My 1971 521

[datzenmike]

3 hours ago, d.p said:

I

12289-W0400 - Rear main side seals

12279-R4611- rear Main

 

 

 

12289-0W400 fits all

L16/18 L20B in the 620

L24 in the 810/Maxina

L28 in the 280zx

A10 L20B and Z20

L20B, Z20/22 and Z24 Z series engines

S110 200sx Z20 and Z22

Z24i in the D21 Hardbody, WD21 Pathfinder and Van

 

Should be noted that all L16/18L20B in the 521/510/610/710/S10/240/260/280Z  use an earlier part number but I'm sure it's the same part.

 

12279-R4611 Rear crank seal

Same as above and will work on All L series 4 and 6 cylinder and all Z series engines early and late.

 

[Crashtd420]

I thought the L20b cranks was a little bigger than the L16/l18.... I'm surprised they would use the same rear crank seal.. I guess the difference is more in the journal diameters and rod length used..... 

[datzenmike]

The main bearings diameters are larger on the L20B than the 5 bolt L16/18 cranks. It would be advantageous to use just one seal for all L and Z series engines to avoid excessive parts inventory and confusion.

 

The pilot bushing on the '65 Roadster was still being used in 2004 VG33E Pathfinder. May still be used

[d.p]

Also note if you order the side seals they are sold individually so get 2.  OEM has no nail either, they are just thicker and more robust then the fel-pro ones.  

[d.p]

Going to tackle the rear main cap + seal, anyone got a tip to getting it in straight?  The two times i have done it already its so tight that it goes in at an angle and a bitch to get straight.  

 

Someone show me the way. 

 

 

[datzenmike]

A piece of pipe the same diameter that fits over the crankshaft? The installation tool is somewhat like that.  

[d.p]

Talking about rear main CAP not the seal.  

[mainer311]

What if you take 2 C-clamps and clamp the sides of the block, thus creating a kind of guide that you can slip the main cap down into. Then just give it a couple whacks to seat it.

[d.p]

I’ll figure something out. 
 

I read somewhere about putting the rear main cap in the freezer to get it to tighten up a bit then using 2 head bolts to ‘guide’ it into place.  

[Crashtd420]

7 hours ago, d.p said:

I’ll figure something out. 
 

I read somewhere about putting the rear main cap in the freezer to get it to tighten up a bit then using 2 head bolts to ‘guide’ it into place.  

The freeze will only shrink it so much, the freezer at work for shrinking was set at -80deg.... by the time you make it to the engine block it will have warmed up....

I did mine with a dead blow mallet and just tapped it into place... not really sure why this is giving you problems....

You can definitely use bolts as a guide , Don't use them to actually pull the cap down....

Maybe the seal is part of your issue getting the cap in straight I would just get the cap installed and do the seal after......

 

[datzenmike]

The rear cap is snug but there are thousands out there and they DO fit. Often you have to use a puller to lift it out or wiggle a lot. Why not do the opposite and warm the block with a torch to widen the gap and drop the 'cold' cap in???

[d.p]

Yeah maybe it is trying to install the seal before the cap but thats what the book says to do. 

 

I read that as well but wondering what, if anything, heat would do to the silicone sealant?  Meaning apply sealant, heat block drop rear main cap in?  

[datzenmike]

Not red hot just hot. Engine gets hot and silicon plug wires are good to 400-500F?.

 

What are you supposed to do if the seal needs replacing later take the engine out and apart? take crank out put seal on then assemble the cap? Pretty sure they just tap in and seat. The outer edge is steel and a press in fit just like the transmission and front crank seal. Put in last using a piece of pipe the same diameter so it fits over the crankshaft and hammer lightly till seated all the way in

[d.p]

Obviously that's how its replaced.  All I am saying is the book tells you to install the rear main seal before putting the cap on.  Why? I have no fucking idea but I can only assume because it's easier?  

[Stoffregen Motorsports]

Installing the seal after the cap is installed can damage the seal. It is much easier to shimmy the seal over the rear of the crank and into the block with the cap removed. I use vaseline on the seal lip, and gasgacinch on the OD of the seal.

 

The RTV goes in the corners of the main cap and also a dap at both ends of the side seals. Gasgacinch helps slide the side seals in place too.

 

Installation of rear caps can be difficult. One way to help this is to file the harsh edge off both the cap and the block. Just a teeny bit. Do not hit the cap into place, as it could cause the bearing to fall out of it's groove.

[d.p]

Freezing + head bolts seem to make it A LOT easier.  Also when I turn the crank there is a little resistance when 3 and 4 come to BC. Meaning it’s not completely smooth when I fully rotate the crank. It seems to get a little tight when the counterweights pass the thrust bearings.  Having never done this before I am not sure how smooth it’s supposed to rotate?  Hopefully that makes sense.  
 

 

 

 

Truck out of hibernation and running like a top.  Picked up some mulch yesterday.  
 

 

[Crashtd420]

Did it fell that way before the pistons were installed?

Do you have any feeler gauges?

There are side clearance numbers for the rods I believe...

[d.p]

I seem to remember it only happening after I installed the pistons. And yes have feeler gauges.  not sure where exactly to measure though?  I may just pull the pistons and start from there to see what is doing. 

[Crashtd420]

You should be able to get a feeler between the side of the rod and the crank. ... I'll see if I can find the page in the book.....

[Stoffregen Motorsports]

If the rods are stock, they will be fine. I have never had to side clearance stock rods, that is, if they were not damaged. They can get burrs on the from people installing rod bolts or from smacking them with a hammer to remove them.

 

 

[d.p]

I found it page 127. What is the ‘rod big end?’ Ok it’s the bottom of the rod. So I can get .008 in one side and nothing really on the other side of the rod.
 

 Is this right? 
 

 

Edited April 9, 2020 by d.p

[d.p]

If I can get .008 on one side of the big end and nothing on the other side of the big end does that mean I need to pry the crank back towards the rear?  It’s the side of the big end facing the front that I can’t get any feeler gauge in between.  

[Crashtd420]

6 minutes ago, Stoffregen Motorsports said:

If the rods are stock, they will be fine. I have never had to side clearance stock rods, that is, if they were not damaged. They can get burrs on the from people installing rod bolts or from smacking them with a hammer to remove 

 

5 minutes ago, d.p said:

I found it page 127. What is the ‘rod big end?’  I can get .008 in one side and nothing really on the other side of the rod.
 

 Is this right? 
 

 

That sounds about right.... you should be able to move the rod slightly side to side... you should be able to check the clearance in both sides.... I believe .008 total would be .004 clearance on each side....

Not 100% sure... it been a while....

Edited April 9, 2020 by Crashtd420

[d.p]

3 minutes ago, Crashtd420 said:

 

That sounds about right.... you should be able to move the rod slightly side to side... you should be able to check the clearance in both sides.... I believe .008 total would be .004 clearance on each side

Cool. I am able to wiggle them back and forth to get a measurement. Least is .008 and most seems to be .010-.011.  I cannot get .012 in there. So does that mean everything should be ok even though it does get a little tight when rotating?  I’m taking ever so slight bit of resistance. 

Edited April 9, 2020 by d.p

[Crashtd420]

Ok says to check between rod big end and crank-throw face....