Crankshaft Timing Sprocket Question

[bamashooter]

Background: 

Changing timing belt, tensioner, front oil seal.

Took close to 10 man hours with a heavy equipment mechanic buddy of mine doing most of the attempted removal of the sprocket. Beating the dog crap out of pick forks, crowbars, etc. Budged enough to get a claw-style pulled on it. Perhaps another 1/64" moved with it. I finally took an air chisel to it and after about 10 minutes it cracked / popped free.

 

Between the sprocket and oil seal is a large-diameter shim / washer, etc piece of metal. Believe the common nomenclature for it is "crankshaft timing plate". Haven't found it's role but I'm thinking it's for keeping the timing belt away from the oil pump housing. Not a guide in the traditional sense. It got beat to hell and back during the process. I tapped it and squeezed it in a large vise between two 1x4s. Perhaps useable in an emergency.

 

Two questions:

 

I purchased a Dayco sprocket from Auto Zone online. Never could find what I thought was the proper "shim" online. Went to the local Nissan dealership. Two things. No mechanic had any experience or knew zilch regarding the VG30 V6. Amazing. The parts kid managed to order a 2-pack of the shims. Received and as all others I found online, these are the same diameter, however, they are slightly dish / cupped on one side. Slotted for key. Fairly certain the factory shim was not however it appears to have been machined with a slight recess on one side. The more I compare the more similarity I see between the 2. Convex side out toward radiator. Any comments on the shim?

 

The sprocket:

 

The teeth on the factory sprocket are deep. The new sprocket shallow. Both the new / old belts fit perfectly in each sprocket. The only difference I see is an empty space beneath the belt lugs on the older, deeper sprocket. My friend tells me that space is for cooling the belt. No idea if that's true. I have yet to see a photo of a new, deep sprocket. Everything I see online is the shallow style for the VG-series. Comments? I am considering having the sprocket drilled and tapped for 6mm bolts to use with a simple puller should the need arise. I have now pretty much polished the front end of the crank shaft. Yesterday morning was 1 degree and got up to 9*. It's current a balmy 12 here in north-central Alabama. Rolling blackouts. Not a bunch of fun. By this coming Friday it shows pushing 70. Crazy.

 

Third:

 

Replacing lower radiator hose. I find nowhere online the small section which connects to the thermostat housing. None. Mine "seems" ok after a good cleaning and drowned in silicone. Thinking perhaps I could buy a short straight hose and cut-off a short length?

 

Fourth: (Evidently I can't count)

 

I mostly see the cam shaft timing marks configured at an angle which would form a V-shape ultimately. I found one pic/reference where the guy swore up and down (my words) that the 2 cam sprocket dots should align vertically with their corresponding rear cover marks. I also read where the more accurate method is to count belt teeth from passenger-side mark (sprocket?) to driver-side mark. Followed by the counted teeth from driver-side mark to crank mark. I have no sign of a dot, line, nothing to align the crank sprocket dot to the oil pump housing. Guaranteed not there. I had read days ago another method on the crank 

 

Thanks guys and have a safe, Merry Christmas.

 

 

 

 

 

Edited December 26, 2022 by bamashooter

[Strato_54]

I can not confidently answer 2 and 3, but as for the shims those are a "quide" and to keep it away from the pump. The dome shame should be on both and should go on facing each other, not facing out. This is how my unopened vg33 came and to me makes sense the way it goes together as the shaper edge on the shim would catch the belt if it was ever to start walking.

 

EDIT: This is also how my brothers 95 came as well now that I think about it

Edited December 26, 2022 by Strato_54

[Slartibartfast]

IIRC mine looked like the one on the left. If the tooth profile is the same, the new one should be fine. There is a round-tooth variant (mid '93 and later), doesn't look like that's what you've got there though. 

 

The diagram in the manual makes it look like the washer between the sprocket and the oil pump is flat, and the one between the sprocket and the balancer is dished out (bent away from the sprocket). I would assume you'd want the washer curving away from the belt to guide it without shredding the edges. I don't remember exactly how mine was set up, been a while since I had that apart.

 

For the rad hose, I think I just bought a piece of straight hose of the correct diameter and trimmed it to length. 

 

The marks on the cover are approximate. Count teeth. 40 between cam dimples, 43 between the driver's side cam dimple and the crank dimple. 

[bamashooter]

Thanks guys. BTW, I see 2 guides mentioned to include in diagrams but upon disassembly, mine had only the one between the gear and oil seal. So basically from the rear it's guide / crank timing gear / guide, remainder.

[bamashooter]

Thought I was getting close to completion. Craziest thing. Keep having coolant leakage issue. Get everything dry, etc. 2-3 days pass and all is dry. The next morning there is coolant on oil pump housing and other locations on engine front. With a mechanic's mirror, I hopefully discovered the leak source as being a messed up water pump gasket, primarily on the bottom. Removed pump and discovered the gasket was arguable the worst-condition gasket I have ever seen. Not knowing the history, last night I ordered a Gates (China) pump and gasket. I trust Gates. Additionally, I feel confident now that little "knick" on the bottom of the oil pump housing is indeed the crank timing mark. Watching yet another Nissan video, the poster happen to mention the timing mark is approx 10mm to the right of bottom, right-most casting "thing", I measured and it was precisely 10mm. Marked it. 

 

Noticed a dot of coolant on the upper hose "burp" valve". I personally find that thing to be worthless. Removed, siliconed the threads and finished doing same to the head of it. No reason with the front elevated that it won't bleed the air when changing coolant. Pump should be here in a week or so (Amazon).

[bamashooter]

Update: Though my timing belt replacement turned into a disaster, I stand corrected regarding that little coolant "burp" valve. I must have spent well over an hour trying to get the air out of the cooling system. And that was with the front elevated on a set of ramp. It would just boil (not overheated boiling) and boil. Looked like a green volcano. Kept adding coolant, etc. Finally, I removed that little white plastic screw. Within 5-10 minutes, the air was finally gone. I now love that little turd. Don't understand why the normal way wasn't getting it done but that's how it worked out. I have googled til the cows come home, anyone have  source for that plastic bolt/screw or a brass equivalent? Thanks.

[Slartibartfast]

The MPFI intake uses a regular bolt as the bleeder. I've heard of the plastic bleeder on the TBI, but I don't think I've ever seen one, and I can't find a picture, let alone a listing. Does it look like a standard fastener, or does it have the center drilled out like a brake bleeder? If you can work out the thread pitch, you might find something close enough from mcmaster-carr.