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Created: March 23, 2017
Any aluminum head will have advantages in lighter weight and better cooling due to aluminum being able to shed heat better than iron.
Created: April 25, 2014
Most motors will go at least 80,000 miles before "needing a valve job"! But what are the signs? How do I determine if I really need it? Do I do it myself or pay a local machine shop.
Created: January 15, 2014
Valve stem seals: The o-ring style seals are used on the early small bore heads, most later heads use the umbrella style. As an engine wears, the clearance between the valve stem and guide increases; as this gets beyond tolerances the car will tend to smoke under deceleration (when you take your foot off the throttle). Good valve stem seals will allow for greater wear before the smoke becomes intolerable.
Created: October 10, 2011
Call them cotters, collets or keepers, these little items are often overlooked during a head rebuild. If yours are worn and need to be replaced, make sure you order the right ones. Minis used three different versions over the years.
Created: February 03, 2011
The engine build I recently covered in previous Mini Magazine issues developed into a bit of an ongoing 'project'. During a discourse with the editorial staff at Mini Mag, it was decided the build feature presented an ideal opportunity to demonstrate just exactly what such an engine build is capable of in days where it's generally believed you have to have an all-singing, all-dancing 1380cc engine to have an enjoyable road burner - leaving those with very limited budgets a little depressed.
Created: July 24, 2006
Last time we started building a small-bore engine for maximum power. But there is no point having a good engine and putting the wrong head on it. I'm going to use the 12G202 head, as these are the best to modify for our purposes. They are a bit smaller than the 12G295 or 12G206 heads, which gives you a bit more metal to play with when grinding. As far as a standard head goes, you can't go past the 12G295 or 12G206.
Created: January 28, 2006
Fastener Retention Overview There are three methods that can be employed to determine how much tension is exerted on a fastener; using a torque wrench, measuring the amount of stretch, and turning the fastener a pre-determined amount (torque angle). Of these methods, use of a stretch gauge is the most accurate.
Created: February 09, 2004
This addendum to the Cylinder Head section was fueled mainly by pictures of combustion chamber shapes and folk's excitement at what they could possibly do for them. It is also prompted by the 'new isn't always great' teaching. So what's in these varying and dramatically different chamber shapes?
Created: October 27, 2003
Detailed description of the numerous cylinder heads as built by Mini-Tec
Created: July 24, 2003
There is no specific large-bore (1275cc-based) head casting number that will fit the 998 engine any easier than any other. They all have the same problems - generally requiring exhaust valve relief cut-outs machined into the block and re-alignment of the front water gallery transfer ports. However, I would avoid using heads with valves bigger than 35.7mm on the intake since these are too big for most 998 engines unless they are absolutely full-race spec where top end power at high rpm is all that is required.
Created: July 11, 2001
First a brief word on head gaskets. If it is not a genuine Rover or Payen gasket, don’t use it.
Created: April 10, 2000
On 2" inch main 1275 engines the use of main studs gives a solid improvement over the stock bolts. Factory bolts, at the very best, only have 65% of the clamping force of an ARP stud, and consider that the combination of the firing load and inertia at RPM cause loading's that amount to thousands of pounds. On the 1275 Mini there is something to look out for that doesn't arise on an inline engine. Due to the proximity of the gear box webs at both ends, there is not enough clearance for the nut.
Created: March 08, 2006
The following article was originally found on the NGK web site here. Spark plugs are one of the most misunderstood components of an engine. Numerous questions have surfaced over the years, leaving many people confused. This guide was designed to assist the technician, hobbyist, or race mechani...