V-12 Engine into 308 Build, over on Grassroots

I follow this thread every day. Excited to see what is next. This is not what I like to see. So sorry to see the problems. However however whatever you take to keep such a positive attitude... please share!!!! I'd be balled up in a corner. I'm impressed with the skill, knowledge and tenacity you have in doing this build. Its the kind of stuff I'd love to do, but I know I don't have the knowledge, skill, or temperament to even contemplate. All the best going forward.

 

The valves and all the valve train are Kibble White and mostly all NLA. Ferrea has similar valves so likely that is what I'll use.

The why does a head fall off at 1500ish rpm? Did the screwy timing damage the plug and the ceramic fell off and help the valve open? I had just cleaned them so maybe? Or something else got in there? I don't know.....but now I can weld the port and return oil leaks.

 

+1

 

Well that sucks (NLA)..
KW is good stuff, so that's wild.
I like superformance, since they specialize in Euro vehicles they've got an extensive catalog of "little" valves. Many a custom used a longer then needed stem and we just had the machine shop cut to length and add new keeper grooves. You could give them a shout, talk to Willy.
Teardown will be more informative... Man that's a bummer.

 

Yeah, these were blanks that I cut to grooved. KW used to have an amazing selection for custom builds but it looks like they've dropped it all. Ferrea has a close replacement, a bit pricier but the right sizes, very similar profiles so should be fine. I used their exhaust valves when I damaged a couple on assembly last year (?).

Why though........as you say, maybe I'll see something on the tear-down.

 

Oh, as weird as it sounds when I started grilling the mfg on the rpm ranges our engines were going to spin to, they couldn't guarantee that the valves would survive long term. Odd i thought, but then again running the numbers for the forces involved it gets interesting above 8k, esp when going for 11k+ . Superformance though has a decent selection of race valves for motorcycle that will see those speeds so that's why I went in that direction. Valve stem was smaller but that's not a deal breaker for all the custom work on those builds.
Valve train harmonics with spring rates, spring design, ramp rate etc.. I built many a spread sheet to track all that. It's what drove the 11k+ valve train to a custom beehive spring and lots of Ti.

I gotta say, winding that engine out on the Dyno to 10k was beyond pucker factor 11.. God what a stressful week that testing was!

 

Supertech... No idea what it kept getting auto corrected to superformance...

 

Well here's a set forward, I have a piston. I don't recall exactly why I have it, the skirts scuffed a but so it probably measure undersize so I replaced it before I realized the3 bores were going to be oversize and I needed to coat the pistons and this one will certainly coat to fit just fine.
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So bloody close..

 

They all said I was daft to try this!

 

I started pulling the engine and if I'm being honest describing the effort as 1/2 hearted would be an exaggeration. But I drained the coolant, decided to flush it so on reassembly its antifreeze free and ready for head gasket sealer...then I realized I need to get the water out of the block and fought 1 of the drain plugs out. It will be out Friday or Saturday I guess and hopefully head off Sunday.

About that time amazon brought me the MAP sensor I wanted to see...its small and nice. In theory I could probably put 1 on each port but they would block my access to the manifold bolts. I'll look at that a bit more when the engine is on the bench but right now I'm thinking use a short hose and hide them under the air box when all the hoses are now.
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The aluminum tube i ordered for the bumper mount came...but I didn't order what I thought I ordered exactly. This is 3mm wall, I thought it was 1.5mm. Also the grommets I bought give a smaller ID than I was thinking o a different tubing might be better. I would have liked to wrap this up so before pulling e3verything apart but I don't want to wait for more bits so I'll pack it up for now.

 

Could you remote mount the MAP sensors then run a vacuum line to each one? This way you would just have a little vacuum line running to each one and you could still get to the bolts.

I bet it’s less than half hearted, I would feel the same. My uncle use to say “it will feel good when it quits hurting”

 

Yes, that is kind of what I was on about with the pic of the sensor over the fuel rail....like a 4 or 5 in hose to move the sensor over the fuel rail but still hidden under the airbox. Right now I use pretty long hoses and have the sensor board over the fuel tank and that is ok, the hoses are kind of mess is all. I was looking at switching to a smaller OD hose while its apart to neaten it up a bit, then got thinking about these newer style MAP sensors and just ding away with the multiMAP board.

I like having all 12 readings but 4 is probably enough to have a good MAP reading so that is an option too and if I lock up the TBs then bank to bank is all I'd ever care about....or I can play a bit more with the meter I built, it seemed to kind of work but I think it was leaking. I was reading just under 1kPa and I thought it should be a bit higher. I build it sit into the taper on the stancks, but they really aren't sealed in anyway to the TBs so I probably use an o-ring that seals to the TB.

 

Today there was still water on the floor from draining the block yesterday....I squeegeed it and moved on the picking up because I have bits of all sorts of things everywhere let form the get it done push plus it was honestly a mess before and that has to do with me being easily distracted from work I don't enjoy...oh look at all these spark plugs is various stages of fouled.
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The NGK set I've been using was looking pretty worn out so they went in the trash but I have another NGK set (or 11 = 1 smashed from the last failure) that look pretty new so I ordered a 12th and cleaned the 11. I also have 2 full sets of autolites, fouled. In the V8 blower engine I really like autolites which is probably why I bought these for the V12. They look hotter than the NGKs and I'm not sure how I feel about that which is likely why they are sitting, I honestly don't recall.
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I did drain the oil before coming in. Then Standing there waiting I took a closer look at the muffler....man I did a poor job building that, its off a full inch right to left so one more thing on the list.
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I spent some time avoiding the ferrari...I figured I should let it sit a bit and think about the way its been behaving so I helped my son with the oil change on his bike and hopefully we got a small oil leak sorted. Then more picking up and finding places for stuff that has really not had a home since I finished the basement and drug it all to the shop.....Whoa! I have a full new box of plug wires!
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The project has been going on so long that I no longer have any idea why I have the wires but the wires have been on/off so many times they are starting to fail and thinking I was out and they are NLA I'm pretty sure so yay!

With that score in hand I got after getting it ready to plug and made decent progress...should be out tomorrow.

 

Its out, now it see what's wrong

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well....
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Tis but a scratch!

 

Holy s*&%!

 

Yeah.. definitely less than ideal.

 

I wonder how you will feel about your car when you are done. Will you cherish it or be sick of looking at it.

It is an awesome amount of work your doing... daunting even.

 

Looks like the head just snapped off the valve. I think I see the residual end of the valve stem still in place. Piston can be replaced easily enough. Any damage to the bore? Head looks like it might be beyond saving, or at least require a good deal of welding and machining. Best of luck moving forward.

 

I have have had that same question spinning in my head for a number of years now. I suspect that once3 its running good I'll be afraid to drive it......

the bore looks ok with a quick glance, we'll see once the piston is out. The heads are irreplaceable so repair is the only way. My guess is its about 10 hours of work to get the chamber sorted and I'll probably have another 20 sorting the intake port oil leaks. Head gaskets take months to get and I'm not sure what tariffs do to the cost. Running in October is probably best case though.

 

The question is why that intake valve failed. I definitely would like to see the end of the valve stem. Just an observation......that one exhaust valve looks lean compared to the other cylinders although I don't believe that caused it to fail.

How the head of the valve came off will come down to whether it was making contact with the piston or a manufacturing defect with the valve.

I had a similar experience decades ago.....a valve guide got some debris in and caused an intake valve to stick open until the piston came up and hit it closed. Several cycles of that and the head came off the valve at 8,000 rpm and destroyed the head and the cylinder. It was only when we pulled the valve stem out we found the stem scored.

It is heartbreaking to watch you pull that engine again. It seemed so close to settling in.

 

Right, About the time this thread begins I was recutting the valve pockets because I could see evidence of contact. I said I inspected the valves and they were all within .004 TIR but 1 needed a light smack and I had a buddy regrind them.....what do you want to bet I just found the one I smacked? But I can't be sure so now I need to think about replacing them all.

 

Sorry to see the damage. That does suck!