Thread: Rough running v8

Havent decided whether I will take the plunge. I have done v8 head gaskets before. My first car was a 1968 HT Monaro with a 308 and I did that myself at the age of 17 but it was an old school v8. Did another set on a 351 falcon i owned as well. I am a bit older and lazier these days but I can invest in all the equipment, do it myself and still have all the tools at the end and be better off financially. I wish I could confirm once and for all that this is what the problem is before I pull it to bits but I am not game to take it to another mechanic as it just jacks up the expense and two mechanics later I still dont have an answer.
Thanks for all of your advice so far. Luckily we have 4 cars in the household so the disco is just languishing on the front lawn of my mothers house so I don't have to look at it until I can psych myself into fixing it.

Mechanically the rover V8 is still pushrod tech. It's really just an old design (pushrod/timing chain), updated slightly (crossbolted) and with EFI. Whatever you'd do to your 308 you'd be on the pitch with the rover.

Studs make a huge difference. The newer engines use torque-to-yield (TTY) bolts that are designed to stretch slightly at a predetermined tension. trouble is I tested this theory on both rover (with tin & composite gaskets over probably 4-5 whole sets) testing stretch at each bolt using a steped torque system, straight to full torque & also tension + 90deg systems. Scary variations including one bolt that was finger tight. Also did this earlier on Toyota (potentially better quality) and had similar results. Main studs not so important but measure & compare your bolts to std sizes to see if they've stretched before reusing.

The MAF sensor is prone to failure and a replacement item at 75-100,000k's. Coils as said use genuine only or source genuine from other makes using same part. Good leads are also a must (recommend Magnecore) as are plugs (I use Bosch Platinum plus 4's (from BP Utah, $80- set vs $40-ea)).

Also if it has gotten hot or blown a gasket it a good idea to have the heads and block (if out) to be hardness tested. They can soften at high temps.

Should see everything back to normal.

The indication for ARP studs is good, but has anyone used bolts and washers like they used to use on 3.5s until TTY became the flavour of the month?

I've now done 4 different engines using the older style ht bolts and washers, and I've been able to get satisfactory, even head clamping and no comebacks. One vehicle repaired in this way (99 D2 v8) has done 220,000 km since.

Just another thought.

Pete

Originally Posted by Pierre

The indication for ARP studs is good, but has anyone used bolts and washers like they used to use on 3.5s until TTY became the flavour of the month?

I've now done 4 different engines using the older style ht bolts and washers, and I've been able to get satisfactory, even head clamping and no comebacks. One vehicle repaired in this way (99 D2 v8) has done 220,00 km since.

Just another thought.

Pete

I've replaced a few sets of TTY bolts with early bolts and washers, not yet had a problem either.

I'm sorry but I would still advise you change the ignition leads before you do anything else. They DO fail on D2 V8s anywhere after 100k and they will not always throw error codes. The same applies to the MAF.

They're cheap to buy but a bugger to replace - most mechanics (fitters) will hate ther job but you can do the job yourself in a couple of hours. Small hands help......

Just save some money and do these before anything else. Worst case, you'll still have a new set of leads after a new head gasket etc.

As for a chirping noise? I've never yet seen a head gasket that is audibly obvious other than through a cylinder misfiring.

Comment post reading compression tests...:-

Compression tests? "might" indicate a HG failure but could be many other reasons. The Rover V8 is very sturdy so even with low compression in a single cyclinder it will still run ok. Are you losing water? Is there any oil/water emulsion in the rad/sump? If answers are all no, then just let it be for now, you can be pretty sure there's no Hg issue, maybe just a damaged valve seat etc. If you inject some oil into the suspect cylinder immediately before you run the test you can tell if it's a valve/seat or piston ring/cylinder issue.

FF