really long rod stroker 427

[frnkeore]

Ross, are those bearings for large chamfer, "H" BBC journals?

If so, they would fit the tangs and you would only need to chamfer them in the rod, while narrowing it.

If not, the tangs could prove problematic. I've never done it but, it is sad that you don't need the tangs but, that's makes for, another machining operation.

In general, 7/8 wide rods, need bearings no wider than 3/4.

[My427stang]

Yes, the CB743H is the narrow BBC, had a typo on my phone but that was an actual measurement

How much you had to massage the bearing would depend on the crank and how much you were able to take off the inside of the rods

[TomP]

I will check into those bearings. Is that what is normally used on an FE stroker do those cranks have wider journals?
 I mocked up the pistons and crank in the block today. I don't have the 7.1" rods yet (just ordered them from Scat) but with a 6.7" Scat rod it sits just around .400 down. Not exact since the .985" pin is loose in the .990 pin hole but a couple thou deck clearance is not an issue.

[My427stang]

I use those Clevites or ACL on strokers.  Speedpro also makes a narrow bearing

[frnkeore]

The position of the bearings, when install in the rod, will tell you how much you need to take of of the inside surface (rod to rod). Measure that first. You can take that down to .005. The the rest will need to be taken from the outside surface. You will need to know, from the manufacturer or measure the filet radius. Then the chamfer has to be,  more than the filet radius, or there will be metal to metal contact, in that area.

[My427stang]

Here are some real pics.  I stuck an H mockup bearing I have in a SCAT BBC H-beam.  Bearing is .835, you need to get rod down to .870

Very little to no room to cut on the inside.  Approx .060 to play on the chamfer side.  You need to cut closer to .110. 

I think that even if you eat up the extra on the chamfer side, and reduce the chamfer depth itself  to a minimum, you'll still be into the bearing on one side or the other

I would love if it would work, and you likely could wack the other .050 or so off the inside of every rod and bearing, but seems like a lot of work for not much gain

[frnkeore]

Ross, it looks to me like he has the work in his crank to save, $650 on a crank and $700 or more to save on pistons. I'd say that comes close to $1700. Plus he gets to use the parts he has in the manor he wants.

I get a lot of satisfaction out of doing things like that myself.

Regarding the machine work, that needs to be done. It is rudimentary and can be done at any general machine shop. I would say that the work would take about 3 hours (that's what I would quote, for a job like this) but, to be successful, you have to know the width of the journal and the filet radius.

[My427stang]

Frank, the decision is not mine to judge. However if he could find someone like you to do it, maybe it would be worth it.

I would advise against trying to force it based on having parts, but if you can find a willing machinist, it does look like fun

[winr1]

Tom

How high an rpm are ya looking at an how much does a 7.1 rod weigh if I may ask ??

I might have missed how much the pistons weighed

No access to machine shop tools anymore or I would do for free

I get real interested in builds such as yours



Ricky.

[TomP]

I don't even see the weight listed for the 7.1 rods. I'd imagine in the LeMans rod territory. The pistons are light to make up for them. It probably won't see high RPM anyways, it's for a street car, but 7000 is plenty safe.

[plovett]

Got pic's of the pistons, Tom?

pl

[TomP]

Good news on the rods, they will sell me ones with unfinished pin bushing that come .969" ID so that saves changing them. Not in stock so he says around three weeks. Just need to be narrowed and i'm sure the local machine shop can handle that. Maybe i could even buy the equpment to do it mysef by then.

Pictures of pistons, and the crank.

[TomP]

As you can maybe see the pistons use pin buttons instead of clips. They also come with a raw dome and since i don't really want a 17 to 1 compression ratio those will be cut down to a flat top.  The oil holes in the road journals didn't migrate out too far.

[KMcCullah]

Cool pistons! I'll bet they'll end up pretty light.

[e philpott]

I had a 93 inch Harley shovel head in the early 90’s that made 158 hp that used Teflon buttons instead of a clip , they worked great back then