308 V12 conversion begins

All this stuff is in the basement and we have hot air heat with the units in the basement, so anything in the basement air ends up in the house air as soon as the heat/AC kicks on.

I built the hood out of a couple sheets of cheap under-laminate. I had a pretty long run with a couple turns to where I want to exit the house through an existing window, so I went with 10" ductwork and I used an in-line blower I got from mcmaster-carr # 1967K17 rated at about 600 cfm. The fan is the blue thing in the duct in the first pic.
Image Unavailable, Please Login

 

The welding is coming out pretty goodI think and once it’s machined no one will ever know the difference. I got almost ½ way today before running out of argon which finally ended a pretty bad day.

Just about everything that could go wrong did today. I fired-up the welder but my foot pedal that controls the current didn’t work, it was full power all the time. I found a broken wire and fixed it…still broken. Pulled apart the potentiometer and cleaned it up, back together and this time all was well. About an hour into the job I stop for something and I see a puddle on the ground. The touch is water-cooled and one of the fitting sprung was leaking. Just needed tightening. A couple hours later I get covered with water while holding a live welder set to 325 amps…I had let the hose touch the hot block and it burned a hole. A little electric tape got it slowed to a dip and I got back to work. Then the argon ran out and while cleaning up I Lana, who had been out, came home and “informed” me that the hood was not completely effective. Time for a drink.

I’ll finish the welding next weekend. I can really do it after work because it take a while to get the block up to temp and ready to go, better to have a whole day. I'll get the argon and see what I can do to get the hode fixed in the mean time. I've had the welder for 5 years and never had a problem with...I guess it was saving up.
Image Unavailable, Please Login
Image Unavailable, Please Login

 

hmmm......it does look like a pattern and I know that our favorite weber lover is now dating a Russian woman too. They're getting us all one by one......

 

If anybody knows where I can find some worn-out, left over after a rebuild (very cheap) liners form either a 348 or a 328 please left me know. I'll get the nikasil re-done went all the machining is done so poor condition is just fine, they just have to be cheap.

I think I'm going to have to do some welding to make the nikasil liners fit too. It needs a little more metal at the deck for them to seat on and a little more at the bottom of the water jacket to get the o-ring seat in the right place. No more corrosion issues, no more pressing liners and about 30lbs less weight, so I’m thinking this is a good upgrade to make “while I’m here”.

I really need to find so liners to mess with. I'd like the 85mm 348 liners and have a 5.3 liter, but I guess the 83mm 328 liners would give me 5.06 liter and less cutting down in the spigots.

I'm also thinking that I've never even heard of a liner failing, so clearly they are too thick . A QV liner is 3mm....I don't think it would ever even miss a 1/2mm. I know the porsche guys open up their liners, I'm goig to see how thin they go. so that means 84mm bore with the 328 liner and 86mm form a 348 unless I find ferrari already thinned them up.

James at Norwood suggested stroking it while he was explain why the nikasil liners don’t fit and wouldn’t be a good idea. I don’t think it will possibly be in budget, but it is a path to a 6.0 liter engine which would be very very cool. I may follow up with him and get some pricing.

I'm starting to remember why after after building my first supercharged engine I said "I'm never doing another naturally aspirate engine, it just too much work".......

 

I'll call him tomorrow, thanks.

 

I'm trying very hard to make them fit on this block, but they are kicking and screaming the whole way.......

 

Thanks....it's amazing how these projects get out of control so fast. The big bore is a done deal becasue I need cylinders, need new pistons, and need to maching the block after welding any way.

The stroker crank is going to come down to money honestly. With an 86mm bore I need a 86mm stoke, which is 8mm over stock and that should work with stock connecting rods. An 85mm bore needs a 88mm stroke and might work with stock rods. 84mm bore needs a 90mm stroke and I see no hope for stock rods. If I can get it welded up and re-ground for $1000 it's a done deal, but at $10k (or probably even $5k) it's flat out of the question.

 

I got a positive sounding maybe from an f-chatter on liners! Hopefully at the final word by the end of the week.

If that falls through, I also found good used ones at a reasonable price (the same as reconditioning spent ones)….but I hate to buy good ones because that would give me no excuse to punch them out to 86 or 87mm.

I'm still waiting on pricing to re-work the crank, but I'm leaning toward 86mm bore and stroke making 5995cc. Hopefully it's not a million dollars to do the crank and I can justify it to myself. I had a VW bug crank done years ago, It think that was $100

 

Now don't go confusing me with facts

There are a few things that set the redline such as the loads (reciprocating weight), the piston speed, the strength or stiffness of the block and crank, life expectancy requirements, valve train and such.

On piston speed an 86mm stroke should be safe for extended use to about 8500 rpm, maybe a little more. The load on the block and life would be the only concerns I think…which are not trivial but at least the pistons won’t fly apart. Ti rods or even new steel rods (I’m told they save about 100 grams) would make me feel better about the bearings living a reasonable time at that rpm, but it shouldn’t come apart I don’t think. Heck even the nascar boys run an 89mm stroke all day long at 8000 rpm with steel rods….but I’ll bet the bearings are all done at the end of the day.

I don’t see it spending a lot of time at up there anyway because I think it will stop making hp above 6000 or maybe 6500. The heads flow what they flow and a 6 liter engine will use it up at about 25% less rpm than a 4.8 liter would. I though I could get the 4.8 to pull to 8k, but with the same heads a 6.0 will be done at 6k. Unless I can get more air through the heads somehow 8k will be short burst because I want to hear it, but the real shift point will be around 6500 to maybe 7000 if the heads come out great.

The advantage in my mind to the larger engine is about 25% more torque everywhere and that is really nice in a streetcar. It’s nice to down shift because you feel like it, not because you have to.

I will change the rods if there is anyway to fit it in the budget, if not I'll just keep the revs down to something reasonable most of the time I guess.

 

That’s the choice exactly, pretty much the same peak hp, but lower rpm and more torque with the longer stroke.

An 86mm bore with the stock 78mm stroke is 5437cc. If I push a little more and go 86.5 I get a nice round 5500cc or 14% more displacement and torque with no change to the redline and no expense for the crank. The peak hp rpm would still drop the 14% to about 6900, basically stock 308QV rpms. That would not be a bad engine in any way either.

What I might do to help with the decision is finish up the basic conversion work and figure out how the intake manifold needs to go then see what I get for air. The bigger bore will let me run bigger valves without the cylinder wall interfering with the flow. Once I see what the flow is, if it will support more displacement, then I do the crank. Maybe. And if I’ve gone 86.5 on the bore, the stroke would be 85mm to hit 6.0 liter.

 

They look pretty, but I'm not sure about Chinese rods….plus I don’t have any money

 

I think the "occasionally" part is key.

I had harley with a 96mm stroke that I would shift at 8000 at the drag strip and it was happy...stock rods.

Same harley with a new 83mm stroke that I road raced a couple years and shifted at 9000...I still have the bike, it's next on ebay I think. I ordered carrillo rods for it because I needed a custom length, but they were a ridiculous lead time back then…and I didn’t want to miss the first race, so I took the stock rods and cut an inch off the small end and welded a new small end on and put them in the engine….and raced them for 2 seasons.

That engine would live all season if I shifted at 8000, but at 9000 the rings and other stuff was spent after 2 race weekends which was maybe 4-6 hours of track time (hp peak was at 8600 so I liked to shift up near 9000). Load is proportional to stroke times rpm squared, so it a 78mm stroke is ok to 8000, then an 86mm stroke is the same loads at 7600, the piston speed is higher, but the loads are the same.

This car will never see a road racetrack while I own it because guardrail hit don’t buff out. It will go to the autocross from time to time. I’m not scared of the stock rods (with good bolts) with an 86mm stroke and 8000 rpm for occasional use, better rods would make me fearless.

The bigger concern I think is if there is a point to reving to 8000. With a stock QV engine there really isn’t any point to it because the hp is dropping after 6800. when you plug the torque curve and gear choices into excel, the 7700 redline is the best place to shift, but just barely, any more in the top gears at least would be a mistake.

I like the concept of building an engine that is safe to 8000 but leaving the “normal” use shift point around 7500. I'll run the biggest bore I can, then pick a stroke based on the air flow I can get through the heads. It will sounds the way it should sound and I don’t have to go through all the trouble and extra work of having to changing the face on the tach to correct the redline

 

The whole stroke issue might get settled easily....one of the 2 guys I asked about stroking the stock crank told me he doesn't recommend it and gave me a contact to have a new crank made, which is obviously not in the budget. In theory I could make a crankshaft myself. I made one for a harley once and it worked, and I've got access to a large enough lathe but I think I've got plenty on my plate already so I don't see that happening. I haven’t heard back from the second place yet.

I got an interesting email from a friend today. Apparently a friend of his is a partner in a small ecu company and offered to design and install an engine control system for me….which is way cool. I had a motec that I got a deal on, but I had optioned for the supercharged V8 so I sold it (to pay for the cool TR heads) thinking I’d get a another one optioned more appropriately for the V12 when the time came, so I’ve got nothing at the moment. Hopefully something good will come of this.

Heres who they are:

http://www.vems-group.org/