TR6 TR6 engine rebuild. Too tight?

[TFB]

I agree that sound like a reasonable number.
BTW you got me reading up on Cerakote.
HAve fun
Tom

 

[Got_All_4]

I'm beginning to think that too. I used Creakote on the tappets too and seem to spin much easier. Also in the timing cover where the chain tensioner rides.

 

[CJD]

Just some background info:

The most common, and cheapest rings are straight cast iron. They do not have a perfect contact surface, so the cylinder bores must be prepped by honing to a relatively coarse cross hatch finish. This rough finish speeds lapping the face of the rings to achieve a perfect seal. Because of this, cast iron rings have a relatively long break in period...like several thousand miles. A side affect is the rough cross hatching increases the drag between pistons and cylinder. I bet these are the rings you used.

The next step up is moly faced rings. Molybedneum (spelling) rings are pre-lapped in a hardened steel cylinder during manufacture. Because the face is much better prepared, the cylinders should be honed to a mirror smooth finish. Moly rings will break in within a hundred miles of running...and if a break in procedure is used, they break in in a matter of minutes. The side affect of having rings and bores this smooth is there is little friction between the piston and cylinder...so the engine will easily spin by hand after assembly, compared to your build.

Then there are the specialty rings...chrome rings in iron bore, chromed bore with iron rings, nickel plated aluminum bore...and on and on. All the newer designers use a near mirror bore and pre-lapped rings to reduce break in and friction.

Anyway...most guys rebuilding our TR’s are still using the old school iron rings on a rough honed bore...so a lot of friction after the initial build is to be expected. The end result is just as good as modern engine builds, but you will have a longer break in time.

 

[TFB]

One of the nicest features of the TR3 design is easily replaceable and relaltively inexpensive cylinders.I use only cast iron rings in my vintage bike motors but cylinders are rare,softer cast iron than modern bores and I would rather have the rings wear ,not the cylinders.They are also more forgiving to a not perfectly round bore.Burnishing the final 220 grit hone with a few qiuck passes by hand of some 400 or a burnishing brush nocks the peaks down but like John mentioned longer break in is required .
The only problem I have ever heard of with the three piece oil rings was incorrect install with the spring spacer not set right.
Im always amazed when top fuel dragster guys replace pistons and rings and blast a full out run.They have pistons with gas ports to pressurize the rings.
Someday I may find out whats in my TR3 as the short block came to me rebuilt.12k now,hopefully good for another 100k.
Arnt these just the coolests motors!
Tom