V-12 Engine into 308 Build, over on Grassroots

Wow, this really sucks. I thought you were gonna be grinning from ear to ear all summer scootin this thing up and down the road. Two steps forward and at least three back. But you have made it so far, you'll get there. Never seen a more insane project from start to finish.

 

I’ve read through the posts but there seem to be a few mentioned.
Cool project!

 

You should have been selling merch Mark as you went along, could have paid for the whole thing. I'd have bought the T shirt!!

 

No work yesterday (no need to poke the bear) and a late start tonight but I did have time to pull the other head and for the most part all is well. Oil
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So while I epoxied the huge port leaks there are clearly still leaks in most of the ports waiting for me to weld shut. Over the next couple days the plan is get the piston out and see what the rod and bearing look like then I can start making a repair plan.

 

Way back I talked about selling the chips from all the cutting and machining. Now I could auction of shelf of shame items which is about to get some additions......

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It's surprising what people will buy. Over in my shed I have a box of used up top fuel engine parts - pistons, rods, valves, rockers etc. Elsewhere, I have some used up turbine blades from the ill-fated North American Eagle land speed car.

 

My wife got me this t shirt 4 years ago (car is still not done):

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It appears that they were. (Appears to be in adjacent cylinders)

Maybe slightly retard intake cams (or cut deeper reliefs if there's enough to cut).

I would be replacing all of the valves at this point.

 

hmmm....it does look like that in the pic. I'll take a closer look when I get home tonight. I wasn't really thinking along those lines because when I re-did it in 2020 I realized they were too close (aka touching on the OD) and recut the valve pockets then clayed them to be sure...or I clayed then recut, I'm not exactly recalling if I did the final check or just trusted the numbers. But now I 'm wondering if I had that intake cam buggered even thought I know I looked at it several times? This bank was acting different to the other and a cam issue was my 1st thought but convinced myself it was just sync and the injector choices. I'll take a closer look tonight and maybe make plans to re clay them.

 

Looks like the relief is the right size and location, just interference. (flat to flat not radial)

I don't recall if you had any compressed head gasket thickness difference from current to previous.

 

Yeah. I don't see it in the pics of the other bank...maybe 1 valve in #9, maybe not but bank 2 looks different from bank 1. I may have other pics form the head gasket swapping to look at to see if this is new.

All the head gasket I've used are supposed to be 0.050" compressed.

 

Found it, I did do a final clay test....so mis-timed cam is looking increasing like the answer
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and a pic from 2022, other problems but no visible valve strikes, at least not that I see.
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No, it's both banks.....I'm so confused how I management to clay good when they are not good. But at least now there's an answer for the broken valve.

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The other possible explanation is overrev/loft/bounce, even with a rev limiter. One of the reasons I like to set the valve springs up close to coil bind at max lift. (how close you can get varies on the components of course).

Also why I had titanium retainers made for my F355 (lower weight, less chance of losing control)

 

Valves springs near coil bind - check.
Ti retainers - check
5mm stems - check
shim under bucket - check

They are hayabusa bits and weight about 1/2 the oem TR bits so they should be good for over 12k, . Plus it really hadn't be rev'd very high this go around, 5-6k tops because I just hadn't gotten that far.

Maybe I was sloppy timing the cams when I did the clay? Dynomation says 2 degrees only changes the clearance .010" so I would have had to be way off....don't know but I guess I'll re-check it and see what I get now once I get to a point where I can.

 

Ya know.....zooming in.....yeah, I can see a couple marks there. Its been like this the whole time

 

I wonder if you're dealing with thermal effects. Is the clearance also accounting for thermal stack growth? On the 4L build when I went to the tiny stem valves I also went with a cuprate seat, to help with thermal loads and getting the heat outta the valves ASAP. One of the reasons Ferrari went beryllium on the 355, though they still are prone to burned valves.. But for other reasons.

I'm neurotic with all those clearances so I built an entire 3D model of the engines, heads and valve train with the cam profile data and just run a virtual check. It also lets me check valve to valve clearance that dynomation doesn't have.

If you want to cut your own seats, moldstar 90 is what I'd recommend.

 

Engine off the trans
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and...no spun bearing!
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Its looks a little sad but its pretty cheap.
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What about head gasket thickness causing your clearance issues?

 

Right now I'm just assuming I screwed up the cam timing when I did the clay test because it is hard to do on this engine. New thought is I'll pull the lift numbers from Dynomation in 5 degree steps 20BTDC to 20ATDC, set the crank and measure the clearance. If that doesn't find the problem I can mount the timing cover and cams and check the same range with a feeler gage. If neither method finds the issue I''ll start thinking about heat and stretch and all the fancy stuff.....but the simplest answer is usually right and that is I just screwed up measuring.

On the gasket question, I have used 2 brands, both claim 0.050" compressed thickness.

 

I don't recall, do you have a cam doctor reading on all the lobes? How close in timing is each lobe to each other? The variance should be little enough to really not be a problem that can't be handled with shim clearance, never know I suppose.

Are you using a cam doctor or s96 file for the cam in dynomation? Their point conversion is not accurate enough for lift/° measurements in my opinion as it's not the exact cam grind.

 

Files are from a test lobe I think. I have cam doctor and s96, I use he cam doctor in DM.

The problem is pretty much all cylinders so I don't think this is a tolerance issue....the simple answer is I just screwed up checking it and it that is the case the problem should be obvious when I measure valve travel at various crank positions and its easy to do so that is tonight's project I think. If its not obvious I'll get more serious about the hunt.

 

Damaged piston out, popped out the real springs on #1 put in my testing springs, head on the block.....no they most certainly do not hit so......but clearly they do hit so WFT?
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I'm leaning toward saying I do not understand, but another 40thou should fix it. I need to drink on it a bit....

 

What's clearance at the kiss point?