616 replies to this topic

[cp2708]

Air leak would cause lean condition to the best of my knowledge, and the extra heat he mentioned. Happy to be corrected. 

[johnR]

Yes, you're right, my air leak caused lean running and the excessive heat, running over rich would probably cause bad running by sooting up the plugs and cooling the engine to the extent that is doesn't run efficiently?

[johnR]

I've been playing around with the carbs - so much easier to see what's going on and make adjustments with the engine out of the car. They're fairly well balanced now so I've been sorting out some niggles and starting to tidy up some of the painted parts that need it. The coolant drain tap was weeping which was because of indifferent machining of the internal taper. I used Autosol chrome polish as a lapping agent while pushing and twisting the tap into the body and this has cured it. I also bought some new copper washers so it now sits upright on the block. There had been a slight oil leak from the back of the engine whilst running it in the car - there is no sign of it now except around the rocker cover gasket so I think this was the culprit - I'm pleased because I went to great lengths to build a dry engine after friends and family complained about deposits on their drives from the old 998! I'm rubbing down the radiator shroud, alternator fan and pulley, brake servo and heater box panels ready for a fresh coat of paint.

The new zinc coating peeled off the exhaust headers again so I'm going to give up and paint them in VHT silver - this lasted well on the cast 998 manifold.

Edited by johnR, 15 November 2019 - 04:51 PM.

[johnR]

Alternator fan finished, rad shroud and alt. pulley sanded and given several coats of highbuild primer

[johnR]

A package arrived today - half of the rockers I ordered and a spacer kit

[Vinay-RS]

A package arrived today - half of the rockers I ordered and a spacer kit

 

Only half? Did they mess up the order? 

[johnR]

Yes - but will rectify by sending the other four with postage at their cost

[mercenary62]

could you try running it on a single carb again just to see if its a fuel or carb setup problem ,just an idea mate

[johnR]

Unfortunately I don't have a single carb/manifold for a 1275 otherwise I agree it would help narrow it down to try a set-up known to work.

[johnR]

I've fitted the new rockers and shimmed them as best I can. It's not possible to completely centralise all the rockers on their valves without machining material from the rockers or the posts but more of them are central than was the case with the standard set-up. Also I will be able to better set the gaps - the concave wear on the old rockers was without doubt preventing accurate setting. 

[tankertanker]

How's it going ? Any progress

[johnR]

No - I'm a bit of a fair weather mechanic so haven't done any more. She-who-must-be-obeyed has tasked me to re-floor and decorate a room in the house, then back into the garage!

[johnR]

Office re-decorated so close to getting back on the Mini!

[johnR]

I've dipped my toe back into the Mini works - exhaust manifold wire brushed to remove the remains of the zinc that bubbled off for a second time - going to use VHT paint this time.

Edited by johnR, 01 April 2020 - 01:23 PM.

[johnR]

Car taken out of the garage, polished and put back in again. Really must get on with putting the head back on and getting it running again.