Volvo K24 7400 Rebuild question

[gmac78]

Nice one, that 2.5" Cobra is not one i've seen before, looks like it fits spot on to the compressor housing and clears the bonnet catch upright. I wonder where he bought it from? I need to speak to this guy, is he on S2 forum? Thanks for the link.

[twoqu]

I'm pretty sure he had the inlet machined down! Thats why I suggested reading the thread.
I wonder if there is a normal comp housing from somewhere that would solve the issue of clearance. Certaintly the Porsche one resembles the Audi one more closely as it does not have provision for the integrated recirculating valve. Again its unlikely to be a bolt one so additional costs vs ease of fitment.

[gmac78]

I was only having a quick flick through on my lunch break, totally missed the bit at the start about machining down the compressor housing inlet. This is quite possibly the route i'll have to go down. I found where he purchased that elbow from.

https://www.intakehoses.com/mm5/merc...c8&Screen=SRCH

[twoqu]

It's difficult to pull all the possible solutions into one place. Perhaps you can do it later!
Phucbucket doesen't help much either as you can't see what others have done. Sounds like some have basically machined the comp housing to remove the dump valve and weld up the port leaving a more or less regular comp housing.

[Vorsprung durch Technik]

Andy10v also had a go at this but i couldn't find the thread it was on his green 3B Coupe. Anyone have it subscribed?

[gmac78]

It's just the OD of the compressor inlet that need machining by the looks of the link above. The BOV can just be blanked, plates can be bought for this, or the cheaper option would be to just cap off the pipe that comes from it. When i was clocking the compressor housing it looks like it can just be capped off and still route the oil/water pipe work past it. I'm liking the idea of machining the OD down to 2.5", this makes things a lot easier for a cobra head. A few calculations today is pointing me towards the do88 2.5" cobra head hose, i think the shape of it will allow slightly more clearance. I'll need to double check before buying one though. I'll be home from offshore this week so will get the measuring tape out again.

[newsh]

It's difficult to pull all the possible solutions into one place. Perhaps you can do it later!
Phucbucket doesen't help much either as you can't see what others have done. Sounds like some have basically machined the comp housing to remove the dump valve and weld up the port leaving a more or less regular comp housing.

There are patches for google chrome and Firefox which will download the p bucket pics

[Vorsprung durch Technik]

Did you make any progress on this?

[gmac78]

Hey.

Well yes and no, car is up and running but seems to be smoking bad after it's warmed up, shut down and then restarted. Wasn't like this when i parked it up before the winter! Number one plug is fouling causing a misfire and oil visible on top of piston. Changed the valve stem seals when i had the head off a year or two back so need to investegate number one cylinder again, all the other cylinders are clear of oil and plugs in good condition. Is Victor Reinz a decent make for stem seals as that's what i put in it?

I'm not getting 1.6 bar boost as i should, normally 1.35-1.4, once seen it creep to 1.5 bar. Sometimes i get a real hard cut on WOT perhaps something to do with No 1 cylinder oil ingress.

I only took it for a few spins and parked it, busy upgrading a B5 S4 i've got so that's been taking up a lot of my time.

The Volvo conversion went not bad actually, easier than i thought. A few head scratches here and there but ended up looking pretty good, very tight for the Cobra intake hose though!!.

I was waiting until i got it running spot on before updating the forum with pics etc but that's where i'm at at the moment.

Waiting for a tool to arrive in order to remove the valve springs etc with the head still in place. Intrigued to see how it works out and what i find wrong on No1 cylinder?.

Cheers

[Vorsprung durch Technik]

Shame about the oil in no1 cylinder causing you grief. As far as i'm aware victor reinz head sets are good? Perhaps the valve stem seal has come loose on that cylinder or damaged in some way when installed? Seams an odd one if that were the case.I hope it's nothing major and you can get it sorted right enough. Defo looking forward to seeing this up and running and putting a huge grin on the face. I'll eventually get round to mine someday but like you, i'm snowed under with 2 many cars.

Let us know how you get on.

[gmac78]

Yeh i know, i'm a bit miffed what happened since parking it up 6 months ago. Surely the cold winter hasn't affected the new stem seals already? Like you say one could have lifted from situ perhaps, a bit strange if it's taken 1 1/2 years to do so, you never though!

Looking forward to sampling it when the car is running properly. Hopefully get some time next week to have a closer inspection.

[Error404]

Sounds like you are getting fuel cut - boost leak test first. I'd also check the injector harness for deterioration. Fault codes?
Where did you get the 1.6 bar figure from? (Boost you're are expecting?)

[gmac78]

Morning.

Had a few light refreshments last night so this is me surfacing today. When i first took the car for it's maiden spin with the 7400 fitted i didn't notice the smoke as it seemed to start once the car had been shutdown for a few mins and then restarted when up to temp. With the boost issues i was having i decided to do a boost leak test. I found some minor leaks that required nipping up but nothing major. Tested to 1.5 bar through turbo inlet. Infact at first i thought it was me testing up to 1.5 bar that had damaged a seal on my new turbo but obviously after further inspection i noticed that No1 cylinder was the source of my smoke plumbs with what looks like oil on top of the piston, could be some unburnt fuel mixed in there too?

As for fault codes i'm getting -


00525 Oxygen Lambda sensor G39
03-10 No signal intermittent

00281 Vehicle speed sensor G68
03-00 No signal

and the usual 00513 Engine speed sensor G28
03-00 No signal

I fitted a new Bosch Lambda sensor a few years back and has covered very little miles to be fair. After looking at the sensor i noticed that the heat shielding on the airbox had been rubbing against it and had gone through to one of the wires. This is due to the airbox not sitting exactly where it was previously. I repositioned the airbox to clear the wires, cleared codes and the sensor code never came back in, however there is a bare wire visible so will need to see if i can repair it. I'll get a new sensor if needs be.

The 00281 code is one that started last year and comes in intermittently, when the code come in my avergae MPG etc stops working but comes back on after a while. Not got to the bottom of this one yet, annoying though!! Don't believe this would affect my boost in anyway, is that correct?

The figure of 1.6 bar is what S2Central said the chips should boost to so i'm going off Paul's instruction on that one, it was him that supplied the chips. He'll kindly have another look at them for me, to make sure everything is as it should be, but i want to explore all other options before returning them. It's no doubt an issue my end that i haven't found yet.

Very interesting that you say check the injector fuel harness for deterioration as you've just jogged my memory from last year so thanks for that, hehe!!

Basically i nipped an injector harness wire when mounting the distributor last year, i think the wire lost a small amount of it's insulation and was kind off out of shape from what i remember. However, due to it's location i simply straightened out the wee kink and left the wire as it was with the intent to fix at a later stage. It seemed to cause no issues last year following that as was running 1.9 bar on the TS RS2 chips.

However it's been sat in a cold damp garage over the winter so perhaps that did it no favours.

One thing that made a big difference to how it pulled was cleaning the pins on the MAF connector. However it did not make a difference to max Boost. The wiring to the sensor is not in great shape, infact one wire in particular doesn't look like it could be moved too much before the wire snaps of the pin. However it's still intact and no MAF codes so not sure if that could be a contributor to the boost issue? I played with the F96 sensor last year and set it up as had drifted off calibration, it seems to be more or less in keeping with typical seal level pressures so think that is ok, roughly 1020mbar.

So far i'm a bit underwhelmed with the power from the Volvo turbo, it's not as punchy as i thought it would be, however the car is not running right with what looks like oil ingress and plug fouling on Cyl 1, hard cut on WOT and not achieving max boost figures so perhaps once that's all sported it will feel like a different car. It's not helped that i've been driving my B5 S4 a lot recently on a really aggressive map for the K03's which gives so much punch low down that it made the S2 feel a wee bit tame.

However, until the car is running as it should be it i can't say for certain.

The joys of tinkering with these old cars eh!

Keep the fix suggestions coming in though.

Cheers
Gordon

[gmac78]

Been out having a wee play with the car. Started it and left idling for 5 mins or so. No smoke, usual wee bit of condensation. Disconnected the WGFV as S2central suggested trying to tweak the WG spring slightly to see if it would force slightly more boost up top. I was getting 0.4 bar boost initially, after winding the spring down as far as it would go, ( i was expecting it to bottom out but it just seems to turn and turn without going any further down) is that right? I was getting around 0.5 bar. With the spring fully wound down say, how much spring boost should it make?

Anyhow, drove around for 10 -15 mins, no smoke at all. Pulled over checked No 1 plug, spot on, nice and clean, no fouling. Plug back in and another spin, started then attempting to drive it to the redline which it doesn't like, that hard cut comes in at around 4500rpm. After a couple of attempts of trying to redline it i pull over, the smoking has started. Check codes, nothing untoward, just the WGFV disconnected.

Re-connected the WGFV and went for another spin, still only boosting up to 1.4 bar, never took it past 3500rpm on the way home so no hard cuts.

Pull in at the house to observe smoking, none present. Switched the car off to check the plug again, No1 showing slight fouling and piston top wet, as i was shining the torch down the fumes coming from the cylinder were going for my eyes, stinging them which must be fuel pooling on top of the piston.

It's RS2 injectors that's in the car, i've got brand new replica ones in garage so might try these to see how it drives.

What you reckon, dodgy injector, wiring to injector or something else?

Cheers

[gmac78]

Well i changed the injectors to RS2 Replicas and so far there has been a big reduction in smoke, No1 plug is no longer getting fouled. It does a puff of smoke every now and then but nothing like it was previously. So far so good!!?

The hard cut/misfire has been narrowed down to the launch control feature of the chips. When fault code 00281 Vehicle speed sensor G68 is active my average MPG on the display doesn't work, there is also no vehicle speed feedback to the ecu so it thinks the car is stationary activating the launch control feature.

When the fault clears the car can rev no probs to the raised rev limit of 7400rpm.

However i still am only getting 1.35-1.4 bar boost, assuming the chips are correct something else is still holding it back from achieving 1.6bar.

Any thoughts gents?