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Author Topic: 1984 vw rabbit diesel performance upgrades  (Read 2156 times)


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    • 1991 mercury capri n/a, 1984 vw rabbit diesel
1984 vw rabbit diesel performance upgrades
« on: September 10, 2015, 07:31:20 PM »

Its been a while since I've been on here and i'd like to share what I've been doing with my cars.

Today i figured out that my 1984 volkswagen rabbit diesel, of which i just added a turbo and custom intake and exhaust, needs a cylinder head. Now i really shouldnt say i've just learned this, as i knew the cylinder head was cracked in three places in between the valves when i replaced the head gasket about 4000 miles ago. It's gotten bad now though, its leaking compression through those cracks and into the cooling system which over pressurizes it and pushes the coolant out of the weakest link, which happens to be the expansion tank pressure cap. Every time i shut it off it's still pushing coolant out the cap.

I figured this leaves me with one option which is to replace the cylinder head and head gasket and use arp head studs to secure it in place. Surprisingly enough arp does make a set of 12mm head studs that fit my block and a 1.9L tdi block. That could mean that this is a common enough problem that an aftermarket performance solution for high compression applications is needed. Now im only pushing 12 psi max in this engine but 12 psi in an intake on a 1.6L diesel is a lot of extra pressure to be shoving in the cylinders. Arp head studs are ratted at 200,000 to 220,000 psi which is about double of what i would need, but i really dont trust the oem tty(torque to yield) bolts that you can buy instead. If im going to spend 300 dollars on a new head, i want to build it so it lasts. The problem is, arp head studs for my engine cost 170 dollars. You're only getting 10 studs. The benefit of this being that you don't have to replace tty bolts every time you pull the head and you have the potential for higher compression which i plan to do down the line(more boost = more compression). With the cost of the head im spending about 500 dollars.

This is kind of a let down as i just spent 200 bucks on inner and outer tie rod ends, lower ball joints, front brake pads, rotors, drum shoes, hardware, wheel cylinders, wheel seals, and caliper rebuild kits. I need most of this stuff just so i can do an alignment on my car at school. Plus half of this stuff is original(30+ years old) so it was long overdue for replacement. After all is done though i'll have a car that rides like new and brakes really well(i went with the good stuff).

with a little research i found a new bare head for 330 with shipping and new arp head studs for 160 with free shipping. i still need new valve seals as id have to swap everything off of my current head onto the new one but theyre cheap on rock auto for 3 dollars and 6 dollar shipping. Also they're fel-pro.