Attention all Toyota 2H Engine owners !
Submitted: Wednesday, Jan 01, 2003 at 01:00
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Matt
I would like to inform you of potential problems with Toyota 2H engine valve rocker gear.
The rockers used with this pushrod engine have a chrome hardened face where it contacts the valve stem. I have noticed that when engines reach 250-350 000k that the chrome face begins to ware through and if not checked, the ware will accelerate and will result in a damaged valve stem, possible damage to valve guides & flaking metal particles being distributed throughout the engine.
It is wise to remove the rocker
bridge assembly & inspect all rockers for damage.
Rockers may be inspected at random by removing adjusting screw & pushrod, sliding the rocker clear of the valve spring & spinning it over to inspect the face. If using this method then beware that when removing the pushrod, the cam follower may stick to the end of it & become dislodged. Spin the pushrod & move it side to side before removal to prevent this happening. If cam followers dislodge then removal of sideplates will be necessary to reposition them.
If rockers are worn then replacement is the only option. Toyota list 2 types, being for early & late model 2h engines. There is about $8 difference in price but I have compared both types & cannot distinguish any difference between the two of them. Toyota cannot tell you what the difference is either.
Owners of “reconditioned” 2h engines may find that their old rockers have been refaced to a smooth finish by the reconditioner & put back into use.
This will result in rapid ware of the rockers & damage to all valve stems as the chrome face of the rockers is no longer present
Cost of 12 new rockers & a rocker shaft will set you back approximately $600
I welcome any comments on this matter, including results of inspection with your engine.
Matt
Reply By: chopper - Wednesday, Jan 01, 2003 at 01:00
Wednesday, Jan 01, 2003 at 01:00
Thanks Matt, that's certainly something to look out for.
I have just put in a RECO motor after the old girl cracked a head at 380 000kms. Going by the 'warranty' dealings i had with the rebuilders i wouldn't be at all surprised to find that they took the above shortcut.
It's testimony like yours that someone should collect (Toyota??) and keep centrally.
...and before any one gets upset and starts calling me names... Iknow that It would not be in Toyota's interest to keep such data... just wishful thinking.
I'll sit back now and wait for the "experts" -- you all know who.
chopper
AnswerID:
10382
Follow Up By: Matt - Wednesday, Jan 01, 2003 at 01:00
Wednesday, Jan 01, 2003 at 01:00
How is the old girl running anyway?
I recently contacted toyota customer service with a technical enquiry on 2h cylinder heads. The customer service officer could only quote figures from the toyota service manual but when I explained that I already have a copy of the manual & the reason I am contacting you is to obtain important specifications that were not published, I was told that I couldn't be helped.
I asked if I could speak with a toyota engineer on the matter & I was told " sorry we dont have any engineers in Australia, thet are all in Japan"
I then asked if I can make contact with Japan an the matter by email on the matter & guess what - "sorry, we have no contact with them".
As a last ditch effort, I logged onto Toyota Japan website. Written in English but no email contact availabe.
FANTASTIC CUSTOMER SUPPORT TOYOTA - THANKS FOR NOTHING
FollowupID:
5443
Follow Up By: Chopper - Wednesday, Jan 01, 2003 at 01:00
Wednesday, Jan 01, 2003 at 01:00
Yeah i'm quite happy, I am looking forward to it loosening up a little more though.
I've always been happy with the Toyota parts guys. Especially when they tell me where to get mirrors for $30 each (non genuine but exactley the same) as opposed to $90 each genuine.
It may be worth talking to hire company operators (mechanics), as they know there trucks inside out. Although I haven't hired a troopy with a 2H for a while, they're all 1hz nowadays.
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Reply By: OziExplorer - Wednesday, Jan 01, 2003 at 01:00
Wednesday, Jan 01, 2003 at 01:00
Matt did you check about getting them re-chromed instead of replacing them?
AnswerID:
10384
Follow Up By: Matt - Wednesday, Jan 01, 2003 at 01:00
Wednesday, Jan 01, 2003 at 01:00
This process would involve refacing the rockers to a smooth finish by a reconditioner as
well as polish to a mirror finish & application of industrial chroming by a plating company. The cost wil be high, also the working geometry off the rocker will be atered.
The
bore of the rocker may be slighty oversize as
well, not to mention that the sides off the rockers become scuffed from the rocker bridge springs pushing against the side of them
Much easier to repace, you can source new ones from Engine Australia or SMS Diesel, they will be genuine toyota parts but cheaper
New rockers come compete with pushrod adjusting screw & nut
FollowupID:
5442
Reply By: Derek - Wednesday, Jan 01, 2003 at 01:00
Wednesday, Jan 01, 2003 at 01:00
Matt, a company in
Brisbane called 'Hardchrome' used to do just the thing that Oziexplorer is talking about. The rockers were bored and re-chromed then turned and polished back to their original specs.This was a fairly common procedure and I would have thought cost effective when compared to OE parts. I've just done some work to a 2H and found the rocker shaft was more worn than the ID of the rockers. Did you check the state of the shaft? Hope this helps.
AnswerID:
10414
Follow Up By: Matt - Thursday, Jan 02, 2003 at 01:00
Thursday, Jan 02, 2003 at 01:00
The
bore of the rockers hardly wares, it is the face if the rocker that wares where it contacts the valve stem.
Rocker shafts last for a long time, repacement cost is $100
FollowupID:
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Reply By: stef - Saturday, Jan 04, 2003 at 01:00
Saturday, Jan 04, 2003 at 01:00
hi matt
I've rebuilt my 2h at 260000 km,and the rockers were badly damaged.
As I couldn't afford a new set,I had them reground(they didn't have a chrome face)and tested for hardness:I think they talked about "rockwell" and they still were very hard.
well 100000km later and several check of valve clearance,the rockers are as new,no
sign of wear.
from the beginnning till the rebuilt ,the clearance had never been done,and I think the valves made the clearance themselves.
best regards
stefan from france(toyo addict)
AnswerID:
10579
Follow Up By: Derek - Sunday, Jan 05, 2003 at 01:00
Sunday, Jan 05, 2003 at 01:00
Stef, there are at least 2 types of hardness testing that I know of. You are correct with the Rockwell method. There is also the Brinell method. I think? one may be American and the other British.
FollowupID:
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Reply By: Derek - Sunday, Jan 05, 2003 at 01:00
Sunday, Jan 05, 2003 at 01:00
Matt. Further to my previous posting, we used to build up the valve faces of the rockers of Cat diesels with hard facing electrodes then grind them back on a special but simple attachment that fitted to our valve grinding machine. Most engineering firms either can't do the the more unusual jobs or aren't prepared to take the risk. I'm sure that nearly anything can be rebuilt, you just have to find an engineering firm who WANTS your business. I have seen some of the most unusual components rebuilt, not because of cost but due to parts no longer being available.
AnswerID:
10630