Jump to content

l18 compression test


sanyantho

Recommended Posts

maybe your timing was off before you did the head gasket and it is set okay now.  True what Hainz said when rotor may not have to be facing the rad.  but at least on mine (L18), front cam lobes is at 10 and 2 o'clock, my rotor is facing the front while it's closely lined up to #1 spark plug or cylinder. This depends on what kind of dist. you have installed (various L series type of dizzy).  So when you look at your timing light are you looking at the passenger side or drivers side?

Link to comment
  • Replies 109
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

You should see a sawtooth timing tab on yours or maybe timing marks is on a pulley.  I have an L18 but my timing marks is on an L16 pulley (5, 0, 5, 10, 15 and so on).  If you could not find the timing marks, how do you know you are 5 degrees with timing?

Link to comment

maybe your timing was off before you did the head gasket and it is set okay now.  True what Hainz said when rotor may not have to be facing the rad.  but at least on mine (L18), front cam lobes is at 10 and 2 o'clock, my rotor is facing the front while it's closely lined up to #1 spark plug or cylinder. This depends on what kind of dist. you have installed (various L series type of dizzy).  So when you look at your timing light are you looking at the passenger side or drivers side?

mines is on the driver side.

Link to comment

You should see a sawtooth timing tab on yours or maybe timing marks is on a pulley.  I have an L18 but my timing marks is on an L16 pulley (5, 0, 5, 10, 15 and so on).  If you could not find the timing marks, how do you know you are 5 degrees with timing?

i can find the timing mark when i turn the cam with a wrench. i can not see the sawtooth timing mark on the pulley when the truck is running and i am shooting with a timing gun. do you understand what i mean?

Link to comment

ok if yours is on driver side you have the sawtooth type timming marker. Just make sure you read it right.

Idle will be high if electric choke till it warms up.

maybe idles hight cause the cable is tight. or your have the speed screw to far in.

 

Intake bolts? Its really the lower bolts that hold the intake and exhaust in the middle if you have a water heated manifold. water maybe suck up in there if bolts are loose or maniifold gasket is bad.Maybe thats why the whitle smoke.

  • Like 1
Link to comment

ok if yours is on driver side you have the sawtooth type timming marker. Just make sure you read it right.

Idle will be high if electric choke till it warms up.

maybe idles hight cause the cable is tight. or your have the speed screw to far in.

 

Intake bolts? Its really the lower bolts that hold the intake and exhaust in the middle if you have a water heated manifold. water maybe suck up in there if bolts are loose or maniifold gasket is bad.Maybe thats why the whitl

the cable is not tight. i will check the speed screw. i think you are right about the intake bolt. i will tighten and see. its a little hard to get to, so it could be loose when i re-installed the intake and exhaust.

Link to comment

well if loose it will leak water once its pressurized up. If not leaks most likely its good unless there was a tear in the gasket between the water hole and the intake hole and then the piston goes down the vacuum sucks up the water.

 

 

early L16s on 510s/521 has the clean mainfolds and ezer to access the bolts around the intake and exhaust. Best to do it cold. I use a box end wrench and able to get my hand under there to tighten. Dont overtight or x thread them aluminum holes!!!!!!!!!!!

Link to comment

I think timing should b 12 degrees. U can also go on olddatsuns and u will see different types of timing marks and tabs. Also it states for L18 is 12 degrees. If u advance your timing then ur rpm will go up. So main thing is to adjust ur timing first bfore u adjust ur idle.

Link to comment

Stupid question, but r u checking timing outside. U should check inside garage so that the strobe affect is visible. Second, maybe u dont have a sawtooth and timing marks is on pulley like mine. As mentioned, i have an L 18 but my timing marks, like 6 of them, are one the pulley so it came from an L16. If you have the matching pulley for an L20 then u only have one indentation

  • Like 2
Link to comment

Stupid question, but r u checking timing outside. U should check inside garage so that the strobe affect is visible. Second, maybe u dont have a sawtooth and timing marks is on pulley like mine. As mentioned, i have an L 18 but my timing marks, like 6 of them, are one the pulley so it came from an L16. If you have the matching pulley for an L20 then u only have one indentation

i have a triangle sawtooth looking thing on my pulley. i will try timing it at night when i sun starts to set. thanks racerx

Link to comment

If this is a orginal motor and you have a sawtooth pulley there should only be one mark(dumple/notch )

so when timming it. the notch will be to the left of the Zero mark when using the light. As the pulley rotates to the right so anything left is BTDC.

 

Sometimes I get a big fat ink pen(clean Pulley) and mark the notch or paint notch. I have yellow Testor model paint just for this I use

  • Like 2
Link to comment

You have to really make sure that what you are marking is TDC so can you post a picture of your spindal, timing mark and the first 2 cam lobes.

I have some oil leaking where the head gasket and the front timing cover meets that I have to fix first. Then I will take a few pic of what you mention above.

Link to comment

yes, I see the choco, milky colored (oil and coolant mix).  Is that fluid in the distributor spindal area?  Speaking of which it looks more like 10:25 than 11:25.   fixing the coolant and oil mix should be the priority.  Sorry to hear that you may have to start again but did you tighten the intake as what Hainz said and maybe torque the head again. I don't have the sequence handy but go on line or maybe someone here can chime in.

Link to comment

Hi Ratsuns,

     So I replaced the head and timing chain for my 620. She starts but runs rough. I was unable to see the timing mark on the pulley with a timing gun. She is blowing a lot off white smoke out the exhaust. When I turn her off, the engine keeps on running for 3 minutes before shutting off. Can someone please help? I am going crazy here! lol

 

 

 

Did you check the 'new' head is flat? If warped it will just blow the gasket or leak. If white smoke out the tail pipe and running rough then head gasket may be leaking.

 

Did you clean the head and the block surfaces? I mean CLEAN. In fact it can never be clean enough. If there is any old gasket material stuck to either the new gasket is going to have a problem sealing.

 

Did you clean the intake and head surfaces? Again as clean as you can get them. This gives the best chance of the gasket sealing properly on the first try.

  • Like 1
Link to comment

spindal is off. needs to be more like 11;28  if you put a straight edge it will be right of the top hole left of the bottom hole!!!!!!!!!!!!  tahst why it idles higher. Spindal rotates counterclockwise so it will be adavnced.

set motor to TDC and cheak spindal and cam timming. but for eleltrical timming it will be BTDC like 7-12 deg in most cases.  Dont put to 10deg BTDC and then cheak the spindal as alot of people think it is.

So your photo of the spindal might be good or bad but if at Zero on crank then its slightly off.

 

question Was this burning up water before? If not then tyou did something wrong or is this a different head.?

 

ifwhats different. reading back you changed this cause of a tight valve but didn't have water leak issues. so whts different. If different head it could be bad.

 

Leaky front is pinched gasket or you didn't get tightis didn't use some rtv up around the front cover head

  • Like 1
Link to comment

yes, I see the choco, milky colored (oil and coolant mix).  Is that fluid in the distributor spindal area?  Speaking of which it looks more like 10:25 than 11:25.   fixing the coolant and oil mix should be the priority.  Sorry to hear that you may have to start again but did you tighten the intake as what Hainz said and maybe torque the head again. I don't have the sequence handy but go on line or maybe someone here can chime in.

They have the torque sequence at olddatsun.com. I buy a new torque wrench, the one i borrowed was pretty warned.

Link to comment

Did you check the 'new' head is flat? If warped it will just blow the gasket or leak. If white smoke out the tail pipe and running rough then head gasket may be leaking.

 

Did you clean the head and the block surfaces? I mean CLEAN. In fact it can never be clean enough. If there is any old gasket material stuck to either the new gasket is going to have a problem sealing.

 

Did you clean the intake and head surfaces? Again as clean as you can get them. This gives the best chance of the gasket sealing properly on the first try.

Do i use a straight edge to tell if it is flat? I will do a better job this time. lol

Link to comment

spindal is off. needs to be more like 11;28  if you put a straight edge it will be right of the top hole left of the bottom hole!!!!!!!!!!!!  tahst why it idles higher. Spindal rotates counterclockwise so it will be adavnced.

set motor to TDC and cheak spindal and cam timming. but for eleltrical timming it will be BTDC like 7-12 deg in most cases.  Dont but to 10deg BTDC and cheak spindal as alot of people think it is. So you photo of the spindal might be good or bad but if at Zero on crank then its slightly off.

 

question Was this burning up water before? If not then tyou did something wrong or is this a different head.?

 

ifwhats different. reading back you changed this cause of a tight valve but didn't have water leak issues. so whts different. If different head it could be bad.

 

Leaky front is pinched gasket or you didn't get tightis didn't use some rtv up around the front cover head

It was a pinched gasket, in my case for the leaky front. I will reset the spindal. thanks so much for you help!

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.