Pin for Timing Belt Idler (1 Viewer)

[Greg_B]

I've been following along with your experience and the most recent one by arnott1 and they have been weighing on my mind as my t-belt replacement was coming up. Two additional data points to check off was pin security and time belt cover gasket condition and making sure it stayed in place on assembly.

Today I started it. Got everything removed, then went to examine the pin. Surprise...no pin. A buddy was at the shop helping and neither he nor I recall hearing or seeing anything drop out when the idler assy was removed. I forgot to look at the pin location when it was all together. So, the assumption at this point is that it has not been in there for 100,000kms, since I did the waterpump, cam oil seal, idler and spring when it was all on the shop floor. Perhaps when I was going through it 100,000kms ago and using the FSM for specs I did not realize it was missing as the FSM timing belt section makes no mention of the pin as has been mentioned by a couple folks in the last page.

About that pin: What does it do anyway? Other then be used as a locator assist for putting in the 8mm timing belt idler pulley bolt and the spring bolt of the timing belt idler?

The idler pulley can move as the hole the spring bolt goes through is oblong and without the pin triangulating there may be the possibility of some minor movement of the plate (what little the shoulder of the two bolts would allow as both are torqued to 20lbs).

Looking at the used idler assy i just removed, the plate between the idler assy and camshaft oil seal retainer (pic of the retainer I mean is on page EM-79 of the FSM) shows virtually no wear, the two bolts that go through the plate and camshaft oil seal retainer show no grooving or wear marks where the plate would be resting when everything is bolted in place.

In my brief peruse through the FSM in other sections I can not find mention of the pin. If anyone locates this section in the FSM please let me know.

So what does the pin do...other then act as a locator? Put it together without the pin again?...unless someone posts up with solid info why not to.

Yup, it's almost free.

@carbon60 With your tappy tap tap installation, did you use any adhesive like locktite?

Thanks
gb

 

[roscoFJ73]

Looking at some old pics I seem to remember noticing a bolt and the pin missing and went to Toyota to order to them. If it was in there before ,the engine reconditoner must have removed it and tossed it in the bin.

 

[carbon60]

@carbon60 With your tappy tap tap installation, did you use any adhesive like locktite?

I did not. It was an extremely tight fit.

 

[roscoFJ73]

With these ones that have come loose, I'm wondering if they have been in/out before.

 

[Dave 2000]

I am in the midfle of some PM, I have just recieved all the parts I ordered, belt, tensioner, both tensioner bolts, new spring and spring retainer, never gave the pin a thought.

Regards

Dave

 

[Cruisin']

I happen to have a 1993 in the shop, so I popped the timing cover off to take a peek, and the pin is there. So is the pin on the other side of the idler assembly, which goes in a hole in the timing plate, and rests against the side of the idler assembly. When I do the timing belt on it I'll be carefully checking that both pins are quite snug in their holes (maybe even pop them out and re-insert with some Loctite on them).

 

[carbon60]

I happen to have a 1993 in the shop, so I popped the timing cover off to take a peek, and the pin is there. So is the pin on the other side of the idler assembly, which goes in a hole in the timing plate, and rests against the side of the idler assembly. When I do the timing belt on it I'll be carefully checking that both pins are quite snug in their holes (maybe even pop them out and re-insert with some Loctite on them).

Wait, there are two pins?

 

[IanB]

Wait, there are two pins?

Good thing you bought 5!

 

[Cruisin']

Wait, there are two pins?

Yes, when you had the idler off you should have seen four holes on the plate on the engine. The two middle ones are for the two bolts, while the other two have pins in them. The one to the right (when looking at the engine) goes through the hole in the idler assembly. That one I think would be important. The one on the left rests against the idler assembly plate. This seems less crucial somehow, but there it is.

At least all you'd have to do to put the other one in is pull the timing cover and tap it in.

 

[Greg_B]

Thanks for posting that info here Cruisin'. It's hard to tell from the epc diagram in post #1 if the two pins references are for those two holes and still have not read detail in the engine FSM on them.

roscoeFJ73, looks like that photo might have been part way through assembly of the water pump/t-belt detail as it looks like the bolt for the cam pulley is missing as well? The pulley is also hiding the detail of where the 2nd pin would go, if it's there. My HD-T came over as a runner and I baselined a bunch on it before putting it in.

No discussion from anyone on "what do the pins do anyway"?

Attached to this post are two pictures of my used idler assy. Other then being a locator, if the pin(s) are designed to keep the plate in perfect orientation to the cam oil seal retainer plate to reduce movement and wear one would think the shoulders of the two bolts that are torqued to 20ftlbs and the contact surface of the plate would show some wear or marks with no pin(s) in place?

 

[SNLC]

Yes, when you had the idler off you should have seen four holes on the plate on the engine. The two middle ones are for the two bolts, while the other two have pins in them. The one to the right (when looking at the engine) goes through the hole in the idler assembly. That one I think would be important. The one on the left rests against the idler assembly plate. This seems less crucial somehow, but there it is.

At least all you'd have to do to put the other one in is pull the timing cover and tap it in.

So reading some of these horror stories lately here on mud. I was working on my truck the other day and decided to take off the timing cover and take a look see. I changed it all out about 2,000kms ago. I have the pin on the right that goes through the idler but I don't have one on the left that rests against it. Everything looks the same in mine as when I did it 2,000kms ago so I just closed it up. The peek at it was for piece of mind!

Cheers

 

[Mookies]

Took a look at my 1PZ this morning just to ease my mind......same as above. I have a pin on the right that isn't going anywhere. I do have pin on the left that the plate rests against but seems like it isn't needed. Gasket looks fine. Toyota must have thought that the pins make sense to locate the tensioner plate but also as a second line of defense if the bolts broke. I wish I could keep the outside of my engine as clean as the inside of the timing cover!

 

[roscoFJ73]

roscoeFJ73, looks like that photo might have been part way through assembly of the water pump/t-belt detail as it looks like the bolt for the cam pulley is missing as well? The pulley is also hiding the detail of where the 2nd pin would go, if it's there. My HD-T came over as a runner and I baselined a bunch on it before putting it in.

Correct. It was 13 years ago but I seem to remember the job had come to a halt waiting on parts like the pin and the missing bolt on the IP pulley and I was just adding on parts to see how it went together.
The engine had come from an ex mine vehicle and some of the bolt hex were a bit damaged, so they were replaced with new.

 

[carbon60]

I tried to put the other pin in, this evening. No way I could do it with any degree of confidence without taking the camshaft gear off, as well as the idler pulley assembly. So I left it out.

 

[HRTROB]

All this talk about timing belt tensioners failing has got me worried. I don't recall seeing any dowel pins when I changed my belt. The parts diagram doesn't list a dowel pin on mine (1996 1HDT 12 valve). Going to pull the cover tomorrow and have a peek

 

[IanB]

All this talk about timing belt tensioners failing has got me worried. I don't recall seeing any dowel pins when I changed my belt. The parts diagram doesn't list a dowel pin on mine (1996 1HDT 12 valve). Going to pull the cover tomorrow and have a peek

View attachment 1681631

View attachment 1681634

The dowel is pictured just to the right of the timing belt, but no corresponding part # on that diagram.

 

[HRTROB]

The dowel is pictured just to the right of the timing belt, but no corresponding part # on that diagram.

Yup it's in the diagram but it's not clickable so it means it doesn't apply to my engine. You can also see in the photo of my engine with the tensioner removed that there is no hole for the pin to go into

 

[HRTROB]

Here's a comparison of mine with @AlbertoSD 's

 

[roscoFJ73]

I'm wondering if the pins are there to locate the alloy plate so you don't smudge the thin bead of seal packing as you fit the plate to the head.

 

[Greg_B]

Thought I would move the line further around, perhaps closing the circle on one item and bring this thread to the top.

In addition to a friend having a pin readily available, I bowed to internal pressure and timelines, (prepping for a trip to Utah Nevada and Arizona) installed one pin, then the new bearing, belt and spring. I used a little Permatex High Temp Sleeve Retainer but figure most of that sloughed off as it was tapped in, however perhaps the placebo effect will work for me.

I've put 10,000kms on that vehicle since then and figured I'd pull the cover and inspect things. All was good.

I've also spent a little more time in EPC. It was really interesting to hear that some of the world market got 1HD-T equipped 80 series till at least 1996 thanks to HRTROB.

EPC calls the aluminum housing the timing detail bolts to the "Retainer, Camshaft Oil Seal" 11382-17010

Using that number (good for 1990 - up 1HD-T) on line pictures show no holes for pins, as per the 1996 1HDT shown above in HRTROB's post. If I needed this cover during a rebuild for my 1HD-T this is what I would get. So Toyota must consider the pin/s not needed; In hindsight I may have well just left it with no pin.

I then looked around at the hydraulic style idler bearing setup used in the 1HD-FT (wouldn't that be nice) and saw the number good for the HZ application after the mid 1990's. As the 1HD-T shares the single cam I then took a look on line at the hydraulic oil retainer cover profile compared to the spring style cover. No go, different profile. It would be interesting and only worth exploring during a complete rebuild of a 1HD-T, but I wonder what would be needed to adopt the hydraulic idler bearing such as the Retainer, Cam Bearing, Cover, timing Gear, No.2 and then things in front like the cover. Or what else changed and would make it not viable.

gb