Thread: Death rattle. Unexpected, require quick contingency plan

At 337,000km it's time to rebuild the engine. At least that's much quicker and easier than the conversion you planned! My guess is that a lifter or two has given up the ghost?

Pulled the rocker cover today, expecting to see bent pushrods or caved in rockers or broken springs.... all OK.

Except.... the rocker cover is absolutely filthy with carbon... wtf are these rover engines doing to create so much carbon?, so are the rockers, springs etc. but the heads themselves are clean - probably because of my maintenance regime.

So I performed a few more checks and while there's nothing sinister, I'm blaming noise on severely worn cam lobes & Lifters. No point in pulling the inlet off.

At this stage I don't want to spend any $ on this engine. I might decide to rebuild it, but not yet. I have an existing project that is consuming my time and funds.

Will keep you posted on developments. For now I can live with the jackhammer.

Someone said to me "just put an LS1 in it - you can get an LS1 & trans for 1200 bucks"

So the fool in me started looking around. I figure any LS engine at that price would have to be completely shagged, and I'm not too keen on it, but geez, they are cheap.
It doesn't make sense.

You could just drop the sump and clean it out. The oil pickup might be partially blocked by sludge and causing aerated oil to reach the hydraulic lifters. I stripped down a blown up stage 1 engine once on which the sump was filled with more sludge than oil, causing it to starve on the freeway and self destruct.

It's clean as a whistle inside, at least where any oil resides. When I purchased it I ran diesel oil in it for the first few thousand, then flushed, and a couple of short changes with new filters. It's run for 20,000 odd kays now and not given any trouble, under the maintenance regime. I dropped the oil 3 days prior to this occurring, and yes, I'd thought about sludge etc, but the oil is CLEAN and stays that way for nearly every km until I change it.
Oil's definitely making it's way up top, and the situation with the noise is very odd.

I've run into random big end / little end / lifter / rocker issues on customer engines before, and this one sounded initially like I'd spun a big end on at least the 2 rear cyls on the drivers side, but it's not, because you can rev the snot out of this unloaded, and it makes no noise in the top or bottom, other than what you would call 'acceptable' valvetrain noise. Even for a high-km engine, it's actually pretty darn quiet - well, quieter now than when I purchased it.

So the issue is that the noise only comes under load, in gear, with a throttle application of at least ⅓ -? pedal travel and from about 2000-4000 rpm. Above 4000 it's not discernable anymore - there is some valvetrain noise there I know - but that's obviously only since the issue occurred.

I don't believe it's directly a result of the oil change, because it took 3 days before the noise to reveal itself, after the change.

I guess it is possible that an oil gallery is sludged, but the noise sounds to me like a failed hydraulic lifter - it's OK in idle rpm, but as the speed ramps up, the lifter can't hold the oil and it's bleeding off. 'rap rap rap rap' almost like a diesel with piston knock on cold start - Perhaps once the rpm gets high enough, there is barely enough oil in the lifter and sufficient pressure and reciprocation of the lifter body to dampen the noise somewhat...

Here's the kicker..... There doesn't appear to be any power loss - I'm not saying that there isn't, it just feels like there has been no change.

So let's say for example, the quickest, cheapest fix is cam, lifters pushrods, rockers... it's still probably not worth it. The engines got too many km on it to not be a candidate for a full rebuild.

Now, I'm going to really throw a spanner in the works for you.

I have an opcon autorotor twinscrew (MX422) supercharger, which has been sitting here waiting to go on my spare 5.6L merc. If I rebuilt the 3.9, I could possibly put that on, for more power, but I really don't know the internal strength of the 3.9, and probably wouldn't trust it structurally.

For a fleeting moment, it could have been an interesting idea, but I think that something like that would certainly be wasting money.

Might be worth checking your plenum trumpets:

http://www.aulro.com/afvb/technical-...-trumpets.html

From what I've observed of Merc motors the sumps tend to be front bump types which could play footsie with the diff pumpkin.

Originally Posted by bee utey

Might be worth checking your plenum trumpets:

If your plenum rattles check yer trumpets

From what I've observed of Merc motors the sumps tend to be front bump types which could play footsie with the diff pumpkin.

You are absolutely correct with the sumps. nearly all are front-biased. There are some exceptions with certain offerings in sprinters and Gwagens, those are a relatively speaking 'rarity' and a new genuine sump is more than $500 in some of those cases.

Having said that, the sump carries 8 litres in standard form in the v8's. the 6's are not so great, but the older gwagen has a deep sump, as does the transmission.

I'll pull the plenum. I'm not sure what I would expect to find in there, but it (noise) sounds much closer to the right rocker bank...

will report back if I find anything or not.

"... will report back if I find anything or not...."

Well, you've had a whole DAY, what news ???

Sure it's not some external attachment that's vibrating at certain RPM ? I once had a broken exhaust hanger on the engine.. only moved apart enough from the engine torque under load and resonated at speed... thought the engine was grinding itself to pieces.

Be cautious about an ally Holden V8, - my #1 son's Statesman overheated yesterday (cold, rain, snow, or feels like it !) and it turned out to be low on OIL.
Coolant was full, and clean, no bubbles or oily stuff. He can't see evidence of a smoke screen behind, or the car 'marking it's territory'.. Claims he checked the oil last week (?) but adding a litre seems to have cooled it and got him home on "Normal" temp. He's gone to work this morning, and no frantic phone calls... Yet.