Se7enLifes

http://s1218.photobucket.com/albums/...20tear%20down/

after a recent diss-assembly to my half bridge engine. I found excessive iron wear on the "hot" or 3 oclock postion where the side seal kinda saw blades across. This seems to measure about .005. I have a builder telling me that is possible my cryo treated side seals are too aggressive, while i have another builder telling me that this wear is negligible and just put it back together.

I had just hand lapped the irons with valve grinder compound and a flat marble surface. This wear was not there less than 4 drift events and 5 dyno passes ago. The engine wasnt the greatest to hot start (always cold started) but just before i seized a front bearing it had begun to just flood.

So opinions?

mazdaspeed7

Were the housings previously lapped? If the lapping goes through the hard nitrided(is that the process?) layer on the irons, the soft cast iron below will wear far faster than housings normally should.

Another consideration is balance issues. An out of balance rotor/rotating assembly will wobble, and aggravate wear on some parts of the engine.

heretic

What are you using for an air filter?

Also, what did the oil look like? Was there a lot of metallic sludge in the oil pan and elsewhere? Failing bearings can act like lapping compound.

Measure the height of the side seals and compare to what they were when installed.

Se7enLifes

i have been discussing possible issues with another builder and we suggest that it was the cryo treated side seals. I am honestly not that in tuned with the metalurgy of the motor but i can see the side seals themselves being to hard for a nitrated cast iron surfaces.

But to answer your questions i did have a bearing fail on the front gear. there was a good bit of metal in the pan obviously, however i am not running a omp. Balancing was done by roger mandeville and unless he has fallen off his game recently i have never heard anything bad.

Alittle frustrated obviously but i am going back to stock seals and replacing the center iron with a good tolerance one and lapping the other two as best as possible. then i will tear down hopefully at the end of the season (fingers crossed) and see if i have any further issues. or if i keep having a hot start problem then i will tear down and see sooner

heretic

Just because there is no metering oil pump doesn't mean that the debris can't hurt the seals. 400-grit oil will affect the side seals because they get all of the splash lubrication that can make it past the oil control seals.

Again - how is the height on the side seals? If the wear was from debris-filled oil, the seals will show sigificant wear, and will probably have noticeable taper wear where the center is .002-.003 taller than the ends. If the wear was from too-hard side seals, the seals should show negligible wear.

Lynn E. Hanover

The Nitride is about .0025" thick. The irons start looking bad when the wear is at .004" and that is the wear limit. So if you lapped until no were marks remained, then it is possible that you did remove the Nitrided iron. However, no early irons were Nitrided and they held up for about 100,000 miles when the oil was changed on schedule.

I have found the best result from lapping the irons against each other. So you get two surfaces finished at the same time.

Then I go over the surface with 320 Wet or Dry silicone carbide paper on a orbital sander in a solvent bath to get some nice circular scratches in the finish. These hold a constant oil supply for the seals to run on. The wear, as best I can determin from the photo is more likely from abrasive debris. Just lap them again and take them to the car wash and run a dollars worth of high pressure soap over each surface.

Then premix one ounce per galon of Redline or other name brand synthetic 2 cycle oil. It works for me.

Make sure there are no leaks around the air filter system. And mound new filters with a bit of bearing grease on the mating surfaces. Do not use Fram filters for anything.

Lynn E. Hanover

PhillipM

I've got the exact same wear pattern on my Renny after the builder ground the side irons....

Grizzly

Bit of a thread revival, but which Corner seals are you / where you using? I know the Stockers are chromed and are allot easier on the Plates. Recently seen a few motors using "aftermarket" Corner seals that had quite bad wear in the same place and what was also a little odd was the Corner seal its self was quite badly worn. Now i don't know if the engine had been resurfaced or the condition of the plate that was used in the last rebuild but the Stock seals seem to weather much better.