Cam tower spacers

[d510addict]

I believe I am having an issue with chainslap, which would make sense since the head I am using has been shaved 30 thousandths + and has no shims. So I have been poking around and was wondering if the shims that are sold for a z car L motor will work for a L4?

[banzai510(hainz)]

Highly dought that .030 is going to make the chain slap

more wore out oo a bolt busted on slack side guide is loose.

open valve cover and push on it and look down there

 

http://www.silver-seal.com/results.cgis?catalog=&keywords=datsun&x=13&y=8

 

 

look at Daniels 521 build and see what hes chain was doing.got good photos

[DanielC]

Here are the pictures Hainz was referring to.

 

Loose chain.

 

Tighter chain.

The pictures are of all the same parts. Same chain, guides, tensioner. The only difference is I moved the curved guide into the chain, before tightening the bolts that hold it in place.

[d510addict]

I did the same thing as you Daniel. It was a brand new jap timing kit so I dont think anything is worn. Can anyone describe what chain slap sounds like? I know the shaft in my dizzy is real sloppy but I dont think its the dizzy making the noise anymore (the dizzy itself was moving alot had to change some things to tighten it up) how can I tell if something is broken with out pulling the front cover. (dear lord I don't want to pull the motor again :()

 

Hanize are those shims 1 set for $15 or 1 each? I figure i need 2 shims per so 2 sets?

[banzai510(hainz)]

Hanize are those shims 1 set for $15 or 1 each? I figure i need 2 shims per so 2 sets?

 

I dont know havent bought from them. I assume the 4 cylinder one would be a set and you would order 2. or they are .015

 

a slapping should could be a guide wiggleing loose,from abolt broke or backing out.

a grinding could be the lower tensioer pushed out and cocked and wore down to the metal

I also seen where too long a bolt on the thermostat housing pushes the tight side guid IN and the chain will hit it,making a grinding sound.

 

to take from cover off you dont have to pull the motor. Just the radiiator and everthing else.

 

I could be wrong but I dont think .030 will make a difference too much in lengthening the chain. I myself you use the cam tower shims before even putting this motor together. But you should have timming the motor and see where the head cam timming marks were and then adjusted for this. say #2 or #3 on cam sprocket

[d510addict]

Alright last question before I go and try to fix this thing,

 

I've noticed that the sound (which I think is chainslap) doesn't happen at low rpms or while not under load. I can rev the engine out of gear and it sounds fine, but when I am in 3rd/4th on the freeway or accelerating slightly aggressively it will start the tap tap slap sound. It is also more prevalent if I drive the car with out warming it up (I know I know not a good practice). If it is the adjustable side guide then wouldn't I be hearing this non stop? and getting worse as I accelerate? (The sound does speed up when I accelerate but cannot hear it at low RPM). I wish someone near me could hear this sound to help diagnose it before I try and tear it apart again.

[DanielC]

The chain tensioner has oil pressure behind it, as wall as being spring loaded. Your oil pressure changes if the engine is hot or cold, and also changes with the engine RPM. Oil pressure is also affected by engine wear.

 

As the chain wears, it also gets longer. This makes the tensioner have to deal with more slack in the chain.

 

What oil are you using in the engine? How is the oil level? If the oil level is a little low, it takes it longer to get back into the oil pan, when it is cold, and this could possibly cause your oil pump to draw some air, and this air bubble going through the oil system could temporally cause the tensioner to lose some pressure.

 

Before you dissassemble the engine, put it exactly at TDC, #1 firing. Look at the notch in the back of the cam sprocket, to see where it is compared to the slot in the camshaft thrust plate. If you have to use the number three tooth, and hole on the camshaft sprocket, your chain may be worn a little too much. If the oil pump is slightly weak, or the bearings are approaching the end of their life, the oil pressure may be down a little.

[d510addict]

Its a fully rebuilt bottom end, with a new timing kit (less than 1 k on the motor since rebuild) using chevron 10w 30 oil and wix filter, the oil was changed last week and it is topped off.

 

 

 

 

Edit

 

I should mention I have the cam lined up with the #2 hole to begin with.

 

Edit again.

 

I removed the valve cover and the little plate on the front of the head. The slack side guide is pushed all the way towards the chain and the chain seems tight. The tight side guide had a bit of flex to it but seemed solidly in place. With the cam lined up to the number 2 hole in the sprocket the right side of the mark on the thrust plate is just touching the left side of the notch on the backside of he sprocket. Keep in mind this wasnt exact TDC I eyeballed it a bit.

 

I did notice 1 thing while I had the cap off of my dizzy. The center shaft that the rotor hooks to has about 1/4" to 3/8" or more of play side to side and about 1/8"-1/4" play vertically, and when moved around it replicates the noise I am hearing. So I wonder could that worn dizzy be t he cause of the noise?

[wayno]

Its a fully rebuilt bottom end, with a new timing kit (less than 1 k on the motor since rebuild) using chevron 10w 30 oil and wix filter, the oil was changed last week and it is topped off.

 

 

 

 

Edit

 

I should mention I have the cam lined up with the #2 hole to begin with.

 

Edit again.

 

I removed the valve cover and the little plate on the front of the head. The slack side guide is pushed all the way towards the chain and the chain seems tight. The tight side guide had a bit of flex to it but seemed solidly in place. With the cam lined up to the number 2 hole in the sprocket the right side of the mark on the thrust plate is just touching the left side of the notch on the backside of he sprocket. Keep in mind this wasnt exact TDC I eyeballed it a bit.

 

I did notice 1 thing while I had the cap off of my dizzy. The center shaft that the rotor hooks to has about 1/4" to 3/8" or more of play side to side and about 1/8"-1/4" play vertically, and when moved around it replicates the noise I am hearing. So I wonder could that worn dizzy be t he cause of the noise?

 

 

There shouldn't be any side play, all my dist. shafts are solid side to side, I'm surprized your dist. cap isn't destroyed, what does the inside of the cap look like? Do the posts in the cap look buggered up, like they have been hit by the rotor?

[d510addict]

I think I explained that wrong. It has rotational play and up and down play with a tiny tiny bit of wiggle side to side. If there was a bad contact it would be the one in the top of the cap but I didn't check it.

[d510addict]

Yes wayno the cap (just a month old) looks like the rotor has been hitting it although not horrible so.

 

Before I purchase shims (which I believe I will do) will shimming it back up 30 thousandths require me to replace the lash pads?

[wayno]

The rotational play is likely the mechanical advance, and is supposed to be there.

I know nothing about shimming the cam, seems like that would be something a machine shop would do, but I have heard that if you remove all the rocker arms, install the shims, and then install the cam, if it rotates freely, then I have heard it would likely be OK, but this is what I have heard, I have never done it.