V-12 Engine into 308 Build, over on Grassroots

Which aviation sealant do you prefer? I experienced same with boosted engines, and the only good fix for those old stupid Maserati biturbo engines has been Loctite 515

 

I think it carries a new number... MR 5923.. used to be a 30517

515,518 etc I use for different applications as those harden. The other does not. Excellent for gasket dressing and oil leak prone mating surfaces that use a gasket. 5* series is best for flanged surfaces that don't move.

 

The whole gasket or just around the bores? I've been using a little around the stud hole but no where else

 

The whole enchilada!

Here's a story....
In the development phase one of the blocks was nothing but trouble, thankfully it was a 2V so the nuts were easy to access. After yet another failed pressure test I sprayed the gasket -both sides- with the old school copper stuff, once together let it sit over night, then took it all apart again. I was looking for the pressure transfer witness, something I noticed the spray would do.

What I found was that even with new studs the block moved too much. Stock liner setup, new o rings etc. Uniformity was just not there. At that point we updated the embossing again and to be doubly sure on the boosted engine.. Coated the gasket both sides with 30517. After that... No leaks, holds pressure. It's messy if you're not overly cautious, tacky sticky etc... Does clean up with alcohol or solvent. Stays flexible indefinitely and good to 400*F.

 

Any coolant in your oil yet? Have you checked which cylinder(s) it is? Pulling the plug wires one by one might show a slight drop in smoke otherwise look at the plugs. Perhaps back off the head nuts half a turn in sequence and then retorque a couple of pounds extra (and add the stop-leak as suggested.) A few heating-cooling cycles may allow the stop-leak to reach the leak.

 

sounds like it should be used to seal the block to gearbox mating joints as well then.

 

What they now sell as aviation sealant was call formagasket and has been around a LONG time...their was the liquid the a paste and I think a hardening version iirc, I remember seeing it 50 years ago on my fathers too tall for us to reach shelf and I suspect it goes back to the 40s or 50s. I think the only reason they still make it is its the approve case sealant for old aircraft engines? I keep buying it and using it of stuff and can't figure out if that's because its really good or because that's what I always use for that job kind of think. My XR1000 H-D race bike had no head gasket but about 1/2 the time I'd decide it need the black goo so I know for sure it doesn't burn out even on a hot air cooled engine so if R&R the heads and treat them to aviation sealant is step 2

Step 1 is K-Seal as its the only product on the evans list that says it seals head gaskets. The reviews are about 2:3 so in an hour when I don't feel bad making noise in it goes.....then I expect Sunday I'll start pulling the engine to replace the gaskets but today it mechanic in a bottle day.

As for offending cylinder, its really more which is the most offending...6, then 3, then 7, then 12. I'd heard the end cylinders are the worst because the forces are unbalanced as the bolts clamp on 1 side not both....this result would agree with that. 6 is pretty bad and didn't always start once I ran out of ether which I guess is why I thought it was getting better and might be just the buggered mixtures. 3 concerns my a little as it could be something else...but maybe not

here they are, all rich running around 0.9 lambda but at least starting to look similar, they were literally black and white a couple days ago...stupid ITBs

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The k-seal christmas miracle

 

that is idling at about 1500 full hot btw. The throttles are effectively fully closed and that got me to about 2200? so I pulled out some timing, its at 13 degrees now. Once I get a bit more confident I'll pull out a bit more timing and try to get it to 1000 or so...but honestly just having it idle at all has me thrilled.

 

Sweet! Awesome... Love it when mechanic in a bottle works!

Formagasket is forever old.. It works. Like the other shellac one, Indian head.

 

You can and I have when I've been out of the 5 series anaerobic sealant. It's just messier and weeps a bit, till set. But it'll seal like it was welded together.

 

It'll be very interesting to see how stable and low you can get it to idle on those cams. I'm guessing 1200 will be probably the smoothest and below that it'll sound lumpy hunting about. Then again you've got 12 cylinders of firing...

 

Compketely missed this. It runs!!!


Cobgratulation mike

 

sadly I think i was over optimistic and the Christmas miracle was ether. When I have clean plugs and start with ether all the cylinders run...and burn the waterless coolant and I see a little blue smoke. when the cylinders cut out the coolant vaporizes in the hot pipe and I see a cloud of white smoke. I tried some more of the one they say is stronger just now and will do a couple more heat cycles tomorrow....then I assume monday I'll order new gaskets and start pulling the motor. 2-3 weeks.

I did drive it around the block. The new steering felt good the new final drive ratio felt odd...1st gear and reverse are quite fast, the engine was running awful, very very lean..please make it home, please make it home....but I drove it for the first time in 15 years and the 1 car I past the guy had his thumb up and head out the window looking at it

 

Glad you got to drive it around the block. Sucks that it's a back out job again.

 

No fire. No bent valves. Back home. Win.

Re thumbs up: 308s are much beloved. Welcome back.

 

Yes, it made it home so it counts as a drive in my book

I mentioned in the other post I did remember to play with the new faster power steering a bit...I like it. Again, pulling out and heading up the road I really didn't notice it which means it felt close enough to a modern car as that is all I've driven....a lot like the BMW really once I started to pay attention, still higher than average effort but not objectionable and not so quick it was twitchy, at least not at 20-30 mph. I like it. My street is a horseshoe with 2 connections to a larger road, at the stop sign the steering did catch me off guard a bit as I rolled to a stop while starting the turn and looking up the main road not really thinking about anything other than looking for cars until I felt the steering wheel refuse to turn....right, its now quick steering and it had hit the limit, don't need that much for this turn so that will take a little getting used to.

I mentioned the speed in 1st and reverse. To remind everyone I swapped the clutch and trans gears in the drop gear case so I'm happy that it drove at all really The idea here was that with the last blower motor making 400-450 ft-ft torque 1st gear was pretty useless, the tire would just spin so for quick launches I used 2nd gear. This new engine should have similar to higher torque so I swapped the drop gears putting 1st about 1/2 way between the old 1st and 2nd, but also make revers much faster. The engine was running pretty bad so while it was a bit awkward to get the car rolling it seemed to be the engine not running so I'll hold further comment.

I set the ride height 4" frame to floor. In and out of the driveway were smooth (there is an angle and bump at the road). I had done an up/down and before heading out and knew nothing hit or rubbed so I swung into the driveway at 15-20mph to feel the bump to try to get a sense of the new springs...almost unnoticeable. I'll call that a good sign but again hold further comment.

The new larger (F430) but manual brakes were good enough that that I didn't notice them. I was home and car in the garage before I remembered I was supposed to be paying attention so I'm going to call the fact that I didn't even notice they are now manual proof that they are just fine this way.

I'm not so sure the Evans coolant will be staying. I know I'm having head gasket problems so there is probably air in the cooling system but right now the engine is getting pretty hot. I currently have a 180F t-stat but replacing it really wouldn't change anything as it doesn't look like the the radiator and fan can get the coolant temp much below about 100C sitting at idle, admittedly high idle, but idle and the drive (bottom graph wasn't better. Also note the oil pressure falling as coolant temp rises as you'd expect with straight wt oil....but it ends under 10psi, oil temp gauge touching 200F and that is from the tank so hotter in the engine hence the low pressure. We'll see.

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Are you sure the gaps of your spark plugs are correct ? It looks a bit to big gap for me...

 

They are biggish at .040" in the pics. Since I'm struggling to keep the gap clean I decided to open them up a bit, at least for now. A quick google of the factory spec for the engine the coils came off said .044-.060" depending on the plug type so I figured .040" was plenty safe for low power testing and I'll worry about the risk of high power misfire when it happens rather than struggle today with a gap setting designed to solve a problem I'm not having.

 

I do and don't like Evans. It's an absolute must on the Siamese liners, hot spots that would flash boil water/coolant. If there's a head gasket leak it won't make the milkshake and will burn so there's some saving grace. It also runs at zero pressure so that's a bonus. And it doesn't contribute to galvanic corrosion, best reason for it.

When it burns though, it's a lean burn and that'll spike temps real fast. It'll also foul the O2 sensors... Yeah more fun.

Oh... What type of gasket are you using? Found out during testing that the composite gasket from one company.... Disolved the material. Yikes! So for the 89mm bores it's MLS only. I'm not saying that it'll do that with all composite material, just something to look for when you get to teardown and inspection. R&D can be a real hair pulling experience sometimes.

You got to drive and collect data... Progress!

 

If I leave the Evans in, it will likely need a bigger radiator, and the one I have is already much bigger and much more aluminum than stock.

The head gasket are cometic and are custom

I think after 3 heat cycles with no obvious improvement from the k-seal I am going to let it cool a bit and see if I can remove the cam cover....I don't think I can without removing the intake....but I want to pull the cam covers and make sure the head bolts are tight. If they are the engine come out, if the turn I'll give it 1 more chance.

 

Did you go with MLS or composite?

You might not need a bigger radiator, once you get it to stop leaking it's very possible that the volume is good.

Here's to hoping you can get to the studs and all they need is a re-tq..

 

It looks like it will come off....try later, I was redirected to a floor.

Cometic composite head gasket.

The system currently holds 6 gallons, the radiator itself I'm not sure but it worked flawlessly with the supercharged 8.

 

oh, and even running badly, clutch up aggressively at around 2500 rpm and it will take the tires loose so its got some torque.

 

Then it should be fine with the 12 NA, I'd have to grab my worksheet but the btu of a compressed 8 is going to be high.