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Bent valve?


Scrapson

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You mean these bumps on the L20B cam?

 

It's better to pay $129 than cheap out on this very hard to get at and replace  part. This sounds about right. There will be two plastic covered chain guides in the kit When installing, shove the tensioner side as far towards the driver's side as you can then tighten. It'll be in Hainz's video.

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I been waiting for a update here on this one

 

unbolt flange? you mean the exhaust? Your lucky the bolt didn't break.

Get some anti seize compound and put back on there.

 

Your whole paycheck for a timming kit? time to find a better job. bertter yet sell me the truck

 

where some photos of this bent valve.

 

Yes the center lobes on the can can be used to put a wrench on to breal the cam bolt loose then put back to TDC before removal of the cam sprocket. I think I mention this in there but I had a L16 in the vid which don't have this LOBES

Edited by banzai510(hainz)
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I got it looked at they said the valves are fine I guess TDC is just the valve is I thought was pretty far down. I pump gas part time after school making minimum wage 15 hours a week so not much. I can’t quite figure out how to get the front cover off do I have to unbolt two bolts down and left to the water pump?

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Set accurately to TDC first. Drain the cooling system and remove the hoses from the timing cover and the thermostat housing. This is preferable to twisting the thin pipes on the rad and fucking them up. Remove the rad so you don't slip and punch a ratchet through it. Loosen the alternator adjustment strap and take the fan belt off. Remove the distributor cap and wires and hang over the valve cover out of the way so it won't get broken.

 

The distributor and oil pump have to come out. Expect the drive spindle to drop out with it. Expect a 1/8 cup of oil to drip and have rags ready.

Water pump has to come off.

Crankshaft pulley has to come off.

The 10mm oil pan bolts across the front and several down the sides thread up into the timing cover and have to come out

There are two10mm bolts on the lead  at the front corners that thread down into the timing cover than have to come out.

 

Now you can start removing the bolts that hold the timing cover to the block. Don't overlook the one that is behind the oil pump. If not sure take lots of pictures.

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Okay so I have to loosen the oil pan to get the timing chain cover off? Man datsun breaking my wallet with gaskets and shit. Yes I’m going to replace the oil pan gasket since I’m there and just do a full service since it’ll be cold soon. I watched hainz video and I know now I have to remove the oil pump drive bolts and such. I cleaned my intake up today and made a block plate for my EGR shit that’s gone. 

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You'll have to remove the front and maybe one on each side that screw up into the timing cover and the two on the head that screw down into the cover, yes. Probably good to loosen one or two on the side of the oil pan to allow some wiggle room so the cover can pull forward and off. But if replacing the pan gasket this won't matter.

 

Make sure you get a good tight seal on that EGR plate or you'll have a problem vacuum leak.

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personally I think you were looking for a major proplem that didn't exist. and in a rush you dismanteled the motor.

 

YOu got the vedio . 

 

I see a for sale sign comming

 

key is be patient and go slow. changing pan gasket is not as ez as one thinks most people rush doing the front cover gasket(pinched it) also and it just becomes a leaker( I did this myself) why because it was COLD !!!!!!!

Edited by banzai510(hainz)
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11 hours ago, Scrapson said:

  Man datsun breaking my wallet with gaskets and shit.  

 

Well what does a garage mechanic charge an hour? Divide what you make an hour into this to see how long you have to work to pay someone to turn a wrench. Lowest I found was $70 - $100+ . Roughly 10 hours to pay for one of theirs.

 

 

 

 

 

1 minute ago, banzai510(hainz) said:

personally I think you were looking for a major proplem that didn't exist. and in a rush you dismanteled the motor.

 

YOu got the vedio . 

 

On 11/12/2019 at 8:09 PM, datzenmike said:

A little knowledge is very dangerous.

 

 

What I was thinking on page one.

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So I know now that it’s just the timing chain skipped a tooth but it’s nice to know that headgasket has been redone. I’ve seen oil pan leaks and how to prevent them with some oil RTV by some I mean a moderate to large amount. I also do want to find where my timing chain parts went because the rail has a piece missing I think and there’s a little rubber thingy just floating around in the timing chain housing atleast it looks like rubber I couldn’t take it out. The garage mechanic does sound like a great option but I don’t want to pay that money and it’s my senior project as a requirement to graduate. I live in the sticks of the valley in Oregon so there not uncommon just pricey. I also like doing all the work myself it’s fun 9 times out of 10 but sometimes it’s a pain in the ass. How would I break the pulley bolt loose would I have to put the head back on? Because In the video correct me if I’m wrong I was half asleep but it looked like it was still on. 

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I think it skipped a tooth because it wouldn’t idle at all and it might be the tensioner I don’t really know. That makes more sense now so I have to put the head back on and the sprocket to do it?  Well I didnt think about the timing till I was like huh maybe it skipped a tooth or two or more. It idled at like what sounded like two grand to twenty five hundred but it just was just awful. It just started randomly it accelerated with some hesitation. Also it made clanking noise when it high idled like that. I thought it might be the valve slapping the cylinder or something in the timing chain area broke. I would like to think maybe it was just it skipping a tooth. I don’t plan on selling it either I have time invested into it and effort for me to wanna sell it maybe when it blows a rod through the block but otherwise no. 

Edited by Scrapson
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Lack of proper idle can be dozens of things don't assume or guess. Even without the tensioner in place I don't think there is enough slack for the chain to 'skip a tooth'. 

 

The tensioner can only pop out if the cam sprocket is removed without putting a wedge in there to hold it in place. If it's out, someone fucked up and you have to fix it.

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if you watch the vedio and see how I put it the motor to TDC and YOU check the Cam timming on the sprocket you would know if it skipped a tooth as you would see this.You do this on all motors when you get them you get to figure out your base setting of timming ect….. distributor timming.

 

If you say a valve is bad a compresstion cheak or a lash pad adjustment might catch this.

 

 

good luck

 

Find a Kia Forte in the meantime

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In all my years of building Datsun engines, I have only a couple times see a skipped tooth. It's more likely that someone put it together wrong.

 

BTW - Scrapson, you're scaring me. Some of the things you say make it sound like you definitely do not have a firm grip on the parts inside your engine or how they are assembled. The rubber thingy? If it's the tensioner you're talking about, that's a pretty freakin major part of the engine and if not installed properly...well, let's just say I fear another Datsun is about ready to bite the dust. No disrespect, but it sounds like you're rushing it, not doing the homework and cheaping out. If you can't afford to fix it right, set it aside and come back to it when you have money.

 

And "no disrespect" means no disrespect. Take it as I meant it and think seriously about buying a book or bringing it to someone to at least have a second pair of eyes look at it.

 

Do you have any Datsun engine books? This one alone would be extremely helpful - https://www.amazon.com/Rebuild-Your-Nissan-Datsun-Engine/dp/1931128030/ref=asc_df_1931128030/?tag=hyprod-20&linkCode=df0&hvadid=312014160183&hvpos=1o1&hvnetw=g&hvrand=8582177563154070579&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032596&hvtargid=pla-684015945792&psc=1

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I have the chiltons and haynes aswell as a how to rebuild your datsun engine. It was allegedly rebuilt but I think it was done poorly since it leaked so much oil when I bought it and had a broken valve cover bolt aswell as the back 2 bolts of the head were loose. I’ve been trying to do everything right with a lot of help from this forum and a local mechanic. I’ll post a picture of the sprocket and the I now know tensioner. 

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afpCKaB.jpg

 

Last summer I lengthened a chain to fit an L head on a Z24 block. This was an L20B chain and the  block was 2cm taller so 2 X 2cm links were added. Just for giggles I made the gap shown above 3 links wide. Down by the tensioner the chain was floppy and easily touched the tension (driver's) side. No tensioner would have worked. Two links was perfect. NO WAY a chain will skip a tooth. If you have one it was put on that way. The tensioner won't stay in with that much slack in it. Just look at a fan belt and how tight it is and yet you can still push it to the side with your thumb.  

 

Each tooth is 9 degrees the cam is out.

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Okay now that I’ve done all this pointless work for no apparent reason I better have a running datsun before winter break for the snow season. I appreciate all the help from everyone. Waiting on the timing chain kit to come but as soon as that’s done that means my 50 hours for my senior project is done so whoopee I can graduate. I’ll look at the carburetor to see if that might’ve gotten messed up but the butterflies look good so it’s not that it might need rejetted well it does I would think since it runs quite rich but that’s okay for the cold. 

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Ill check for a vacuum leak but otherwise I am not all that sure on that one. Can't get the pulley off right now just rewatched your video and I don't know what I'm supposed to do to get it off like it is really on there.

 

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I wonder how many Datsuns have met their demise simply because someone pulled the cam sprocket without blocking the tensioner. Epic fail on the part of Nissan's engineers.

 

At this point, have you actually found anything wrong? After re-reading the original question, have you looked at the "gulp valve"? I believe a problem with that might give the symptoms you originally described. I also know that they are problematic. Beyond that, I don't have much experience with it, but it may be worth a look.

Edited by Stoffregen Motorsports
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Let me open up the chiltons guide to figure out what that is. Yeah the tensioner is a bit of a problem but now I know that for next tine it’s just a learning experience for me at this point I can pull the head off pretty easily but after that everything else is kind of a guess and check. 

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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.

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The FSMs were available online off of one of the nissan web sites I heard they got taken down though... I'm sure some one has one.

 

That l series book mentioned earlier is really good too. They can be found on ebay or amazon for a decent price sometimes 

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