My experiances with rebuilding the VM motor

lacabrera · **Posted:** Fri Sep 11, 2015 8:56 am

There is a lot of talk recently about rebuilding the lower half of this motor. I recently completely stripped down and rebuilt mine and would like to share my opinions. I am no expert but with the knowledge I have with rebuilding engines this one is a rare beast.

Opinion 1, I have read that there has been some connecting rods that have failed probably due to lack of oil/pressure. It would be interesting to know which ones have failed because if its numbers 2 or 3 I have a very good idea of the reason for this. The crank shaft has 3 centre main bearing carriers that float within the crank case. The problem with this I have found is the oil path that lubricates these 3 main bearings and than goes on to lubricate the 2 big end bearings within the connecting rods. With a cold engine the aluminium floating main bearings carriers have a loose fit between them and the crank case and the high pressure oil passage passes from the main oil gallery to the bearing carriers and than to the main bearings. Because of the loose fit, oil pressure will be much lower due to leakage between the crank case and the bearing carrier and in my opinion will effect lubrication to the 3 main bearing carriers and than on to the big end bearing of 2 and 3.
All the bearings were in good condition except 2 of the main bearings and also con rod bearing 2 and 3 showed signs of ware.

Opinion 2, No matter how strong the connecting rod bolts are they will fail if there is not sufficient oil pressure to keep the 2 metal faces apart.

Opinion 3, I know ARP are a first class fastener manufacture but I don't think it will help us in this issue.

Opinion 4. Some how the design of the sealing of the oil passage between the crank case and the bearing carriers needs to be improved.

My motor had 82,000 miles full service history with 2 very badly worn main bearings and signs of ware to big end bearings 2 and 3.
Hope this maybe of use to you all. Andy

pjigar · **Posted:** Fri Sep 11, 2015 10:44 am

Wow, bearing failure with just 82K miles. What are the signs of bearing failure? We all would like to keep an eye out for these signs.

thermorex · **Posted:** Fri Sep 11, 2015 10:50 am

I have to say "wow" also, like Pjigar. 82k and those issues? Can you speculate on why you think this happened this early? Insufficient engine warmup and pedal to the metal? Or some sort of bad luck like Geordi?

Mountainman · **Posted:** Fri Sep 11, 2015 10:59 am

Thanks for the insight! I have to wonder with some failing early if it isn't like head bolts, where some people probably just got a bad one (poor bolts, or poors QC on tightening).

This is enough for me to be even more careful about how soon after startup I put much load on the engine.

lacabrera · **Posted:** Fri Sep 11, 2015 2:37 pm

when I say the bearing are bad, the soft metal surface has been removed by the lack of oil between the 2 metal rotating surfaces. This is not sufficient to make them addible. Because they have signs of ware it can only be oil starvation not a mechanical breakage.

diesel_guy86 · **Posted:** Sun Sep 13, 2015 5:51 pm

Could the bearing carriers have 2 o ring grooves machined into them? Would definitely seal up better as well as provide a bit of dampening when things are cold.

Mike92104 · **Posted:** Sun Sep 13, 2015 6:32 pm

I wonder if there is some differences in the tolerance of the center bore. When I took my crankshaft out of mine, those bearing carriers wouldnt budge. I had to pound on the cranksfat with a 3# mallet for quite a while to get it out.

lacabrera · **Posted:** Mon Sep 14, 2015 6:16 am

Before I removed the crank I could move the bearing carriers forward and back so they were a loose fit. No signs of ware on the carriers? Because the carriers are only held by that 1 pin preventing them from spinning I don't think an o ring would last it would need to be more robust but also flexible because of the movement. Personally I don't have an answer to this. (and I would guess neither did the designer)
When I re-installed the crank I tightened the carrier bolts at half torque with a planes to complete the torque after installation but was un able to insert the crank due to a tight fit. only torqueing them to the required torque allowed the crank to slid within the case. When completed with the pins inserted the carriers had a much better fit.
I was surprised how much difference it made with the tightness of those bolts.

thefunk · **Posted:** Tue Sep 15, 2015 12:34 pm

Is this engine something that a well-equipped engine machine shop can work on, or is it weird enough that they're going to turn it down? For example, Deutz diesels and the big Mercedes diesels are notoriously weird. Last I checked there is one machine shop in the US that can mill the big Mercedes blocks, and they are in NY. Not much good when your Claas corn chopper is down with a blown hole.

flash7210 · **Posted:** Tue Sep 15, 2015 1:21 pm

There really isnt much that can be machined.

You cant over bore the cylinders. All you can do there is install new liners and hone them.

You cant align hone the mains. Main bearings are contained within their own carriers.

You might be able to deck the block but not much. And that would mess with liner protrusion head gasket thickness.

You can definitely re grind the crank. And Im pretty sure oversize crank and rod bearings are available.

Yeti · **Posted:** Sun Sep 20, 2015 7:39 am

lacabrera , what oil gradation you suggest for a cold start in the morning ..........I live in the Alps ......for give a right pressure?

my brother have found in other engine the connecting rod are near to failure at 90k km

I've see the 0w40 take much more time to shut off the oil light compred with a 5w40 like a Penrite HPR 5

Mountainman · **Posted:** Sun Sep 20, 2015 10:58 am

Yeti wrote:

lacabrera , what oil gradation you suggest for a cold start in the morning ..........I live in the Alps ......for give a right pressure?

my brother have found in other engine the connecting rod are near to failure at 90k km

I've see the 0w40 take much more time to shut off the oil light compred with a 5w40 like a Penrite HPR 5

90k km

I have to wonder on engines like that if a previous owner put non synthetic in them, like strait 10-30 like we've heard about a couple of times. 0-40 sounds risky if the oil light took longer to go out, yikes

Yeti · **Posted:** Sun Sep 20, 2015 1:58 pm

it's a renault k9k engine 1500-1600-2000 dci mounted in europe model in

Suzuky
Renault
Dacia
and maybe mercedes .......one model

last day when my brother is at the mechanic for this job , another people with a renault megan 1600 dci arrive with a tremendous sound .....3th and 4th connecting rod like a piece of paper and dead cranckshaft

now I want an oil that is very fluid at low temp , but have high cst at operating temp , and I look at Penrite, Redline or RoyalPurple ....and Amsoil why not , here in Europe you can allready find an oil branded Bardahl ...is an oil with him additive

Mountainman · **Posted:** Sun Sep 20, 2015 2:21 pm

ahh ok, different engine. I would just find a way to plug it in if you're really worried about cold start lubrication.

Yeti · **Posted:** Sun Sep 20, 2015 3:00 pm

I do not have the heater :cry:

Mountainman · **Posted:** Sun Sep 20, 2015 3:26 pm

Oh yeah, I forgot you told me that before. Is there even a hole in the block for it with a big plug? Would be an easy mod.

Yeti · **Posted:** Sun Sep 20, 2015 4:13 pm

yes there is

Mike92104 · **Posted:** Sun Sep 20, 2015 4:50 pm

If there isn't a block heater, you may be able to find an oil pan heater like this:

http://www.amazon.com/Kats-24150-Watt-U ... B000I8TQD6

I would almost think these are superior to the coolant style block heaters since they heat the oil. The aviation guys love them since most of the engines are air cooled.

Mike

Mountainman · **Posted:** Sun Sep 20, 2015 6:34 pm

Yeti wrote:

yes there is

Nice, a little PB Blaster, and some silicone and you'd be set. Or, like Mike said, use a pan heater, just have to find a way to hold it against the pan, or find a place on the block? There's a flat spot between the block heater (plug in your case) and the starter that you might find a fairly permanent spot for a magnetic block heater. There's a place where even if it popped off on a bump, it would be trapped between the starter and block.

Yeti · **Posted:** Mon Sep 21, 2015 6:12 am

thank you guys

My experiances with rebuilding the VM motor

Who is online