Bent valve?

[demo243 1,130]

Actually I have a digital copy of the '78 service manual I can send you. 

 

Dm your email and I can send it.

 

Or check here-

 

 

[Scrapson 23]

12 hours ago, datzenmike said:

I wouldn't use Chilton's or Haynes for TP. When you can afford it, go to e-Bay and buy a proper Nissan produced FSM (factory service manual) for $25. Get the one for your year truck, not those others that cover the entire '73-'79 in generalities and nothing specific to your year.

 

ONE THING AT A TIME. Get your timing chain sorted out and replaced, stop worrying about anything else on a hunch.

I got the front cover off someone definetly replaced it before me because the amount of RTV I peeled off was impressive but I’m ordering the chain, sprocket, rails and new tensioner since the old one looked like it had seen some carnage there were clear wear marks so now I’m glad I’ll be hopefully putting it back together right thanks to hainz video which came in great use for keeping track of bolts. When I get it out back together and off the jack stands I’m going to go terrorize the little town I live in. I’ll post a picture of the rubber tensioner and the rail that had a piece broken off and the wear marks on the head from the chain. Once this is done I’m never doing it again one last upgrade and I’m done for now when it blows up I’ll take it somewhere for an engine swap. 

[datzenmike 38,396]

Clean the two surfaces and use just a gasket. The only place where RTV is good to use is a dab in the two 90^o corners where the pan and timing cover meet and the two there the timing cover and head meet. When it comes to RTV LESS is more.

[Scrapson 23]

Alright good to know hopefully have the scrapson running by thanksgiving or something so I can finally drive it to work and possibly some snow if Oregon isn’t going to pull an Oregon on me

[620slodat 188]

Western Oregon is------------well, western Oregon. Snow of much accumulation, and lasting for more than 24 hours, is almost non-existent. And what does stick for a few hours is usually very slushy. Back in 1972 it did actually snow. I was living in Grants Pass at the time and it got down to -4 degrees below zero at the water intake at the rive in Grants Pass. My parents were living north of Albany (close to Jefferson) and at the radio station east of Albany it was at least -14 below zero (maybe -17, memory is fading). Two weeks later when I went home for the weekend there was still a bit of ice under the overpasses on I-5 north of Eugene.

 

Which way from Scio do you live? My in-laws live east of Scio. You cross through Hannah bridge and go up Burmeister Road.

 

Don  

[Stoffregen Motorsports 5,418]

2 hours ago, datzenmike said:

Clean the two surfaces and use just a gasket. The only place where RTV is good to use is a dab in the two 90^o corners where the pan and timing cover meet and the two there the timing cover and head meet. When it comes to RTV LESS is more.

This job is slightly more difficult than it should be due to two factors - the engine is in the truck, which makes it harder to get everything lined up straight, and the new aftermarket gaskets are flimsy (compared to the originals) and tend to be mis-shaped right out of the box. A thin gasket adhesive will help, but you don't need to use RTV.

 

Use a bit of Gasgacinch to hold the gaskets in place while you're getting the cover on. A dab of grey or black RTV in the corners, on both sides of the gasket (as Mike suggested) is important too.

 

https://www.amazon.com/s?k=gasgacinch&gclid=EAIaIQobChMI7qmT1OuF5gIVUxitBh3SMgj0EAAYASAAEgIhcvD_BwE&hvadid=177570413940&hvdev=c&hvlocphy=9032472&hvnetw=g&hvpos=1t1&hvqmt=e&hvrand=3037536312957635044&hvtargid=kwd-3005708661&hydadcr=6583_9585028&tag=googhydr-20&ref=pd_sl_9avadsjq2t_e

[datzenmike 38,396]

Both sides have dowels to hold the gasket in place and so does the water pump....

[Scrapson 23]

11 hours ago, 620slodat said:

Western Oregon is------------well, western Oregon. Snow of much accumulation, and lasting for more than 24 hours, is almost non-existent. And what does stick for a few hours is usually very slushy. Back in 1972 it did actually snow. I was living in Grants Pass at the time and it got down to -4 degrees below zero at the water intake at the rive in Grants Pass. My parents were living north of Albany (close to Jefferson) and at the radio station east of Albany it was at least -14 below zero (maybe -17, memory is fading). Two weeks later when I went home for the weekend there was still a bit of ice under the overpasses on I-5 north of Eugene.

 

Which way from Scio do you live? My in-laws live east of Scio. You cross through Hannah bridge and go up Burmeister Road.

 

Don  

I live in town in the new development just down the street from the fire house off of 6th. I know where your talking about those bridges are slick and burnouts are crazy. I’ve been up there fishing and such. Is that the radio tower next to millerburg? I’ve taken the datsun up to Washburn heights if you’ve been there did better than a 79 Mercedes diesel haha. 

Edited November 26, 2019 by Scrapson

[Scrapson 23]

So I got all my parts in and such but minor problem is my TDC because someone did it was 2 and 3 cylinders so do I just put it together like that because nothing has been touched besides the cylinders moved. TDC on the sprocket was wrong I assume someone did this before and didn’t put it together correctly. Do I just pull off the cam and spin and rotate it or what do I do. 

[datzenmike 38,396]

Don't move anything!!!! You may bend a valve.

 

You had this running so it has to be close. Don't get distracted.

 

 

Are you at TDC????

Are the front (#1) cylinder valves closed???

Is the notch on the crankshaft pulley on the 0 (ZERO) on the timing scale????

 

IF YES... when the cam sprocket is on the #2 hole, you should see this.....

 

 

V on the back of the sprocket is below or slightly to the right of the horizontal line above it.

 

[620slodat 188]

57 minutes ago, Scrapson said:

 Is that the radio tower next to millerburg? I’ve taken the datsun up to Washburn heights if you’ve been there did better than a 79 Mercedes diesel haha. 

 

I'm not familiar with any cell towers within the city limits of Millersburg. The only radio tower I can think of is on top of Knox Butte, but I'm sure there are some around here that I'm not aware of. We are located just north of the north boundary of Millersburg. Millersburg has exploded in population over the last 10 years. The only Washburn Heights I am familiar with is between Brownsville and the freeway, although I've never been up there. I've been many places around Albany, Corvallis, Lebanon, and even several places up to over 100 miles away because of the job I used to have, but never to Washburn Heights.

 

I'm not very familiar with most Datsun motors. My dad bought brand new a 1973 Datsun 620, which I still have. It had the L16 motor in it, which no longer runs. The L16 is the smaller, older brother to your motor. The SD-22 diesel motor is what I'm more familiar with as that is what I plan to put in the 620.

 

Don

[Crashtd420 4,649]

8 hours ago, Scrapson said:

So I got all my parts in and such but minor problem is my TDC because someone did it was 2 and 3 cylinders so do I just put it together like that because nothing has been touched besides the cylinders moved. TDC on the sprocket was wrong I assume someone did this before and didn’t put it together correctly. Do I just pull off the cam and spin and rotate it or what do I do. 

Read what Mike is saying.... more than likely your 180 degree out.... you need to be on the compression stroke of cylinder one with all the stuff lined up like he described...... 

If you do as you described you will likely ruin something if not the whole motor...

[Scrapson 23]

10 hours ago, datzenmike said:

Don't move anything!!!! You may bend a valve.

 

You had this running so it has to be close. Don't get distracted.

 

 

Are you at TDC????

Are the front (#1) cylinder valves closed???

Is the notch on the crankshaft pulley on the 0 (ZERO) on the timing scale????

 

IF YES... when the cam sprocket is on the #2 hole, you should see this.....

 

 

V on the back of the sprocket is below or slightly to the right of the horizontal line above it.

 

Okay the front cylinder 1 valves are closed the lobes are not down if that makes sense they aren’t putting any pressure on it but my problem is that when I pulled the head cylinders 2 and 3 we’re what it said was TDC as soon as the head was off I was like well I’ll just put the head back on and not mess with the cylinders but I got a buddy to help he’s like what’s your TDC I said #1 but it’s at the bottom so what do I do. I’ll post pictures of the pistons when I pulled off the head and the head because cylinder one valves are closed. 

[Scrapson 23]

Cylinder head valves. https://drive.google.com/file/d/17zbuTfbwCklEWTVCKg2QWnP7Ne9XOCjK/view?usp=drivesdk

Block at alledged TDC

https://drive.google.com/file/d/1nm7HdX5Dut6zuOEicSCLiTuXcMzYHS8o/view?usp=drivesdk

the mark was saying it was at TDC but someone put it together wrong

[banzai510(hainz) 4,712]

I see a bent valve coming!

[Crashtd420 4,649]

17 minutes ago, Scrapson said:

Cylinder head valves. https://drive.google.com/file/d/17zbuTfbwCklEWTVCKg2QWnP7Ne9XOCjK/view?usp=drivesdk

Block at alledged TDC

https://drive.google.com/file/d/1nm7HdX5Dut6zuOEicSCLiTuXcMzYHS8o/view?usp=drivesdk

the mark was saying it was at TDC but someone put it together wrong

That's definitely not right....

Do your self a favor and ignore anything the previous owner did..... 

Start from step one and get cylinder 1 to top dead center and then proceed...

 

In the pic you posted of the cylinders have you done the front timing cover or was that an old pic.... i dont see a wedge holding the timing chain.... 

There are marks on lower gear that should also indicate a start point.....

 

[datzenmike 38,396]

31 minutes ago, Scrapson said:

Okay the front cylinder 1 valves are closed the lobes are not down if that makes sense they aren’t putting any pressure on it but my problem is that when I pulled the head cylinders 2 and 3 we’re what it said was TDC as soon as the head was off I was like well I’ll just put the head back on and not mess with the cylinders but I got a buddy to help he’s like what’s your TDC I said #1 but it’s at the bottom so what do I do. I’ll post pictures of the pistons when I pulled off the head and the head because cylinder one valves are closed. 

 

There are TWO (2) TDCs on any gas engine. You want the compression stroke on #1 when the two valves are closed and the timing mark on ZERO. Set this before you take it apart.

 

 

[datzenmike 38,396]

16 minutes ago, banzai510(hainz) said:

I see a bent valve coming!

 

Then the title would be relevant.

[Scrapson 23]

Yeah I smell bent valve too. So set the block to TDC do not touch the head? Okay so I have cylinder one at the top aswell as cylinder 4 now do I just put the head on or loosen the valves and spin the cam by hand?

[datzenmike 38,396]

If the head is off, adjust the cam and set the #1 cylinder valves closed. They would roughly be at 10 and 2 o'clock as seen from the front. The little cam dowel that fits into the back of the cam gear will be at the top or 12 o'clock. The cam gear should be on the #2 hole. If you have the front cover on, the tensioner should have a blocking wedge in against it to keep it pushed back into it's holder. The wedge only comes out when the cam gear is on the cam.

[Scrapson 23]

https://drive.google.com/file/d/1ukwncLlkd-dbcWTgrS_OEKF2TYAbJjDF/view?usp=drivesdk

head/cam

okay so there is one valve open on cylinder one but the motor is turned to the correct TDC. 
https://drive.google.com/file/d/1nm7HdX5Dut6zuOEicSCLiTuXcMzYHS8o/view?usp=drivesdk

block

[Scrapson 23]

Just now, datzenmike said:

If the head is off, adjust the cam and set the #1 cylinder valves closed. They would roughly be at 10 and 2 o'clock as seen from the front. The little cam dowel that fits into the back of the cam gear will be at the top or 12 o'clock. The cam gear should be on the #2 hole. If you have the front cover on, the tensioner should have a blocking wedge in against it to keep it pushed back into it's holder. The wedge only comes out when the cam gear is on the cam.

Okay so loosen the valves to adjust it or what?

[datzenmike 38,396]

If the head is off the engine, #1 cam lobes at not at 10 and 2 just turn the cam till they are. Cam dowel should be at 12 o'clock or at the top. 

 

Make sure the #1 piston is at the top.

 

Now both are properly timed to go together. Cam sprocket should go on the #2 position.

[Stoffregen Motorsports 5,418]

19 hours ago, datzenmike said:

Both sides have dowels to hold the gasket in place and so does the water pump....

I understand that, but only one on each side. Even with the dowels, cheap gaskets can move around and the gasket sealer helps them stay put.

[datzenmike 38,396]

It does.