Timing chain replacement suggestions

[family_2k]

So, as my first post, I may already know the answer to my question due to the great knowledge amassed on this great forum, but here I go anyways...

I finally had a chance to inspect the evil L and believe I am in for a chain replacement. However, it appears that just removing the timing chain cover has some risks (like not getting it back together w/o damaging the head gasket). Based on what I can see on the L bracket, and the play in the chain, it has to done, but I would like a second opinion. Even if I put something behind the tensioner to keep it from retracting completely the chain still has enough play to move quite a bit.

I am looking for suggestions on what else I should take care of while replacing the chain. I am pondering everything from removing the entire engine to just the head. I don't believe the valve seats have been replaced (not sure how to confirm w/o removing the head) and I am not sure what else needs attention without running it. I have read all the machine shop horror stories so that makes me nervous about any head work.

I already have all the cooling system parts and carbs off. I would like to get everything right before starting it up, but would prefer not to do a complete rebuild or major upgrades. From what I can tell the engine is sound (not stuck and valve train in good condition) but has not run in 15+ years. I can't see a reason to remove the transmission either at this point. There is a lot of oil at the back so a rear seal may be bad, or oil may be leaking from somewhere else. The lower exterior of the the engine is coated with baked on oil. Not sure if it had ever been cleaned in its lifetime (95k miles). I have also read that a lightened flywheel would be nice too if I end up removing the engine. I really do not what to get over my head with this one since I can't wait to finally drive it. I know the timing chain parts won't be cheap either!

I have attached some pics of the evil L damage, sprocket, and chain.

IMG_2074.jpg

IMG_2063.JPG

IMG_2060.jpg

Sorry if the chain tension pic is upside down. I couldn't find a way to fix it.
Any guidenance and suggestions would be greatly appreciated. I would be happy to post additional valve train or engine pictures if it helps.
Thank you in advance!

FYI, 68 2000 in SoCal.

[spyder]

I don't know how many miles are on that engine but the gears look very worn. If it were mine, I'd replace the gears and chains. Minimum, head off and oil pan off. However, if I have to go this far I would go ahead and pull the motor and at least replace bearings, rings, gaskets and freeze plugs. Don't want to go that far, shim the tensioner, cross fingers and drive it.

[Gregs672000]

The pics of you cam gear shows that it needs to be replaced, as the teeth are starting to look like Christmas trees... undercut. Fortunately they are relatively inexpensive and available. I personnally bought JT68's adjustable one (original version), and am very happy, but there are options. There are pros and cons to going adjustable, i.e. to get the adjustment right really requires a dyno and some time, but it can be set to "stock" using the dowel pin from your old one. Whether this is the correct cam timing or not will remain, as there are several factors that go into proper cam timing. Nevertheless, I would get an adjustable one so you have the option going forward if needed. JT68's latest version uses offset bushings that will adjust the cam by a set number of degrees (ask JT68 for details).
I would consider cutting off the L flush with the vertical surface of the head, or replacing it, or watching it very closely for continued contact and fatigue. The consequences are dire if she breaks! If cut, after that you will need to use something (I use a cut down pointed wooden paint stir stick) to pin the chain against the guide to keep it from falling into the engine when the cam gear is off.
I think you should pull the head. You need to inspect your timing gears for the Christmas tree look and replace as needed (you can post pics here and we can guide you). With the head off, take it out for inspection and cleaning at a good shop (recommendations in So Call 311's?). You will want to see about the material and condition of the seats (replace brass with stainless steel), guides, valves, and seals... at least know the condition so if needed you can plan if you don't want to do it now while still driving it. Consider replacing the head bolts, as according to Nissan they are a true stretch bolt and should be replaced if unknown. Chase all the holes in the block with a tap. You can opt for head studs if desired, pros and cons to both but a stock engine won't care. Cut/clean the head's manifold studs. Shim the tensioner. As in the pic, without oil pressure you will have a lot of chain slop. That is one reason why I crank my engine over 10-15 times before flipping my kill switch and firing it up, as it brings up oil pressure to the tensioner faster... it's a choice.
Note that the front cover has some locating pins and studs instead of bolts in places when you are disassembling it. Gonna need a head gasket, manifold gasket, front cover gasket, may as well replace the front crank seal, possibly the oilpan gasket. Water pump gasket too, or you can make one (easy).
That's what I would do!

[bakerjf]

Off the top of my head, because of the small studs on the outside forward portion of the head, you can't get the timing cover off without removing the head first. I remember replacing those studs with 7mm (IIRC) bolts when I rebuilt my engine so that wouldn't have to be the case in the future.

[jamesw]

Removing the timing cover with the engine in the car is a big problem. You will also need to remove the giant bolt that holds the crank pulley onto the front of the crank - as it goes through the timing cover and the front seal. It's hard to get off even with the engine out of the car.

[Linda]

Ron at RD Machine, Chatsworth, CA is capable of checking, cleaning the head and whatever else you need. His shop is about 5 miles from Dean at Datsunparts.com so very easy to get parts.

Linda

[mraitch]

as to the bolt that holds the crank pulley - can be done in car - remove radiator - put in gear and have someone step on brake - use a LOOONG breaker bar. Did this on R&R on Linda's car and tightened to spec using this method.

[SDkvrd]

... There is a lot of oil at the back so a rear seal may be bad, or oil may be leaking from somewhere else. The lower exterior of the the engine is coated with baked on oil. Not sure if it had ever been cleaned in its lifetime (95k miles). I have also read that a lightened flywheel would be nice too if I end up removing the engine. I really do not what to get over my head with this one since I can't wait to finally drive it. I know the timing chain parts won't be cheap either!

I have attached some pics of the evil L damage, sprocket, and chain.

IMG_2074.jpg

IMG_2063.JPG

IMG_2060.jpg

Sorry if the chain tension pic is upside down. I couldn't find a way to fix it.
Any guidenance and suggestions would be greatly appreciated. I would be happy to post additional valve train or engine pictures if it helps.
Thank you in advance!

FYI, 68 2000 in SoCal.

The fluid leak(s) are a valid reason to pull the engine and transmission, in order to separate them and check inside because as you mentioned, the rear main seal could be compromised after the years, mileage and the long term disuse doesn't help either. Also, sitting for a while isn't good for clutches. Your "L" looks a little worse than mine was and the consensus from the forum with regard to my engine was to replace the timing set (since purchased from Stan Chernoff, who sells quality stuff; aka "Fairlady Products" he's in Torrance http://www.fairladyproducts.com/)
In summary, changing only the top timing chain would only briefly delay the inevitable overhaul

[family_2k]

Thank you everyone for the great feedback. I know this is kind of a reoccurring topic. This is just the kind of guidance I was looking for! You guys are great and don't think I could make it though the restoration without this forum.

Unfortunately, I already have the brakes out and the car on jacks, so I don't know how I will get the front bolt off the pulley. Can I just use an impact? Or, will that damage the balancer, bearings, etc? I have seen videos where you can block rotation at the crank with a hammer handle (since I'll have the pan off). My understanding is I will need a puller for the balancer as well. Does the balancer need to be rebuilt as well, or are they good unless damaged somehow?

I will, at a minimum, replace the chain and gears. It was really a question of how far I should go from there. From the feedback it sounds like I will be in for removing the engine, and possibly the transmissions, sooner than later to replace seals so I may just bite the bullet now. That is really what I am pondering.

Is it any easier to pull the motor and trans with the head off or on? Also, what does it mean to cut the manifold bolts?

Do I need to worry about the guides and tentioners or just the gears and chains? I didn't even consider the studs at the front of the head. Replacing with bolts sound like a good option for the future. Hopefully, I won't need to do this again

Sounds like an adjustable cam gear would be good for tuning once I can learn its benefits. At least I will have options going forward.

Thank you Linda for the shop suggestion. With so many in the LA area it's hard to know who you can trust with the precious head.

Looks like it will be a long spring. Hopefully, I can get the work done before the heat hits SoCal.

Thanks again, Alec

[Gregs672000]

With the pan off you can just keep the crank from turning by putting a small section of 2x4 between one of the crank counter weights and the side of the block to be able to remove the front crank pully bolt. The front vibration dampner can be rebuilt if needed (had mine done, So Cal shop as I recall but I don't remember which... fast turn around though), but unless it is showing signs of coming apart it is probably fine. A puller is good, but I just used a wood drift and a hammer to slide it off. "Cutting the studs", I was referring to just running a dye (or is it die?) to recut the threads as they get damaged... that's all, sorry for the confusion. It makes reassembly a bit easier when your're trying to cram your hands in there to start nuts. Tensioner, especially the upper, will need to be inspected (post a pic of the pad surface and we will guide you). You must replace the tensioner's gasket against the head, and it must have the hole that allows the oil to reach it. I make my own gasket out of thick notebook paper or thin gasket material with the proper hole (you'll see where the hole is needed). I "season" or wet the paper with oil and it works fine. The guide for the bottom chain is often left off, or found in the bottom of the pan. It rarely needs replacement, even if it is gone, as it is questionable if even needed (I think mine is off). Use locktite on the bolts regardless. Regarding the upper guide, I guess it depends on if you are ok with cutting the L off or not, or feel comfortable watching for continued problems. The notching causes weakness and fatigue, and engine vibration and continued chain strikes can cause it to crack and launch through the cam cover (! I had a welded cam cover on my car when I bought it, and no longer had the original engine block). Nevertheless, there are several running around with guides that look worse than yours, so it is up to you (and cost). If they are stupid expensive I would just monitor it, shim the tensioner and drive it with the new gears and chains... start up is when the chain strike is most likely to occur. Like me, you could hide a kill switch that interupts the coil circuit so you can spin the engine prior to initial start to bring up pressure (may help keep your car from being stolen too!). Also, be sure that you have the oil filter tube for the oil filter that helps keep oil in it, as the pump has to fill the filter before it sends oil to the top of the engine which also delays the tensioner getting pressure. I do NOT recommend the Mobile One filter that supposedly does not drain back... false! I had to ditch mine and go back to a Hastings with the metal tube. Clean off the engine and see if the oil is coming from the distributor pedistal, particularly the tach cable connection and the flex tube etc. There are o-rings inside the pedistal that go bad and leak oil such that it looks like it is coming from the bottom (rear main) area when it is not... up to you if you wanna mess with the rear main if it appears dry when (if) you pull the engine/trans (you can probably look with the oil pan off). O-rings are available from the venders (Got mine from Dean). Look up the thread or talk to JT68 about the adjustable cam gear, or discuss with Stan or others as I believe they sell one too and may be part of a package (at a better overall price?). I don't think it makes any difference pulling the engine head on or off, but given that you will still have some coolant in the block and may be tilting the engine some, I would keep it all together to just keep fluids under control and not going into the cylinders etc. (really not a big deal regardless). Hopefully the head, valves, guides etc all in good shape. I would do the seals regardless (cheap).
Keep posting!

[spyder]

You have to pull engine / transmission as a unit. There is a triangular stiffing gusset which blocks access to the starter. Someone previous to me removed it so I can reach through and pull off the starter. With the starter off, I can pull the engine / transmission as is.

[family_2k]

Thank you everyone for all continued and great suggestions. It's tough to put together all the knowledge on this forum, so starting this post has helped me keep all the good tips together.

I have pretty much stripped the engine and believe I have it ready for removal. All cables off, starter off, exhaust/intake off, drive shaft out, motor and trans bolts off. So, looking good...I just need to procure a hoist and stand.

In the mean time I removed the upper tensioner and it has seen better days.

IMG_2105.jpg

I was able to get the front pulley bolt off as well by putting a piece of wood in the crank. Now I just need a puller to get it off the crank. I also started removing some of the bolts on the timing chain cover as well. Do the studs for the water pump go all the way through to the block or are just part of the cover?

I did notice that the oil filter did not have the tube so I'll have to replace that. It must make for a really messy oil change, but I am guessing it is better than what happens to the engine while it is waiting for oil.

The brackets for lifting the engine are on the top timing chain cover bolt (passenger side front) and back rear manifold stud (drivers side). Are these the correct places for the brackets? I just want to make sure I don't break anything when I remove the engine and trans. Does anyone have a weight estimate for the combo? Also, I will probably put some additional jack stands on the rear of the frame since the rest of the car is on stands and I am not sure what to expect when all the weight in the front is gone. I unbolted the motor mounts from the frame as that seemed easier that taking them off the on the engine side.

IMG_2104.jpg

[Gregs672000]

Yep, tensioner is done. No oil filter pipe probably contributed to increased guide and tensioner wear. They don't complicate the oil change much at all. Available from the venders.
Not sure where your lift bracket is, but I always go with the biggest, strongest bolt place I can find. As I recall, there are some large bolts near the fuel pump that I use, but I don't use a bracket but bolt the chain direct to the engine. I also have an S hook attached to one of the trans to block bolts that I leave there for removing the engine when needed. I don't have any original lift brackets on my car. I think the engine and trans are under 500lbs easy. Don't think you need to worry about upsetting the car off the stands when you pull the engine so long as the car is on the stands securely.

[family_2k]

So, I was able to get a hoist setup and started to pick up the engine/trans and it seem to be getting stuck on the two transmission studs. According to the tech wiki all I should need to do I remove the two bolts (which I have). But, as I try to pick up the engine it just pivots on the trans studs and tilts back. Hopefully, I didn't do any damage to the hood release. I didn't notice the valve cover pushing on it until it was already there.
Is there some trick to get the trans to lift high enough so the studs will clear the bracket? I can't pull the motor forward until they are clear and that does not seem to be happening. It appears the bracket can be removed via the four bolts, but neither my manual nor the wiki says that is a requirement.
I am picking up the unit via the top rear driver's side exhaust stud and on the top bolt on the smog plug bracket (where the bracket meets the block, bracket is removed).
I'm sure this is noted somewhere in the forums, but my searches always seem to remove importance words even when using the + symbol.
Any help would be appreciated (just a bit frustrated), thank you.

[spl310]

I'd drop the crossmember and not over think things.