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pjdhill
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168 Posts
Discussion Starter · #1 ·
I'm almost ready to put the heads back on my 4.7 - blown head gasket cylinder #3. I've been seriously considering the ARP(or is it APR) head bolts but the head rebuilder guy who checked my heads over told me it's best to go with bolts that stretch as the motor was designed for. Using Felpro MLS gaskets. I still may go with HO cams but for sure Gibson Headers and muffler and already have a home made cold air intake so I'm not talking major increase in power - maybe like +20 horse and torque. After reading a few internet articles on headbolts and again talking with a guy with 30+ years experience doing nothing but heads I'm now almost certain I will be using factory head bolts that are stretched upon installation. Any opinions?
pjd
 

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K-State fan
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619 Posts
I'll be tackling the same job next weekend. I've got a blown head gasket on passenger side and will be using the stretch bolts just like the factory put in. I would have done it today, but I'm waiting for my HO cams! :)

BTW, what caused your head gasket to fail? Did it overheat?
 

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AirFuelEddie
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5,443 Posts
He's correct. The reason for the 'strectch' is because of dis-similar metals used on the cylinder head and block. One is alloy the other cast iron. They expand at different rates. The gasket is very important here. I would use the factory head fasteners. But if Cometic makes a head gasket which is MLS,(Multi-Layered, Steel), Viton coated, it should seal almost anything, Nitrous, Boost, Hi-Compression ect,, www.cometicgasket.com they may be able to make a set for you. This way you wont need studs.
 

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pjdhill
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168 Posts
Discussion Starter · #4 ·
My 'D' with the 4.7 has the 3.55 gearing. I pull a 27 ft cabin trailer. As long as there is little to no wind it is up to the task. Much wind and the 'D' really struggles. Unfortunately I was pulling it along the Columbina Gorge between Washington and Oregon into winds that were gusting to 55KPH. Instead of pulling over and waiting the wind out (it usually subsides somewhat at night) I drove it for over 3 hours int the wind The heat never went up but it was shortly after that drive along the gorge that I started blowing antifreeze out the overfill tank. After wasteing $1,000 at the dodge dealers in Salem Oegon and The Dalls Oregon replacing thermostat, water pump, radiator that the "d" didn't need I managed to get back home by constantly putting antifreeze in the radiator. It never overheated above the 3/4 mark or so. I first knew I had a problem when I got antifreeze on my windshield and the heat guage went above 1/2 way. I did a leak down test at home and when I put 150 pounds pressure into cylinder #3 I blew bubbles into the radiator so I pulled the heads. I guess the stress had caused the head to 'wander' on the block a bit and squished the seal between the cylinder and the water jacket. I think the MLS gasket will be the solution as it will allow the slight 'wandering' of the head on the engine block without damaging the gasket.
pj
 

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K-State fan
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619 Posts
The best deal I found on the Perma-Torque MLS gasket was through O'Reilly Auto. They had to order it, but it was only $38 for one gasket.

What was the part number for your thermostat? I might as throw a new one in while the coolant is drained.
 

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HC-Racing,LLC
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1,841 Posts
head studs are superior in every way, period.

You will have zero head lift, and if I had already had gasket problems in the past, especially considering how afforable arp studs are, i would def. go that route..

TTY is "better" than a standard bolt IMO , merely because it allows for a minor bit of contraction in length as the gasket compresses thru heat cycles. This IS criticle for irom block aluminm head engines [such as the 4.7 and hemi]
Thats why they are used in these applications.
And should be used again {NEW OEM BOLTS IMO even if the old ones still meet the relaxed length spec**
However,
I/we {at my shop** typially use a 3 or even 6 step tq process to begin with, then come back later to re-tq to our spec after a few heating and cooling cycles..
If,
Your willing to take the covers back off after some driving time, chk and re-tq as necessary, head studs are def a better way to go for both performance and longevity..

I/we use Victor Reinz mls coated head gaskets and have never seen a failure even with most of our builds featuring large ammounts of boost.

just my .02
 
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