Cracked a cylinder - too much boost

[risk]

[jhoefer]

[Chip]

[veedubcrazy]

Is this engine put back together yet?
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1967 Deluxe Sedan

[mark tucker]

just wondering, how is the lower half of the cylinders cooled? the oe type 1 plates leave a nice aera somewhat uncooled and the typ3 need to be connected to the uppers so the air go's through them to cool & not escape out the sides. either style can be made to work just fine for the most part with some mods. but a hoter aera could also cause this ussue under "stress". I do preferr the typ3 "cool"tins with some mods&conected to the upper tins. but with some work the typ1 will work just fine too. remember vw didnt boost these cars or make the power or the big motors, so thier cooling needs to be addresed too. the fan is blowing enough it just has to get everywhere it needs to be to remove the heat. air in the right aera dosent get it done it needs to scrub the heat off the head&cylinders. Ive wondered if a slot about1/2" above and below the head between the first&second fin of each cylinder to let some of the pumped air go around the unfined part of the barrell and out the botom to remove some heat. some heads go through in many places any way when flycutting for biger cylinders.that portion of the cylinder needs cooling too.or possiably a series of cooling holes across the top half of the head&bottom 1/4 so it go's around nicely&out after all of the cylinder has been cooled.remember the cylinder isant tight for a good heat transfer.it needs air to remove it there. some air can go through the studd holes,(94 bore)I doubt it would cool even like it needs to. just somethen to think about.

[[email protected]]

You can have one engine with 30psi boost that runs fine, and another at 10psi that will split cylinders.

CYLINDER PRESSURE splits cylinders, boost doesn't.

Cylinder pressure is created by the combination of

fuel
boost
A/F
timing
compression

What so many don't "get" is that if you change one of those 5 things, you likely have to change 1-4 of the other one ALSO to optimize things. The most common mistake is some guy bumps his boost up, doesn't change anything else, and then splits cylinders.

Your A/F has to be right, and more boost will usually require LESS TIMING. But people only change one thing at a time, and make the changes too fast, and then run into problems.

You have to sneak up on the tune slowly. Make a change in boost 2psi at a time, then optimize the other things. Log your changes. Only after you have made several small steps can you make a big one BACK to a combo you had tested before, and know the result will be ok.

"Theory" doesn't always cut it. Guy changes from 10psi to 20 psi boost, and his mega-squirt does the "math" on the appropriate injector timing change. He goes out and BOOM. Oh, the fuel pump and lines weren't capable of that much fuel flow, oops. Or he didn't pull out any timing and split 3 cylinders, even though the A/F was good.
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[risk]

[mark tucker]

if you will look at it from the bottom you can see where the cylinders are not covered or getting air forced through the fins.you can exten the type 1 plates about 1.5~2" formed to the cylinder. or extend from the uppers down to about 1" from the lower plates (so the air has a good place to escape, (if it can get out it cant cool). steel or soft aluminum formes pretty easy and can be rivited to the other parts easely, I also like the way the 356/912 tins are done with a spliter in the center between the cylinders(kinda like the type 3 cool tins has)so the air id directed and not just hiting a flat wall then having to fight to get out,just like a head intake port a better path will pass more air and cool better.

[mightymouse]

[risk]

[veedubcrazy]

Dont blow this one. I aint got no more cylinders...
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1967 Deluxe Sedan

[mark tucker]

Im going out on a lim hear,as I realy know nothing about this stuff, but I did have a friend that did(well afew that realy did) but this 1 guy had a shelby turbo glh omni,(aka vw I think, Im not sure if it was the vw motor or the mopar motor) and that thing would fly, turbo,spray, and I remember him saying he had addedn a 5th injector to the intake plenum, and no more blown off hoods & inter coolers&motors. I dont have a clue as to how it was fired or any of that. this was a full bodied street car just as it came from dodge, other then engine mods.as I recall it ran in the high 6's(1/ with stickey tires.and was his daily driver.& it was under warranty from dodge,when he blew it up the first few times He would pull the spray & the extra injector off & tell them it went boom, and they would repower it. so is thera a way to add another injector up streem???that would add just enough so you dont have to eff with the flow of the others so much?? remember it's just a thought& I know nothing about hairdryers & FI. other than friends stuff(mostly v8's, outlaw&promod)

[Boolean]

There are kits for that reason. They work - but give some of the same problems as a single carb, i.e. uneven fuel distribution.
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[risk]

Interesting that you guys brought that up...

I would like to add some alcohol spray in the intake, as my intake temps are pretty high.. I have no intercooler.

So.. I was thinking about this:

I have an older SMC alky injection controller, that pulse width modulates the ground signal to the pump. It has two adjustable setpoints for coming on at a certain boost pressure, and maxing out at another boost pressure. I was thinking about wiring it up to an injector to see if it would work that way. Since I'm running E85, I could just tap off my fuel rail and let the SMC unit control the injector. Might be an easy way to have progressive alcohol injection?

[risk]

[miniman82]

[mightymouse]

^^^ this. Buy ID1000's and smile.

Also.. who is tuning it?
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Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.
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Note to EVERYONE.
Know your ZDDP levels or you WILL lose a cam and lifters.

[Chip]

[mightymouse]

[Chip]