind would be worth it to me.

I was planning on rebuilding the engine again this next winter so if smoke comes out the back, I wouldn't mind too much.

What is the purpose of doing a leak down test vs. a compression test in this situation? I have both tools so it doesn't matter, just curious. If I had a bent valve, then it seems like I wouldn't get any compression from the valve not sealing on the seat? I can clearly see the cylinder wall and piston crown and they generally look fine. I am sure that if there is damage, it would be a valve or the compression chamber.

Compression vs Leak Down:

Compression tells you the condition of the rings and valves but does not identify which.

Leak down will give you an indication of where the problem is. After pressurizing the cylinder, you listen where the hiss is coming from .... in the exhaust, it is the exhaust valve; in intake, it is the intake valve; and if in the crankcase, it is the rings (or a combination of the above).

Pretty simple .....

So in my case, a compression test would be acceptable? The rings are not where the damage is and if there were damage to a valve- it would be on the exhaust valve cause gravity pulled the nut to the bottom of the cylinder. The engine was never run so there shouldn't be any issue with the intake valve.

Since my piston rings are new and not seated, what psi range should I be getting for the compression test?

I would pull that head in a heart beat. Running it with an issue can cause you even more problems, $$, headache.

heres one ,,yup its free.."where is the nut ??"
I don't know, but it turns now...20minutes later

It was really quite spectacular.....nut exited at 4k rpm

Mike-
Come over to my house and fix my engine!!!! You would have a blast pulling the head for me. I really don't want to pull it. Pulling /6 head sucks. I am going to rebuild the engine next winter so no big deal if it blows up.

My main fear would be that a sharp edge around an indent has been created by the nut. A sharp edge creates an area of heat concentration (ie. "hot spot") within the combustion chamber, thus risking detonation when the edge can be at a temperature above of combustion temperature of gasoline.. The sharp edge can also cause stress risers, and a place for a crack to propagate out from. Neither of those are risks I'd be willing to take.

I would pull that head off and inspect everything as the other's have mentioned. 6 cylinder engines cost too much to fully rebuild and replace, to risk catastrophic failure.

worst case scenario, you have a tweeked rod...
either valve could be tweeked
a minor valve bend also creates a hot spot, possible burned valve situation and with time a dropped valve head

the leak down will tell you which specifics about what is needing attention and how much of a leak/problem you have

With head off you can measure to see if rod is bent. I would doubt it, but nice to KNOW rather than HOPE. I would be glad to come up and pull the cam/cam housing, head. Its time consuming but if you have the tools it is not too bad. I would want to know what the head chamber looks like. We can get rid of sharp edges that would cause hot spots and running issues. I had messed my 2.7 up originally when I trusted that I had the right used p/c from a shady (now I know) 911 parts vendor. Broke a ring landing, blew smoke rings out the tail pipe, not serviceable as an engine only a skeeter killer.

With the rings seated, I would expect in the 150 psig range.

Without seating the rings, I don't know what the numbers would be, BUT they should all be within 10 - 15% of each other (assuming the rebuild was done correctly).

If you do a compression test and #5 cylinder is really low in comparison to the rest, you have identified the problem and pulling the suspect head is the only means of fixing it.

Soooo- if I do a compression or leak down test and it is normal, can I just run as is? There definitely was not enough force to bend the rod. The intake valve is ok. The piston crown has a small dimple in the valve pocket. The cylinder wall appears normal. The exhaust valve looks fine however I cannot see 100%.

I am almost certain (based on the things that I can clearly see with a scope and considering the force that I put into turning the engine) that the only damage is a small dimple in the valve pocket and most likely a 2-3mm dimple in the combustion chamber. If that is all the damage that there is, it seems to me that running it would be ok? Agree?

You must be made of money. It is a big deal if it blows up through the case and you get to buy another 6 cuz you junked the crank , case , some rods , pistions and heads all of which would not have to be replaced if you pulled it down now.

You make the choice.

I ran an engine (2.7L) for about 200 miles with broken ring lands in #1 cylinder. I only ran it because I was 200 miles from home and it still was running, but throwing a bit of smoke.

On teardown, the cylinder, piston & head were toast. The broken parts of the piston were in the sump.

Maybe I was just lucky.

cast pistons can fracture,,is the concern I have that's what destroyed the above pic I posted

Ok I got the nut out of the cylinder. It was oval. There is a major indent where the exhaust valve pressed on it. Here are my compression numbers.

Cyl 4- 160
Cyl 5- 0
Cyl 6- 165

Are these numbers ok? Lol. Just kidding.

Obviously I bent a valve and the heads must come off.


Considering that there is most likely a bent valve, damaged seat and damaged compression chamber- can a head like that generally be rebuilt or do I need to start new? Either way is ok, just curious.

So if I remember correctly- I will need to remove the engine. Remove the cam tower on the effected side after removing the chain gear..., repair the head, cylinder, piston then reinstall the heads and cam tower. Set the cam timing, adjust the valves and button everything up? Sound right?

Kind of annoying but I would rather have this problem now vs later.

I just wouldn't let the kids play in the garage any more.

Make them pull the head.

My kids are all older now.....different stuff now.

Ya, Steve. That is about it Told ya.

I removed the heads today. There is no damage to the cylinder walls. There is mild damage to the piston crown. Here are some pictures of the cylinder head. Obviously the valve is bent.

Does this look like a repairable head? Obviously it needs a new exhaust valve. What else would you have done? If it appears repairable, who is the best person to send it to for the repairs?

Blurry picture however you can clearly see the valve isn't seating.

I am not sure if anyone has said this as the focus has been on the mechanicals, but: I am very sorry that this happened to you. What a bad thing to happen!!
It almost looks like the nut came from the manifold side of things and then got wedged in the valve betwixt valve head and seat.
The only good thing I can see is it could certainly have been worse had the engine started up.
Again, tough break. I am glad that you have the ways and means to tear into it so fast.

Check out the intake closer when you pull the valves . . . thinking if it had to fall through from the intake port who knows if it got trapped there and got tapped. .

Tornik, Sorry to see that.

I would highly recommend Craig Garrett (Cgarr on the bird board www.G2Performanceshop.com ). He is in MI, does excellent work for reasonable $$ in a short time and is very accessible. Check with him to ensure he can make this repair, and if he can, he is the man.

Since the cylinder to head sealing surface is compromised, you need to have him do all 3 heads on the bank so that they are at the same height IF they cut the sealing surface on the one head you are having repaired.

Ya, busting a nut can cost you in so many ways....

I feel for you. The reason I needed a replacement cylinder which lead to the wrong size and busted piston was because when I tightened the head down the head gasket unseated and warped the seating groove. Small thing, big headache, stupid mistake I have not repeated since. This weekend is shitty, but I might be able to help once I get caught up on my transmission backlog.

That link goes nowhere. Typo?

Copied and paste from bird board. Look for him over there. cgarr