80 series

Submitted: Monday, Jul 14, 2014 at 20:14
ThreadID: 108739 Views:1522 Replies:4 FollowUps:6
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how often do you adj the tappets I HDT how hard is it [do the get looser or tighter] thanks malb
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Reply By: Ross M - Monday, Jul 14, 2014 at 21:14

Monday, Jul 14, 2014 at 21:14
There are no tappets as such, they have a cam running directly on a upturned bucket with a shim captured at the top for adjustment purposes.
The valve clearances get less with use and that will begin to affect the sequencing of the gas flows in and out of the engine if not as they should be. ie, less power and economy.

The adjustment is done by shim thickness and requires them to be measured and appropriate substitution and or replacing with the correct shim thickness for each valve.

Bad cases cause the valves to be held open and if it happens especially on an exhaust valve, the sonic speed of very hot gas will burn the valve faces.

Often Toyota Technician serviced vehicles may reach 200,000km and have never been checked because everyone trusts everyone before them to have done it. Naughty naughty.
Quite a few on another forum with 80 series have had it happen to them.

Best done by a reputable mechanic/ 4wd repair shops, will often do it right. Check of course.
AnswerID: 536063

Reply By: The Bantam - Tuesday, Jul 15, 2014 at 08:02

Tuesday, Jul 15, 2014 at 08:02
as mentioned above modern overhead cam diesel motors do not have tappets.

All the diesel performance articles will tell you there can be bing improvements from adjusting the valve clearances.....on the other hand many modern diesel motors go their entire lives without any adjustment...and by entire life I mean 300 000 pluss.

cheers
AnswerID: 536066

Reply By: pop2jocem - Tuesday, Jul 15, 2014 at 08:58

Tuesday, Jul 15, 2014 at 08:58
Strictly speaking any engine that uses the particular design of in head or side valve mechanism as being discussed here does have "tappets". What the overhead camshaft style of engine has dispensed with are the pushrods and rocker arms. As there is not a hydraulic or other type of automatic valve lash or clearance adjuster the necessity to periodically manually adjust the clearance between the camshaft and the end of the valve exists.
For these particular engines I would have the clearances checked and if necessary adjusted every 100,000 k to maintain optimal performance and avoid the possibility of burnt exhaust valves. As Ross has explained the adjustment involves the selection of the appropriate thickness shims.
Not difficult to do for someone with ability to read and understand a workshop procedure.

Cheers
Pop
AnswerID: 536072

Reply By: B1B2 - Tuesday, Jul 15, 2014 at 11:08

Tuesday, Jul 15, 2014 at 11:08
G'day Mal,
I think the manual recommends 60,000km.
It is easy to check the clearances of the bucket tappet using a feeler gauge.
Only 2 positions of the engine are required.
Rotate c/shaft until notch on pulley lines up with pointer on timing cover. No1 firing.
Clearances Inlet – 0.15 - 0.25mm
Exhaust - 0.35 – 0.45mm
Then check with a feeler gauge
No1 - Exh & Inlet - will both be loose
No2 Exh
No3 Inl
No4 Exh
No5 Inl
Rotate 360° and line up the notch again. - No6 firing
No6 - Exh & Inlet will both be loose, and check the other tappet of the previously checked cylinders.
If you decide to go this way, be aware there are drain holes through the head and these should be covered to avoid dropping anything through.
You will at least know which - if any needs adjustment. I have found I only needed 2 or 3 tappets removed and a very small amount surface ground.

Good Luck,

Bill

AnswerID: 536075

Follow Up By: Ross M - Tuesday, Jul 15, 2014 at 13:53

Tuesday, Jul 15, 2014 at 13:53
It is strange that if the book procedure mentions 60,000km intervals for the checks, but professional service people ie, a trusted dealer workshop, have always serviced a vehicle and never looked at them.

It is often the second owner who discovers that has happened, or rather not happened in the case of the valves.
Sort of destroys the faith a little. Can destroy the engine too.
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FollowupID: 820133

Follow Up By: pop2jocem - Tuesday, Jul 15, 2014 at 16:58

Tuesday, Jul 15, 2014 at 16:58
Exactly why I do my own servicing and repairs. OK not everyone can do all the work but a relatively simple job like checking tappet clearance ain't exactly rocket surgery.
When I had the old 1HZ engine in my ute it used the same shim adjustable method. I checked the tappets at the same time as I changed the drive belt. Personally mine did not need adjusting until around the 200,000 k mark. They seem to require looking at fairly early on in the vehicle's life and then settle down to what I would term normal wear.
There is no way on Gods green Earth that I would allow any dealership apprentice loose on the valve bridges of the 1HD-FT.

Cheers
Pop
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FollowupID: 820138

Follow Up By: Member - Mal B - Wednesday, Jul 16, 2014 at 19:29

Wednesday, Jul 16, 2014 at 19:29
Thanks for the help could you tell me the name of the lifter required to get the shims out can you buy one or make one thanks malb
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Follow Up By: pop2jocem - Wednesday, Jul 16, 2014 at 19:39

Wednesday, Jul 16, 2014 at 19:39
Mal, there is a Toyota service tool available to compress the valve springs so that you can get the shims out and in but I have found a couple of flat blade screwdrivers do the trick with a bit of practice. Just be careful the cylinder you are attacking has it's piston nowhere near TDC.

Cheers
Pop
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FollowupID: 820225

Follow Up By: B1B2 - Wednesday, Jul 16, 2014 at 20:31

Wednesday, Jul 16, 2014 at 20:31
Mal,
You can make one easily with a couple of pieces of flat bar and a bit of threaded rod. The idea is to make a lever to push the bucket down. If you have a helper it is only a matter of flicking the bucket out. I used a cable tie to hold lever down and did it on my own. Use the rocker cover thread holes for your anchor.
Have a look on LCOOL. http://www.lcool.org/forum/viewtopic.php?t=4328&postdays=0&postorder=asc&start=15


Give it a go,

Bill
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Follow Up By: Member - DOZER - Thursday, Jul 17, 2014 at 21:54

Thursday, Jul 17, 2014 at 21:54
the hdt needs checking every 40,000 by the book, or rule of thumb upon purchase and every time you do a belt, check tappets, change big ends. The hdft 80 series (95-97) and hdfte 100 series 4.2 td went back to tappets, to actuate 4 valves....so not all Toyota over head cam diseasals have buckets.....if you do not check them, and the gap closes due to valve seat recessing, the valve will burn out. Friend found out at 500000kms the hard way.(91 hdt) the valve seat overheated and popped out of the head, lunching the valve into the topof the piston. New head, piston, rings, etc etc....
b4 you bag me out, walk a mile in my shoes, then your a mile away and have my shoes :)

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