Skip to content
View in the app

A better way to browse. Learn more.

rollaclub.com

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

4k Decompression Gasket

Featured Replies

can you get decompresison gaskets for 4k's?

if so, who from?

 

cheers

-ALex

Hizotimang, talk to me on msn. I have a bit of information, though not sure about the gasket but something just as good hopefully.

No, but you can get a thicker copper gasket, so you don't have to use a HG on each side of the decomp plate. Copper gasket requires O-ring the block and/or head though.

 

Or.....Just retard the timing to reduce compression "at the time of firing" by locking the dizzy and running 20-25o BTDC static and you'll be set.h

Edited by Taz_Rx

Didn't know they made copper head gaskets for 4ks. Wouldn't be cheap though I imagine.

Edited by WinKE55

  • Author

locking the timeing asin blocking off the timeing vacuum advance? and running shitloads of timeing?

 

hmmm,

 

wont a copper gasket be thicker anyway(in theory making it a decomp gasket), and how do you o ring the block

 

whats a better idea, decomp plate and 2 gaskets or cooper gasket with o rings?

 

 

Or even, how would stock 4k with 3k pistons and new rings and seals cope with boost, say 6 psi, possibly more coz il probs be like f@$k it and crank it up at a much later stage lol

Edited by Shizotimang

Oringing would be the best option, but this requires a bare block to be taken to your local machine shop.

You can do it yourself even with the block still in the car (as somebody here did) but frankly I wouldn't trust myself with the tool, so I'm going to get it done for me.

 

Locking up the dizzy means you lock out the MECHANICAL advance, not vac advance. Pull you dizzy apart (its a 4k right?), ie pull all of the points plate out of it and you will find the weights and springs of the mech advance. Remove the springs and replace them with some tie wire. Set at 20-25o BTDC static and forget about it.

 

Decomp plate is one of the worse options IMHO.

Myself and others have run over 20 psi on stock internals/compression ratio, so just leave it I say.

 

Putting 3k pistons in a 4k will do absolutely nothing, as a 4k is just a strokied 3k.

  • Author

yeah i know it wont do anything to compression with 3k pistons, but ive got some and i heard there stronger so might aswell use them?

 

and the block will be going to a engine recons anyway to get a skim,

 

how much does o ringing cost?

 

I'm thinking il just stick with stock comp tho, in the end its just a 4k. another 40 bucks will get me another one lol

i bought a 5k a while back, was straight out of a stocko liteace camper and it had a steel decompression plate and used one head gaskett on one side and soem spray on compound shit on the other, the old guy reckons thats how it came from the factory??

I got quoted $120 if I took them a bare block.

Copper gaskets are around $100.

 

Copper head gasket are the go if you want to run big boost and have no possible gasket issues and you can re-use them over again.

 

Yes the block needs to be oringed.

 

Matt

Please sign in to comment

You will be able to leave a comment after signing in

Sign In Now

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.