Rod Clearances
 

Just did a check on a new GT3 crank and new R+R SC Spec rods. We have .229-ish on rod side clearances. They spin ok, not free, but not binding.

It is important to note that in PA, it is 35 degrees in the AM, and my shop is just that when I was doing this check.

I am using Federal bearing lube, and it is very thick, so this may be a valid reason for the drag? My thought is yes..

It is just hard for me to judge, since my last build was a CMW 2.9 stroke, with used components, and those Carrilos spun free and fast on the bench.



Sound about right?

not one reply.. Wow..

It must be the season. Or, like me, some don't think they have anything useful to say?

The assembly lube (Torco) I use (because a mechanic gave me a bottle and said I should 10 years ago) is stiff enough that usually, when mating the case halves, I can get the three top rods to stand straight up (barely). Is your stiffer than this?

did you mean .00229?

I wondered about that, too. Maybe it is in mm? 9 thou?

Well I don't have anything useful to say, but I'll ask a dumb question just to take this to the top..

What should your side clearance be? I notice in Waynes SCs clearance is spec'ed at 0.200 to 0.350 mm. Another way to check might be rod width vs rod journal width. Rod width with bearing installed is supposed to be 22.00-22.05 mm.

Double check those number though. I just noticed that Waynes book and the Bentley don't agree on rod width for the 3.2s.

Good luck.

.229mm is the reading, .2 is the low side for an SC rod.

SC rods on a GT3 crank is the reason for my question, since most spec books only list SC rods on an SC craow these are moving, they rotate well, just seems the lube is a bit thick due to the cold soak here in PA..

Thanks All, they will be assembled later today..

Clearance
 

Also important what are your bearing clearances, if you know they are good then the assembly lube is going to slow the movement.
Mike Bruns

Nothing usefulll to say...
But were the rods new..New to you>? Brand new ? re sized?
I say mike them..
Or you will never ever know .........
and as a last test drop test =Bolted to proper on crank =lift rod horizontal (level) drop it.
On a street engine it should fall nice even smooth action with some slow attached.

Rods are custom SC Big End R+R Rods. and Crank is a new GT3 from Porsche Motorsport. Side to side is in spec, and bearing clearance will be checked later in the weekend.

Bearing clearances are in spec, ranging from .051mm to 0.76mm per the plasti-gauge method. All rods are on the crank, just waiting to stretch each bolt.

So Far, the R+R rods seems very well machined, all specs seem good..

The 3/8 ARP 2000 bolts want a stretch of .0055 with no higher than 50 Lb-ft of torque.