Blacktop 7age Noob Questions

[Jamin]

I've just begun a blacktop 7age build, I want to keep the factory rods My main question is about piston selection after the block is milled. I know that using the BT pstons puts the compression ratio into the 12:1's . Can you use Silver top pistons to drop CR back? I've read about people making ST block /BT head hybrids.
Does this make the engine interference or non interference with vvt?

Is milling the .6 off the block deck necessary with a thin enough gasket?

This is for a daily driver in an aw11

[Flannelman]

Anyone else, please correct me but this is what I see...

7AGE - that's using a 7afe with a 4age head. Using stock 7afe rods (these are longer than a 4age) is not a good idea.

ST/BT pistons. The difference between them is 3cc. The BT is +5cc and the ST is +2cc.

0.6mm off the deck? Well, how much did you have to start with? If the piston was at -0.4mm before then after it will be +0.2mm out of the block. If there was 2mm then going 1.5mm may be needed. However, as compression is something you want to lower, I would suggest just skimming the block so that its a true surface for the gasket to seal to. Also, go standard head gasket not the thinner TRD one. Again, this keeps the compression down.

"Interference fit" the ST has valve reliefs, BT has not. Under a slap it together and go the ST MAY give you a non interference engine.

But all this goes out the window as... The block is being skimmed. You will have to measure the clearance. Best done before as you will know how much space there is between piston and valve.

If your going longer duration cams, I would suggest grabbing as much compression as you can. But it also depends on what your going to feed this engine as a staple diet. 91, 95 or 98. Up the compression and you will be rewarded with more torque/power but will need 95/98 - dependent on how greedy you get.

[matt dunn]

Using stock 7afe rods (these are longer than a 4age) is not a good idea.

Why's that?

Can't use the 4age ones as the big ends are different size,
and even if they did fit the piston would be so far down the bore at TDC,
your comp ratio would be so low I dont know if it would run.

[thegreatestben]

I think the cost of making a 7age isn't worth it unless you can really pump some $ into it.
Barry has made it a lot more accessible with great products like the timing gear with correct keyway position.
I think I would rather throw money at a 4AGE/ZE, I enjoyed my 7agte but someone else spent the bucks on that, which is probably why I liked it so much.

I guess my concern would be is there much to gain from building a blacktop 20v 7age with standard 7afe rods? Would it pull the revs without ventilating the block at a track day? My other AW11 with stock blacktop 20v was super fun! The decent LSD and 20v really made the smiles happen

[sergei]

Why bother with 7age when you can get 2ZZGE for a fraction of the cost?
You will have to spend tens of thousands of dollars on 7AGE (non-turbo) to get the stock performance of 2ZZGE.

[Jamin]

What about an ARP bolt solution for the stock 7afe rods? Wouldn't that make the rods a little more reliable at high rpm?

I was hoping to avoid a big dollar project, these are just parts I have laying about and want to make use of.

[QikStarlie]

I think the cost of making a 7age isn't worth it unless you can really pump some $ into it.
Barry has made it a lot more accessible with great products like the timing gear with correct keyway position.
I think I would rather throw money at a 4AGE/ZE, I enjoyed my 7agte but someone else spent the bucks on that, which is probably why I liked it so much.

I guess my concern would be is there much to gain from building a blacktop 20v 7age with standard 7afe rods? Would it pull the revs without ventilating the block at a track day? My other AW11 with stock blacktop 20v was super fun! The decent LSD and 20v really made the smiles happen

agree with this ^

you'd spend the money better sticking with the 4a block. use silvertop rods with arp bolts. get the compression in the 12's. plus cam and valve spring upgrade. will get it going a bit better and be good for 8500+rpm. decent extractors and exhaust will help too

[matt dunn]

Is milling the .6 off the block deck necessary with a thin enough gasket?

I run Turbo where I think you are NA, but I have never touched the surface of the block on any of my 7A builds.

[Paulio]

Redneck it.. double head gasket ftw