Piston Ring Replacement & Cost

[Dom]

Evening,

I have always had a thin blue emission from exhaust under acceleration.

I'm guessing one fault may be with the rings. The history suggests a top end rebuild in the 80's so I'm working on the basis its all a bit old inside and I'm fast approaching 120k miles.

Obviously I'll carry out other checks/tests before concluding worn rings but in the event that this is the cause, am I right in thinking this is dealt with in the 'full refurbishment' at around £2.5 - 3k at a stag specialist, or is this a bigger job than the usual refurb? (i.e. at that price is it usually just the heads and crank etc or do they usually do the rings and bores?)

Just planning for the budget.

Dom

[stag157.7]

Evening,

I have always had a thin blue emission from exhaust under acceleration.

I'm guessing one fault may be with the rings. The history suggests a top end rebuild in the 80's so I'm working on the basis its all a bit old inside and I'm fast approaching 120k miles.

Obviously I'll carry out other checks/tests before concluding worn rings but in the event that this is the cause, am I right in thinking this is dealt with in the 'full refurbishment' at around £2.5 - 3k at a stag specialist, or is this a bigger job than the usual refurb? (i.e. at that price is it usually just the heads and crank etc or do they usually do the rings and bores?)

Just planning for the budget.

Dom

first thing to do is compresion test wet and dry
are you using much oil?

could be the carb dashpots leaking oil
40k not a lot for engine to need rebuild

alan

[Westfaling]

Dom
It all depends on the condition when you pull it apart. It's hard to guess and pre-order your parts. A compression check wet & dry should give you a good idea of the condition of the rings as you're probably aware.. The thin blue smoke could also be valve guides. If you decide to pull it apart then the rebuild options are much like any other car. There are few "must dos" like timing chains and crank re-heat treatment if it needs a regrind. Again like any other car there are a whole bunch of "might as wells" when you have it in pieces. What you re-use and what you replace has to come down to budget but given the spurious quality of many of the new replacement parts it does make the decisions more difficult.
Plenty of help on here though when it's time to decide.
Nick

[flying farmer]

If the bottom end hasn't been touched for 120K then it may well be the rings. As Alan says, do a wet and dry compression test first.

If it isn't burning a lot of oil I would leave it alone for a while unless the smoke screen gets embarrassing!.

If you are paying to get it done I would go for a rebore and new pistons rather than rings as the labour costs are a big part of the rebuild and once done properly the bottom end should be good for another 100K

Neil

[Dom]

Thanks for those prompt replies,

I have ordered a compression tester online so thats the first job. The smoke really isn't to bad at all, just at high revs. Not the carbs as have used both refurbished Stroms and new Weber choices and whichever is on, the same smoke is there.

Ive noticed a pressure in the cam breather pipe (as I was adjusting the system for the weber by plumbing in an oil catch tank) and this is has compounded the theory.

The cars history is a little potted. Just had a better look and it shows rebore and rings in 1993. The mot a year later showed 88k and im at around 115k at the moment. The trouble is that the invoice doesnt bear the reg number and is a very sparse, handwritten receipt from a random garage. Not entirely sure the PO was the most genuine of sellers, but that may be a little harsh

The engine runs very well, but to be frank, i'm spending far too much time looking at the oil pressure gauge and temp gauge whenever I'm driving. I maybe one of those with full paranoia but this has prompted many thoughts of a full refurb, mainly to put my mind to rest whilst driving. I use the car daily and need to be at work promptly so its a 'peace of mind'
solution also.

I know its an expensive choice but I do use a fair bit of oil, which may just be the leak im attending to at the moment.

I really don't think my DIY is up to a full rebuild like that so was contemplating sending the car off for the work to be done.

Thanks so much,
Dom

[wilf]

If it runs OK, leave well alone.

Oil is a lot cheaper than an engine rebuild. You never know what expense you may end up with once you start to fully disassemble a TV8.

Mine uses oil, smokes on start-up, but runs absolutely fine. It is staying just like that.

JMHO.

[Ian Durrant]

If it runs OK, leave well alone.

Oil is a lot cheaper than an engine rebuild. You never know what expense you may end up with once you start to fully disassemble a TV8.

Mine uses oil, smokes on start-up, but runs absolutely fine. It is staying just like that.

JMHO.

Have to agree with Wilf here. A full engine rebuild won't help the paranoia, it will just cost money. I had a new short engine which went bang in 3000 miles. Back then it was my daily driver and still under warranty. Would you do sufficient mileage in a year for it to have shown up if the rebuild was defective?

Don't even consider a rebuild until after the compression test and if that's ok and your car isn't lacking power or smoking enough to fail an MOT then i'd drive it and leave the rebuild money in the bank so you have it there for peace of mind if it should go bang. all IMHO