Help with my broken 406

[Barry_R]

First off is that we can likely get a Diamond "non-stocking" but catalog piston for the 406 for somewhere near the lower end of your price range. They're pretty nice parts to boot. And they are available in a 4.155 bore without needing to alter your rods.

I much prefer the aftermarket rods for exactly the reason the other gent mentioned - - 30 years of fatigue will take a toll that you cannot see or measure. There's no way to know if or when they're gonna "sign off". Cheap insurance.

On a sleeved engine I'd really want to use a torque plate and at least check the line hone. The sleeving process disturbs a lot of metal and adds a press fit into an area previously not stressed in that fashion. Things are bound to move as a result. Sleeved engines work perfectly fine (I ran one for years with five sleeves), but you do need to check that stuff after doing it.

Barry R.
Survival Motorsports

[Monster]

John- Ive talked to Tom regarding pistons, but since I'm building and someone else is machining he didn't seem to want to provide much information. As for second guessing the machine shop. It's more like getting a second opinion before an operation. That said, I may change "doctors" if I haven't been hearing the right proceedure's.

Ted- I wasn't considering boring to 427, only that most recomend that when boring a 427 that a torque plate should be used because of the thin cyl. walls. My question was "is this a concern with 406 since it has thicker walls"?

Blykins/Barry - I've been talking to Diamond and they are on the top of the list right now for pistons. That's where the 4.155 came from (it's the size of their .020-406 piston which is not stocked and cost about $620). I didn't ask about .030 to see if that was off the shelf but it's worth a phone call to find out.

I agree with all on the rods, which is why I bought a new set of Eagles, but I had yet another conversation today with another expert FE builder who said "you don't need change the stock rods, they are just as good as the new ones for most applications [unless your racing]" had me questioning myself.

It seems the more I ask the more "opinions" their are on what's needed and whats not.. so far I'm going with:

Torque plate's for boring (they could only help)
H-beams (already bought and the reason the engine broke was due to another components fatigue, not necessarily "cheap insurance" but they are insurance
Diamond pistons- The alternative would be $200 less but it's about piece of mind and the alternative was by the same source that said I didn't need to change the rods

Thanks,
MIke

[ted]

Originally Posted by Monster

Ted- I wasn't considering boring to 427, only that most recomend that when boring a 427 that a torque plate should be used because of the thin cyl. walls. My question was "is this a concern with 406 since it has thicker walls"?

I mentioned the 0.100" cut only because some 406's can actually take it and have a better cylinder wall thickness than a stock 427. I've got a 406 service block that's like that. The '62 models on the other hand were not as liberal in cylinder wall thickness.

I still like to torque plate hone the cylinders as it does promote a quicker ring seal. Thicker walls do to a small degree help in retaining cylinder wall integrity during honing but torque plates still help. Another thing to keep in mind is if the shop that's doing the cylinder walls hones it fast or with heavy pressure, you can end up with egg shaped cylinder walls regardless of using a torque plate. This is because the cylinder wall themselves are not concentric or even in thickness and a heavy cut will create more heating at the front and rear of the cylinders versus the top and bottom. For this reason, I like a very light hone on a cooled block for the last couple of thousandts.

[Monster]

Well, It's been about 3mos. since I first posted on this thread and I thought it was about time for an update.

FIRST: I would like to thank the members of this forum for the information that they have directly and indirectly provided (I used the search a number of times during various phases of this rebuild and the comments and pictures came in handy on more than one occasion) so THANKS TO ALL MY FOLLOW FE OWNERS/Contributors here.........

So here's where I'm at: I stuck with my original machinist and I'm glad I did, he did an excellent job. I had the block bored and decked.

The engine before breaking was pretty stock with only a mild Isky cam and streetmaster intake.

I went with
Custom Diamond pistons w/file fit Power Seal rings (10.5 to 1 comp)
Eagle rods
Comp Cams: 294S cam w/springs & lifters, roller chain & gear, roller rockers
Edelbrock 60069 heads (portmatched & ported)
MSD Pro-Billet dist.
Clevite & Felpro for bearings & gaskets
I have a 2x4 intake, but I will go with the single Streemaster & 750 untill I have broken in the engine.

Here's link to the before & current progress pictures: http://pg.photos.yahoo.com/ph/mdvmon.../ph//my_photos

I should have the final pieces back on and the car running this weekend .

Thanks again!!
Mike