Big end problems. Advice on what to do.

[Trikky]

what brand of cam do you have? unless you are trying to chase every last once of HP out of the engine the dot to dot method works fine(just use the dots on the gears) in nearly all cases
Only time it can be an issue is if the cam was ground offset, but if you have a crow or comp cam you should be fine
When I built my engine I just did the dot to dot method with a rollermaster timing chain and a comp cams camshaft and it has been fine

If it is the cam bearing that has failed I would suspect one of the three things to cause it cam bearing not sized correctly or damaged when fitted (did they have the cam when the bearings were installed) or one of the cam bearing oil feeds has gotten blocked but if this I would expect this from something left in the oil galley and to happen almost straight away not a couple of years down the track

Do you have an oil pressure gauge fitted? what sort of oil pressure does it have at idle and while driving if you do have one fitted?

 

[Immortality]

One thing I'm worried about is dialing the cam back in, I would have no way of knowing what the hell I was doing. Would dot to dot work on the Rollermaster double-row gear I have (I would obviously make new dots, not factory stuff)?

Before you pull it apart, rotate the engine until the timing marks line up, make sure the crank sprocket is visible and take a photo so that you can see the timing marks as well as the keyway slot that is been used (they are also numbered i.e 0, +2, +4 etc if it's a rollmaster set). That way, when you put it back together you'll get it back in the same spot

 

[acarmody]

what brand of cam do you have? unless you are trying to chase every last once of HP out of the engine the dot to dot method works fine(just use the dots on the gears) in nearly all cases
Only time it can be an issue is if the cam was ground offset, but if you have a crow or comp cam you should be fine
When I built my engine I just did the dot to dot method with a rollermaster timing chain and a comp cams camshaft and it has been fine

If it is the cam bearing that has failed I would suspect one of the three things to cause it cam bearing not sized correctly or damaged when fitted (did they have the cam when the bearings were installed) or one of the cam bearing oil feeds has gotten blocked but if this I would expect this from something left in the oil galley and to happen almost straight away not a couple of years down the track

Do you have an oil pressure gauge fitted? what sort of oil pressure does it have at idle and while driving if you do have one fitted?

Yeah new bearings where installed, as the whole engine was being rebuilt, the cam went in at same time.

Before you pull it apart, rotate the engine until the timing marks line up, make sure the crank sprocket is visible and take a photo so that you can see the timing marks as well as the keyway slot that is been used (they are also numbered i.e 0, +2, +4 etc if it's a rollmaster set). That way, when you put it back together you'll get it back in the same spot

Cheers mate. I will run a light scribe mark straight down both gears, and do a photo.

 

[acarmody]

So had a go with the stethoscope and its also very inconclusive. The noise is just a audible from the intake manifold as the front of the sump. You can hear it quite nicely from the extractors too.

I am now trying to get the smell of smoking oil out of my nose

 

[Immortality]

Is it a knock or a tapping type sound? I still think you should check the lifters, what lifters did you fit?

Have you checked the oil pressure?

 

[acarmody]

More like a very loud tapping noise, not much deep 'thud' to it. They are MACE Comp lifters. Like I said before I did forget to pre-soak them first.....

I do have a cheap SAAS oil pressure gauge that I haven't fitted yet, I'll whack it on tomorrow. If its a bearing, pressure should drop with RPM applied right?

What would be the easiest or best way to see if its the lifters? I'm still contemplating removing one pistons worth of rockers and rods at a time, as well as injector unplugged.

 

[Immortality]

Run it with the rocker covers off, just idle it otherwise oil will splash everywhere. It might show one rocker/lifter not opening properly.

 

[GTP 85]

A big end would be felt very clearly thru the block... sort of like a ball peen hammer hitting the bottom end. Cam bearings/ lifters/ timing chain tend to be a bit more clacky and ticky. If its a cam bearing the engine will have to be disassembled. The tunnel will have to be line bored for OS bearings. Hopefully its not the cam cuse the cam MAY aso be damaged

I recently had to change my lifters cause they were getting quite clacky (The engine sees very high RPM). I just bought some stock replacements... squirted them with oil and installed them. No need to soak them. Fired up first time, the residual oil keeps them lubed til oil pressure reaches the top.

IF the engine needs rebuilding ...again... i'd just be hunting down a clean Low km VX, VY bottom end and bolt on all your good bits. cheaper and easier. a few years ago I pulled an engine from a VY with 100k, cost me $400.

 

[acarmody]

So I hooked up an oil pressure gauge (T-piece to stock sensor), check out the results in this vid.

I'm really confused now, no oil pressure drop. Might just have to replace the lifters and see what happens, also chuck the rods for straightness, also check the rockers for cracks.

Also honourable mentions for Immortality in this vid

 

[Immortality]

Hi Mate,

OIl pressure is good, oil pressure should rise with revs so that's good also. Smoke..... not so good for your lungs and makes a mess under the bonnet, when I fitted my rockers It a quick rev and I was cleaning oil of the gaurds

Anyway, it does sound like valve train to me. Mine sounded a bit like that (for a few seconds) until oil pumped up with the new rockers fitted.

Cheers