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Joe M

VR Bottom end options

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As some of you may know I hit some engine trouble on a trackday last week, found out the damage today and its not good. :(

 

Big end shell bearing? on cylinder 6 knackered, probably would have got away with replacing the shells if it wasnt for the rest of the damage.

Big end shell bearing on cylinder 4 also knackered, but worse, scoring the crank and the piston has also badly scored the cylinder bore. :roll:

 

The cause, oil starvation, even though the oil was still above minimum on the dipstick, vr owners take note: Always keep the oil topped up to near max....

 

So, what now?

 

Option 1. Find a 2nd hand 2.9 engine and swap it over with my cams.

Plusses - Relatively cheap if I can find an engine.

Downside - Engine will be unknown and may not last too long, especially as the car will be used for trackdays again.

 

Option 2. Rebuild the block by going to 3.0 and finding a crank.

Plusses - mmmm, 3.0

Downsides - Expensive and would need another remap, I just had one done at the start of the month.

 

Option 3. The cheap rebuild, find a crank, 2.8 block and a single piston, bore out the block to 2.9 spec and rebuild using the rest of my existing parts, replacing bits only where neccessary.

Plusses - Again, relatively cheap.

Downsides - Reusing a lot of old parts, will it last?

 

So, what to do. If anyone can give me rough costs on what they think the above options are likely to cost, especially the 3.0 option please post up, also if you have any other suggestions or comments im listening.

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Damage sounds a little worse than I'd imagined.. :(

 

Personally, I'd go for option 2.

Advantage: you'll have more power & you know the history of all parts that you'll be using.

 

Disadvantage - finding some pistons - I'll send you a PM. :wink:

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Joe, I am on the case for helping with option 3. A mate of mine replaced a smokey bottom end. Hopefully it has at least 3 good pistons and a good crank.

Gavin

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Andy at Awesome actually said to me that once its sorted he recommends I get a baffled sump, he reckons someone will definately do them.

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I bet schrick would? Failing that I'd be looking up any of the VR drivers in the old slick50 series.

Gavin

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Providing I get the crank and pistons from the other thread I cant decide between options 2 and 3 at the moment.

 

Option 2 I can get EIP Pistons for $800 (best price so far) and would have to pay for a rebore and other associated parts, but would save in not having to buy a block, and would have a good engine at the end up.

 

Option 3 I would also have to pay out for a rebore, but would also have to buy a block or probably full knackered 2.8 engine such as g60renshaw's, though would save money not buying pistons and would likely have parts to sell on.

 

Decisions, desicions... :?

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Stealth racing sell 82.5mm and 83.00mm (max. advised rebore) mahle piston sets inc rings etc for about £700.00. They said there isn't any real power benefits between the two sizes though so I just went for the 82.5mm incase it needs another rebore in the future.

 

What sort of power increase would you recon to get making it a 3.0L? Have heard of 3.1's but ovalisation can be a problem then cos of the heat and there isn't much metal in the bore walls.

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Option 4 - Fit a 24V engine.

 

Nah, seriously, if you're going to rebuild, you may aswell get a little extra whilst it's out, so option 2 gets my vote too.

 

The JE pistons seem to be very highly regarded among VR over borers.

 

I don't think the extra power from the 3.0 (assuming everything else stays the same) will blow anyone's skirt up but if it's built to a high standard, you'll have a good, trouble free engine for years.

 

And yeah, get a windage tray put in your sump.....Stealth sell them. Or maybe look at a dry sump system if you regularly track it.....

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Just sent stealth an email actually. Am I right in thinking 82mm is the standard vr piston size?

Would probably go for the same as yourself with the 82.5mm for the same reason, hopefully ill get away with not going for a remap.

I doubt theres much increase in the power tbh unless the engines had a lot of other work at the same time, maybe up to 10bhp if that at the top end, probably more of a difference mid range. How do you find yours since its been doneRpmayne?

 

Kev, I would have liked to take the time over the summer to fit a 24v but I have no garage or driveway and its not the kind of thing to do in the street. :(

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Kev, I would have liked to take the time over the summer to fit a 24v but I have no garage or driveway and its not the kind of thing to do in the street. :(

 

Yeah I'm thankful for my drive but I don't think I'd fancy doing the job myself anyway. And it's one of those jobs that can end up costing a lot more than predicted! Cracking engine though the 24V.

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Joe, it looks like my mate has most of a 2.9 in his garage complete with head. It did have highish oil consumption which was why he replaced it. He was night flying last night and hasn't called me yet.

Gavin

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Cool, im still in need of a crankshaft at the moment and could probably use the conrods as well, pick the 6 closest matched from the 12.

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When I first got the car it was rolling roaded at 194bhp. Then started to progressively rough running and drinking a litre of oil per 1000miles. Obvoiusly feels better than it ever has now but not sure there's any extra power. Has only done 13k since the rebuild anyway so has probably got alot of loosening up to do before I get it rolling roaded again.

 

I thought those JR forged pistons were only really good for heavily modded track cars, and suffer from piston slap when cold.

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I think thats just the nature of forged pistons, they expand as they heat up so are slightly loose when cold causing the piston slap.

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I've heard standard 2.9 and 2.8 engines slap when cold in the mornings....it's just a VR thing....loose tolerances! It can get really bad this time of year but providing the noise has gone within a minute, there's nothing to worry about.

 

Mine slaps a lot but Vince said the factory honing marks were still in the bores when he did the head at 93K, so it's not that bad. Uses about a litre every 3000 miles at 110K.

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Yep, the oil use of the forged JE pistons is a characteristic - This is where your clifford intellistart comes in handly to warm the engine fully up to temp before jumping in and going for a hoon.

 

Mine was going through a stage of doing a litre of oil every 500 miles or so, but this has died down to more realistic levels. I do get a bit of oil blow back, but this is more likely to be the the charger recirc delay as the engine comes of boost and onto Vac.

Worthwhile getting a catch tank... (note to self to get round to fitting it!) off the oil breather on the rocker cover.

Good luck with whatever you decide on Joe, as I said to you in my PM in hindsight I wish I'd gone down the 1.8T route - or V6 24v. But I suppose the VR6 pursit in me took control of my spending habits! -

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Got an email back from Vince, he recommends only using the JE pistons on forced induction cars and said to use the 82.5mm pistons Rpmayne mentioned.

Its going to cost a lot, so im going to consider a 1.8t conversion as an alternative before commiting, will start another thread regarding this.

 

 

edit: Vinces name in red, the main man, first time ive seen that feature. :lol:

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Plenty of scope for tuning with the 1.8T! It might also be a better engine for track days as it's lighter. Are you going to keep the VR gearing or use a 20V gearbox?

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If you remove the number 4 rod, oil will pi$$ out of the crankshaft. You could maybe put some shells on the crank and hold them in place with a jubilee clip? Unplugging the injectors will prolly throw up a load of faults on the ECU.

 

Join the RAC/AA and get it recovered. Pay Andy to throw it back together for you.

Gavin

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