308 V12 conversion begins

The main bearing caps all fit again now. Tomorrow I'll make the oversize bushings to go with them and that mess will be fixed.

 

Dave got back to me with some rough pricing on the shim under buckets and its not too bad. There is one that is available no question and one that might be available and if it is will be probably be cheaper. The stock shim over stuff would probably work, but the shim under conversion removes all doubt.....and I do want this engine to rev

It looks like a done deal that I'll be converting to the shim under set-up along with changing the intake valve spacing by 2mm, going up to 33mm intake valves and probably reducing the valve stem size to 5mm or 5.5mm at least for the intake side.

On the exhaust side I'm going to do a wait and see on the valves. The ports are much bigger than they should be and flow proportionately too much as is….but I’m trying to get the intake flow up 50%. That will leave the exhaust ports still too big but the flow will be too low and fixing to may require a slightly larger valve so it’s a wait and see.

I’ve got too many irons in the fire on this project and I’m have a bit of trouble keeping everything straight in my head. Hopefully it will be worth the effort. I will be very disappointed with anything under 600 crank hp and I’m honestly believing 600 rwhp is possible and that is what I’ll be designing for….at least until the flow bench tells me otherwise.

 

I THINK I'll be ok with the front headers. One will come through the cut already in the right gas tank where the AC compressor used to sit and the other will come over the top of the bell housing.....at least that's what it looks like at the moment. The left gas tank may very well get it's corner cut to make room for the drop gears though. I'll know more when I get a little further along.

 

That is an option, but I keep thinking I'd like to get a spare back up there at some point. I think I'll be ok with the stock tanks.

 

I wouldn't even know where to begin hotrodding a TR engine..........all the parts already fit together

 

Plus I think it's a good idea to see if any of this stuff actually works as planned before making any copies.

The hp predictions all hinge on being able to get the heads to flow a LOT more than they do stock. I started playing a bit with the head on post 128 and by post 134 had it up about 10% with the stock valves....but still well short of the goal. If I go up to 33mm valves and maintain the same port efficiency I will exceed my flow goal, really a 32mm valve should do it but I’m going to make sure I have room for the 33s just in case. Once the head flow is sorted any good shop should be able to build the engine to go with the heads and make hp.

 

Well there's a boring 3 hours of my life gone, but the bushings for the bearing caps are done. 50 year old $700 lathes and jobs requiring a toleranca of a couple ten thousandths of an inch just don't go all that well together it turns out. With as much fun as 14 bushings were I can hardle wait until it's time to make the 48 custom valve guides.
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This is a very hard question. To make an additional 200 hp it would probably be cheaper to an put less strain on the engine to do it with boost of some kind. It will however be a very different sounding and feeling engine depending if you go natural aspiration, turbo, or supercharger as they each have distinctive characteristics.

For 600hp in a naturally aspirate engine you would need the head work I’m getting ready to do, cams, custom intake probably, may ITBs, pistons, rods are recommended, oversize cylinders would help, ECU. I’d guess about $25k-$40k depending on if you do any of it yourself of not.

For the turbo of blower you could go with a stock engine if it’s tight, but my guess is you’d start with a rebuild so the prices would be in the same ball park. With a turbo you would have the option to intercool and go up even more on the hp if you chose. Or you could do the head and cam work the same as the NA engine and have 550-600 before the turbo.

Lots of option. It all comes down to how you drive, what you are going to do with the car, what you want and what you can afford. I suggest you make a list of the things that are important to you and also a list of things you don’t want and the right choices will be more obvious.

 

That sounds like good advice. Anytime a shop has the flow and dyno results for all their engines you know they know how to deliver what they promise.

 

Thanks. There is good chance when it comes to the guides I'll at least get one of the guys at work to rough them for me on the CNC....some jobs are worth owing a favor for and I think that will be 1 of them. The valves will be another and the cylinders (when they ever get here) a 3rd. There are 4 or 5 guys in the shop so that leaves me 2 jobs.....no wait, the drop gear hubs will use them up.......

 

Short nap tonight

I got the block up on the mill and indicated in. The front side needs about .020" removed to straighten it out. That will be tomorrow night's project.

 

The front side is good as new. Next will be the bellhousing end then on to the bores.
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This is a good question and one I've never felt good about either doing or not doing. I like the idea of sealing the aluminum so any sand or anything else left in the surface straight there and out of the oil. But I always worry about any type of coating flaking of and clogging an oil passage. I've never been able to convince myself I know what the right answer is......

The flaking here I think is my fault from the heating and welding, but my fault or not I'm going to remove all the old coating for sure. But what to do next?

I was ¾ thinking I would simply have at the rough casting surfaces with a sanded and clean them up a bit. That will certainly make it look better and the oil will drain better but will also more likely leave some abrasive material embedded in the aluminum just waiting to end up in the oil.

I could clean it up with a carbide cutter but it won’t drain the oil as well of look as good.

I could re-coat it and figure it will certainly be apart again long before flaking would be a problem….this is me we’re talking about after all.

Traditionally I worry more about flaking that could cause a catastrophic failure than about abrasive left behind causing increased wear rates and lean toward the sanding. Maybe that’s not the right thinking though……

Edit:I just noticed this was the 1000th post to this thread.......clearly I talk way too much