By joining you will help ensure that we can continue to provide this service
JOIN HERE!
Reaming data for valve guides?
- Micha
- Posts: 768
- Joined: Fri Oct 12, 2007 2:24 am
- Location: Israel
- Has thanked: 11 times
- Been thanked: 5 times
Reaming data for valve guides?
I would like to get my hands on such a chart regarding tolerances of reaming new guides for a bike that lives in a warm climate.
Is this information available at all, or does a workshop perform the reaming according to some personal knowledge?
Thanks!
R51/3 1952
Engine Nr. 529466
- jwonder
- Posts: 784
- Joined: Wed Nov 23, 2016 7:50 pm
- Location: Long Island, New York
- Has thanked: 3 times
- Been thanked: 8 times
- Contact:
Re: Reaming data for valve guides?
I just finished my R 50/2 a month or so ago and I measured the fit with the gauges and then made them looser. Measure with a very thin oil as well to get a good feel.
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York
- Rodolfo850
- Posts: 65
- Joined: Sun May 29, 2011 11:05 pm
- Location: Guatemala, Central America
- Has thanked: 1 time
- Been thanked: 1 time
Re: Reaming data for valve guides?
I rebuilt mine R60/2 LK cylinder head, but request Machinist shop the closes tolerance, to avoid burning oil.
Yesteday after 20 milles since rebuilt on my way to the Distinguished Gentelmans Ride, my engine started to sound like a typewriter and stops...
Exhaust valve sticks to valve guide......so it returns on my trailer to house...
- jwonder
- Posts: 784
- Joined: Wed Nov 23, 2016 7:50 pm
- Location: Long Island, New York
- Has thanked: 3 times
- Been thanked: 8 times
- Contact:
Re: Reaming data for valve guides?
List of KPMI components
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York
-
- Posts: 1
- Joined: Fri Apr 05, 2024 11:30 pm
Re: Reaming data for valve guides?
retro bowl
-
- Posts: 1294
- Joined: Wed Aug 05, 2009 9:06 pm
- Has thanked: 20 times
- Been thanked: 18 times
Re: Reaming data for valve guides?
R69S - R60/2 - R67/2 - R51/3 - R69
-
- Posts: 73
- Joined: Fri Oct 27, 2006 3:00 am
- Has thanked: 1 time
- Been thanked: 8 times
Re: Reaming data for valve guides?
- Use caution when viewing listed data. 0.04mm is ~0.00157". This is a case where considering the mm->inch conversion of 0.04mm to three decimal places in inch will most probably be catastrophic.
- When the BMW factory listed their guide reamer sizes, it was based on supplier valve stem dimensions that did not have a significant variance, respectively for the 7mm or 8mm size. To properly process the guide ID's with the current valve supplier market, a range of reamers is required to optimize the desired stem clearance. That is, valve stem diameters from the current suppliers (SI, TRW, KPMI, etc) vary, and and most vary between the intake or exhaust.
- There is also tooling and material removal variance. HSS and carbide reamers can process to size differently in bronze guides, and the guide material will also have a process to sizing impact.
- Depending on the reamer design and type used, material amount to be removed, speed & feed, etc... will determine the accuracy of the finished guide bore. Also when reaming guides, it is ideal to brush hone the bore to achieve the final required Ra finish
- Investing in quality reamer tooling can be pricey. If only doing one pair of heads, the honing process should be considered. Honing will achieve bores that are straight, sized accurately with respect to the required stem clearance and achieve an optimum surface finish. Most all quality machine shops and speed shops have a honing machine.....and know how to use it.