V-12 Engine into 308 Build, over on Grassroots

After pushing the last couple days, today I was slow. I figured I should confirm the shaft is sitting right and since its hollow it was as easy as measuring the drop then removing the housing and resetting the drop...perfect
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I forgot to cut the locking detents in the shaft so I took care of that.
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then the outer bearing needed a spacer, Its a slip fit over the shaft and light press into the bearing
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Then it's more obvious where the nut goes once the thread is cut
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Then fixed the idles bearing a quick test fit...working gears.
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I did check the outer bearing and cover quickly and discovered the existing bearing pocket is just a touch too deep. tomorrow project.
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I'm not very good at getting square corners to weld in fully so I ground it away a bit then welded
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Then on to the mill to fit the bearing.
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Clean it up a little
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and it fits. the new bearings need a bit of preload, I used .004" figuring the case will flex a touch
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All that remains is add a little cover to the cover to make room for the added length needed for the nut , then I can clean up and tear into fixing the engine.
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The little over took longer than I hoped....I didn't have much useful stock
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Eyeball a radius cuz I can't find a cutter
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Weld
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then I always spend more time giving it the "obviously its original" treatment but its done and time to clean the shop for engine work.
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See, easy fit, just like factory new.

 

I need some manifolds for my 308 FrankenFerrari project - do you mind if I move in with you for a few weeks? I don't eat much.

 

What are you building? I thing I still have a 308 manifold jig kicking around.

 

QV block and heads, 360 crank and rods, slipper pistons, bigger bores, yet to decide on cams and ITBs, but will need some sort of manifold so that it all fits under the hood with a carby type airbox and cleaner.

 

Hyabusa TBs will get you to around 400hp, maybe a bit more. and no reason it needs to sit taller than OEM.. easy Peay. Reach out if need help

 

The QV I did and you ported the stock heads, runners and plenum made 375HP on the dyno. The 3.4's work great and the best bang for the buck.

 

That intake kicked my butt. I remember I promised 15% more air knowing I could get 25% out of the heads then fining out the intake was already about as good as it could be. I left it so thin you put a wrench though it trying to install it. . A custom intake would have made the job so much easier. Remind me, what rpm did that peak at? I think a 3.0 with the same parts would have peaked at nearly the same hp just 15% higher rpm and 155 lower torque.....its the increased torque that makes the larger displacement a good investment imho.....there is no replacement for displacement.

Fast forward 10 years and I don't see anyone talking about porting anymore. air=hp but every built thread I read is about bolt-on stuff which limits hp to around 300-325.

I flow at 10inwater
stock=92/93=300ish hp with everything right
your 3.4=110 = about 375
mine is 156 = 850 as a V12 or 570 as a V8, assuming rational redline rpm (yes Scott, I'm talking to you )

My how times have changed.

 

I think 400bhp is about the sweet spot with this chassis - I'm not sure it could handle much more. My mechanic said the QV head flows quite well standard, but I think some minor port cleaning up was done, and 1mm bigger valves. I'm looking at the Formula GT manifolds, but I may yet be on the next plane over...

 

HP is in the heads. My favorite quote comes from when I was young and explaining what I was building to a guy I later learned was a race engine building God and his response was "I don't care if you're Jesus Christ himself, without air you aren't going to make HP". He was not wrong.

As i said the stock head flows about 92/93 @ 10"h2o. and the exhaust flows about 90-92% of the intake which is too high. This is why you see cams with about 10 degrees more intake duration then exhaust to try to balance it out better. its been a while so I may have a my numbers off a little, but 31.25 intake valves are about optimum flow v velocity wise and can be installed on stock seats but 32mm will fit in the head. 348 valve are 30mm(?) and work ok too, 30-31mm valves on stock seats the head will come up to 110-120. New seats and 31-32mm valves 120-140 (140 is what I measured a 360 head at)

The stock intake though was designed to work at 92/93 and immediately becomes the main restriction as soon as your touch the head. On the setup I did for Paul I'm remembering the heads came right up to 115 and I was pretty happy until I bolted on the intake and spent the next 2 or 3 weeks getting the assembly to 106 or 108. As a reference on my engine with 34mm valves the head flows about 157/158 and the full assembly with intakes, TBs, Stacks flows 156, about 1/2% loss which is what you want to see with properly matched components.....well 0% loss is what you want to see but this was the best I could do with TBs I could get reasonably cheap on ebay.

The what is the sweet stop for a 308 comes up often and honestly I think its more about driving style and comfort then the car. The first blower engine I built made 301rwhp, so maybe 350-360 crank and while it was WAY better to drive than stock I personally found it lacking. The next made 420rwhp, so maybe 500 crank and made 1st gear worthless but the over-all driving and autocrossing experience was quite good. I remember another 308 owner who was considering a turbo for his car came up for a ride and the description was "this car doesn't accelerate, it launches". In the little driving I've done with the new 800(?)hp engine, its not much different from the last because the torque output isn't much different and all the extra hp is a product of extra rpm. It feels different, the new motor mounts left a bit more vibration into the experience, the noise with the hood off and pretty loud muffler makes it seem like its reving higher than it is but it drives quite nice assuming I'm not pushing the throttle more than I should be like in the burnout video...play stupid games, win stupid prizes - max throttle was 47.9%, MAP climbed all the way to 68.2kPa so not even close to but should be right around 350ft-lbs which is too much for 1st gear but quite nice in second as seen in the send much more controlled burnout.

I think the real difference in these setups is what % of time the car spends at full throttle. the 350hp (280fl-lbs?) engine spent quite a lot of time at WOT, I'd says it was rare for me to take it anywhere and not open the throttle at least once and autocrossing I found myself wondering why it wouldn't go already. The 500hp engine, but more importantly 400ft-lbs torque engine was different (its torque at the wheel that makes them spin not hp). I'd says it was rare for me to fully open the throttle on the street and only in certain places at the autocross. Now, had I gone to a road course and played in 3rd-5th instead of 2nd at the autocross the answer would be different and it would want full throttle a lot more of the time. So for me personally the sweet spot is more about the torque and around 350-400 ft-lbs torque and a well done naturally aspirated 4V will make about 100ft-lbs per liter, so 3.4-4liter or a 3.0 with some boost? I don't think more is a problem of any kind but it just doesn't get fully used most of the time.

But the idea that the chassis has a hp limit I just don't really get. Front engine rear drive cars twist. I helped a buddy put a 460ci engine and big tires in/on a fox body mustang and within 2 months the rear window was leaking so we had to add subframe connectors and a few other things to make it marginally ok....that chassis could not handle the power. Mid- engine cars don't have any such issues though and the classic answer to when do you have enough is when there are black stripes from the exit of one turn to the braking point at the next you have enough....that however means you don't get to mash the throttle to the floor any time to please without hurting yourself

Time to go fix and engine.

 

Thanks Mark. Interesting stuff.

 

tear down day. every time I look at these end plates Brian G made for me I smile, they just look like they belong
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I'm clearly not professional mechanic material ...I cut 2 orings installing the cam covers
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When I originally set it up I made the studs in the top of the timing cover removable thinking they could go on last,

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but then I need to compress the oring while installing the cover so I switched to installing the cam cover last. This time I will remove the razor sharp edge on the inside corner and maybe replace it with a radius...I am curious where the missing piece might have gotten though.
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The buckets and cams still look very good, that's a plus
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Slight bend exhaust valves in #12, so the no compression is an easy fix
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Found the missing piece of oring, yay
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Now the important item the liners are basically flush with the deck. I don't know is something moved or I had a corner touching a radius or some such when I originally measured everything but they are flush now so I think I make the copper flame ring and aluminum head shim the same thickness and see what happens.
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Looking at the pistons there was clearly still some leaking happening, hopefully viton orings work some magic.
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The pistons cleaned up nice with a little lacquer thinner and the bores look great, yay again
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Have you talked with Bill at cometic? Ultimately we ended up using MLS with my supplied embossment pattern and that solved so many leak issues. Well that and liberal aviation sealant. The embossment provides that o ring like squish to keep things sealed. Ferrari uses the deck as a coolant plate, makes keeping everything contained an adventure.

 

Not that I recall but cometic was making the composite gaskets for me. MLS requires tooling does it not?

 

Yeah it does but it's not terrible.

Just a suggestion Mark, but I think a little test stand for this motor while it's in the experiment phase would be amazing. Maybe even one that is the correct height to hook it up to a dyno too

 

Yeah...and I have a dyno (just missing the water pump) and everything to connect this engine to it sitting in the garage. It could be wonderful

The problem I have is there is no actual $$ cost to install/remove the engine from the car but there is a cost to built, equip, wire an engine test stand/dyno. Every penny I spend out in the shop for any reason is assigned to the car budget, which by default is set to $0 very year making every purchase a new request for emergency funding (its an emergency if I want it now and not some undefined time in the future like the heatpump that is supposed to be heating and cooling the shop and was in the original build spec and I'm told is still on the purchase list and we'll get it soon, and that has been the case since 2018).....and that makes just doing the labor to remove and reinstall the engine in the car by far the less painful option.

 

OK, shims and flame rings ordered...hopefully this gets it sealed. Delivery is Feb 2 so time to get the valves sorted and everyhting cleaned up in the mean time.

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On second thought there is a fine line between tweaked and dangerously bent so I think I'm not going to take any chances and just go to go ahead and replace these valves....
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It is not my night....my valves are discontinued. I found something I think is very similar from a better company (ferrea instead of kibble white) but in 29mm instead of the 28.5 and $47 each+$20 shipping . More money and I have so I will need to cut them down but I think they'll work

 

If you haven't purchased yet, try supertech, Martin or Willy. They stock piles of valves in loads of sizes/materials and coatings. West Coast though, Bay area.

 

Or Manley

 

No at supertech, close but no at martin, couldn't find Willy

no at manley

I have motorcycles valves so most car places can't help. I could go up to 5.5mm stems which are honda car but then the retainers are more a custom problem.

Ferrea would make them so if I was doing the whole engine that would be an option but buzzing 1/2 mm off the OD is seconds of work, worst case I also need to have the seats reground. The funny thing is 29mm is what I wanted in the the first place but the KW 28.5 were 1/2 the price and off the shelf so that is what I used. I have KW buckets too, which are also discontinued.

 

The valves came today so cop saw, mill, lap, cut the keeper groove and cut the OD down
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Then I was feeling a little wood chucky and ground the seats on the lathe
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but they came out just fine
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