Jungle 4K overhaul gone wrong

[rebuilder86]

I am in need of a bit of advice from anyone with experience in the area of engine rebuilding.
I've done lots of rebuilds in my time, about 20, of which only 5 involved/required professional machining, and never once ran into so many problems.

Short version, i had coolant leaking in to oil, pulled the head, couldn't see any obvious leaks, but suspected the fact that because the head was quite warped (~0.5mm) that it was just simply a head gasket failure.
The head has serious problems, but i cannot source a new one, so I'm doing a bit of a dodgy patch up just to get the car into a position where it can be run.
While i have the head off, i thought now would be a good time to change the big-end bearings, as there has always been a bit of a knock or slap when hot.
When i got the bearings out, i found they were 0.25 under size, so this crankshaft has previously been ground. the crankshaft pin journals looks mint, and to be honest, so did the old bearings, but i had the new ones and thought, what could possibly go wrong, plus i am hoping that the new ones would quieten the noise by increasing oil pressure which is notably low.

There is no such thing here as plastigauge, or assembly lube, so I'm roughing it. I am relying on the fact that i just removed 0.25 mm bearings, and am replacing them with identical new ones. I torqued them up with everything covered in 20-50 oil, but its just completely locked up. I have never experienced this before.
So i undid them all a bit and found that if i have them tight at all, as in, as tight as my hand around the head of the ratchet handle, with minimal hand torque, its completely locked up and if i loosen them, it turns, so it is definitely the conrod bearings causing an issue.
After this, i checked the bearings, and number 1 seems to have a bit of scoring already. nto terribly bad, but bad enough for me to scream so loud that the village thought the car fell on me.
Now given that it has just had a head gasket failure, and water went through it all, i suspect it simply needs some gentle encouragement, in the form of some oil pressure. 
So i attempted to put as little back on the engine to build up oil pressure, but then realise during that attempt that jsut cranking isn't going to give me sweet fek all..

So my predicament,
If i tighten the bolts, enough to safely run the engine, the engine wont crank.
If i loosen the bolts enough to crank it, i don't want to start it because I'm worried something will rattle loose.. (anyone ever done this?)
i can't just crank it because the pump needs to be running fast to overcome the gravity to prime the system.

Is there any dodgy yet miraculous resolution anyone can think of, short of scrapping the whole thing?

I have been thoroughly clean. I'm under the car doing this with a spray can of degreaser in hand, cleaning everything, before smothering it in oil. Dirt is not the issue. 
 

[rebuilder86]

if i had just left the  bearings i wouldnt be in this mess

[Banjo]

OK, Jeremy; Lets look at the facts.

As the oversized (+0.025") big end shells you removed, were in the engine, & it rotated OK, we have to assume the rod journals have been ground undersized at some time, & had oversized slipper shells fitted. However, if brand new +0.025" shells have now been fitted & they are tight, then either . . . . .

1. The crankcase journals were not ground undersized to 0.025", and the grind was something less, & very worn 0.025" shells were fitted.

OR

2. The new +0.025" shells are incorrectly marked or labelled.

Stranger things have happened !

In the absence of  accurate vernier calipers, so you can measure each journal at three points, you really have no option, but to reinstall the shells you removed. It is possible that these are also very worn & that's why your oil pressure is low.

One option you have is to "shim", the rear of the big end bearing shells.  Bear in mind that oversized shells come in various sizes.  +0.005,  +0.010 etc. so a +0.025 has plenty of white metal on it, as the shell metal backing would all be the same thickness.

I've never shimmed a big end shell, but an old mechanic, once showed me one how to do it, and it certainly worked for him.

With the rod & cap ends & slipper shells spotlesslessly clean, he would line the shell backing contact area with 1 or 2 cigarette papers. (Tally Ho was the brand I think he used)

Before fitting the shell bearings, he would work each end of each shell on wet & dry emery paper, so they could come closer together. He'd then assembly wet,  & tighten, & then spin the crankshaft.  He would do this a little at a time, until he felt it was just getting tight, & then put enough cigarette papers behind, until it spun freely.  He did this with each journal one at a time, with no other rods connected.  It could take him all day, although I must admit he was working on an old straight 8 cylinder American car at the time.

This may seem an extreme fix, but if you are in the jungle" & do not have the measuring equipment, or resources to do a complete repair, this might be an option.

Frankly the problems you have had with this 4K in your "Jeep", I would suggest that you try & get hold of one of those 4K or 5K long second hand engines, you told us as being freely available in the Philippines, & assign this engine to the scrape heap, or as back-up spares. 

Cheers Banjo  

Edited January 14, 2018 by Banjo

[rebuilder86]

yeh its looking that way hey.
there are plenty here, so i should be going that route next year, but can't afford it yet.

So were u saying, the mechanic used tally ho papers as permanents shims????? hahah wow.
I couldn't quite follow exactly what you were saying but whatever it is, thats awesome, and thats the kind of ingenuity I'm after.

I will be under again today to remove the sump full of clean oil i just wasted, and check the bearings and have another go.

I eyeballed the new bearings against the old ones and they realy do look identical, but in this country, parts are so cheap, this set of bearings was about 10 dollars, so its possible they just cut out piece of aluminium pipe, ccut them in half and tang them haha

Edited January 15, 2018 by rebuilder86

[rebuilder86]

update, 
and this is embarrassing.
I simply replaced the bearings one at a time, like i always do, and installed them the same way there were on before, by looking at the next rod along and lining it up the same way, but it turns out, it must've always been wrong because the tangs on the bearings ended up on opposite sides hahah.
SO its always been backwards, god knows how the engine builder got it to turn when they did it.
the bearings that came out actually looked flawless, but are now rusted and contaminated from being in the dirt so they're not going back in.

This is just typical of the sorts of workmanship u can expect in this country, and i may be no better by trusting and copying the person before me.
The pistons are installed in the correct orientation, dot forwards, but this leaves me wondering if the builder installed the conrods the correct way around in the pistons, if not, then the reversed caps would actually be correct... christ sake

Edited January 15, 2018 by rebuilder86

[rebuilder86]

noo, the caps have always been backwards compared to the rods, because the tangs (on big end and cap shell) are opposite instead of next to each other!

[rebuilder86]

7 hours ago, Banjo said:

As the oversized (+0.025") big end she

hey banjo, u talking in inches here, this bearing is marked 0.25. 
I think 0.025 inches is the clearance, not the size, am i right in that thinking?

Nah here we go, you're bloody close, but these must be 0.25mm.

[Banjo]

My reference to 0.25 in is in inches. That's why I added the 0.025". That (") means inches,  25 thousandths of an inch.

If you have bearings marked as +.25 oversize, then that is in mm, (1/4 of a millimeter)

 I suggest you check the main bearing caps. They usually have an arrow on them, that faces forward, & a number 1-5 indicating its position front to rear.

The Pistons have a mark on the top, which should face the front of the engine.  The conrod is straight, & has a mark on the front side also. The match marks on bearing caps, should always be together, & be on the camshaft side of the engine, off memory.

I guess you are going to put it all back together again with caps it the right place, and new bearings, & see whether the tightness is still there ?

Cheers Banjo

Edited January 15, 2018 by Banjo

[altezzaclub]

Hmmm.... when I had this exact problem it was because the new bearings where an absolute whisker wider in the contact area on the crank and they were getting stuck on the thin film of sludge in the corner of the web.

In the end I pulled the crank out and had a shop make it spotless, then everything worked.

 

[rebuilder86]

yeh altezza i thought it couldve been the bevel/web catching also but now 8m certain tge conrod caps are backwards, and always have been I'm jist praying that spinning them back the right way will fix it. I just can't understand how it was running before backwards with such little and very uniform visible wear.

i had previously done the rings 2 years ago and when i did that i followed the same process, one at a time and copied the orientation of the other caps. I'm ceryain i didnt start this backwards nonsense haha.

anyway, i am dissregarding the apparent even wear on the bearings due to the fact that the cap doesnt take much load, other than during the compression stroke, and thats probably why it looked fine but had low oil pressure. (an easy exit path through the rod cap when the crankshaft oil hole turns to to the cap side.)

This would also explain why when i give it some stick, then just slightly but quickly let off the power, the oil pressure would instantly rise the moment i lift my foot: about 8 psi difference between full throttle and quarter throttle while coasting at about 2000 rpm. When under power, the bearing cap would be pushed away from the journal and let the prrssure escape, and when letting go of power, the cap and journal recenters and pressure gets slightly better.

Banjo, yeh the mains are all good, and i pulled 2 off (2 and 4) and they are mint and also 0.5 undersize so the crank has had work all over which is nice to see.

My bearings are undersize, i confirmed this when i accidently bought std size and eyeballed it and the 0.25 is def undersize (for undersize crank) as opposed to 0.25 oversize (for oversized caps).

but that there would probably be a common trap id imagine. 

 

my lesson learned, is to not just blindly follow the last engine builder and accept that the engine has been set up correctly. like u said banjo, checking the marks lined up wouldve completely avoided this trouble.

[rebuilder86]

all sorted, turned them around the CORRECT WAY (LOL) and shes sweet. Just needed to speak to people about it to clear my mind, and it helped.
So i have been driving around for about 4 years with reversed rod caps! probably needs another grind back and next size under bearings now :/