Engine/Transmission (1994 - 1998) Head, Porting, Gasket, ARP 625 Head Stud Recommendations

[MMcCallie]

My head gasket finally let go just behind the thermostat housing. The quotes I'm getting just to get parts for repair are more than double what I paid for the whole motor so I need some advice.

I'm told 9 out of 10 heads are cracked and that I should just start over with a brand new complete head from Cummins. Another reason I've been given is that with an engine having over 100,000 miles, valve seats, seals, etc. will need replacing. Supposedly prices add up to near the price of a new head, which I'm told is $1,200, plus $350 for o-rings and a head gasket. Calculating costs to ship my head, have it disassembled and magnafluxed, then decked, o-ringed and rebuilt replacing parts most likely worn, will cost around $800, with shipping being nearly half that amount. I don't want to spend a few hundred just to have the head checked out and find that it needs replacing.

Is it true that the head is usually cracked if the gasket is leaking? I definitely expect warping since the engine has overheated many times and EGTs are very hot. What about the head needing to be rebuilt? I've got heavy duty intake and exhaust valve springs so I'll probably have to eat that cost when swapping mine onto the new head.

I was hoping Cometic would have a gasket solution that wouldn't require o-rings, but they told me today over the phone that they've had so many leakage issues that I'd have to sign a waiver to get one. Sounds like a risk I don't need to be taking. They've been working on a redesign for months and have no idea when the revised gaskets will be ready.

So I'm looking at a stock thickness replacement Cummins head gasket. I don't want to lose any compression as cold weather starting is already hard enough. I also don't want to sacrifice any low end response since my truck is a rock crawler.

One of the biggest decisions I'm now trying to make is which ARP head studs to get. I already make over 47 psi boost with my single HTT 62/12 and water injection and 17. 5 degrees of timing in very cold weather at 7,000' elevation. I plan on compounds and nitrous someday and from what I've read and been told, the regular 12 MM head studs may not have enough clamping force for my future plans. The 625 12 MM stainless steel ARP head studs are supposed to hold as well as 14 MM studs. Do I really need to spend more than double for the 625 studs? Are they worth the extra money?

I'm also wanting to have the head ported. I've seen huge results from folks porting heads on motorcycles, and know a guy who did it on his own Cummins and gained 2-3 mpg, much lower EGTs, and greatly improved drivability power. I'm curious how great the results are for other Cummins owners from porting the head.

I live a couple hours from Salt Lake City. Gillette Diesel is recommending a shop over a hundred miles further south for any and all Cummins head work, haven't talked to the guy myself. I work an average of 15 hours 7 days a week and have no shop so I will have to be paying for not just the parts, but all of the labor as well.

Does anyone have recommendations for best prices, quality and service on regular or 625 head studs, a complete, brand new Cummins head, stock thickness head gasket, and head porting? Any constructive advise regarding which parts I need and what I should be paying for the work is welcome.

 

[RHestand]

It would seem the first and most important thing is to find out if the head is cracked.

I would hand carry it to a local or somewhat local machine shop and have it magna-fluxed.

Any automotive machine shop worth worth going to, can do this for cheap, and in short order.

You can make all your plans and decisions after that.

Good Luck, Ray

 

[PRohr]

How close are you to Denver/Golden Colorado area? I know a guy there with a shop that has built some sweet rucks and he won't BS you on what you need or don't need.

 

[MMcCallie]

I'm about an 8 or 9 hour drive from Golden, Colorado so that's not an option for me. I'm also a 2 hour drive from Salt Lake City which is the nearest town that has a machine shop capable of magnafluxing. I work 15 hour days 7 days a week so finding time for a 4 hour trip is also pretty much impossible for me, I'll have to have a shop deliver it or just ship it. This truck is my daily driver so I need to figure this out today.

Why would I want a . 10 over gasket instead of stock thickness? Doesn't a thicker gasket mean there is more of a softer, weaker surface of gasket between two thicker metal surfaces of the block and head? Doesn't it make more sense to have the metal surfaces closer together so air pressure pushes against less of a softer surface so the gasket is less likely to blow?

Is it true that virtually all used heads are cracked? Is that supposed to be acceptable as long as it pressure checks? What about head studs, are the 625 ARP studs necessary for my application? Does anyone have names and phone numbers of shops I should contact?

 

[PRohr]

Call and talk to Rob... he is the owner of the shop I was talking about:



PERFORMANCE CAR & TRUCK, DIESEL PERFORMANCE

GOLDEN ,COLORADO

303 278 8038



He can do the machining and stuff and send it back to you. He's a good guy and won't sell you stuff you don't need and is a straight shooter. Tell him Phil aka Duster318 sent you.

 

[MMcCallie]

Thanks Phil, I think I'll go that route. I'm really interested in his milling off the intake and building his own.

 

[PRohr]

Yeah. . I want to get that done as well..... gotta save up my pennies. I take it you called and talked with him then.

 

[MMcCallie]

Phil, thanks for your recommendation. I've been very impressed from talking with Rob, he seems to really know his stuff. He thinks I can drive all the way there with a retorque and several gallons of extra water. I'm going to take over a week off work and try to get this done. He says the machine work will take 10 days.

He's going to port and port match, mill the intake and bolt in his own, resurface, o-ring, do a 3 angle valve job, use a . 30 over Cummins Marine head gasket, and use the regular ARP head studs. I'm very interested in seeing the success of his totally unique method of torquing the head studs. Rob claims I'll be able to romp to the max immediately. He says there is absolutely no need to go with the expensive 625s. He also doesn't see any need to spend the extra $1,200 to extrude hone the head since the truck is a daily driver.

I'm going to try to drive down there Friday night and Saturday to get it in his hands ASAP. He has to go to Reserves duty next weekend so I'll be missing quite a bit of work, going into the week after next. I'm trying not to dwell too much on the cost of all of this as I was informed my job is being cut at the end of May. I'll need the truck reliable and ready to live in again come summer.

 

[Grumpy John 4x4]

head

Hopefully you already have a Full billet trans & TQ and guages a must have

 

[PRohr]

Great. I have talked with him numerous times on the phone and I am going to get a set of his injectors and a turbo from him in the near future. I am working a deal on another head for my truck so I can send it to him and have him work it over as well. His MAXIntakes are SWEET. Glad i could help you out and him at the same time.

 

[MMcCallie]

Yes, I have a BTS 4R100 with a PCS TCU for shifting gears, and a BD-Power X-Monitor for boost and EGTs. I have yet to see pictures of the MAXIntake but just his description is very intriguing.

 

[MMcCallie]

Made it all the way to Golden, CO having to add just a half gallon only an hour into the trip. Other than an initial overfill, haven't seen a single drip, not even after sitting all night. Morning I left there was a huge puddle on the ground so I'm surprised the pavement is dry. I tried to keep boost under 10 psi, hit a max of 17. Maybe there was enough heat clamping the head to the block and cylinder pressure was low enough that no coolant was pushed out.

Mechanic who found the leak swears it was leaking, he says it looks like the leak was more between cylinders 2 and 3. He retorqued my head bolts but said they just cracked and only went barely 1/4". Was supposed to drop off my truck at Rob's shop today but no one has called me back. Guess I'm waiting until tomorrow. Does anyone have a link to look at pictures of his custom intake?

 

[PRohr]

Here ya go..... I am not sure if this will work or not if you aren't a member but I think it does:

Diesel Ram Forums: 12 Valve Head Build

Here is another thread showing the build up of the engine:

Diesel Ram Forums: The Build Up

 

[MMcCallie]

Both links were good, thanks again Phil. I will be learning more in the morning. I have yet to really see and understand the need and benefits of the modified intake but am still very intrigued. The security of not having to worry about my engine during normal driving or flogging is of the most value to me. Especially in the harsh climates I endure. I'm really hoping the truck can be back on the road by the end of this week.

 

[PRohr]

It allows you to port the intake side of the head and you can make the plenum larger allowing more air to be packed into the intake for the increased flow of th eported head and better more even distribution to all six cylinders. Kinds of like a tunnel ram intake for a gas motor. With a forced induction motor the exhaust side is more important and usually concentrated on more for flow as it needs more help to get the air out as there is something (ie: Turbo or Super charger) pushing the air through the intake. To get the most out of the motor though both sides should be worked on to help with flow in and out.

 

[MMcCallie]

That's a great description. I finally got to see things myself this morning. Rob took my truck for a spin, said the pump is noisy and that I programmed my 2nd gear shift too early. I'm going to have him do his AFC mods, possibly delivery valves, possibly pump timing too. He claims he can get much more drivability out of it. I think he's being fair with the price but it sure is expensive. He says he'll have it torn apart today and call me if there are any other problems when he turns the motor over by hand, checking for scoring on the cylinder walls and any other problems from overheating. Best news is he plans to have it done this week. That's really good for me. His shop is very clean and the 24 valve he's working on is virtually spotless.

 

[PRohr]

That 24V is sweet..... P-pumped now and with twins. I have been following the build on the DR site. You are in good hands.

 

[MMcCallie]

Just got bad news from Rob. My head is cracked, total garbage. It would take the rest of the week for him to acquire a useable head from out of state. Have to pay big bucks to get a new one from Cummins. He's calling to see if he can even get his hands on one so the truck can still be ready by the end of this week.

 

[PRohr]

I know where he can get one..... I'll call him and let him know.

 

[PRohr]

I was looking at getting one from a guy but it's going to be a while before I get the cash to have it done so he can get this one coming for you. It's in Nevada. I called him and talked to him for a bit I just need to find the guys number so he can call him.