Heads off!! Engine still frozen... Advice?

[fpretzer]

Well, finally took the heads of the frozen 2.4 last night... the pistons and cylinders look good, none of them are frozen, in fact no sign of any rust around rings/inside cylinders, etc. But engine is still frozen up solid as could be!! No bolts hanging up around the flywheel, the heads are off and they look OK, timing chains and intermediate shaft (what I could see) look good. The oil that was drained from the case looked used, but not overly dirty or no burnt smell, and just trace amounts of metal around the drain plug and screen. It does appear that the engine was gone through recently due to the condition of the case, new presure sender, little wear on the obvious areas, and still some orange case sealant in places. One interesting thing though, no oil was in the cooler when I removed it, also plugs were brand new. Any speculation what happened?
Even more important, anything else to look for before I split the case? If I do split it (looking more probable everyday) hints as to what to look for inside? I don't want to sound cheap, but with the rest of the motor looking so good, I hate to replace anything I don't have to. Thanks for the previous advice everyone gave on freeing the motor up, wished it would have worked!

Fred

[Groesbeck Hurricane]

Fred,

You sound prudent, not cheap. If it ain't broke don't fix it and never throw money at a problem you have not properly diagnosed.

Are the pistons still in the motor but the cylinder heads removed? If the cylinders are still on, have you removed the plugs? I am thinking there is something keeping the drive shaft from turning. Have you removed the chain towers? The chains can easily bind if they are not tensioned. If you have taken the cylinders off, shine a light around inside the case and see what you can see. I am worried about the trace amounts of metal. There could be an actual metal piece lodged somewhere preventing the motor from spinning.

[fpretzer]

David,

I've taken it down to the point where all is apart except taking the cylinders off. That's the next step, you're right, when I do, maybe I can see more inside. I'm going to try and take the P/C's off together as sets, separating at the rods. Thanks for the advice.

[Groesbeck Hurricane]

Oh, where in Texas? Some of us might be able to take a look with you.

[Wayne 962]

Make sure that you spec everything out, and replace the parts that are out-of-spec...

-Wayne

[CliffBrown]

Fred

It would be easy to remove the distributor to make sure it's not causing interference.

David's suggestion about removing the chain housings will allow you to visually check for a chain problem.

Cliff

[fpretzer]

David,

Thanks for the offer. I'm north of Ft Worth, west side of Flower Mound, so it'd be a good drive for you. Looks like I will probably end up splitting the case, I can't see anything else obvious that would be causing it to be frozen. Chain towers and heads are off, distributor out, sump plate off, it still won't turn in either direction.
Those of you who would know, could the main bearings be bad enough to completely freeze up a motor like this? If so, what will the effect be on the crank surfaces? Reusable?????

[Rot 911]

It would be hard to imagine the bearing seizing to the crank, but anything is possible. I would try removing the cylinders without the pistons and try to see if this is what is causing things to seize up. You are going to have to pull the pistons out of the cylinders anyway to re-ring them and check out the bores.

[fpretzer]

Pulled the pistons and cylinders off, at least the 4 that I could, 2 are down in the case too far to get to the clip to remove. (Remember, still frozen up). All looks fine with the pistons, rings, and cylinders. I put a light in the case, looked where I could and and couldn't see anything obviously wrong there either. The rod bearings move freely, maybe a spun main that has caused it to lock up? Remember, I didn't find much metal in the drain plug and screen when I removed those. Looks like I will split the case Tuesday...

[tt_targa]

My uneducated guess would be oil pump and intermediate shaft.

The suspense is killing me!

[CliffBrown]

I'll second the oil pump theory. Without knowing the sequence of events leading to the seizure. It's easy for the pump to injest something and get lodged in the gears.

[Wayne 962]

I'll wager that it might not be so obvious...

-Wayne

[dtw]

I am going to vote against oil pump - all the oil pumps I've seen which have ingested something large enough to stop the pump, at operating speed, have simply blown up. They turn real good after that though...higher flow with extra ventilation in the oil pump housing . Also, I don't think the mains would seize to the crank. My wager is going on the chains/intermediate shaft, either a chain cocked in the sprocket or foreign object in there.

Do you even get a click in either direction? Or just completely frozen, won't budge a bit? Not that it matters...we're all going to be dying for Tuesday here. Good luck.

[Groesbeck Hurricane]

Fred,

That is one heck of a drive... I would pull the cylders off the pistons. All the dimensions should be verified, you are there already. If there is a major problem with one of the piston/cylinder combinations then the motor will not be able to turn by hand. This would also account for the bits of metal if the cylinder walls were scored. I hate to think of something as extravagent as that, but I would check out all possibilities. Looking forward to hearing what is going on Tuesday. Can you post some pics?

[ChrisBennet]

If the crank is really frozen wouldn't that would rule out the intermediate shaft? If the intermediate shaft was locked up you'd still be able to rock the crank a little due to the backlash in the gears.
-Chris

[fpretzer]

Well, here it is. I'm still not fully sure what had it locked up so tightly, but after I removed all the through and case bolts it freed up!!! In fact it may have freed up before I had them all removed, I wish I would have checked. However, just out of curiousity, I refastened and tightened it down again and it all still turned freely. Some of you experts tell me what that's all about?

I went ahead and split the case, and there is some obvious wear damage on #1&5 main bearings (grooves down to copper), but it doesn't look like any corresponding damage to the respective surfaces of the crank. What caused that? The rest of the bearings look OK, but they are all getting replaced. Also some wear on the rear main. Everything else looks good inside, there were no leaks on the engine before, it was clean inside and out, in fact it's apparent it was rebuilt not too long ago (20K miles ago?). The oil I drained was dark, but not dirty. The heads, valves, and valve train look OK. All bolts seemed to be correct types and torqued correctly, it looks like it was rebuilt properly.

Where do I go from here? Obviously, I'll measure everything and make sure all is in spec. New bearings, re-ring and have cylinders honed, all new seals and gaskets, anything else? New oil cooler with the bearing damage?

Appreciate all the advice and support...


Fred

[dtw]

OK - I'm changing my vote?! Bent crank or twisted case, probably the latter based on the history of mag cases...

Glad you didn't find anything catastrophic but be sure to get a really good inspection of your case, crank, and other hard parts per the advice on this board, Anderson, Wayne, et. al.

[ChrisBennet]

Hmmm, a little friction welding action at work perhaps? Put me down for twisted case too. Sounds like someone rebuilt it who thought that "it was fine before so I just bolted it back together with new bearings".
-Chris

[jgparker]

Fred,

Great picture! Thanks for posting them. IMHO, You need to send the case and crank out to a good Machine shop that knows 911s. If you slap in new bearings, you'll end up right where you are now again. Mag cases tend to constrict on the crank when you skip the line-bore. There are lots of good recommendations for machine shops in the archives of this board. I have had good luck with Ollies myself.

Good luck,

JP

[Groesbeck Hurricane]

Fred,

Don't forget to clean everything before putting it back together. After you have cleaned everything, clean it again, just to make sure. Wishing you the best!!