Rod knock.

[ProductUser]

Randy, is there anything you don't do at your shop? Cool stuff. Thanks for sharing.

[rf900rkw]

On the M/S52, #5 is the problem child because it is the least cooled cylinder. Most prone to cracking, detonation, etc.


Didn't know you had an RF30.

[Randy Forbes]

Randy, is there anything you don't do at your shop? Cool stuff. Thanks for sharing.

I'll try anything once...

Ron Stygar once took a xmsn drain plug to a shop he regularly visited to counterbore & tap for a temperature probe, the machinist said it couldn't be done__no way to hold it.

I didn't know any better, so I cut a 2" cube of Delrin, drilled and tapped it to hold the plug and gave Ron the finished piece when I saw him at HC that year.

Since I didn't know it couldn't be done, I was able to go ahead and do it anyway

On the M/S52, #5 is the problem child because it is the least cooled cylinder. Most prone to cracking, detonation, etc.


Didn't know you had an RF30.

There had to be a reason, and now I know what it is (glad you're back!). It's also the cylinder showing the most wear__usually__on the S-54 too, not surprising given the similar block layout.

I picked that mill-drill on the basis of table travel; it was the absolute cheapest one with enough x-y travel that I could do the engine-turning on the Healey's instrument panel with a single setup. There was no way I was going to attempt it without a positive index__OR like the guys in the 20s & 30s that used a hand-drill, a wooden dowel and valve-grinding compound! I used Cratex abrasive rods, 2" long to not flex, and frequently "dressed" the end with 320 sandpaper. Consistent dwell and contact pressure counts for a lot too, but I didn't want it so perfect to NOT look like it was done by hand.

Even Gerry Coker, the man that designed the Healey Hundred (AND Ford's 2-way wagon tailgate in the 60s) complimented it; he wanted to do it for the 100, except that "it had already been done by Duesenberg, Bugatti & Mercedes."







Hi-res: http://spcarsplus.com/gallery3/var/a...g?m=1304277055

[325bob]

I don't know why, but #5 is the problem child; loose plug, spitting connecting rods, or just worse wear on the big-end bearings.

If let go long enough, you'd have had to resort to this (yep, it's #5)...



Spot-facing the top of the plug hole to restore a flat sealing surface





Heli-Coil thread insert (required two__2__coils due to length of thread, second coil being trimmed)







After spot-facing, this cylinder will always require the use of a sparkplug indexing washer to reset the electrode depth

I was very apprehensive on torqueing the new plug into #5,after a few hundred miles of aluminum thread abuse, seemed ok, maybe the extra Shark rpm loosens#5?,harmonics?

[Yellow14150]

Darn it. I wish I had read this thread earlier. I had an S52 sitting at my house until last month. I took it California to swap into a different car. If you decide to do it yourself I have just about every tool you could need in the area. And a lift in my garage. As long as it only takes a couple days you are more than welcome to use it. I live in Cave Creek.