Crankshaft seisure?? New rebuild!

[Wayne 962]

Oil sample? Sounds silly to me, you have an obvious problem. Of course the engine doesn't get sticker, these engines expand when warm, and any tight clearances open up (didn't I mention this earlier?).

You said yourself that you had trouble turning it over by hand. You're like the guy with some deadly disease who is in extreme denial...

Walt can be reached at http://www.competitioneng.com. I spoke with him on Sunday, and he's quite busy...

-Wayne

[biggtbiggt]

I agree that I am in EXTREME denial!! It just seems that the damn thing is so close that I hate to take apart again and maybe come out worse! I guess I don't totaly understand the align bore thing and that is maybe what is scaring me. If I would of left my perfectly looking old bearings in the case would I still of had to get it align bored??? It is killing me haveing this thing sit in my garage an dI am not able to drive it!!

[911pcars]

While we all sort of agree that the crankcase may need to be line bored, I think your wrench's oil analysis idea would further validate the bearings are not in alignment (you will see abnormally high levels of aluminum or lead or whatever type of bearing material you have - in the oil; bearings are sacrificial to a certain extent). If it was my engine, I'd want to be convinced that's what it is before letting the impact wrench fly. A couple of days wait is not too long. You can spend the time prepping the car and disassembly area.

Have you exhausted other engine diagnosis like ignition timing too far advanced coupled with high compression? Just wondering.

Sherwood

[biggtbiggt]

I thought that high compression could be a factor. The engine will spin no problem with the plugs out even if it sits for 2 days. It is just that when the plugs are in the compression must be putting the starter tot the limit and it won't spin right away. I also suppose that if I had a high torque starter it would also turn right away. I will wait until the sample comes back and see what it says. Maybe I just have a tight engine that needs some run time!
Thanks...Tracy

[biggtbiggt]

I couldn't handle the stress and have the motor out and half apart!! I will post the results tonight or tommorow when I have the cases split.

I also took the engine out without the tranny and I think it was easier taking it out with the tranny attached. I know it will be easyier to put together with the tranny attached and then put in but would like some more advice on that.

Thanks...Tracy

[snowman]

Dont't split that case yet. Hope this is not to late for you. If the engine spins fine without the plugs, even after setting, the crank is not likely the problem.

It sounds like fuel building up in a cylinder when the engine is setting for a long period. This may be due to some kind of leak in an injector or carb. Most likely if its got carbs.

The oil analysis is an excellent idea. It can rule out the crank, best case, or worst case leave it in the mix.

There is a possibility that the starter is indeed the problem. The crank is usually ok if you can turn it at all by hand with a small wrench. Slight binding may be ok on assembly. By slight I mean that you can turn it over using about the leverage of a 10mm wrench.

The line bore can be checked very easily, in about 10 minutes at almost any machine shop or at home if you have a known straight rod and a feeler guage.

In any case with a problem like you have its best to have a lot of patience. Don't jump to any conclusions, and don't drive it either. With the ammout of time and money required to rebuild it again, I would even take it to a good shop first for a real diagnisis. This is an art and the experience really helps.

[snowman]

MOre thoughts on the stickiness problem.

There is another likely cause for a problem like you are having. Bead blasting. IF the case or most anything else was bead blasted, it is almost impossible to remove all the glass beads. THe beads will work their way to the crank, the rod bearings being most susectible. The symptoms can be the same or very similar to what you are having. Hope it is not so, as at this point you will have trashed an engine, maybe completely.

Glass beads do incredible damage. They ruin the crank, the piston rings, the pistons, the cylinders, the oil pump, the rockers, the cams, the timing chains, the intermediate shaft. Depends on how many and it don't take much.

This is not ment to scare you as it would be to late for you. But anytime an engine dosen't work right on reassembly it is mandatory to find and correct whatever is wrong BEFORE all the damage that can be done is done. THis includes a complete teardown, if however reluctantly necessary. A gasket set is relative cheep, compared to those real expensive engine parts.

[biggtbiggt]

I got the engin down to the block and cylinders today and will take the rest apart in the morning! I am sure that it is a slight warp in the case as it was tight before I installed the cylinders. I just hope that I did not damage the crank!! On disassemble I noticed that some weeping has occured allready around the breather housing!! I am wondering if I should install it with some curil-t on reassembly??
I also notice that most of the bolts holding the fiberglass shroud were also very loos and am wondering if they should have lockwashers or loctight or something!

[biggtbiggt]

I got the cases split and the crank out and measured up. 3 of the hournals are about 6 thousands to tight so I am line honeing on Saturday. The bearings looked good but on the tight 3 there were some shiny spots were you could tell it was tight. I would imagine that after a few thousand miles I would be in for an expensive rebuild! This one is just costim me some time, gaskets and a Line hone job!

BTW I got Waynes colored copy of his book! Wow I can't believe it is the same book as the preview copy. I thought the preview was good, this is incredible! Thanks Wayne for a wonderful book!!

[dtw]

Good job! I'll hoist one to you tonight.

[911pcars]

"....3 of the hournals are about 6 thousands to tight"

Can you explan further? Were the crankcase bearing saddles out of line or was the bearing clearance incorrect? How did you determine the clearance was 0.006" too tight?

Sherwood

[farleyd]

Hi guys, i am rebuilding a 2.7 as well and i am intrigued by something. One said that along using Plastigauge for checking clearance, you could fit the crank, bearings - but no rods, and be able to turn the crank by hand on ce the case is torques to spec????

I had my case measured with a straight edge AND a feeler gauge, and was within 1.5/1000 on every saddle. Guess the case is right????

Thanks for replying.

PS Still waiting for delivery of Wayne?s new book. its in the mail!

[Wayne 962]

You can't effectively measure your case with a straight-edge and some feeler gauges. You need to measure it when it's all torqued down, and the only way to do this is without the crankshaft installed and with a dial-bore gauge.

See page 50 of the engine rebuild book. You really can't short-cut sending your case to the machine shop.

You should really think about having your case brought back to std/std. It will actually probably be cheaper than align-boring it out. I did hear a rumour that a certain machine shop (rhymes with dollies) bought all of the oversized bearings and now is the only source for them (we don't have them). I think they wanted $500 for a set? Just what I heard from a pretty reliable source...

Food for thought. You probably want to send your case to Walt (Competition Engineering) to be resized and inspected...

-Wayne

[snowman]

I do not understand. If the case is straight, it is straight. A straight edge (round rod) and feeler guage is all that is needed and is the traditional method of measuring line bore.

There is the potential for non round journals. This would require both halves to be bolted tagather and a bore guage used to check roundness. Roundness is NOT the same as line bore, although the same cure is used for both. I do beleive that if a straight edge is used properly, ie check at several points around the circle, it will yield the same results.

Bottom line. IF you assemble the crank,with lube, less rods in the case and troque the bolts the crank should turn freely, ie by using your hand only, maybe on the outside a 10mm wrench at most.

Plastiguage can be used to verify bearing clearences. A more accuraate method is to check using a bore guage and mic the crank. How much more accurate? Well plastiguage is only accurate to about 0.0003 to 0.0005 thousands. But wait, isn't this good nuff?

[snowman]

PS
biggtbiggt ,

If would be helpfull for all to know where the 0.006" came from. Do you mean a 0.006 feeler guage slipped under the straight edge?

Shiny spots may be somewhat normal, depending on how shiny. I would tend to measure bearing thickness to see how much was taken off. If that was 0.006" then indeed you had a line bore or clearence problem. The clearence problem could also be due to out of round journals.

In any case if there were no small grooves due to grit or glass beads, be thankfull.

CE is one of the best there is and they will tell you what really happened. Let us know.

[jgparker]

I think both Ollie's and Zim's have the std crank/1st over case main bearings in stock. Both were priced between $200 and 300 for the set last time I checked, so technically it could be cheaper to do an oversized linebore, and use the 1st over bearings. Generally it is a good idea to machine the mating surface anyway, since it will improve the probability of a leak-free engine.

[biggtbiggt]

The machinist used some sort of long dial guage that went down the bore and measure each journal. The one's that were tight were the ones that had the shiny bearings. By the look of it the journals they must wear into an oval shape. I gues just a quick rub with the line hone is supposed to clean them up. I had to bring the block home from the machine shop and manufacture a cradle to securely fasten it into the line hone as they usually just work on american engines and the mounts are different. I done't think you could measure this with a straight edge and feeler guage as it would be too hard to get acurate! we are taking a very small amount here and with the curve of the journal it would be damn near impossible to get in their.

[Doug Zielke]

Originally posted by biggtbiggt
The machinist used some sort of long dial guage that went down the bore and measure each journal. .......... I done't think you could measure this with a straight edge and feeler guage as it would be too hard to get acurate!

Very true!
I've watched the process at a local shop, and they sure as hell don't use a feeler gauge.
Looks like you are back on the right track with your motor, bigg'.
Good luck!

[john walker's workshop]

there you have it. don't you feel good now, sort of? if you haven't timeserted the 8mm studs on either side of the intermediate shaft bearings, now would be a good time. they tend to pull, especially that long one. were the cylinder bases trued, the cylinder spigots (bore) made round, and the head studs inserted already?
i agree that the straight edge is virtually worthless in this application.

[snowman]

Well to check for a warped case they certainly do use a simple straight edge and feeler guage. Heres an excert from a college level shop manual thats used to train for ASE certification


The bore guage is used to check ROUNDNESS as it cannot tell if the block is straight or warped at all.

An inexpensive alternative to the bore guage is the snap guage, the whole set is $15 at Harbor tool. It is just as accurate, but a pain to use.


Note that there are things beside the case that can cause the same problem, ie bent crank (easily fixed) as well as improper bearing crush, dirt, and more.

Anyway a straight edge and feeler guage are basic tools that ARE used by the best shops to check case straightness. The bore guage is NOT used for this purpose as it cannot do the job.