Intro and Update: Slugmobile and Mean Mini! (long read, but worth it)

[wheming]

MeanMini update!
i recieved a call from Brian today with an update. The good news is, it was able to be confirmed our theory the combustion gas was the cause of trhe coolant push. he was able to get a positive read with a block tester using a slightly differnt method than before.
this was further confirmed when the head was removed and there was some indication on the head and block. he said it appears 2 of the 4 cylinders were doing this, and it was in the rear of the block, not the front. there were a few headstuds along the back that were not quite at 95 ft-lbs, although they only moved enough to tell. (I found the same the 2 times I checked my torque). so not sure why that was, unless my torque wrench was off, but the others were good.

So the path forward at this point is to clean/refinish the head & block surface and install a fresh new Cometic.
Brian did mention upon initial ispection of the combustion chambers , cylinders, pistons, that everyting appears to be in good shape. - so that eases my mind!

Got the new headgasket ordered through TU today, so Brian might get it by the end of the week!

While the head is off, I've asked Brian to give me a port on the compressor outlet for a boost source. I hope a source there can help reduce my boost spike with the EBC.

She's coming along! Thanks to Brian & Mike at Auto-Time. :thumbup:

[wheming]

Here's some pics of the head after removal...

[vntned]

Love what you're doing with these!!!

You should bring one of them to the Mopar show at Piedmont Dragway this weekend, Aug 26. Probably only an hour drive from you. And it'd be great to see some old school TDs sticking it to some late models!

[wheming]

Love what you're doing with these!!!

You should bring one of them to the Mopar show at Piedmont Dragway this weekend, Aug 26. Probably only an hour drive from you. And it'd be great to see some old school TDs sticking it to some late models!

Not sure what the weekend plans will be. I only have Slug here right now, but I wouldn't call her show ready.
I towed the van all the way up to Piedmont Dragway to race the van onlyto find out the track is 1/8 mile! So, i just turned around.

Who all is going?

[vntned]

I know a lot of the local mopar guys going. But non of us will have our TDs there. They all are in various states of disrepair.

[wheming]

MeanMini update:
The short story is the block was found to be a bit low in the areas that had the blowby on high boost. If anyone is in the steam plant industry or similar, you know when a steam valve or flange develops a leak it eventually gets "cut" from that flow. Same thing here. The areas on the block were found low by 0.002".
The head has already been resurfaced and now the block needs disassembled and decked.
Plan is to go back with a new Cometic, but not sure which thickness. That decision will be made upon final measurements of where we are at with block height and chamber volume.

I hope to have it back for Cecil, but with the workload Brian has at the shop, we will just have to see.

[Vigo]

Talk about a smoking gun. Those pics are clear as day! What's ironic is that i just put an engine back together (not a TM) after checking the decks and finding they were within the spec.. of .004.

[wheming]

Talk about a smoking gun. Those pics are clear as day! What's ironic is that i just put an engine back together (not a TM) after checking the decks and finding they were within the spec.. of .004.

We did of course have the option to go back with a composite gasket, a MP gasket or Permatorque, which should have sealed. But, we both wanted to know everything was right, and not addressing the low spots would always make that a weak spot with a composite. And, there's no way to know how long that would be ok and up to what boost.

Since this gasket has been doing this for a while, even my current record at 25psi it was passing gas to the coolant. I'm thinking she should be able to make a new best at the same 25psi after all is fixed.

[Vigo]

Yeah, it seems .004 is a limit for sealing a composite gasket on a stock (i.e. probably non turbo and definitely not 3x stock boost if turbo) application. Flatter is always better and in your case it's definitely worth the effort to knock out as many 'known' imperfections as possible in search of good head seal even if it would fly just fine on a stock engine. I'm just glad your mystery is solved.

[wheming]

Agreed!
Hopefully we are on the road to recovery!
There's still other issues he is working to correct too. The fuel tank mods hopefully will resolve the losing prime on hard launches.

[Vigo]

Cant remember if i mentioned it but i did finally experience what i think was the same thing launching my 2.4 van with ~5gal gas in it.

[wheming]

Cant remember if i mentioned it but i did finally experience what i think was the same thing launching my 2.4 van with ~5gal gas in it.

Do you know if your tank has a baffle?

[lightbulb010]

Sorry if I should already know this, but was this originally a TBI van?EDIT:just reread the thread. Nevermind. Mine(87' V6 should be the same tank as turbo vans) has a plastic baffle and I've never experienced anything like that. I probably never made as much power as you but I had an m62 on the 3.0l at one time running 90psi+ fuel pressure under boost with a RRR.

It's been awhile since I was in there but from what I recall there is a clip that holds the return line in the baffle to fill it as well as small holes drilled near the base to allow fuel to slosh in. The baffle is kind of bedpan shaped and comes up about 3-4" short of the top of the tank.

I've have run the tank all the way down when I had no gas money and had to rock the van back and forth to get fuel in the baffle for it to start. It would then make it to the gas station a few blocks away as long as it was moving the whole time. Drive in a straight line too far and it would sputter until I swerved back and forth lol.

[Vigo]

Do you know if your tank has a baffle?

I've never had the pump out of this one. I'll let you know if i ever find out!

[Ondonti]

We did of course have the option to go back with a composite gasket, a MP gasket or Permatorque, which should have sealed. But, we both wanted to know everything was right, and not addressing the low spots would always make that a weak spot with a composite. And, there's no way to know how long that would be ok and up to what boost.

Since this gasket has been doing this for a while, even my current record at 25psi it was passing gas to the coolant. I'm thinking she should be able to make a new best at the same 25psi after all is fixed.

I don't know if I would ever run a cometic head gasket again. The moment that thing pushes again, and it will push again, you run into the same problem. Maybe if you use a copper O ring set up.
Might be time to dial down the timing at 25psi and see if it runs the same mph.

For reference, I had an interesting copper wire added to mls. Blew out 2 sections with too much timing on the dyno, exited all the coolant from the system onto the roller before motor hit redline. Caught on video. Could not tell from dyno sheet. I have made passes after not knowing i pushed some coolant . I want an alarm/shutdown when sensing excess pressure or low pressure flow in the overflow line during boost.

[wheming]

I don't know if I would ever run a cometic head gasket again. The moment that thing pushes again, and it will push again, you run into the same problem. Maybe if you use a copper O ring set up.
Might be time to dial down the timing at 25psi and see if it runs the same mph.

For reference, I had an interesting copper wire added to mls. Blew out 2 sections with too much timing on the dyno, exited all the coolant from the system onto the roller before motor hit redline. Caught on video. Could not tell from dyno sheet. I have made passes after not knowing i pushed some coolant . I want an alarm/shutdown when sensing excess pressure or low pressure flow in the overflow line during boost.

I don't think i am running excessive timing at 25psi as far as what is indicated in logs. But what could be is higher in the boost range during initial boost spikes.
I still have a coolant pressure mechanical gauge on the t-stat housing. So you can see the pressure spikes during higher boost levels. You could add a flow switch in the overflow line from the radiator also. An electronic pressure gauge on the coolant side could be logged by sending an analog output to the new mpscilink device, and could then be trended during a run.

On track runs in the past where i did not top my coolant back off, i did see some occasional (more often than normal runs) timing retards across cylinders. Thankfully, nothing catastrophic before I honed in on this coolant push happening regularly at higher boosts.

The Cometic gasket on Brian's Shadow sees much higher cylinder pressures than Mini's. So the theory is for whatever reason there wasn't a good seal. Hopefully the re-decked/trued block and head surface, coupled with a heat cycled retorque/check on the headstuds will prevent the occurance again. I think a headstud torque check before its first higher boost pull should be preventatively performed.

[cordes]

I don't think i am running excessive timing at 25psi as far as what is indicated in logs. But what could be is higher in the boost range during initial boost spikes.
I still have a coolant pressure mechanical gauge on the t-stat housing. So you can see the pressure spikes during higher boost levels. You could add a flow switch in the overflow line from the radiator also. An electronic pressure gauge on the coolant side could be logged by sending an analog output to the new mpscilink device, and could then be trended during a run.

On track runs in the past where i did not top my coolant back off, i did see some occasional (more often than normal runs) timing retards across cylinders. Thankfully, nothing catastrophic before I honed in on this coolant push happening regularly at higher boosts.

The Cometic gasket on Brian's Shadow sees much higher cylinder pressures than Mini's. So the theory is for whatever reason there wasn't a good seal. Hopefully the re-decked/trued block and head surface, coupled with a heat cycled retorque/check on the headstuds will prevent the occurance again. I think a headstud torque check before its first higher boost pull should be preventatively performed.

If I'm not mistaken, that's one of the things Stu Davis wanted on the engines originally, but was shot down for cost reasons.

[Ondonti]

I wanted to try logging or even shutting down spark when sensing bypass during boost but have not figured an easy way to do it. I prefer simple shutdown device. I found information while searching of people logging coolant pressure and tuning their timing based on coolant pressure. They were not necessarily gaining power just by adding timing anyways.

[wheming]

I wanted to try logging or even shutting down spark when sensing bypass during boost but have not figured an easy way to do it. I prefer simple shutdown device. I found information while searching of people logging coolant pressure and tuning their timing based on coolant pressure. They were not necessarily gaining power just by adding timing anyways.

I guess you could use a simple pressure switch somehow to interrupt your spark?
If you want to log coolant pressure, along with MAP, you could use a simple pressure transducer and send the signal to one of the analog inputs on the new mpscilink device. Then it will be logged along with everything else you configure.

I was just using a mechanical gauge, but would have been neat to see a coolant pressure log overlay of MAP vs time.

[wheming]

Been a little while since this was updated.
Basically the short partof the story is, got the van back from SloweSpeed and got to race once with it before the end of 2017, but wasn't able to mske it out again or make a new best.
Longish winter and my luck wasn't starting good in 2018 where any opportunity I had off to tace was weathered out, rain or too cold.
Finally in March made it to the local 1/8 mile hoping to play with retarding cam and work on launch tweaks. But that didn't go so good.
http://www.turbo-mopar.com/forums/sh...ad.php?t=82726
Broke my driver's axle on the launch. First time ever broke an auto axle. But this track is super sticky.
What's worse, the axle won't come out. It is jammed into the diff and havent been able to budge it.
Today with much disgust and much less motivation, I started chipping away at removing the trans.
Got the engine bay free'd up a bit by removing my intercooler piping and the turbo intake pipe.
Got linkage and wires disconnected.
Tried to loosen torque converter bolts and got stopped in my tracks. Maybe I can get an impact socket on then after removing the front motor mount?