ACL rod bearings after 150k kms.

[gerg]

I disagree Wayne. This paper talked about and solved bearing cavitation. If this is indeed what chews these bearings up then there is hope using similar techniques could work here as well. If its simply a bearing being undersized then there is no hope for this engine.

 

[crushers]

nope, disagree.
it talks about main bearing cavitation.
the mains in the HDT have never shown any signs, only BEB.
IF the same indications showed with the mains then you might be on the proper leads ...

IF it is extra power produced by the turbo then a G/turbo might show more rapid signs ... maybe someone that has a G/tubo'd HDT could drop the caps and take a look at ...say ... 80K then again at 120K

if it was harmonics then why doesn't the mains show problems?

 

[gerg]

So yeah I hear what your saying about the mains not being affected. My point was that the paper shows a real bearing modification that was effective at combating cavitation. The root of the cavitation for crank and rod bearings can be very different, but altering the bearing itself seems like a fairly doable thing dont you think?

Im pretty encouraged overall even though the paper isnt an exact fit for the 1hdt, but it very well could translate over. If the BEBs are cavitationg then increased pressure load will exacerabate this. Cource if the bearing is too small right off the bat then turboing it will also increase the problem and grooving the shell will only remove even more surface area making it even worse than normal.

I personally think it would be hard for Toyota to undersize a bearing. I just dont see that happening and making its way unmodified into a widely produced engine. I can see cavitaion being the issue and Toyota using an oil additive (calcium) to combat the problem differing the cost of the mod onto the consumer for maintanance. In my mind I can see, if I were them, I would do that. By doing this, Toyota doesnt have to acknowledge a cavitaion issue and only has to specify a certain oil. Id lets them deal with the problem discretely and cost them nothing.

As ive been reading, rod bearing cavitaion on high HP engines is not uncommon and many folks run bearings modified exactly as the bearings we read about in the paper. So this is sort of the direction my reading has gone to. Diagnosing cavitaion and altering the bearing to deal with it.

g

 

[Hulsty]

Some more food for thought, the problem only systematically appears in the 1HDT, 1HZ (and +T), 1HDFT(E) do not suffer from the problem, there are heaps of unopened ones getting around with big kms on them.

 

[serenity]

My 1hd-fte is unopened as far as I can tell at 280,000km. Would be interesting to see the condition of those bearings.

Cavitation can be caused by a restriction of flow in a hydraulic system, for instance when there is a restriction in the suction of a hydraulic gear pump the discharge will see cavitation.


Bearings require a certain amount of oil flow as well as pressure to provide lubrication, pressure is resistance to flow. Grooving a bearing will increase pressure on the remaining bearing surface and in turn the layer of oil between those surfaces, creating higher resistance to flow but decreasing lubrication. So if we are able to increase flow to the standard bearings we should see an increase in pressure and a decrease in cavitation, without decreasing the load capacity of the bearing.

 

[roscoFJ73]

i am wondering is adding a turbo to the 1HZ might cause this concern.
i know i change out the BEB when i turbo a PZ or a HZ to help alleviate this.
i will need to pull the caps and do an inspection ... maybe it is the higher load of the turbo'd HDT ... maybe it isn't.
that paper really doesn't help at all with this particular BEB concern.

It may also be something to do with the 1HZ being IDI and the 1HD T being DI. Con rod length could also be playing a part.

 

[powermad]

Cavitational erosion is the result of air in the system exploding and making craters.
Little micro bursts that will remove material.

It will do it to a piston liner if the coolant DCA is not correct.
It's not heat related, it's harmonics.

The BEB I posted earlier on the Volvo engine were the only ones showing that type of wear.
The mains all looked great.

 

[serenity]

Cavitational erosion is the result of air in the system exploding and making craters.
Little micro bursts that will remove material.

You're thinking of aeration, where air is sucked into a hydraulic system due to low oil levels in its reservoir. Cavitation is vapour or vacuum pockets caused by a rapid change in pressure. Commonly seen when you have a restricted intake on a hydraulic pump, the pump will create a vacuum on the suction side (low pressure) which is then sucked through the pump into the discharge side where the greater pressure causes the vacuum to implode. Due to the pressure, vapour caught in the vacuum is subjected to intense heat causing it to ignite or detonate which causes erosion.

 

[gerg]

Air entrainment can be a very big problem that degrades your film strength. I'd think if that were the issue you would see it evident all over the engines bearing surfaces. Instead you just really see in on the rods here.
Cavitation causes little vacuumed bubbles that, when they collapse, can create huge shock waves and high heat in very small areas. Almost like little bombs. In part I think that is why ACL used tin alum bearings. The surface is harder and is generally more resistant to cavitation. That is another reason why I suspect cavitation is at least one of the issues.

 

[gerg]

So I found that ACL does indeed have bearings for race applications that are designed for higher load capacity as well as have anti cavitaion mods to them. Not sure if they have them for the 1hdt. I emailed them but no reply. It doesn't list the 1hdt in their catalogue.

Here's a link.
http://www.aclperformance.com.au/docs/ACL_Engine_Bearings.pdf

 

[gerg]

I also found these folks that use a totally different surface feature to increase fluid film strength as well as combat cavitation.

http://www.taihonet.co.jp/e/mgb_01.html
I'll email them guys tonight.


Nice to know there are some in the box solutions to this problem. It might not solve it, but might greatly increase the life of the bearings.

 

[crushers]

curious to see the results ...
i have 6 1HZ to be rebuilt this spring/summer, might as well put in bearings that will last

 

[Dan_J-spec_fj62]

I also found these folks that use a totally different surface feature to increase fluid film strength as well as combat cavitation. http://www.taihonet.co.jp/e/mgb_01.html I'll email them guys tonight. Nice to know there are some in the box solutions to this problem. It might not solve it, but might greatly increase the life of the bearings.

1HZ
1988 D64163CC94100 COASTER -HZB41
1HD-T
1988 D64164CC94100 LAND CRUISER-80 COASTER -HDB51

M707A
63-706-1 63-706-2
7 7
R707A
64-706-1
12
T706A
65-706-1 65-706-2
2 2
C706A
62-706-1
2
P707H
(FOR 1HZ)
67-706-1
6
P707HS
(FOR 1HZ)
67-706-1S
6
P709H
(FOR 1HD-T)
67-709-1 67-709-(L)
6

P709HS
(FOR 1HD-T)
67-709-1S
6

http://www.taihonet.co.jp/e/ebc/all.pdf

Page 19 for the 1HD-T

Dan

 

[Jan-78FJ40]

Jan... Any chance you could post some pics of the ft BEBs or perhaps do some measurement to see a difference? I suspect the engine is all together, but just thought I'd ask.
Thanks
g

Sorry, no. The engine is back together and I did not take measurements.
I put new bearings in anyway and threw the old ones out.
cheers,
jan

 

[gerg]

I figured your motor was all together Jan, no problem.

Thats a pretty complete list for the bearings Dan. Ive been talking with a distributor in Aus for Tahio and emailed Taiho directly last night asking a few questions. Be good to scrounge the web for people that have reported back on using these bearings. Im sure there must be lots of folks that have.

So id never recomend anyone use a bearing that I hadnt already used myself so.... since I dont have a 1hdt... im willing to put one into my truck and be the guinea pig for trials, I just need a kind sponsor to donate me one

 

[B Point]

If you guys need any assistance with communications with Taiho let me know.

 

[Gareth]

I figured your motor was all together Jan, no problem.

Thats a pretty complete list for the bearings Dan. Ive been talking with a distributor in Aus for Tahio and emailed Taiho directly last night asking a few questions. Be good to scrounge the web for people that have reported back on using these bearings. Im sure there must be lots of folks that have.

So id never recomend anyone use a bearing that I hadnt already used myself so.... since I dont have a 1hdt... im willing to put one into my truck and be the guinea pig for trials, I just need a kind sponsor to donate me one

Those are the bearings I put in my truck. Personally I doubt that any bearings can fix a fundamental design flaw.

I have 5k on them so far, I put about 30k+ kms a year so if this thread is still alive in 2019 I'll put some pics up.

 

[Gareth]

double post

 

[ForealBoreal]

Also run if Taihos in my truck.
Only 80,000 more kms to go and I'll have an update post turbo job. Only 4 more years

 

[gerg]

I doubt too that there is a "fix" for this problem, but if you can change several things, together it might have a very good effect on bearing life. If it is an oil flow problem as Dougal suggests, then oil choice would be a major consideration. On so many cavitation threads I've read, thicker is rarely better. If it's a flow problem, then thicker could seriously I exaggerate that as well. I still think that going with the best flowing 30wt multigrade synthetic could really be a good direction to go.
g