North American Turbocoupe Organization



Question about an N/A block
t-bird88 Offline
Senior Member
#1
I have an N/A block, mainly because the ONE TC block that I had found, the junk yard crushed the entire car (motor and all). I searched 4 different salvage yards for blocks, but those damn sprint car guys keep buying them all up.

The question that I have is how much boost can an N/A block handle with TC internals??? I would eventually like to be able to run 20-25# through it. Can it be done with this block???

Jim B Big Grin .
Gunmetal Grey 88 TC!!!!
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Ryan H Offline
Posting Freak
#2
What year is the N/A block? If its a DIS block (no distributor) I think it has the smaller crank journals. If it is '93 and down with a distributor and large crank journals, it is no different than a turbo block except it hasn't been drilled for the oil return line. The boss is there, however. Personally, I think this is a good thing because it means less meat taken out of the block. Its perfectly OK to return the oil to the pan instead.

On edit, I also think the crank is the same but you may want to look into that. Regardless, lots of guys are using N/A blocks, especially the 2.5L crowd!
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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t-bird88 Offline
Senior Member
#3
I was seriously considering a 2.5L stroker if I could not find a 2.3 block.

They only have three left, and they are still good running motors. I heard two of them run. They wanted more for one of them. I paid $150 for this one, and the gaurrentee that it will take a 0.030 over bore.

Now I am going to have an abundance of spare parts for an N/A motor. Like I need any more spare parts, the wife wantes me to get rid of the ones that I have now.

Jim B Big Grin .
Gunmetal Grey 88 TC!!!!
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Ryan H Offline
Posting Freak
#4
I think 0.30 is too much? Look on TF for some sonic testing results. 0.40 is def. WAY too much. The most I would take it is 0.20 over. The 2.5L isn't much more to do if you are starting from scratch. You just have to get a small crank journal block and a 2.5L crank and the custom rods/pistons of your choice. You can even use a 2.5L block if you wish, but I don't think any of the accessories bolt up to it.

Unless you're a firm believer in rod/stroke ratio (I am not), I don't see any reason not to do a 2.5L if you're not looking to make more than ~450 horse. Also from what I have read, I decided to stay away from the bearing spacers, but you can decide that for yourself. They make spacers to put the smaller crank into a large journal turbo block. They seem to be hit or miss.
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Glenn 88TC Offline
Posting Freak
#5
Quote:Originally posted by Ryan H:

Unless you're a firm believer in rod/stroke ratio (I am not), I don't see any reason not to do a 2.5L if you're not looking to make more than ~450 horse. Also from what I have read, I decided to stay away from the bearing spacers, but you can decide that for yourself. They make spacers to put the smaller crank into a large journal turbo block. They seem to be hit or miss.
The stock ranger crank will support as much power as the stock 2.3 turbo crank will. 2 cars have run 9's with them.
NO TC and NO headaches.
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t-bird88 Offline
Senior Member
#6
Well, I found out yesterday that the block is a big journal block and that it has everything (but the oil return hole in the boss) that a TC block has.

I will report back with my findings from the machine shop tomorrow.

Jim B Big Grin .
Gunmetal Grey 88 TC!!!!
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StangBolt Offline
Member
#7
I am using an NA block in my '88 buildup, and like it has been said everything is identical to the turbo block with the exception of the oil drain boss being undrilled. I am actually using the NA crank as well, with the turbo rods and pistons.
It was suggested that it was easier to just have a fitting welded into the oil pan, so that is what I had done. I will agree, with one exception:

*WARNING* When mocking up the motor to measure where the oil return fitting should be welded into the oil pan, MAKE SURE you install the bellhousing AND *starter* so that you can have a very good idea of where the fitting should be welded. Ask me how I know!
I will be taking the oil pan back to my welder guy at lunch today...
'02 Silver Lightning
'88 Silver/Blue Tbird TC
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t-bird88 Offline
Senior Member
#8
Well, this afternoon the guy at the machine shop said that it looked really good. So I am hopeful at this point; keep your fingers crossed.

I alto told him that if the block checked out (bored, decked, and cylinders magged) that I also wanted the boss drilled out and tapped for the oil return. I mean hell, if it is all ready out and there is machine work needing done to it, why not get that drilled out also.

Jim B Big Grin .
Gunmetal Grey 88 TC!!!!
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