On the z31 forum they mention a "W" block and an "A" block. Just figuring out the differences.

Is there a difference between cranks used in VG engines? I've run into an issue with mine that I've dismissed till now. The bolt used to retain the crank pulley on my stock VG, my wife's VG, and an extra VG I've got in my garage are all the same size; a large black bolt with a round indention at the head of the bolt.

In my JDM VG30ET, the bolt is much smaller and the crank pulley does not seem to go onto the crank as far. I tried the larger bolt, and it will not fit inside the crank. I had to find another bolt that matches the approximate length and had the right diameter to use. The bolt I'm using has a "7" at the head of the bolt.

The reason I'm asking this question now is that I've put two front oil seals in this engine including the one when it was rebuilt. I'm fixing to put a third front seal in it. I've checked with Nissan who says that the seal fits ALL VG series engines regardless. But, that doesn't tell me if there are different cranks and whether I have an older series block/heads. Any input/knowledge is appreciated.

 

you suck at teh maxima fixing?

 

Probably! Either way, someone else put the first seal in, I put in the second. They both leaked. Either it was an install problem or there's something going on with my crank for it to leak like this. It only does it once the engine gets warm. I pulled everything off this evening and watched the timing belt spin, waiting for it to leak below the belt....it did as usual. I just wanted to make sure it wasn't coming from around the oil pan or leaking down from higher up on the engine, like around the cam seals.

I'm guessing if the t-belt has gotten oil on it, I need to replace it?

I've picked up some engine assembly lube that I'm going to coat the crank with before installing this last front seal. Is there some trick to installing it? Which lube is best? I'm just using some AutoZone engine assembly lube.

Why don't you come and help Wayne? We'll go to Harbor Frieght and get you something for you B-Day!

 

OoOoOOooo!!!! presents!!!

Are the seals your putting in from the dealer,or idiotzone stuff?

 

Uh, UH! Only Nissan gaskets!

However, now that I think about it....the second MIGHT have been a "Rock" Gasket. I forget who makes those.

 

ok...just wanted to clear that up..


I might be able to drop by your place on thursday/friday?

 

Actually, hoping to have everything back together tomorrow. I was thinking perhaps a trip to Knoxville to test out and see if any leaks happen after the new seal is installed.

Still researching on any crank differences. I'm also researching for tips/tricks to installing the seal. All the FSM says is to lube it up (inner part around crank, not outer part around oil pump.).

 

if youve got a micrometer/caliper, check the crank vs the ID of the seal..
if you dont, and since your going to harbor freight for wayne anyway...

 

ahh..i c..no go tomorrow...I have to do a toyota camry control arm bushing job ..

Honestly,i don't think their is any difference in the crank dimensions from vg30e/vg30et..but i may be wrong..

 

Ben: That is something to look into and had not considered. However, the last seal I put in was "snug" but who's to say if there is a diameter problem that it is not "snug" enough?

I've continued to research this. I can't find any technical data regarding the crank. However, I have learned that the older "A" spec (I think that's the letter designation) Vg engine had a crank with a shorter snout. This does make sense given my "snout" seems shorter than other VG's I've worked on.

Good example of this is the image you all have seen of Goons crank. He has two moon key spots (okay, Woodruff Key) on his crank. His crank should be the newer version of the VG, or "W" series. My crank only has one woodruff key spots, which is shared between the lower timing gear and the crank pulley.

Where is Mtcookson? I know he has an answer on this!

I'm just really confused about all this. The engine was JDM and had the stock T3, non-water cooled. Not sure if that helps to place the exact year of the engine.

 

unfortunately..he is no longer with us here...

but still,it comes down to diameter of the crank on either engine,,which i believe to be identical..

 

So, anyone know then of any "special" install instructions or specific lube for the seal? I mean, good greif....I'd think it'd be as simple as pressing the seal in place and being done! Maybe I wasn't holding my tongue right. Or Perhaps? Or Perhaps this way?

 

i think the first tongue is right...

ive got a '94 copy of the fsm (or a copy for a '94..)
it says put engine oil...


im not sure what a "suitable tool" is, maybe one your kids can play dress-up with?

 

I usually use oil or all-purpose grease when installing seals, depending on which seal it is. For the front and rear main seals, I use a biga$$ socket to tap them in.

 

While Im not sure on the different crank lengths or thickness, there are some major differences between the 84-april 87 engines and may87-89. The earlier was either A or B sub-designation with 7.8:1 compression and the T3 turbo charger. The latter, designated as the W series with redesigned with new water jackets for additional cooling, fully floating piston wrist pins, 8.3:1 compression and a T25 turbo. The W series engine covers ALL 89 and up VG series engines. Hope this helps.

 

Was the front seal leaking when you got the enigne?

before you put the thing back together (probably too late I know)... slowly rotate the engine and take a close look at the sealing surface on the crank. is there a groove worn in it where the seal rides? are there any scratches on the crank where the oil may seep through? how far in are you pushing the seal? you can push them in too far and they won't seal properly. all you gotta do it tap them just below the shoulder on the crank where it necks down and the timing gear & stuff rides on it. if you mash it all the way back until it seats, the seal can't do it's job 100% and you'll get some seepage. AMHIK :grrrrrr:

 

Ben: I thought I read somewhere that you can remove the front seal and replace it without removeing the oil pump. Perhaps I was looking at the rear seal.

Geoffc: Using a socket was what I did last time when I had the oil pump off. Not sure if I have a socket long enough. This time, I may have to use a wrench to get around the crank.

Maxpower: Your info sounds right. I must have the "A" series engine given it came with the T3 turbo and as it appears, a different crank. I'll take pictures for everyone.

Matt: The front oil seal did show some leakage from the beginning. I thought the engine builder messed up or perhaps I had pressurezed the crank case when boosting and damaged the seal, so I put in the second seal. Also, keep in mind that I had this engine completely rebuilt, bottom up. It has only about 3k miles on it now though I'm fixing to put the 3rd front seal in this thing.

As far as inspecting, I agree. I plan on doing that once the seal is out....I intend to pull it today. I hope to be done by this evening. Hmm, I'll be mindful of how far I install it. Never heard that pushing too far was wrong....good info. I'm certain last time I pushed it in all the way!

BTW, if there is scarring or damage on the crank, how would I go about repairing it? There should be no damage unless it was done during the engine build. As I said, I had the whole engine gone through; the crank was turned and balanced.

Here is an image of my crank with the crank timing gear still in place. You can just see about half the Woodruff key. I'll take another image when I've pulled the grear off.
http://memimage.cardomain.net/member...329804_124.jpg

 

maxpwr is right about all his info but he forgot to add that the 84-87 engines are a single keyway cranks thats why the pulley doesn't really fit. 87-89 had dual keyway cranks like the stock vg30e. Thats why you must use the crank pulley that came with your vg30et motor. I had the same problem, also forgot to add you have an 84 vg30et its the only year that came with a t3 oil cooled only. same year i have

 

VGman: My crank pulley does fit. It goes on, albeit not as far as I figured it should and stays. What really conserned me is that no crank bolt would fit. I had to find another thinner bolt that would work, but it does just fine. I am curious though, how in the world would you get the stock VG30ET crank pulley to work on a VG30E? The one I had even had an additional "V" pulley which bolted to the end of it for the A/C pump. I remember looking, and they just won't match up/interchange.

I'm glad I know now what year VG30ET I have. Now I have to figure out what they did differently which changed the compression ratio. I'm guessing that occured when they changed the head design?

 

http://www.vg30et.com/about.html

its the pistons, theyre dished.
load the page, search it for dish

 

To make the pully fit i took the AC compr out and removed that extra V-belt pulley from the crank. Then changed over my alternator pulley to a V belt style pulley and the WP,PS belt line right up. When i was doing my swap i did notice that the stock maxima pulley did fit but it didn't seat all the way in. I thought that might cause the crank to wooble because most of the weight is on the tip of the crank plus the maxima pulley was much heavier. Might be the probem you are having.

 

sounds like the perfect reason to upgrade to a UDP

 

I'm not willing to go to that extent, this is a daily driver and my family and kids are in it often. Perhaps you are right about this being the source, but the leaking has occured almost emediately. The only reason I have so many miles on the engine under the circumstances is becuase I let it go for awhile. Plus, it only does it after the engine warms completely up. Also, it did it even with the crank pulley and all accessories removed. (I was impressed that the engine took 30 minutes + to begin overheating w/0 the waterpump! The ambient temp was around 60 degrees outside.)

Internet: I appreciate the shameless self plug! LOL. Although, if the pulley is the problem, then it sounds like it is mostly due to how far it sticks out away from the crank snout. The underdive pulley, although lighter, would struggle with the same issue. Or am I wrong on this and Internet's shameless plug was helpful?

 

They make Z31 underdrive pulleys too.

 

Still same issue of it having "V" belt grooves. Not sure how much the wieght of the crank pulley plays if this is the issue. Although not convinced this is the issue, I am definately considering it's possibility. I appreciate the input.

 

Update: Getting everything back together now; I've been delayed by other things at home and with the family. I was able to find where I read you do not have to remove the oil pump to remove the front oil seal. It is located in my Haynes manual. I was able to use a small screwdriver and pull the seal out with little difficulty. Greased up the new seal and popped her in. I had to get a new Woodruff Key as the one I had seemed a bit buggered.

 

i was wondering if your crank might be odd-shaped, which causes it to leak around the seal.

 

if the spacing is proper, it's not too hard to convert th ealternator pulley to a V belt instead of grooved. and vice versa.

If it's simply a matter of that groove not needed on the pulley, then take it to a machine shop and ask them to cut it off. shouldn't cost much at all.

 

Ben: Even that page does not explain the change in compression. To clarify, I'm referring to the change between boosted engines (7.8 on early VGT and 8.3 on newer VGT), not NA versus boost.

Update: Let the engine run for a long time and had no leak. I put everything back together and drove to the store and down the road a few miles. Still no leaks and I did go under boost as well. I purchased a new woodruff key, getting one that fit better. I don't want that key to break! I also verified, there appears to be no wobble in the crank pulley. I also made sure that I did not overtighten the accesseries. Now I've only got to track down a minor coolant leak before taking the car too far.

I've got the z crank pulley and a V pulley for the alternator on hand.

 

pulled from VG30et.com


so mebe the 7.8 is more dished than the 8.3. it wouldn't take much to reduce compression when dishing pistons...

BUT!!!!
Im no expert. I can only relay info i see, unless i can base it on experinece(in this case, I have none).

 

Nissan says that all dished pistons were the same in these engines for boosted applications. Here is some additional information that I've run across regarding differences between "A" and "W" engines.

http://www.redz31.com/pages/headwork.html#castings

 

wonder if the difference is in the combustion chamber volume instead of the pistons....

 

it'd hafta be... wouldn't it?