Is there a readily available head gasket that would be better then the 1025. I blew one yesterday and have no idea why. Block and head are machined with studs. I have a 7lb. spring in the waste gate but the waste gate is only a 38mm. The car got loose when I shifted into high and I was paying attention to O2 gauge and the track so I didn't see what the boost was. I'm going to a 60mm waste gate so there will be no chance to over boost the thing. Thanks in advance.

Mike Kirby is suppose to have MLS gaskets.

I beleive there is such a thing as having too big of a wastegate, no?

MBHD

Harry,

Turn up the boost and your wastegate will work, 7 psi is not enough to hurt anything if air fuel and timming is right. At 7 psi the gate has to much exhaust to try and control, don't need a bigger gate unless you only want 7 psi, but why?

Those gaskets may work N/A but that's it, if you make any error on the tuneup it's gone.

Cometic would be a good choice but will only work with a Kirby head, square water passage may not seal to round embosed gasket, thats the water hole at the spark plug.

Were did the gasket fail?

Good Luck
Harry

Cometics can be ordered, but you need to give them the specs & there might be a minimum of so many HG that needs to be purchased? Minimim HG's.




MBHD

The gasket failed between cylinders 3&4. I have a 7lb spring in there because I thought that would be a safe place to start then turn the controller up when I get a handle on the tune. My timing is 38 degrees, all in by 2000. My afr was close to 10.5 when she went. By the way turbo 6 thanks for the advice on the 4500 converter. That woke it right up.

What fuel are you using? Are you going to pull timing with boost or limit it down further than 38?

X2,,,38 degrees of timing with what fuel are you using?

Might want to install one of these to automatically pull timing when it hears detonation.
http://www.jandssafeguard.com/

I have one on my Syclone & the other is going on my inline 6.

I do not much about your build, was there a post hear about it?

MBHD

This was on 92 octane pump gas. I have an MSD 6BTM set to pull 2 degrees per pound of boost. I also have water/ methanol system with twin nozzles set at 5 and 10 pounds but it was not turned on. It was only on it's third pass on an 1/8 mile track shifting at 5000rpm. I sure wish I was watching the boost gauge but I tend to watch the track. I need one of those Go Pro cameras for a co-pilot I guess. Do you feel that is to much timing? I have a knocksense on it and it did light up right at the second to high shift. I can sure see how that boost can be habit forming. My old 13-31 Hoosier Quick times don't stand a chance when the boost starts.

I believe 38 degrees of timing is pretty high on 92 octane, especially w/the water/meth system not on.

Asumeing the BTM was working correctly it should have 24 degrees of timing. Not real high, but not on the safe side IMO.
Also asumeing you were only running 7 psi of boost pressure.

A guy on here hooked up his wastegate incorrectly & was seeing over 15 psi of boost pressure, 87 octane & no intercooler & high timing, with no BTM.

Engines will tend to knock more when the engine is loaded down the most hence top gear knocking, they can also knock right after each gear shift w/an auto trans.


Tlowe run low 20s in timing I believe & run 12 psi of boost pressure.

What are your intake air temps?

Do you have an intercooler?

Do you see pitting on your piston tops?

I always say, just because you can not audibly hear knocking, does not mean it's not knocking.

Good thing you have a knock sensor, but it does not do a thing to save your engine as far as being able to pull out timing.
By the time you saw some indication of engine knock it sounds like it was already too late.

What kind of ET's did you get out of it?

MBHD

I'll lower the timing when I get it back together. I was counting on the MSD BTM to pull the timing back but how do you tell if it is. I suppose a chassis dyne would be the only way. Your system is a little to expensive for me right now. Maybe over the winter. Pistons look just like I got them from Tom. Some carbon on #1. I don't know what my inlet temperature is but it is noticeably cooler coming out of the intercooler. My first 2 runs were aborted because afrs out of range (high 13s). The last run when I hurt it was 7.76 at 82mph in neutral coasting. I was surprised how good it felt. It's in a 3300 lb. 53 studebaker. The 500 cadillac I used to run in it had best of 7.78 1/8, 11.84 118 1/4. I'm sure this is going to be a lot faster. But I've got to keep it together. Thanks for the help.

Sounds like it was running in the 12 second ET's w/the 1/8 et you posted.

That is really good if you were only running 7 psi of boost pressure.


Goodluck w/the repair!

Would like to know all the details on your build, unless you do not want to say.

MBHD

When using the timing retard boxes you need to start higher with how much it pulls out per psi of boost. Only pulling 2° of timing out per psi might still not have been enough. Also when using power adders and pump gas together is never a good combination, the quality of gas is so unconsistent and a crap shoot it usually ends with issues like you are experiencing.

Harry,
I agree use racing fuel on a new setup, once you know were you are you can go down on octane.

Strange it's between 3&4, normally between 2&3 4&5 show the most heat since there are two exhaust valves together.

Did it push in one direction like from 3 to 4 or 4 to 3 are the ends curled in towards a cylinder or just burnt away?

The A/F meter was it a wide or narrow band, was the O2 one wire?

Since I'm not sure a cometic will seal the square water passages at the plugs, you may want to try a copper gasket, I use a rubber coated copper from Flatout gaskets in Illinois.

Harry

The stainless rings on the gasket were curved in towards their cylinders. About 3/4 of an inch in the center is gone. The O2 is a wide band from Innovate with a analog gauge. Also my pyro was 950 degrees when it went. I'll check on the gaskets you use for pricing. I'm doing this on a pretty tight budget. Do you have to run o-rings with your gaskets? As far as an et I'm sure it was on a low to mid 11 second pass. It was all ready faster then the cadillac engine that ran 11s. I guess I'd better get some race gas to develop a tune. Even 110 around here is $7.00 per.

Harry,

I remember seeing something on a gasket blown like that, just looking for the info.

What heat range plug are you using?

Sorry it took so long to get back to you. Got home late. I'm not sure the heat range but it is a champion off the shelf for a stock 292. The ground strap was discolored a little less than half way half way across so I think the heat range is close but not perfect. I priced the Cometic head gasket at $185.00 and the Flatout at $172+ o-ringing so that will probably have to wait for winter. I have another 1025 so I'll try it again with less timing and better fuel. Thanks for the help.

As an update. Installed another 1025 and a 50mm waste gate with a 4lb. spring and went racing. 1st pass was a 13.50 at 4lbs. with the boost retard set at 3 degrees. Second pass was just a little quicker at 13.46. These were both at 30 degrees locked timing. For the third pass I turned off the boost retard and ran 12.67. Fourth pass I turned the boost up to 5lbs. and ran a 12.43 at 110 mph. Fifth pass was the same and then pop goes the head gasket on the 6th pass. On all runs the afrs were in the 10.50 range and egts were in the 1200 degree range at the line. This morning I bit the bullet and ordered a cometic gasket. They assured me it would handle the boost. Oh well what do they sayabout doing things the same and expecting different results? Also these were run on 110 race gas. Try it again next week.

iF YOU ARE GOING TO USE THE cOMETIC mls GASKET CHECK YOUR HEAD AND BLOCK MATING SURFACES FOR SURFACE FINISH.

The Cometic gasket works best when the mating surfaces have a very smooth surface - unlike the FelPro which can tolerate a much rougher surface. You want to get a lot closer to "mirror finish" for the Cometic gasket to perform better than the FelPro.

Been there.

Is/ has the head and block been surfaced? Almost sounds like bad sealing surfaces.

Yes both the head and block were surfaced. I couldn't get a thou and a half feeler gauge under a straight edge on the block or head. In fact I tried several different straight edges just in case. Sure is weird it blows in the same place with both sealing rings blowing inward. I've only got a few more races to go to this year so I'll give it one more shot with the cometic. Do you think the difference in the torque between the 110 lbs on the head studs and the 90 lbs on the lump bolts could be a problem?

Could this be happening when I come off the throttle? It didn't slow down during the pass but when I turned on to the return road I noticed the miss.

110 vs. 90 is way too excessive of a difference between the bolts to torque, plus its too much torque to begin with. Your probably pulling the deck around the bolt holes away from the rest of the deck surface on the ones your torquing to 110. Use a file to lightly run across the top of the bolt holes and see if it shines the deck around the bolt holes before it does the rest of the deck between the cylinders. How did you come to that torque to begin with, stock is only 95 ft.lbs. Also, if your mixing studs and bolts together thats not good either, they each pull the block completely differently when they are torqued, you either need to use all studs or all bolts, and the correct torque should be used for either one to work properly. I think your starting to unravel where/why your problem is occurring/recurring.

The ARP studs call for 110 lbs and the allen bolts that came in the lump port kit called for 90 lbs. I would think that is because of the thinness of the head under the lump. Should I reduce the head stud torque to 90 lbs.

Well, like I said earlier, use either studs or bolts but not both together. The ARP studs are designed to be used as a set, not mixed with a dissimilar fastener.

When I tq down studs and bolts. 100 is used on the studs and 90 on the lump bolts. The ARP studs specify 110 and I feel this is too high for our thin blocks. For a 250, the front DS head bolt/ stud only gets 85-90 by me.

The short lump bolt does not grow much compared to a full length bolt. Tq any higher and the short bolt may snap because of no room to stretch when head thermally expands.

Sounds like something else is wrong for the gasket to blow in the same spot in the same way. Fuel mixture and distribution come to mind.
I have yet to blow a gasket (1025), with pressures higher than yours. Maybe I am not trying hard enough.

Are there any signs of detonation in the suspect cylinders?

No sign of detonation. The rear two cylinders are running richer than the front four but I was told that is normal. Maybe I'll either lower the torque or try to put some studs in the lumps at the lower torque or go back to all bolts.

Try a different heat range on those two Plugs. Yrs ago guys used to run 3 diferent heat range on the plugs to Kinda help?? with that issue.

This might be obvious, but is your boost gauge working right?

I got to thinking about 5 psi and it is not much pressure at all.

You never know?!!

Boucher'

I've never checked the boost gauge. It is a new Autometer but I did have one of their fuel pressure gauges that didn't register at all so I'd better check it. With the 4 lb waste gate spring thats where it stayed (4 lbs) all the way through. I turned the Hallman boost controller one turn and it stayed at five lbs. Seems good but I will test it. Thanks.

Harry,

The difference in torque is because of the long stud VS the short bolt, the stud streches more to hold the same as the short bolt, when I ran a lump port I ran short bolts and short studs at the torque that you use without problems.

I do think your plugs are too hot of a heat range and are acting like glow plugs. Do any plug gaps open up on a run?

You may want to set your water/meth kit to turn on under boost automatically, this way you if you forget it don't matter. Colder plugs for sure. Change them at the track if you find them fouling on the drive there. Do you have a spark plug magnifier? You will be surprised what shows up that you can't see by naked eyeball..

Boost gauge tested good with shop air and a pressure regulator. I'll go a couple steps colder on the plugs. As far as the lumps go are they needed on a turbo engine? I would have to open up the center hole a bunch to use a stud and 1/2 inch nut instead of the bolt. I haven't used the water/methanol yet. I thought at low boost it wasn't need but I will turn it on at the next race. I have two nozzles on two pressure switches. Now one is adjusted to come on at 5 lbs and the second one at 10 lbs. I don't street drive it, it lives on a trailer. Thanks for the help.