308 V12 conversion begins

All true.......but, and there is always a but, the optimum flow number math is based on the header being there. All the flow loses you talk about are real and will be there in the realy system and the flow bench mearures them. With the header in place the exhaust shold flow about 70% of what the intake flows then extraction effect when the engine is running makes up the difference to get to 100%. If I flow without the headers then I have to guess a bit at what flow number I'm looking for and make the unlikely assumption the port will flow the same into a short tube as is does into the actual header with it's bends starting basically right at the port. At the end of the day I have to make the hearders anyway so I might as well use them to do the flow work.

 

Finally the cams out gone. Now I guess it's 7 days to CA and god knows how long after that.....

 

Tell me about it......

 

Only 3-4 months? Man I wish I had the pull you must have

I should be able to start cutting the flywheel soon and there will be a lot of cutting. The hunk of steel currently weights about 35 lbs and will be about 7 lb when finished so 80% of it will be chips

 

Speaking of OCD.....

I decided I'd take care of the little mismatch in my rods tonight. It you'll recall I pieced together a set of 12 360 rods from a set of B and a set of C rods to make a B+/C- set that only had 1 rod 0.5g outside ferrari's 4g spec. Easy....or so I thought.

while I had the scale out I decide to weight the rods complete, just the caps, just the rod, and also the big end of the rod. The reason is all those numbers matter.....and my matching job got a lot harder in a big hurry.

The caps were out 5 grams, the rod bodies 5.5 grams and the big ends over 10 grams

I worked until the debate and I got the caps all within 2 grams and decided to hold there incase I need the 2 grams to help even out some of the other mess. The pic of the ground on every surface vs not touched shows what was the heaviest next to the lightest and what it took to lose 3 grams.

I guess the next step is get the big ends all close then re-weight the rods and see where the total weights are and what I can do to straighten it out.

None of the mismatch has anything to do with this being combined sets, the heavy/light in each category are randomly distributed between all the rods.

I also noticed that 1 set has oil grooves on the big end and the other set does not…..I missed that before. I guess the real first step is to cut the grooves into all the rods and re-weight them.
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Yes, both sets of rods came from 360 engines. I can only assume the oil grooves were added as part of a continous improvement program. 355 rods do not have them.

 

First....you can't end balance rods without a fixture becasue you get a different weight every time you put it on the scale....so the picture I posted is how NOT to do it

I'll have the fixture ready tomorrow.

The new TB came the other day. It's nice and big, but wold need a lot of modification to work and look decent. I may use it to flow test, but I've got to keep looking for something that'll be a keeper.

 

I'm thinking 50mm is the absolute minimum and somewhere in the 52-54mm range is probably optimum....all based on exactly what distance the TB is from the head and exaclty what size the port opening in the head ends up. With the port what it is right now about 50mm is right, but the port is currently not tapered as much as it should be according to the math. The TB in the picture is 52mm

 

It looks like I forgot to post the pic....I'll get it tonight. Whatever I end up with will be butterfly...simpler and much cheaper.

with a steady taper I need 54mm, but I'm not sure I can open the port that much. Where it is right now I need a 50mm TB.

 

All good questions that I wish I had answers for. I'm pretty sure the grooves go between the rods...but I ned to confirm that. I think you're right that the coating will need to be re-done and I'm pretty sure it can be, but again I need to confirm.

 

TB pic I forgot yesterday
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Tonight I milled the oil grooves into the 7 rods that didn't have them.

Then I went back to balancing. I made a fixture....that was too heavy for my scale leading me to lighten the fixture as much as I could which got it working. It's still a bugger to get the numbers to repeat. I found I could still get number that varied 4-5 grams but if I used the same technique and took an average of 3 readings I was within about 0.3 grams and I think that will do.

The new number have all the rods within 4 grams on the big end as is. Looking closely at the rods, all the rods from the B set show more corrosion in the big end bearing area than I am comfortable with. So, I think the thing to do is to get them re-sized before going any further with the balancing. I should be able to get this done locally.

I also need to find out for sure about re-coating them and what state the rods should be in when it's done. I'd liek to do it after I do the balancing so I know there is no way I could damage it with the sander. More to do.......
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Without the jig you can't be sure what part of the rod will touch the scale so you can't be sure what the test length is. If the test length varies so does the weight as it changes what % is on the scale vs. what % is supported off the scale. The test length must be controled as close as possible or your results will vary reading to reading and certainly will vary rod to rod making the measurement meaningless. If you notice on the jig base there are 3 bolts. They stick out the bottom and are what actually touch the scale and since 3 points define a plane the jig will sit exactly the same way every time and can not vary or rock, it just sits.

The jig must stay on the scale for both the big end and small end measurements. The pin in the jig fits both he big and small end adapter bushings. It's the only way to do it I think and even with the jig it's difficult to get good measurements