Head Studs

[TOM REED]

I have a Head gasket problem on my 3406E C15 Cat engine. This engine has 3.9Million KM on it and the head bolts have been reused several times. The engine run abt 700 HP to the ground and abt 50 or 55 lbs boost under load which greatly improves compression, efficiency and horsepower but increases stress on the head bolts (prob why I have a gasket problem). When I do the repair I would like to replace the head bolts with studs. Does anyone know who possibly makes a stud kit for this engine? I have already sent for a catalog from ARP but it looks as though they only make kits for gas + smaller diesels. If I can't buy a set I could make a set but what material should I use? Would 4140 pre hardened or stainless be good enough or would I need to use something else and have it heat treated. I don't mind this route as I could then use coarse threads as on the bolts in the block and fine thread in the head for the nuts which should give better torque values. Also when talking nuts and torque I only have 2 good nuts hihi but what should I use for nuts and torque specs? I will also be cutting the block and setting cylinder protrusion to max to assist in sealing the genuine cat head gasket as this is the best available for this engine at this time. tom

Only knowledgeable should reply, I posted this on PM and some of the responses were from blowhards without a clue.

[PixMan]

Tom,

I would never profess to know more than 10% of what you yourself knows about the subject. With that in mind, it sounds like there would be extremely high pressures involved and studs would need to be made of VERY high tensile strength steels, with rolled threads for ultimate thread integrity.

I once made a 12-piece set of studs, threaded on both ends. They were cut threads though, not rolled. The application in this case was downstream filtration equipment for a high-pressure plastics extruder. I had to have a minimum of seven leads of thread pullout taper., and I did all 24 threads on a manual machine by hand. I am sorry but I don't recall the exact alloy, but it may have been 420 stainless steel, pre heat treated.

Perhaps a read through of this Wikipedia entry can shed some light on maraging steels. I'm no metallurgist, but I would think that your application shares some characteristics of those mentioned in the article. Among those characteristics is the important one of retaining high tensile strength even under elevated temperatures, with minimal dimensional growth.

http://en.wikipedia.org/wiki/Maraging_steel

Here's a candidate steel for you. Compare the 270KSI strength to even an AISI 4340 steel, and the Vascomax appears to be a winner.

http://www.magellanmetals.com/maragingc300.html

That's the best I can offer you for now, and do remember my disclaimer.

Ken

[B34VD]

Ck liner height dims & counter bores for distortion. Leading cause of head gasket failure in 3400 series engines.

[ETC57]

Tom, probably already been there but have you called cat to see if they have an existing part for your app in stock?

Just a thought.

Jerry.

[TOM REED]

(03-18-2012, 04:30 PM)ETC57 Wrote: Tom, probably already been there but have you called cat to see if they have an existing part for your app in stock?

Just a thought.

Jerry.

Nothing avail from cat but replacement studs, I may be lucky though I originally diagnosed my problem as injector failure,m the head gasket diagnosis was from cat, they said cold cyl because of a pushed head gasket and they also said I could run it for a while till it started going thru antifreeze, also quoted $25,000.00 plus for a complete overhaul. It just had inframe 2 yrs ago. Anyway today it started making oil (diesel in the oil) which again p[opints to injector so tomorrow if possible will get the injector pulled on #5 hole and get a leak down test done which will tell me if the head gasket is the problem or not. I really still think it is an injector/injector cup problem at least I sure hope so 1 new injector abt $600.00 installed a newe set of 6 for about $3800.00. Will keep my fingers and toes crossed. tom

[B34VD]

Does the engine have a miss? If you had an injector that was dumping enough raw fuel into a cyl to raise the oil level the piston would look like an orange. If the engine runs smoothly and the problem is fuel in the oil, check the fuel supply pump.

[TOM REED]

(03-19-2012, 03:17 AM)B34VD Wrote: Does the engine have a miss? If you had an injector that was dumping enough raw fuel into a cyl to raise the oil level the piston would look like an orange. If the engine runs smoothly and the problem is fuel in the oil, check the fuel supply pump.

Engine has a miss at low rpm light load until you put your foot into it then it clears up and runs fine, smokes heavily at low speed also idle, when doing cutout test smoke clears when #5 cyl is cutout, generally power is down some especially below 1400 rpm when boost drops off some, above 1500 rpm with your foot into it it pulls well, still runs up to 45-50 lbs boost. n fuel restricrion is very low but U will check fuel supply pump also as it haqs never been changed. tom

[B34VD]

It just occured to me that you have an ecm controlled fuel system with the electronicly controlled inj.. I was thinking of an older DI style fuel system. Yes a bad inj/ with a leaking injector cup can give you the symptoms you have. If they ran an injector fill test, It should show big difference in #5 to the other cyls. As far as the head bolts go, I don't have an answer for you. I've always used OEM with no reason to look elsewhere. I can say that Cat head bolts are hard on the surface and soft in the middle. They're nothing special if you have to drill out a broken one. Good Luck.

[TOM REED]

(03-19-2012, 07:04 AM)B34VD Wrote: It just occured to me that you have an ecm controlled fuel system with the electronicly controlled inj.. I was thinking of an older DI style fuel system. Yes a bad inj/ with a leaking injector cup can give you the symptoms you have. If they ran an injector fill test, It should show big difference in #5 to the other cyls. As far as the head bolts go, I don't have an answer for you. I've always used OEM with no reason to look elsewhere. I can say that Cat head bolts are hard on the surface and soft in the middle. They're nothing special if you have to drill out a broken one. Good Luck.

Got the old girl to the shop today and it is the head gasket, problem got much worse returning from Manitoba. tom

[B34VD]

Ouch, that's gonna sting a little.