Engine tightens up under final torque of mains... :-(

turbodave · Post by **turbodave** » Sat Jun 04, 2011 10:52 pm

Well, I'm really getting pi55ed off with this block I got from V8Developments. After doing a lot to get it to the point I was happy to build it, It locks my crank solid when the mains are torqued over 50Nm.

The Crank came out of my last block, 120K miles, and has only had a light polish. Still standard size, and right in the middle of the specs.

At first I thought the reason for it jamming was the crappy main bearings I was supplied with my block (had to be gently hammered onto the centre-main & wouldn't sit neatly on the tang groove) so I bought some OE bearings.

The clearance is up around .0015" when I torque and measure each individual journal... A little tight - but probably OK I feel.

I don't believe the crank is bent because when I torque each of the mains up to 20Nm, it spins, a little tight, but cleanly spins without a tight spot or anything else that I suspect would happen with a bent crank (not that I've ever had one though)...

I can fully torque journals 1 3 and 5 and have it spin, but when 2 and 4 are torqued - these are locking it up. Conversely, torquing 2 and 4 and leaving the others loose and it also spins.

I'm going to take the block and crank to the machine shop on Monday to have it checked, and line honed if needed.

I'm just curious if it is common for these engines to need line-boring. I honestly don't know the history of the engine block, nor the main caps as I paid the surcharge for them to supply me a block. I was just hoping (assuming) that this would have been checked by the guys at V8D - I'm nowpretty confident this isn't the case however, given that they even forgot details like running a tap down the holes, cleaning the swarf out of the rear cam plug, honing the block to an acceptable surface finish, and stamping the block with the numbers to match the paperwork...

I do still have my old engine block - I'm tempted to stick the new shells and crank in there to see if it's the same, as I know this setup worked together at least. I guess that'll help point to the crank or the block as being bad...

Any advice opinions or insults welcome!

CastleMGBV8 · Post by **CastleMGBV8** » Sat Jun 04, 2011 11:53 pm

Dave.

Is it a 4 bolt main block. if so are you torquing up the cross bolts as well?

Kevin.

turbodave · Post by **turbodave** » Sun Jun 05, 2011 12:42 am

Sorry - forgot to mention that...

Yes. I'm putting the cross bolts in with just a nip of torque, then torquing the mains, then torquing the cross-bolts. Torqued to the numbers in the LR rebuild manual: http://www.landroverresource.com/

Perhaps I'll try putting 10Nm on the mains and side bolts, then torque the side bolts, and then the mains... I know it's not the way it's meant to be - but this is getting annoying.

minorv8 · Post by **minorv8** » Sun Jun 05, 2011 6:29 am

I don´t know how much new liners affect the rigidity of the block but I guess that it is possible that the mains are not in line after top hat liners are fitted. Having said that, I have a 4,6 block that got top hat liners. I put the crank and old bearings back into it simply to keep all components more organized (they tend to get lost if not properly stored

...) Anyway,with worn bearings the crank spins OK but I have not tried with fresh bearings.

Since you don´t know the block it is possible that the caps are not even from the particlular block. As you know from Mini scene everything is possible ! Have you checked the mains bores for size / ovality ?

Hope you get it solved

Jukka

unstable load · Post by **unstable load** » Sun Jun 05, 2011 6:47 am

Get yourself some Plastigage http://www.plastigaugeusa.com/how.html and check the clearences with that, then go back to the supplier with the info and ask for redress.
You paid for a serviceable block and you should get one. The moment you go to a third party they can potentially tell you to get lost.

ChrisJC · Post by **ChrisJC** » Sun Jun 05, 2011 7:48 am

I don't know how you can do this, but it sounds like you need to check that caps 2 & 4 are for your block.....

Chris.

SimpleSimon · Post by **SimpleSimon** » Sun Jun 05, 2011 7:52 am

unstable load wrote:Get yourself some Plastigage http://www.plastigaugeusa.com/how.html and check the clearences with that, then go back to the supplier with the info and ask for redress.
You paid for a serviceable block and you should get one. The moment you go to a third party they can potentially tell you to get lost.

Good advice there,and may well save any arguments later on

Boosted LS1 · Post by **Boosted LS1** » Sun Jun 05, 2011 10:25 am

I'd look for witness marks on the bearing shells, there may be a clue there.

I've found that cross bolt tension usually 'frees' up the crank. What happens if you add a little more torque to the cross bolts? Have you tried the mains at the lowest torque setting?

gelmonkey · Post by **gelmonkey** » Sun Jun 05, 2011 11:25 am

Is it just the crank that is in the block or do you have the rods and pistons assembled and fitted as well?
Cheers
P

turbodave · Post by **turbodave** » Sun Jun 05, 2011 12:30 pm

Just the crank. I always make sure this is perfect before fitting the rods or anything else.

Have used plastiguage - that's how I got the clearance (measured one cap at a time rather than clamping all five down then measuring them all at the same time). I guess I could measure the clearance all at the same time?

I will try adding more cross-bolt tension. It should take another 20Nm quite easily I reckon?

Checking 2 and 4 are for the block - yes, I agree. However, they seem to have the same slight discoloration as the others, and are all stamped '95' along with the block - so that is looking promising as I'm suspecting this isn't relating to the year, but was a stamping applied to ensure the block and caps weren't mixed at the factory.

I would have sent this back already, but I'm in the USA and bought this to replace the block in my discovery where the liners were freely moving up and down, and was in the recall range for the mis-machined front-cover dowels (yes, LR managed to mess that up in 2003)...

Witness marks: yes - there are some witness lines going across some of the shells, and witness 'contact patch' markings only on one side of the #1 shell. I'll take some pictures later and post them up if I don't get this sorted with more cross-bolt tension.

gelmonkey · Post by **gelmonkey** » Sun Jun 05, 2011 1:35 pm

Dave
Is it possible for you to fit the caps,torque them down and then measure the internal diameter accurately?
With and without shells would be best I think.
Also do you have any signs of cap fretting?
Whilst this is probably unlikely with a 4 bolt set up it would still be worth checking imo.
Cheers
P

Boosted LS1 · Post by **Boosted LS1** » Sun Jun 05, 2011 5:36 pm

I'm pretty sure this will just be an assembly issue where special care is needed. I've had several cross bolt blocks and ls1 blocks go tight on me but with some playing around they usually free up. Tightening the cross bolts usually sorts them out.

turbodave · Post by **turbodave** » Mon Jun 06, 2011 1:10 pm

Well, I got close, but not close enough for me to be happy.

I went back and very carefully scraped, and cleaned all the journal bores, faces relating to the main caps, and including the rear face of the shells to work this out. I had already cleaned and checked prior to the first assy attempt, but went to extra special detail this time. I probably spent 20 minutes on each journal...

I followed the LR engine manual to a tee, and still no joy. The best result I had was putting 15Nm on all the bolts, then torquing the side bolts to 60Nm (stripping the thread off one bolt on the LH bank that didn't seem to have a lot of thread engagement for some reason - but easilly replaced- in the process), then torquing the main bolts down.

I also looked at the power tune rover v8 book on google books, and read the chapter on the main caps, where it talked about lightly oiling the faces of the caps, which didn't seem right - but seemed to help along with everything else I did differently I guess.

The crank now spins without any tight spots, but is way too tight for my satisfaction.

The block and crank are at the machine shop now. The guy there also echoed Boosted LS1's comments about it being an assy issue, until I told him everything I'd tried.

He does think that the .0015" clearance might be a little tight.

He's going to measure the block with the correct tools - he wants to avoid the hone as a last resort. He's going to check the concentricity of the main journals to each other (doubtful as an issue - but more as a sanity check as it's easy and quick to do) and then measure the block.

His preference if the parts check out, is to put the crank through the polishing again, to take a very small amount off - which should be enough to keep inside the limits, but at least allow the engine to spin like it should on a new build. He is at least being a realist about reminding me that this is a stock engine - and that having a crank a little on the higher side of torque to spin on a new build is not a disaster as it'll bed in and will not make a huge difference to the noticable power output, especially in a discovery...

He asked what assy lube I was using - Lucas hi-performace (the green stuff) which he seemed happy with - this is a very light lube. He commented that some different (usually cheaper) brands of assy lube are like treacle and can make a crank fit that is ok, feel too tight.

So, We'll see what happens.

One thing that I'm wondering if anyone knows - what the correct diameter of the main journals in the block is meant to be. Does anyone know?

spend · Post by **spend** » Mon Jun 06, 2011 4:10 pm

Have you had the crank ground, tuftrided or something by any chance?

Grinders can be slightly out of true & treatments can leave a (larger) deposit/swelling.

Boosted LS1 · Post by **Boosted LS1** » Mon Jun 06, 2011 4:49 pm

Tuftriding causes all sorts of dimensional issues despite what the people say about it only being microns, lol. Every crank I've had tuftrided has ended up tight until polishing. It's probably best to lose .001" before the tuftriding process.

OP, run a straight edge across the decks or have the machine shop check the block for straightness, it may be twisted. I'm sure the caps will be correct. I've had to fettle a few blocks in my time to get smooth crank rotation. I also, in my early days had a crank that was really stiff and it needed a lever to get over the initial stiction before it rotated. The engine ran fine enough though, much to my surprise.

Also, shove a cam in there, does that turn freely?

I think that if you have the crank rotating by hand or with a spanner it'll be fine.