# Timing Chain



## Iceman62 (Nov 17, 2018)

I am in the process of replacing the timing chain in my 98 Altima GXE (2.4L). Is it recommended to replace the oil pump at the same time?


----------



## rogoman (Dec 16, 2004)

There's no need to replace the oil pump unless it's been proven to be defective. You can measure the performance of the oil pump by installing a temporary mechanical oil pressure gauge. You would remove the oil sensor which is located next to the oil filter and install the mechanical oil pressure gauge in it's place; you may need to get an 1/8 BSPT to 1/8 NPT adapter to hook up the gauge. With the engine fully warmed up, the pressure should be as follows:
idle - at least 11 psi
3000 RPM - 60 to 70 psi


----------



## Iceman62 (Nov 17, 2018)

I already have the engine most of the way torn apart. The reason for replacing the timing chain is that the lower chain tensioner failed and skipped a tooth or more. Engine stopped running. it must not have skipped too many teeth because there were no bent valves when I took the head off.


----------



## smj999smj (Jan 1, 2006)

The oil pump is part of the front cover assembly and they are pretty reliable. Unless you had oil pressure issues, I would leave the pump alone.


----------



## Iceman62 (Nov 17, 2018)

smj999smj said:


> The oil pump is part of the front cover assembly and they are pretty reliable. Unless you had oil pressure issues, I would leave the pump alone.


No oil pressure issues. The original equipment timing guide which was all composite broke and allowed the chain to slip enough that the engine wouldn't run I've already verified that no valves were bent so it's really just replacing the timing chain.
But since I had it all the way apart anyway I decided to go to the extent and do a rering job and basically get it back to like new condition. Good thing it didn't need bored because I didn't see any availability on pistons.
I do have a question regarding a part though. Just below the head at the front of the engine there is a part bolted to the engine that has received a tube that goes to the bottom side of each intake near the cylinder head. Seems like this is pcv but can't find any information on it.


----------



## Iceman62 (Nov 17, 2018)

I received the cylinder head and block back from the machine shop and only one alignment dowel is there for head to block alignment. I assume there should be two. If the machine shop can't find the second one, does anyone know where I can get a replacement?


----------



## rogoman (Dec 16, 2004)

Iceman62 said:


> I received the cylinder head and block back from the machine shop and only one alignment dowel is there for head to block alignment. I assume there should be two. If the machine shop can't find the second one, does anyone know where I can get a replacement?


Yes, there should be two. Ask a Nissan dealer parts guy to look it up in his catalog. Otherwise get one from a junk yard or have a machine shop make one.


----------



## Iceman62 (Nov 17, 2018)

rogoman said:


> Yes, there should be two. Ask a Nissan dealer parts guy to look it up in his catalog. Otherwise get one from a junk yard or have a machine shop make one.


Thanks for the prompt reply. I will check first thing tomorrow.


----------



## smj999smj (Jan 1, 2006)

There are two, head to block dowels, Nissan # 11053-01M00, about $3 each. While a picture of what you are asking about would be helpful, I believe you are talking about the PCV separator assembly, which bolts to the side of the front timing cover and is where the PCV valve screws into. Refer part code 11830M:


----------

