DIY: Replacing GR Tappets

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Bennoz
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DIY: Replacing GR Tappets

Post by Bennoz »

As promised folks, here we go....

You will need:
12mm socket
10mm socket
10mm ring spanner
Ratchet with extension bar
Large flat screw driver
Small quantity of engine oil
6 pack
smokes

Before I go on - word of warning: This is NOT for amatuers... you need a reasonably sound knowledge of mechanics to get this right.

Also note - this is based on the front bank of cylinders. I will go into more detail about the rear bank later in this post. Essentially the job of replacing tappets is identical on both banks, just that there is a WHOLE lot more parts that need to come out to get at the rears... that & the angles you physically are working in are best left for Pilates instructors

First up - remove the 6 x 10mm bolts on the rocker cover plate

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Next up, remove the 6 x 10mm bolts that hold the coil packs in place. Unplug the leads from the coil packs first. Be gentle when you remove the coil packs as they are connected to the spark plug boots. The whole assemble will come out of the spark plug guides.

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Remove the 9 x 10mm bolts that hold the rocker cover down. These bolts can be an arse as they go through both the rocker gasket & rubber grommets. The grommets are to seal the oil in the rocker. When you undo the bolts they really dont want to unscrew all the way out of the grommet without a fight - thats fine cause we dont need them all the way out. Once they are un-threaded from the head, thats all you need to do.

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Now remove the 3 x 10mm bolts that hold the cam belt cover to the rocker cover.

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Remove the vacuum pipe & pcv valve & line from the rocker cover. These just slide out. If they are a bit stuck, gently lever them off the a small flat screw driver. Also time to remove the oil filler cap.

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Now to remove the rocker cover.... can be tricky. Chances are if its been on a long time it will be stuck to the head. What we want to avoid is tearing the cork gasket that seals it to the head. DO NOT try and lever the cover off with a screw driver - you may well slip and tear the gasket. Easiest way I found was to give the rocker cover a couple of light taps with a rubber mallet. It jarred it free, then it just lifts off. Again being carefull when lifting it off not to catch it on anything & ripping the gasket.
Low & behold - this is the view that you will then see....

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And your tappets are located under the rocker arms - see pic

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Now for a bit of tech talk - the basic operation here, is the cam rotates its eliptical lobes around > these lobes push down on the rocker arms > the rocker arm pivots off the tappet > the rocker arm depresses the valve. Reason for the tech talk is because at any given time on the GR motor, there are 6 vavles that are depressed in each head - either fully or just about to. Meaning that you cannot attempt to remove a tappets that is under load - ie depressed. This following pic may help. The tappet on the left can be swapped out - the one on the right cannot because the valve is open (ie under load from the cam / rocker assembly)

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If you want to get really technical about: if you rotate the motor till its at TDC (Top Dead Centre) where No.1 piston is at the top of its stroke) you can do 6 of the 12 tappets in one go. You can then rotate the motor 180 degrees (No.1 at the bottom of its intake stroke) and then do the other 6 tappets.

Or, if you're a dodgy prick like myself, you can just give the ignition a flick & the motor will turn a bit & roll the cams off the tappets you need to get at. I needed to flick the motor 3 times to get at them all.

Your new tappets should look a little like this:

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Now to lever the old ones out. This is by no means a science, you lever of whatever you can find, just DO NOT lever of the cam lobe itself. You can do serious damage if you scratch the crap out of a cam lobe, then drive off at 9,000 rpm.

I just levered off the edges around the head.

Tip: because these are oily buggers, I only used one hand to remove them. Keep your other hand clean to lever with the screw driver (learnt that the hard way!)

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If you dig the screw driver to far under you may end up try to lift the tappet out as well. Just re-adjust your lever till you have just the rocker.
Try to lever the rocker up & across to the side a little just enough for it to still sit on the tappet, but not properly. You can then re-adjust your lever to keep going.

This is where it gets scary - now knock the rocker off all the way. As its sprung loaded it may fling off. It usually lands in the area around the tappet that is hardest to get at with your fingers. When you develope a technique, you can avoid this springing business.

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Now just remove the tappet by sliding it out of its seat. You can remove the rocker arm as well.

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Comparison of old & new. Note the wear and tear around the edges of the old tappet body and on the tip.

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Also note on the new tappet - you can see how much I can compress the spring loaded tip. That is almost impossible to do on a worn one. Stiff as you like....the main reason for 'tap! tap! tap!'

ImageImage

Now to install the new ones. Ensure you give the new ones a good lube with oil. Then just slide back into the head.

Tip: GO SLOWLY when reinserting. Why? Becasue the hole that it sits in has an oil gallery running off it. If you go in quick - you will push the oil in the line, that line inturn pushes the oil out into the head via another oil gallery. It just so happens that the oil gallery into the head squirts straight up - into your eye!! (also learnt the hard way)

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Now it gets a little fiddly. Rest the rocker arm back onto the valve tip. You then have to lever the tappet end of the rocker arm back up onto the tappet. Pics can only do so much to describe this. Need to do it to know. I got quite nifty at this & was able to do them first go. Some times when you lever the friggen rocker pops off the valve & falls into the head etc etc etc... just check the pics :P

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Now all you have to do is repeat that 11 more times! :D Or 23 more times if you are doing the rear bank as well.

All done:

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Re-assemble every thing in the reverse order that you took it off. Only thing to note - do not tighten the rocker cover bolts excessively. They are pinching a cork gasket to the head remember. Only needs to be nipped up.

Now as mentioned, the rears are a nightmare to get at. Procedure is the same, but the intake manifold need to come out. As a DIY on this has already been done, Im not going to do it again - just use this one:

http://www.ftooc.org/phpbb/viewtopic.php?t=23905

It goes into great detail as to how to remove everything you need to get at them - then just follow this guide to swap them :wink:

Genuine from Mitsubishi, these tappets are $35 odd dollars each - when you need 24 that adds up very quickly. Kempys do these aftermarket units for $240 a set of 12 - $480 all up.

Garages will also charge like wounded bulls to do this work and you will be told that the cams & rockers assemblies need to be completely removed in order to do it. I've heard of quotes upwards of $2000 with gen parts.

The front bank took me just over 2 hours in total.
The rear bank took me over 4 hours in total.

If anyone needs help doing this I am more than happy to talk with you about it. If your in Sydney I may even be able to help you.

Cheers,
Ben
Last edited by Bennoz on Sun Mar 19, 2006 7:41 pm, edited 1 time in total.
scarecrow
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Post by scarecrow »

Very nicely done Ben! I could have a crack at the front's, but i'll need to do the rears eventually, maybe hold off doing those until the sparkplugs need changing too.

I remember we were gonna get a good discount when i first emailed kempy's about doing a group buy. If anyones interested it would be nice to start that up again.

They're a bit costly, but, to remove the embarrasment of a tappey engine I think the price is almost fair.
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Post by Bennoz »

And when you replace them, your tappet clearances are reset to factory specs - the motor runs like a dream after you do this.
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Post by payaya »

Ive been through it, I'll never do the rears again in my whole life! Couldnt get good leverage on the rocker arms to pull out!

Good way of turning the engine is turn your wheels to the right, you'll see a little plug, take it out a 1/2 inch socket goes in the centre of the crankshaft pulley and you can turn it that way!

What is pissing me off is i still get tapping sometimes!!!!

What oil you using Bennoz? I tried Motul i think 10w40 it ticks!!! Tell me there is something else worth getting as im servicing soon!
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Post by mxysxy »

Great input Ben,
Thank you very much

I guess the same applies to GPXs
only the bolts are in different places.

BTW, I bought a house last Sat, it has a large double garage and work bench etc...
I guess I cant complain about the space now
better get these tappets from NZ
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Post by Bennoz »

Payaya wrote:What oil you using Bennoz? I tried Motul i think 10w40 it ticks!!! Tell me there is something else worth getting as im servicing soon!
Yeah mine still get a tiny tap from time to time now - but nothing that is annoying. I use a Penzoil 10w40, if I go lighter it will tap more. I have a feeling that the cause of further tapping on the GR's is caused by pounded valve springs. After a lot of kms mixed with some hard driving, the springs tend to loose their seat pressure which inturn slows their return rate after depression & tap tap tap again... $$$
mxysxy wrote:I guess the same applies to GPXs only the bolts are in different places

The theory is similar to GPX's just there is a threaded section on the tip of the tappets. Unwinding the lock nut, then winding the tip up or down adjusts the clearance from rocker arm to tip of tappet. Majority of piston engines have similar setups. The GPX has no need to replace them as they are adjustable
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Post by khunjeng »

Thats the best guide I have seen for tappets...great effort
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Post by scarecrow »

Bennoz wrote:The GPX has no need to replace them as they are adjustable
I'm pretty sure the GPX tappets can still be damaged enough so that it is impossible to adjust them correctly, this would be common in high km gpx's i'd think.

I'm extremely disheartened to hear about an occassional tap after a tappet change.. i suppose it's unavoidable though.
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Post by Bennoz »

scarecrow wrote:I'm pretty sure the GPX tappets can still be damaged enough so that it is impossible to adjust them correctly, this would be common in high km gpx's i'd think.
They can - the tip get worn just like GR ones - also the plastic collets around them snap off & get destroyed.
scarecrow wrote:I'm extremely disheartened to hear about an occassional tap after a tappet change.. i suppose it's unavoidable though.
Yeah... but maybe is just my hearing getting super sensitive & sort of 'listening for' a tap noise. When in esessence im really grasping at straws... its nothing compared to the noise previously
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Post by payaya »

you can hear mine clearly! Still nowhere near as bad, but its also almost time for an oil change.

I may go for the Penzoil or Magnetec next.
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Post by G_A_V »

Very Good guide, I am going to attempt these next week, are the rear ones really that bad? any tips on getting the rocker arms off ? oh also couldnt you just hand crank the engine so that the arm is at the top most position to remove and reinstall.
I have a few mechanic freinds, might need to get some help
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Post by Bennoz »

G_A_V wrote:Very Good guide, I am going to attempt these next week, are the rear ones really that bad? any tips on getting the rocker arms off ? oh also couldnt you just hand crank the engine so that the arm is at the top most position to remove and reinstall.
I have a few mechanic freinds, might need to get some help
The rear ones are just an arse to reach (physically) and to find room to lever the rockers off - as you are lot closer to the underside of the bonnet there..... now theres a thought! If you pull the bonnet off it would make it a hell of a lot easier! 8O *smacks himself around the head* why didnt I think of that earlier! :lol:

The rocker arms are really 'choose your own adventure'... when you find a good technique to lever them with your screw driver, stick with it.

Yeah cranking the motor worked for me to move them cams around :wink:

Gimmie a call if you need a hand!
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payaya
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Post by payaya »

the rears are the worst! you just cant get a good enough angle on the rockers!!!

I highly recommend you guys invest in a valve spring compressor for the FTO. You guys can share it around!!!


Will i attempt the rear banks without a proper tool??? No its a bloody bitch!!
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Post by 7gee »

has anyone apart from Bennoz attempted this?

the engine you did the work on... is it by any chance the 6a12?

cheers
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Post by Supplanter »

Yep, FTO GR has a 6A12 engine... FTO GPX has a 6A12 with MIVEC heads.
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Re: DIY: Replacing GR Tappets

Post by incoming »

Bennoz wrote: Genuine from Mitsubishi, these tappets are $35 odd dollars each - when you need 24 that adds up very quickly. Kempys do these aftermarket units for $240 a set of 12 - $480 all up.
Thanks for the write up Bennoz!!
just a Q.. Where's Kempy's?
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Re: DIY: Replacing GR Tappets

Post by Supplanter »

incoming wrote:
Bennoz wrote: Genuine from Mitsubishi, these tappets are $35 odd dollars each - when you need 24 that adds up very quickly. Kempys do these aftermarket units for $240 a set of 12 - $480 all up.
Thanks for the write up Bennoz!!
just a Q.. Where's Kempy's?
They are located in NZ: http://www.kempys.co.nz/

It is cheaper to get things delivered from them than to buy in Oz.
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Post by Tippin »

do worn out tappets constantly tap...?

my engine tapping is on and off while i drive, but it is the worst on cold starts, could it rather be my injectors or injector solenoid? that would explain the loud tapping on cold starts wouldn't it?
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Post by vipfto »

tippin9 wrote:do worn out tappets constantly tap...?

my engine tapping is on and off while i drive, but it is the worst on cold starts, could it rather be my injectors or injector solenoid? that would explain the loud tapping on cold starts wouldn't it?
tappets for sure, are you GR or GPX as mivec ones can be adjusted no need to replace
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Post by I8A4RE »

vipfto wrote:
tippin9 wrote:do worn out tappets constantly tap...?

my engine tapping is on and off while i drive, but it is the worst on cold starts, could it rather be my injectors or injector solenoid? that would explain the loud tapping on cold starts wouldn't it?
tappets for sure, are you GR or GPX as mivec ones can be adjusted no need to replace
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