Need a Quick Answer - Which Valve Guides Do I Buy?

[RobertK]

My brother sent his cylinder head off to be reworked, P&P'd, and get a 5 angle valve. The shop called us back today and said everything looks good except all the exhaust valve guides need to be replaced.

Looking on BMA there are like 5 different types of valve guides I can choose from. Which one are the right ones?

[rs4pro3]

Hi I checked the bentley after you called and it lists them, the dimensions are in MM and is the outside diameter of the guide.
Standard size
Old style 13 mm
New style 13.2 mm

Oversize 1
Old 13.1 mm
New 13.3 mm

Oversize 2
Old 13.2 mm
New 13.4 mm

Oversize 3 13.3 mm

It dosn't list the cut off date from the switch to old to new, So I'd think it be best to call the shop and have them measure the outside diameter of the current ones then order ones .1mm larger

[RobertK]

Thanks Ely.. According to Patrick at BMW no matter what year model it is it could have a potentially different sizes so you have measure them to be sure.

Stock sizes he had listed were:

13mm
13.1mm
13.2mm

BMW couldn't do it the easy way could they?

[winstontj]

If you are replacing guides why not do all 12? I would think for the money it would be in your favor to replace the intake and the exhaust... Just my opinion...

[RobertK]

The guy I talked to at the machine shop said not to worry about the intake guides since they were in really good shape though I had offered to buy all 12.

He finally called me back and said they measured in at .520 inches in diameter or roughly 13.2mm. I bought the 13.25mm guides from BMA to replace them. So now we wait and see.