8 replies to this topic

[Patriot]

Hi,

Is it possible to change the standard 1098 cam for a more performance cam, without taking the engine out?

What would you expect to pay a garage to change?

Many thanks.

[Cooperman]

No point in changing the cam unless you also fit a much better gas-flowed, ported and polished cylinder head or you'll gain virtually nothing.
If you can't do the work yourself, allow £400 for a better head, £100 for a new cam, £15 for new cam followers and around 10 man-hours at, say, £35 per hour (minimum) for the labour.
Then, of course, you'll need better inlet & exhaust manifolds and a freer flowing exhaust system.

[Patriot]

Sorry,
Forgot to add, got twin HS2's, RC40, maniflow manifold and looking for a 12g295 head.

Thanks,

[Cooperman]

Sorry,
Forgot to add, got twin HS2's, RC40, maniflow manifold and looking for a 12g295 head.

Thanks,

Ah, now you're really getting somewhere
If the engine has done a lot of miles, adding a lot more performance often leads lead to early failure of other parts. It might be wise to take the engine out, check the crank, fit new main & big end shells and crank thrust bearings, a new oil pump and probably a new set of piston rings together with a bore hone.
Don't forget that you will need to measure and calculate to get the compression ratio correct as the 295 head has large combustion chambers to match with the 998 Cooper D-top raised pistons which other 998's don't have.
A good cam for that engine would be a Kent 266.

[carbon]

With the 1098 it is possible in theory to change the cam in situ without taking engine out, but will be a right faff. The cam followers can be taken out from the back of the block and (according to Vizard and others) it is then possible to pull out the cam if a suitable sized hole is cut in the nearside inner wing. I doubt if many people will ever have done this.

I have always taken engine out, as Cooperman says that is the opportunity to do additional work. MD266 should work a treat, nice and flexible.

With the 1098 the amount you need to shave off a 295 head will depend on the pistons fitted and the CR you are looking to achieve. Vizard's blue bible (p300) lists the 1098 pistons with 3, 7, and 11 cc dish sizes, and also flat tops.

[Patriot]

Excellent information.....many thanks

[downton69]

Patriot,
Have you seen this article by Keith Calver?
http://www.calverst....g_potential.htm

following is some information from a very old posting on the Mini Forum.

In the Mini Magazine special edition titled "Mini Expert", Keith Calver wrote two extensive articles on tuning the 998. In one of the 998 articles, he quotes chapter and verse with photos and flow figures in an article on putting a 1275 head on a 998. Both articles have rolling road results as well. Great articles, both, so beg, borrow or steal a copy of Mini Expert.



Here's a three-part series of articles on tuning the 1098 written by Aussie A-series ace Graham Russell.
For some reason, the photos are no longer supplied in the article either in this posting or on the original Mini Mania website
but the text alone still provides some VERY useful and dyno-tested suggestions for improving the 1098.

If you haven't already seen the following 1098 articles written by Aussie A-series ace Graham Russell, you might find them useful.

As Russell says in the first article: "The bore for the 998cc and 1098cc engines are the same, but the 1098cc, with its longer stroke, will produce a better spread of torque across the rev range. If you wanted to do a 998cc the process is much the same. The engine will not give as good a torque figure, but it will rev more freely at the top end."

Russell does one article that goes into some excellent detail on cylinder head choices. It is the second one in the list of 3.

You should be able to learn some other useful tuning tips in addition to those covering the cylinder head choices.

here's the three-part series of articles on the 1098 written by Aussie A-series ace Graham Russell.


http://www.minimania...81/ArticleV.cfm

http://www.minimania...82/ArticleV.cfm

http://www.minimania...92/ArticleV.cfm

[Cooperman]

I once had a 1098 Mini which was an MG1100 modified engine in what was an 850. It had a 731 cam, 295 head, twin HS2 carbs and the original 3.76:1 FDR. It was very good in traffic and went well through the gears. It was a bit low geared, but cars were lower geared back then. I didn't try to rev it to over about 5700 rpm, although I did cruise it at 4500 rpm which was about 65 mph. By the way, it still had the single leading shoe drum brakes! That was exciting.

[KernowCooper]

I also had a mini with a MG 1100 engine and yes agreed it did go very well but mine was still on the 1100s diff so low geared but excellent for hill climbs/sprint as long as the straight was not to long -laugh !