Don M

Well I had an intersting Friday last week. Back in the spring I blew a headgasket and just got around to tearing the head off to see about getting it fixed. I have not been driving it. I had installed that head just over 3 years ago and used a marine 20 over gasket and stock bolts. It held up wonderfully for 3 years at 60 plus PSI and over 600 HP for the past year. Around the 570 HP mark for two years prior to that. Anyway, in the course of my Diesel Hot Rodding I have roached more turbos than I care to remember, but three of the best ones where HX40's. They really pop loud when they let go. The little hybrids are fun to drive and spool like crazy, but they hate to make big HP. I was pushing them way too far.

Since I went to larger and stronger turbos I have had no turbo failures. The bad news: that either some or all of the 40 compressor wheels have made their way into the intercooler and into the engine where they were crunched into little pieces of auminum and steel.

After I pulled the head off the truck and and went back to the engine compartment to check the cylinder walls and pistons I was very disappointed in what I found. 3 of the 6 cylinders where completely roached. Deep scuff marks in the walls and little pieces of shrapnel in the piston tops. 40 compressor wheel chunks embedded in the cast aluminum pistons. None of the 3 cylinders can be bored. Sleeving is the only option and not one I am going to take. Luckily I have a nice block here I got back from the machine shop last month and some fresh custom pistons/rings.

Only 1 of the 6 bores is in spec. Number 6 of all bores! The rest are hosed. The rings are shot and the compression was trashed. Two of the bad cylinders has soo much blow by the oil was getting past the rings and into the combustion chambers. Bad enough that number 3 was not ever firing. The exhaust runners were completely soaked with oil and raw Diesel fuel from just not making the heat/compression to burn the fuel completely.

The good news is the truck still made a best 642 HP with all this damage and low compression. I am amazed.

The real good news is: The thing is going to be wild to say the least with a fresh, balanced and blueprinted engine that actually has compression. The engine is going to be close to stock on the rotating assembly with some trick fueling additions. Nothing real radical, but enough to get noticed.

Don~

signature600

UM, DARN?

What else can be said, 642 hp on basically junk?

So Does that mean I can make my engine, which has to be in better shape, make more?

Chris

BTW,

Eskimo

That's just SICK!!!!!!!

5 cylinders, crummy compression/combustion in those cylinders, and STILL 642 hp!!! I've never seen that on ANYTHING.. well, maybe a Top Fuel motor with 7 bad pistons, but still...

I bet the #3 cylinder helped control EGT's with all the nice fresh air!

Don M

Personally I cant believe it made the power it did. I have been scratching my head on this truck for about a year now. I had a BIG power combination of pats in it. A combo that made over 790 HP on another truck with SMALLER injectors than the ones I put in it last dyno runs and only got 627 on a "bad air day"

It was basically firing on 5 cylinders and had 4 other weak ones.

The more fuel I threw at it.... it made more power, but small increments of like 5 or 10 HP. If I reduced the fuel it made less power...so I knew it was not overfueled, so to speak.

Last year I did a compression check on the engine. It was so low I figured I had a bunch of bad valve seats. Every cylinder was less than 270 PSI Many guys with tired engines get at least 320. Most get more. I knew it was tired, but the damage was soo bad I could not believe it myself.

I bet if I get this thing sealed up... its an easy 100 HP without tuning and stock 370's. Keeping the single turbo of course. Maybe it is time to go to twin turbos! My goal was 700 on one charger before twins. Now its time to make the 700 fast on a single and strap on an extra huffer!

Thats if I can get the cash and time to together to finsish this thing. With me its either two things. Time or money. Sometimes I have some money and not any time. Or plenty of time and no money. Lately its been lean on both ends

Forrest

Don ... post the pics buddy Load up that Members Photo Gallery.

mcevins

Better watch that head gasket now that you will be making some compression. My new name should be headgasket blower. Three since December.

Meacham Evins

Don M

Head Gasket Blower,

Did you get the gasket and moly lube I sent to you? Is your truck back together? Hope so!

Don~

Zino

Hey Don, maybe thats why you got such quick spoolup.... The cylinder that wasnt firing right was dumping raw fuel into the hot exhaust and combusting in the turbine housing, so you had a gas turbine/turbocharger!!!!!! Kind of like what the old grand national turbo v-6 guys used to do at the drag strip... they would retard the hell out of the timing while on the line, so that the burn was continuing on past the exhaust stroke and spooling the turbo up, when they took off the timing was bumped back up...........


PS, ring seal is the single most important thing on gasser drag engines, believe me.... We are making 600 HP on a 9:1 compression 350, with stock cast iron heads, 1.94 and 1.5 valves, and a stock quadrajet.. You wont believe the trouble we go through for a good ring seal. And the break in period is critical. Engines that seal up right during the first 5 minutes make 600HP, ones that dont (and have all the same other parts) are lucky to break 500.

Zino

Zino

Hey Don, maybe thats why you got such quick spoolup.... The cylinder that wasnt firing right was dumping raw fuel into the hot exhaust and combusting in the turbine housing, so you had a gas turbine/turbocharger!!!!!! Kind of like what the old grand national turbo v-6 guys used to do at the drag strip... they would retard the hell out of the timing while on the line, so that the burn was continuing on past the exhaust stroke and spooling the turbo up, when they took off the timing was bumped back up...........


PS, ring seal is the single most important thing on gasser drag engines, believe me.... We are making 600 HP on a 9:1 compression 350, with stock cast iron heads, 1.94 and 1.5 valves, and a stock quadrajet.. You wont believe the trouble we go through for a good ring seal. And the break in period is critical. Engines that seal up right during the first 5 minutes make 600HP, ones that dont (and have all the same other parts) are lucky to break 500.

Zino

Don M

Ring seal? You betcha it makes all the difference in the world. The blow by this rig was making is the worse I have seen yet and still run.

I went to a special ring type to help with seal. Not the Total Seal stuff. Something a little different. These trucks come with chrome rings. Great for durability but a real pain to get seated good everytime.

I will leak this engine down after I feel its broken in. If it wont seal, I will yank it down and start over. I have access to a Sunnen and we are building a tq plate. Anything I can do to help this thing seal is being done. Back when Smokey would tell people that an engine with a leak of 5% was junk they would laugh. I see maximum effort engines nowdays getting a ring and hone job that are off as little as 2-3%.

Right on Zino!

Don~

Zino

Yep, we like 1% to 2%. We actually check the leakdown on the dyno with the engine at full load and about 7,000 RPM. We seal up the crankcase completely, and then connect a Dywer flowmeter to the valvecover and acutally measure the true leakage past the rings under operating temperatures and loads.

If you are ever in the mood for a treat, try standing next to a small block chevy, with a stock crank, turning 7,000 RPM holding a flowmeter

There are lots of other cool tricks to a good ring seal too.... PM me for details.....



Zino

Don M

You guys are nuts! Tell me how many stock cranks you have run over at 600 HP. I suppose we are talking about a stock forged crank?

Those twisted forgings always make me nervous at 600 HP and up. I know they will hold up pretty good, but 7 grand is really high.

The worse carnage I have been close to was a JP-1 Hemi that lost a rod. It kicked a window out of the block, threw chunks of crap everywhere and competly ate the Moroso Super fueler wet sump pan up. I was about 3 feet away when the parts began to fly.

The good part is the block was weldable and easily fixed up. We modded the block to say JF instead of JP because the guy I worked for had the initials JF.

Don~

Zino

Believe it or not, cast cranks !!!!! I have run both though. *7,000 is a piece of cake, most of us are turning around 8,000 to 8,400 RPM through the traps I have had good luck, I only broke one engine so far. Dropped a valve right before the finish line at about 8,200 RPM.... Carnage is an understatment.... The only parts I could re-use was the valve covers, intake, carb and headers.


Zino

HOHN

Great posts, fellas!

Wanna talk carnage? How about a Pro Stock engine turning 10K through the traps with 500cid! Of course, there's always the fuelers blowing superchargers skiy-high....lotsa fun.

Don, I know you said you aren't using total seal rings. That's fine-imho- a set of file-fits will do as well in many cases.

But Total Seal DOES make an interesting product that I recommend to EVERYONE. It's called QuickSeat Ring Powder. You basically dust in on the bores and piston skirts before final assembly.

The stuff DOES make a difference! It works best with a moly ring. It's hard to describe what it does, but it REALLY helps the rings seat. Leakdown is usually less than 1%.

Does anyone make a moly ring for the 5.9? I wonder if a custom ring could be sourced.

Another trick I like for bore sealing is the Scotch-brite trick. After final honing, you can use a Scotch-brite pad lightly on a manual hone. It knocks down the edge of the crosshatch, leaving just the perfect finish. Just a couple strokes is all it takes.

The other important thing is valve sealing. Machining MUST be done as close to operating temperature as can be reasonably simulated. Otherwise, you can't even hope to have your tolerances in the sub- .001 range. Valve seat out-of-roundness is perhaps the most critical spec here. Warming the head to 250° -300° before machining it will help a great deal. A kiln works well. Then your wife can do pottery, too

We all know that metal expands as it heats. Yet we seem to be content to conduct precision machining at temps nowhere near operating temp! This doesn't seem practical to me until we get an engine that will operate at room temperature.

Keep this in mind when boring & decking the block, decking the heads, etc.. Torque plates are a step in the right direction, but I think that it's not the complete picture when the temperatures vary so much.

The final component of the temperature picture -imho- is cryogenic tempering. This can/should be done after the machine work is complete. It helps to ensure that the painstaking machining will stay spec-on. Cryo tempering eliminates residuall thermal stresses inherent in the metal. Any cast or hot-forged component will greatly benefit from cryogenic tempering. Pistons have more uniform crown temps across the top. Rods are much more resistant to fatigue and stress cracking. Head studs will have more clamping force. (I'd suspect that ARP 2000 material is cryogenically treated to get the specs they do).

The you slap the whole thing together with Swain Tech coatings everywhere they can be used (at least do Goldcoat on piston tops and PolyMoly on the skirts).

If I got to build another engine on my own, it would take a LOT of time and $$ to do it the way *I* considered "right".

Justin

Zino

Justin, slam dunk, bullseye, on the money with all your comments!!!!!!!!!!!! We hone with 180° water circulating through the block and 200° honing oil. File fit the rings for sure, the pre-gapped rings are WAY to conservative and have too much gap. Coated piston tops are the chisnit... And cyro has done wonders for a friend of mine who races go carts (5hp briggs and stratton engines making 20hP) but I have not tried it yet. Another interesting tidbit.. dont forget that the ring seals in two places, around the periphery of the bore, which we are all talking about, but it also needs to seal against the bottom land of the piston and continue to do so even as the RPM's go up and up and up........I am sure you can figure out the rest....



Zino