thrust main bearing - problem

Seight-V8 · Post by **Seight-V8** » Fri Aug 05, 2016 12:47 pm

hello all,

so today I though....rebuild engine time.

First problem is I opened a brand new set of king main bearings, and the middle thrust bearing wont fit over the web in the block.

So I measure the thickness of the block mains web at 22.30mm...and the inside of the king bearing at 22.00mm....

Pulled the old "real steel" supplied thrust main bearing from the bin.....measures 22.30 and fits perfectly.....

Hmmm...now I'm worried about fitting these king bearings, as the thrust face is also bigger than the thrust face of the crank, so even the crank wont fit in the bearing.

Googled all the part numbers and they are correct for the 4.6 engine, and where supplied by turner engineering.

Anyone else used "king" bearings......

I'm off to spend another 80quid to replace mains, and big end bearings with some from reel steel.....

Its just annoying.....that these are brand new, and weren't cheap and don't fit.....

thanks

scott

ChrisJC · Post by **ChrisJC** » Fri Aug 05, 2016 6:09 pm

I've always found them very tight, but a interference of 0.3mm does sound a bit much to me.

Chris.

Seight-V8 · Post by **Seight-V8** » Sat Aug 06, 2016 7:23 am

ordered a new set of mains & big end bearings from real steel.

Cant afford any problems internally, so need to be sure everything is correct.

got Saturday delivery, so at least I can move on more today and not waste the weekend.

I am sure this will be the start of another fun engine build....and there will be more to follow.....

Spent 2 hours yesterday looking for the camshaft pulley bolt before I found it....

regards

scott

Seight-V8 · Post by **Seight-V8** » Sat Aug 06, 2016 3:06 pm

so got another set of bearings delivered today....yeh it thought....

same numbers as the ones I took out.....

Got it all assembled and cant turn the crank.....locked solid....

check the clearances with some plasigage.....and its well below 0.025mm, which is the smallest it reads.

No sure what's going on here, as its already been assembled once, with the same crank and bearing part numbers....

Spend all day yesterday making sure it was all scrubbed clean before assembly.

As far as I can measure at home, the crank is top size.

I'm not sure if either the block has gone, when they fitted the top hats, or the crank is slightly bent.

I think I might put all the old bearings back in, and see what happens...

frustrating start to my re-build, when it done all this before with no problems.

scott

DEVONMAN · Post by **DEVONMAN** » Sat Aug 06, 2016 3:32 pm

If you lay the crank in with just the block bearings in place and no caps and then spin it. If it goes stiffer at one point then the crank may be bent.

Just to add, On the last two engines I built I had to remove some material from the thrust bearing to get some end play.

Seight-V8 · Post by **Seight-V8** » Sat Aug 06, 2016 3:51 pm

yes I have tried just laying the crank in without the caps in place, and crank rotates fine, with no change in tightness....

I've just put in the old bearings I took out.....although crank doesn't lock anymore, it rotates, but I cant feel its stiffer at some point more that others.

Think I need to check the main diameters when tight, and for concentricity, then check the crank for run out.

All this will have to wait till I'm back at work next week.

Its not something I was expecting, all I've had done is new tophats fitted....but maybe a little stress has relieved itself in the block.

If so can this be fixed?

cheers

scott

DEVONMAN · Post by **DEVONMAN** » Sat Aug 06, 2016 5:17 pm

If the crank is ok and the block has distorted during top hat work then it can be line bored to get it true again.

I assume that you are also putting the correct torque in the cross bolts when checking the free rotation of the crank. The 4.6 blocks have a 3-4 thou gap at one side of the main caps and this closes when the cross bolts are tightened and this is how the block is when the block was originally line bored at the factory.

It's possible the crank has a minor run out and the block is ok.

Real steel once straightened a crank for me but that did necessitate a 10 thou grind.

Ian Anderson · Post by **Ian Anderson** » Sat Aug 06, 2016 6:54 pm

Have you kept all the caps in order?
I have had cranks tighten up as some ponker (me) put them all together and reassembled in wrong order!

Ian

Seight-V8 · Post by **Seight-V8** » Sat Aug 06, 2016 8:05 pm

thanks devonman, for your help in giving my a wake up call....and having the right answer.

It was the side bolts, I was expecting the crank to rotate after tightening the mains only, but no.....now rotates freely when all the mains & x-bolts are done up....

Looks like I've had my "brain fart" day already.....

but major thanks for your input.....

regards

scott

stevieturbo · Post by **stevieturbo** » Sat Aug 06, 2016 11:03 pm

Seight-V8 wrote:thanks devonman, for your help in giving my a wake up call....and having the right answer.

It was the side bolts, I was expecting the crank to rotate after tightening the mains only, but no.....now rotates freely when all the mains & x-bolts are done up....

Looks like I've had my "brain fart" day already.....

but major thanks for your input.....

regards

scott

I recall I had similar issue with my last 4.6 ! I too thought the mains were too tight.

It's amazing just tightening up the side bolts totally freed it up !

unstable load · Post by **unstable load** » Sun Aug 07, 2016 8:13 am

Seight-V8 wrote:Looks like I've had my "brain fart" day already.....

Doubtless, there'll be more.....