Which unleaded head?????

[SvMinor]

I was toying with the idea of buying an unleaded head(prob from BM)

My car is a 1098 does the new head have to be a specific 1098 one, or will others fit?

Ive looked on ebay and I saw a few mini and mg ones, but these state 1000cc 1275cc etc

[bmcecosse]

Don't bother! Unless you are hammering the car for long miles on the Mway - it will survive for many many miles on the standard head - and no additives necessary either! Just set the exhaust valves at 15 thou gap - and check/reset them every 3000 miles.
But to answer the question anyway - if your engine is a 1098 then it needs a 12G202 head.......

[SvMinor]

Spot on Thanks!

[aupickup]

i use my car everyday for general driving conditions and holidays and never had an unleaded head fitted

tho i have a fairly new one in my garage doing nothing

[rayofleamington]

Back in the 90's I' worked on a car that had been run on unleaded for 7 years - on chamber #2 the valve seat didn't exist and when the rest of the gubbins was removed, the valve could be pushed right through the seat area into the port.
(It wasn't an unleaded head, but certainly must had had high quality valve material as the remains of a valve was still there and the car ran fine at speed (tickover was very lumpy though...)!

Needless to say that if the valve clearances had been regularly set, it wouldn't have got that bad as quickly as it did. If the previous owner hadn't been misled into thinking the car was fine on unleaded... It would have saved me a job.

As for the a-series, VSR is a genuine problem. However it takes time (mileage) to make an effect. If you run at high load and high revs for long periods this is the worst case for the engine. If you're doing less than 5000 miles a year it can easily take 10 or 20 years before there is an issue. Much longer if you drive slow and less aggressive / faster if you drive hard and fast and long runs. If you do 15000 miles a year rather than <5000 needless to say you'll run into trouble a lot quicker.
At 2000 miles a year and never thrashing it, the valve seats may well outlive you!

[bmcecosse]

Good reply Ray! The 'unleaded' thing is much overstated - 'good little earner' for many. I always advise that slightly greater exhaust valve clearance of 15 thou (which MG/Rover also specified on later engines) and to check/reset every 3000 miles. I don't do high miles - but the miles I do are hard driven. I rarely find the gaps more than ~ 1 thou tight when I check them.