Just been ordering a couple of parts from one of the P6 specialist suppliers & in the course of the conversation, I was told that the SC engine will run on unleaded, without additive although the ignition may need retarding. No reason to doubt the info but is anyone doing this?
Anyone running their 2200 on unleaded?
- Thread starter Graham T
- Start date
hermione149
Member
i use premium unleaded and Millers VSP+ (lead substitute/octane booster), no problems so far (30,000 mls and counting) 
NickDunning
Active Member
I believe the valve seats are identical material on either SC or TC after a point in about 1969.webmaster said:
Accepted wisdom has it that 2200's are unleaded compatible. This is certainly what Rover literature of the time suggested, and also what the Classic Car press were putting about when real four star disappeared.
However Clive Annable deals with as many 2200's with head damage than 2000's, and for that reason I wouldn't go without a slug of valvemaster in mine. Better safe than sorry.
Cheers
Nick
Retarding the timing is a way of allowing an engine to run a lower octane fuel without pinking.Lowering the compression ratio has the same effect but is a more difficult and costly way to achieve the same thing. There is a slight loss of performance either way, but probably not as noticable as the pinking you could suffer with unleaded and standard timing. Super Unleaded has a higher octane rating so is less likely to need retardation. The other property of lead in fuel was as a lubricant, particularly of the valve seats, so additives are available to replace this.
Pinking (detonation) is not good for engines and should be avoided.Unfortunately the further you retard the timing (particularly in the case of TC's) the more likely they are to run on. It's a balancing act.
4 cyl P6's were always prone to burning valves out even with 5star.
Pinking (detonation) is not good for engines and should be avoided.Unfortunately the further you retard the timing (particularly in the case of TC's) the more likely they are to run on. It's a balancing act.
4 cyl P6's were always prone to burning valves out even with 5star.
OrganDoctor
New Member
I've never been sure how the octane ratings from the states compare to those printed on my 2000TC, which requires 100 octane.
The highest we see listed on the pumps here is usually 94,and that is what I use.
I advance the timing until I get "pinking" then retard it slightly
below that level.
I have never added anything to the gasoline, except Marvel Mystery Oil, and the valves were in good shape at this rebuild.
Dick West
The highest we see listed on the pumps here is usually 94,and that is what I use.
I advance the timing until I get "pinking" then retard it slightly
below that level.
I have never added anything to the gasoline, except Marvel Mystery Oil, and the valves were in good shape at this rebuild.
Dick West
The Rovering Member
Well-Known Member
'Marvel Mystery Oil' What a great name for an additive.
Hi there
I have a 2200SC and was told by many people that the sc head was hard enough to use unleaded without an additive. After a few months the power seemed to drop off dramatically to a point where it used to struggle up the smallest of hills. The problem was traced to incorrect valve clearances as a direct result of usinf unleaded without an additive (apparently the valve seats became worn or something). I had a secondhand head put on the the difference was quite simple astounding. I now use Redex additive whenever I fill up with exception!
If you search the topics, there have been various threads on this over the past 12 months as this is not the first time I have written on the subject.
Hope this helps
Russ
I have a 2200SC and was told by many people that the sc head was hard enough to use unleaded without an additive. After a few months the power seemed to drop off dramatically to a point where it used to struggle up the smallest of hills. The problem was traced to incorrect valve clearances as a direct result of usinf unleaded without an additive (apparently the valve seats became worn or something). I had a secondhand head put on the the difference was quite simple astounding. I now use Redex additive whenever I fill up with exception!
If you search the topics, there have been various threads on this over the past 12 months as this is not the first time I have written on the subject.
Hope this helps
Russ
For the sake of the price of an additive it can make sense to add one just in case, but as I've said before, they were burning out valves on a regular basis long before the advent of unleaded only, and as the problem you had is the worst that can happen on using straight unleaded you pays your money for the additive and weigh that up against the cost of head repair work.
In the case of your particular car,how long have you owned it? It's a minimum of 30 years old so it could have done 150K miles without ever having the clearances adjusted, and without a FULL service and repair history you won't ever be in the position to know.
I'm not contradicting you, because what you say is right from your experience,it's just that they never had valve clearance adjustment as a service item, (and if they did, they would probably never have got done) and in the days of 4 & 5 star they still used to suffer with similar problems on a regular basis.
Only time will tell whether the additive makes a difference, start clocking up the mileage!
In the case of your particular car,how long have you owned it? It's a minimum of 30 years old so it could have done 150K miles without ever having the clearances adjusted, and without a FULL service and repair history you won't ever be in the position to know.
I'm not contradicting you, because what you say is right from your experience,it's just that they never had valve clearance adjustment as a service item, (and if they did, they would probably never have got done) and in the days of 4 & 5 star they still used to suffer with similar problems on a regular basis.
Only time will tell whether the additive makes a difference, start clocking up the mileage!