New ownership of #347 and running problems

Hi all. So after regretfully selling my old 260 #471 back in 2014 I have now got back into ownership having picked up #347 MG ZT 400 SE at Anglia Car Auctions on the 21st June. I've had one blissful run out in the car and now hit problems :(. (I know buying at auction has its risks!).

I had the car delivered as i'm down on the South Coast in Worthing and work/logistics were a challenge. When it arrived the fuel gauge was reading below empty so I drove her straight to my nearest petrol station but she stalled twice on the way (guessing fuel moving round the tank starved her) but thankfully restarted and I manged to get her onto the forecourt for fuel. I brimmed her tank with Tesco 99 octane and headed off for a drive and she pulled really well not missing a beat, so returned home happy as Larry.

I took her out for a second run the following day and did a fairly hard pull in her but with some mechanical sympathy and not flat to the floor, given she new to me and I understand she's recently had and new block and rebuild earlier in the year. And then she went from what felt like 400hp to 100hp and stayed there :(. There's no warning lights on the dash but it feels like the engines redistricted. I thought she was down a cylinder as she seems to have developed a slightly lumpy stutter or misfire but it is subtle. I've had it over to my mechanic for a initial quick look this morning with thoughts on plugs, or injectors as a first port of call. Having checked the injectors they all seem to be ticking away but only have a subtle impact when you disconnect each one. Taking the plugs out is more involved than we had time for this morning but will be done. The concern is she may be down on compression. However one thought is that she feels that she holding back and on a test drive if you give her enough of a prod with higher revs she clears her throat and will spin the wheels off down the road. This then sows doubt on compression being an issue (though not ruled out). Holding your hand over the exhaust when reved there seem very little flow so we're wondering with previous engine issues and work whether a cat(s) have blown and the exhaust is actually blocked? Given the work done the engine "should" be sound! We're going to take the exhaust system/cats out next week and investigate as a starting point but I'm interested if anyone may have had similar or any thoughts before we have to start stripping her back.

Also may be for another thread but the more digging i'm doing it seems she's had a fair bit of history with having had a blow engine originally (I've seen autobahn mentioned!?). I have paperwork detailing an engine install and rebuild from January but it is just an invoice and not the best I've seen as it has very little detail on specifics done (I plan to call the garage up Monday to see if they can give me anything more to go on). I'd welcome any direction to posts which may shed more light on this car and advice (I'm finding bits and pieces but it a bit of a jigsaw).

Really hoping she's not a basket case as she in great condition and spec. I'm happy to invest in her but don't have a bottomless pit of funds so this is a concern so early into ownership.

Cheers,
Alex

Have you got a code reader with live information? Look at the fuel pressure while it is running and the lambda readings, these should give you an idea of what is going on. As you rev it the pressure should rise, a blocked or loose filter could cause low pressure.

Steve

I know my mate has a code reader. Whether it gives live data I'm not sure. Will raise it with him. Cheers.

Alex

For what they cost these are a good investment. Even if you don't have the ability or tools to fix the problem if you know what the problem is that can save time and money at a garage. I had a coil pack go on mine not long after I bought the car, no way of knowing which but the code reader told me the cylinder that was misfiring, luckily I had a spare coil pack and I had replaced it and I was on route in 15 mins.

Steve

This is the Jamsport car with a lot of questionable history.

Hi , hope you haven't bought a load of trouble, from what you describe i would first be looking at the fuel pressure which will need a code reader displaying live data to get it from a facelifted model, no schradar valve on the fuel rail.
It should be between 30-40 psi or mine is at approx 250 KPs, if low this could be down to a clogged fuel filter or the filter housing comming loose.

Quote:

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Originally Posted by AlexZT260

.....................I'd welcome any direction to posts which may shed more light on this car and advice (I'm finding bits and pieces but it a bit of a jigsaw).
..................

Cheers,
Alex

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Hi Alex, welcome back.

#347 was originally owned by GeoffW who had it S/C'd and mapped by Jamsport.
It was then owned by Tomcat22.
and then jdtp93.

It looks as if the map wasn't great and the car suffered piston/plug damage when run at max revs on the autobahn.

You've probably already discovered all of this anyway.

Nich.

Some background reading, Alex. (I think tomcat22 was the owner before jdtp93):

See: https://www.two-sixties.co.uk/mgoc260/html/f0rum/showthread.php?10709-347-misfire-or-even-worse
and this: https://www.two-sixties.co.uk/mgoc26...-chain-tension
and most recently, this: https://www.two-sixties.co.uk/mgoc260/html/f0rum/showthread.php?16916-New-engine-for-a-ZT-400

Your theory about the cats sounds like it could be good. I once bought a V6 Rover 75 Tourer with a blown up engine (knowingly), and quite a while after the engine change, it wouldn't rev over 2500 rpm ! Almost totally blocked cat. No warning lights oddly enough.

David

Quote:

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Originally Posted by David

Some background reading, Alex. (I think tomcat22 was the owner before jdtp93):

See: https://www.two-sixties.co.uk/mgoc260/html/f0rum/showthread.php?10709-347-misfire-or-even-worse
and this: https://www.two-sixties.co.uk/mgoc26...-chain-tension
and most recently, this: https://www.two-sixties.co.uk/mgoc260/html/f0rum/showthread.php?16916-New-engine-for-a-ZT-400

Your theory about the cats sounds like it could be good. I once bought a V6 Rover 75 Tourer with a blown up engine (knowingly), and quite a while after the engine change, it wouldn't rev over 2500 rpm ! Almost totally blocked cat. No warning lights oddly enough.

David

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Post amended, thanks David.

Nich.

Before cats block an exhaust they usually start to rattle. I had one start rattling on an Omega years ago, it was not to bad but annoying with the window open. Luckily for me I went to get the tracking done and the mechanic commented on the noise and said I should get it fixed. I removed it and was amazed to find how the outlet was 80% blocked by the failing cat, a new cat and the car felt like I had doubled the HP.

The usual cause for a cat falling apart is a misfire or ford's ( not the make of car but the shallow water crossing) the thermal shock apparently.

Steve

Thanks all for the info and thoughts. I've spent hours today going through a piecing together the history of #347. It seems she's had her troubles! Well I can't afford to now dump and run so in for the long hall and to get her sorted and enjoyed I hope!
Given she's effectively now had 3 engines i'm hoping my latest issue is not relating to the internals. Though I have some niggling doubts over the engine map and the last engine rebuild/install as having had her on the ramp yesterday at my mates garage there's some tell tail signs of a rush job and/or negligence. Such as power steering leak due to clips broken and a bracket completely missing leaving things to move around (a lot!) and joints seeping. Also bolts missing in a few places on initial inspection! Will be giving her a through going over now to sort these bits and a detailed look for anything else.
I'm thinking the plan of action based on what I know will be:
1. Check the exhaust/cats for damage/blockage. There's plenty of chance given her history of running issues they have been damaged along the way. I did hear on my first run and hard(ish) pull a metallic type rattle sound where I initially thought something metal like a heat shield had fallen off and was dragging under the car but it stopped after a few seconds and never returned. This may have been a cat giving out but I did not get a running issue at that time and just hoped it was a one off quirk, or belt slipping and making an odd sound (ignorance is bliss... well at least initially!). If a cat has failed we can strip it out and see how she runs then. Effectively de-catting her has it's appeal anyway but will have to worry about the MOT later!
2. Next will be seeing what the plugs look like and replacing if required. If they are in poor condition it will raise further questions but worth initial investigation.
3. If neither of the above are successful then it'll be a compression test.
4. If compression is good then coils maybe. They all seem to be ticking away so doubt this will be a cause at this stage.
5. Check fueling is ok.
6. Will get a code reader on her as well and check for errors.
5. My next consideration is whether the map is any good. My mate/mechanic is experienced with mapping and does a lot of Jap tuning but I have read that Dreadnought have invested a lot in mapping S/C ZT's. However i'm not sure they'll map an install they've not done? They are also a 500 mile drive to the other end of the country, though if I can get her running satisfactorily a road trip would be tempting!
One other question I have is for S/C cars, would there be an expectation they should have an up-rated Head Gasket fitted or is standard considered acceptable. The invoice on the paperwork I have for the last install/rebuild says Head Gasket kit but that's it. I am going to call the garage up to see if they can give me any more detail. Thanks.

On 5 Alex, Dreadnought do not look at installs by others. Your best bet is Chris Flanagan or Manjit Saggu. Both will have the knowledge to assist. The existing head gasket should be okay but if its been off a few times a replacement is always a yes.

Thanks Tim.

Ok status update on investigations today. We've found the injector plugs are so worn, assume due to being taken on and off may time due to work undertaken that 3 wont hold and just fall off in your hand! Also 1 of the coil plugs wont hold in place. We figure this in it's own right would easily cause misfire. Pushing everything on as best as possible sees the car rev freely. Have also had the exhaust off and CATs are showing signs of wear but are still all there and flow seems reasonable! Not sure if the back boxes may be an issue and part blocked but figure its best to sort plugs first. So plan is to:

1. Replace the injector plugs.
2. Fit new coil plugs.
3. Will probably De-CAT her while the exhaust is off and save the CATs.

Couple of questions before I start searching the web.:
1. Does anyone know a UK stockist for coil pack plugs, or will I need to source from the U.S.?
2. Anyone know if De-CAT pipes are available for the 260 or we will need to make some up?

Thanks.

Rimmers stock the colls https://rimmerbros.com/Item--i-NEL000010 though might be better with as set of MSD colls https://www.gooze.com/

Cats are, if I remember correctly sports cats, not sure of benefit of changing if they are ok

Coil details are in the Index

Link with the partnumber on the Gooze site for MSD's, Alex: https://www.gooze.com/5649/8242-msd-...mber=MSD-82428

David

Thanks for the info guys. It the actual electrical connection plugs that go onto the coils thats needed though rather than the coils themselves. Think these are the jobbies but would ideally like to get them from the UK if poss: http://www.autolumination.com/wiring...-connector.htm

Get the point regarding the Cats but like the idea of simplifying the system and a bit more noise!

These look like the injector plugs
https://www.ebay.co.uk/itm/4x-Fuel-I...-/263046008741

These people might be worth a call for a UK supplier.
http://trigger-wheels.com/store/cont...n-uk/p250.html

Steve

Good to know your well on your way to sorting out the problems and then enjoy the car.
Regarding the plugs maybe someone has a secondhand engine harness, this should have all those plugs, just a thought.

Well injector and coil plugs sourced. Hopfully they'll be with me in the next few days and next week we can sort that. If that gets her running properly will make some decat pipes up for her as part of a two phased stainless system, the more complex x-pipe and part over the axles can come when I know she's running right.

Fingers crossed it's just a bit of fettling required now.

You might be surprised at how little difference removing the cats make, I know someone who had a pipe made up for a Saab and he reckoned the only difference was it would Rev easier at high rpm and you don't Rev these engines. On a plus he didn't have to refit the cat for the MOT as it would pass without it fitted (just).

Steve

Quote:

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Originally Posted by SCP440

You might be surprised at how little difference removing the cats make, I know someone who had a pipe made up for a Saab and he reckoned the only difference was it would Rev easier at high rpm and you don't Rev these engines. On a plus he didn't have to refit the cat for the MOT as it would pass without it fitted (just).

Steve

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the engine in this car is forged I believe so you can rev the nuts off it

I am sure Scooter said there was a reason not to over Rev these engines, maybe I misread it?

Steve

DO NOT under any circumstances over rev these engines, original engines do not have forged internals. Standard con rods and bolts are weak and not up to over revving.

Nich.

With circa 400bhp i'm not removing the cats to try and chase anymore power. They are showing some signs of damage so taking the opportunity to start the progress of replacing the exhaust system for a wider bore stainless one (was thinking 3", though it's tight over the axle so looks like 2&3/4'' will likely be the max) and fabrication replacing the cats and centre section is fairly straight forward. The rear section is more effort and cost and will be done once I know the car is in full health and saved some more pennies!

I'm not looking to rev the nuts off her but the history and spec of past engine replacement and rebuild confirms she has a forged short block bottom end, forged pistons & con rods from Sean Hyland Motorsport amongst a number of other upgrades. So she 'should' be pretty robust.

Yep. £10/11k for a supercharged low mileage 260 was always alarming low. I hope it's nothing too serious, but make sure you have a repairs pot budgeted

Quote:

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Originally Posted by SCP440

I am sure Scooter said there was a reason not to over Rev these engines, maybe I misread it?

Steve

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on a standard engine yes there is, see the comment from Nich, but with a forged bottom end there is no risk of a conrod making a bid for freedom. There is no power after 5K revs on these engines but there is no risk over that figure with a forged unit

Quote:

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Originally Posted by Nich

DO NOT under any circumstances over rev these engines, original engines do not have forged internals. Standard con rods and bolts are weak and not up to over revving.

Nich.

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Can someone actually clarify what exactly would constitute an over rev? Trackday with 3hrs sat on the redline? Accidental blip/misshift? Hitting the limiter in any way ever just once?