Background:

1968 Stock internal Slant six Block
2bbl Holley 350 blow-through setup
Running 8 psi boost.

Yesterday I was running on the freeway, and did a 2nd gear pull around a car, hit 8psi, then slowed down once i was past the car, never got above 75mph. Then I pulled off the freeway and noticed the temp gauge had hit 200 degrees. It has been consistantly running 190 and that never seems to fluctuate.

The temp did not go back down though and climbed a little above 200 at idle. I drove it home and the temperature did not subside. After it cooled a little, I popped the radiator cap. The coolant was a brown shade of green - still green though - not necessarily abnormal since it's being washed through the stock engine block. This is in an aluminum radiator.

I drained the coolant and put new stuff in, there was no milky-ness to the coolant at all that I could see. The oil was still full, and did not smell off.

Today I did not see it overheat again, and it seemed normal but the car when running definitly smells like burning antifreeze/coolant. It's kind of a weird burning sugar smell. But again - looked in cap - no missing coolant, no white out the tail pipe, no nothing wrong - just the smell - still runs fine, and I pulled each spark plug boot individually while idling, each one made the engine run rough, so there's no miss.

Tomorrow i want to do a leakdown and comp test at my shop, but can't today. I feel I may have a small crack in the head gasket, but can't say where. Or i could not at all - the test will tell.

So if I do pull the head, besides buying a new head gasket there's a couple other things I want to do -

Gasket match the ports
O-ring the block.

I am assuming for matching the ports all I am trying to do is go as far back as I can in the port and make it the same size as the gasket? Or is there a limit to how far back I can go? Does anyone know what it is in thousandths if there is a limit?

For O-ringing the block, I know there's a tool that can be rented but can't remember what it's called - does anyone know? Is it available somewhere like Autozone? Or should i just buy one?

After I cut the grooves, what do I use to lay in the grooves? Copper wire? Stainless wire?

What else could I do to the head while it's off, if I take it off? Remember this is a turbo engine, so I'm not sure if shaving the head is a good move to up compression.

The current gasket is only about 20k miles old, but I'm still not sure if it's broken or not.

You can buy the tool for around $300, or rent the "O" tool from Isky. I don't see it online, so call them. I used stainless wire.

BUT: at less then 10 lbs, you shouldn't need to "O"-ring. If you have head gasket problems at that boost level, you are probably getting into detonation. When I first did my turbo setup (back in 1979), I was blowing head gaskets, so I "O" Ringed the block (big mistake). I was detonating and didn't know it. The gasket was acting as a "fuse" and blowing. When I did the "O" ring, it cured the gasket problem, and the next weakest part broke, pistons. That was when I realized I was detonating.

PS: With the Isky tool, it may be very hard to do number six cyl in the car.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

I'd check to see just HOW low your stock comp really is. I'd say you could bump compression a *little* bit (8.5?) and have better off boost driveability, and possibly fuel economy. But also, tuning a carb isn't as accurate as multiport, so it may be too big of a risk.

I'd definitely look into a better cam as well. I mean, you've already got the head off...

do you make the rings to put in the groove? do you have to run a special head gasket with them?

As far as my research went on the BMW forums Junior, it looks like you make a groove, then place wire into it, and lay it in the same pattern.

It looks like I was about to jump the gun removing the head. Compression test yeilded fine results, and leakdown shows nothing going on, except normal stuff.

The car also has not overheated again, and the smell went away. I am completely stumped as to what the heck happened, but I still would like to do some head work if I have a couple days off work in the near future. It seems the head gasket is fine, but I wanted to be prepared if the head was going to come off.

I still would like to port it out if that will help, I last dyno'd the Dart at 164rwhp and 234'lbs of torque at 3500rpm. I'd like to squeeze more out of this setup and I think it has it in her at 10psi or slightly under. I did do that dyno test with a failing ignition that I've since sorted out, but I don't want to keep doing dyno runs at $80 a pop without doing a multitude of things first. I think the next couple easy enough things would be porting the head, and it sounds like O-ringing the block is overkill for what I'm doing on my daily driver it seems.

Every time i make a modification to the setup I make sure it's daily driver stabilized, so I'm not trying to go too crazy. The piping is coming off as well on the cold side because the sleeves leak no matter what I do to them (and they are beaded) so I'm having the exhaust shop that likes to play with my car make me some welded piping to help this issue, and then just sleeve it at the intercooler and turbo shell. You can visibly see it blow air out when I had it on the dyno so it's going bye bye.

sleeves? the silicone couplers? bang for the buck and drivability would be to play with the timing. get some kind of electronic timing controller. @10psi im pretty sure you could run a little more then 18* and you certainly dont need that little advance before 10psi.

Yeah the silicone couplers. I have been playing with timing recently and it seems like I can't really squeak away with any more than 18 before I hear frying bacon under the hood on boost.

Have you looked into a box like the BTM (Boost Timing Master) by MSD? Retards a certain amount of degrees per pound?

Once I score some money that MSD box is on my list. Are you talking about the blue box? I think it was intended for superchargers, but I doubt it matters.

I would suggest this box, which has come down in price substantially, with an add-on MAP sensor. You can program a detailed advance curve - anything you want. MUCH more flexible than a BTM or any similar device.

http://www.summitracing.com/parts/msd-6530

I have been running this on my turbo Dart for about 3 yrs and no issues up to 9.5 psi, giving 260+ HP at the wheels (from dragstrip numbers). I also use a water/meth injection kit (with windshield washer fluid) from AEM and NO intercooler at all. I have about 20k street miles on the turbo setup and blew one head gasket at about 6k miles before the water/meth inj when I got greedy with leaning out the mix...

Hope this helps,

Lou

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