Barffing up blowby on my Matchin 75 L20b

[PtheDude]

Looking for leads on the best rebuilder in Seattle, that can do a L20b rebuild right, timely, and reasonably priced. You pull oof the oil fill cap and blue smoke "Mists" out the damn thing. I already paid to much for the truck!

 

Went to visit Datsunholic in Taco to get my matchbox dizzy, step bumper and truck speed. got halfway there andd WHOOSH.. big blue smoke...then it stopped smokin... hmmm. pulled over, oil all over. dripping out the front. we replaced the pcv valve hoping... but not So, now the valve cover hose has been extended down to the ground, and I need a quart of oil to goa block or two. but it runs great! Well mostly. got me home anyway.

 

Who ever rebuilds the engine has to guarentee the work for at least 90 days. Yes, I have huge amount of cash just lying around that I'm dying to dump into a 32 year old truck.

 

And my step dad told me to buy an S-10.

[lynchfourtwenty]

buy another long block.. switch some parts around.. maybe changes some gaskets / timing chain or something.. good to go.. for cheap! if that engines blown its because the P.O's didnt take care of it.. poor thing

[datsun dreamer]

That sucks! Hopefully the engine isn't completely gone....Check for everything Coolant in the oil/Oil in the coolant, Spark plug color(did engine get realy hot!)....Let us know what you find.

[RacnJsn95]

Sounds like the engine I pulled out of my 620. It was litterally pumping oil into the air filter housing. Why dont you try to rebuild it yourself? It's pretty simple. If you're lacking in technical knowledge, buy the book "How to rebuild your Datsun/Nissan OHC engine". You could always watch the video that hainz did too.

 

Including buying another L20b/5speed combo, I spent about $1000 rebuilding my engine myself. That includes a bunch of little trinkly crap, like having the flywheel turned, new clutch, materials to make my Y-pipe, and having the exhaust welded up to it.

[DISLEXICDIME]

get a nickel ads and look up engine rebuilders they have napz 2.4 long blocks for 1000 if i remember right.( oh yah it is in the portland nickel ads) so look at it on there web site

[PtheDude]

I'm cool with doing a great deal of stuff myself. but I'd rather pay to have the lower end of the engine done right so I can tow my jetski to the lake. I don't really have the tools and experience to do it correctly. I can do aircooled VeeDubs but... I want to build it right so its good for 100k+

 

My numbers match. Shouldn't I keep the block I have? It's not seized. still starts and runs.

[]2eDeYe]

Autosport in Seattle. Terry knows his stuff ;)

[banzai510(hainz)]

Im winging this one but change the oil filter first and see what happens.

[PtheDude]

It's new. I will, but datsunholic and I replaced the pcv valve in hopes that it was the culprit. no luck.

[datsunaholic]

He doesn't have a head gasket leak... no oil on coolant, no coolant in oil. I saw it- the valve cover breather was blowing oil into the air cleaner. It was so full the oil ran out the air snorkel and all over the headlights, as well as ran down the hot air intake tube straight to the exhaust manifold.

 

When he pulled the oil cap with the engine running it was like an oil sprayer- the pressure was unbelieveable. I've had engines with blowby, but I've never seen something like this. Well, except on 65 year old aircraft engines. What's so weird is it's running pretty good for all that pressure.

[datzenmike]

A compression check results would be nice. Either all cylinders are low or the gasket is blown forward into the timing chain, or to the rear oil drain hole at the back of the head. Is it overfilled with oil? Exhaust valve guide broken?

[Bleach]

My numbers match. Shouldn't I keep the block I have? It's not seized. still starts and runs.

matching numbers doesn't matter too much with those trucks. There aren't enough serious collectors to make the truck worth more. And even at that, it would only be worth it if your trucks body and paint were in absolutely perfect condition.

 

Maybe get another engine from the Taco Pull a Part and drop it off at Autosport in Seattle.

[banzai510(hainz)]

Autosport does not install motors. only rebuild and machine shop service and the store has some parts.

 

 

my buddy seen this on a Volvo where the thing had no prssure or too much pressure. Removed the motor and tore it apart and could not find anything. They thought it was the oil filter or the relief valve/ball or what ever it is. Im not positive but its worth a 3-6 dollar oil filter.

 

Maybe you just overfilled it???????

[datsunaholic]

When he got to my place it was nearly out of oil. Unless the dipstick is wrong. I've seen that once.

 

I suppose a filter could go that, but the pressure relief valve is for when the filter gets plugged. The oil pressure control is all done at the oil pump... I suppose it could have too high main pressure if the relief valve is stuck shut, but that doesn't explain the excessive cranckcase pressure

[banzai510(hainz)]

Doug Im just making a fast ez guess. Plus its cheap to add another filter.

YOu have to figure what would cause a Faulure of that magnitude that quickly? So I guessed oil filter.

 

Lots of blowby? all the rings going out at once? highly unlikely. If one pistonwas HoLED it woulds seem lke it missing due to no compression.

 

something else plugged???

 

My 521 I drove home then the next morning it backfied thru the carb and smoked a bit. I drove it around the block thinking it would go away.(fouled plug) But it didnt. So I come home later to ck it out. I have #3 clyinder missing but spark is going to #3 wire. I swapped plug still the same. Ck the carb. Its idling ok and reves up but Like its missing. So I said shit I bet the lash pad of the rocker os OFF.

I pop open the valve cover and there was the lash pad at the bottom and the rocker arm hangin sideways next to the spring retainer. I dont know how it poped off. My motor does diesel so maybe it has something to do with that running backwards.

I tried putting the lash pad ON put it was so tight I had to loosen the rocker arm up and reinstall. I got it to .006 intake hoping it will not fall off and lucky it didnt go down in the pan. so for a side not when installing aftermarket lash pads get the bigger retainers so they dont fall off at high RPM.

 

after install it was all good then the next day I got ASSHOLED by newer Chevy Cobalt. I went to tun in the gas station and they just drove off. I said what????? well my bed seam was buckled just a bit but nothin big. IM sure they have more damage as they did more or less run right into the big BUMPER which is to the frame. Well this is why I like my beaters. No stress but I cant believe I coulndt try for a fast cash (my neck isnt hurting line)

[datsunaholic]

I'm not so sure it wasn't a pre-existing condition, but I don't know if he's ever run it that hard for that long as running from Redmond to Tacoma.

 

What is really odd is the PCV didn't seem to be sucking oil through it. Like the PCV system was completely plugged. His PCV hose was an original braided one. Plus the engine has had the emissions equipment removed wholesale, with the EGR manifold removed in a somewhat sketchy manner.

 

I think that a compression test and a leakdown test should be done.

[banzai510(hainz)]

is this a automatic??

wasnt there a guy on here or NWDE and it had something to do with a valve somewhere??? If it was a automatic But IM only guessing now

or maybe sucking up automatic trans fluid?

[datsunaholic]

No, it's a manual. It's motor oil. I'm convinced it's blowby, but I've been wrong before.

[ppeters914]

Doug I'm just making a fast ez guess. Plus its cheap to add another filter.

You have to figure what would cause a Failure of that magnitude that quickly? So I guessed oil filter.

If it's a FRAM filter, CHANGE IT NOW!!!! :D

[datzenmike]

Did an oil change once and the next morning the oil pressure relief valve had stuck (unknown to me ) and the high revs on the highway split the filter and lost the oil. After the 2nd one I went searching for the prob (thought at first I got a bad batch of filters) seems that a tiny speck of casting lodged in the side of the bore, preventing the piston from moving. So it can stick.The 521 ran normally with the extra pressure enough to split the filter case from it's base.

 

Even with high pressure at idle, there wouldn't be much of an oil fog thrown around by the crank. (if the oil was overfilled it sure would, not the case here you say) Don't remember having an L valve cover off with it running, does it throw much oil? If there is some spray from the lifters and cam, an engine with bad blow-by would easily push it out the oil filler hole or the breather. The oil may be a result not a cause.

 

Usually a motor with bad blow-by doesn't run so well. Does the exhaust smoke at all?

 

Try a known good dipstick!! If his is wrong by an an inch there would be three or four extra quarts in that pan and that might just be the problem. Maybe the tube isn't seated in the block. The crank would whip it into a froth that would travel up the oil drain at the back of the head and up the front chain cover. The slightest blow-by would push it out.

[PtheDude]

Never would I over fill. It was an exisiting problem, when I bought it. I tried to add a bit of oil few days after I bought it and oil spewed out of the the cap when I opened it. I was like WTF???

 

Weird. Later I tuned it and when I replaced the air filter there was oil in there. now, no one snigger at me, but I'm an old air cooled vw guy. I THOUGHT oil was supposed to be in there. just was on auto pilot I guess.

ID 10 t

 

 

 

I'm going to try the Hanz filter method of miricle engine restoration, just as I did the PCV. I'm bidding on a compression tester, will have that soon.

 

Thats a great suggestion about the dipstick, I will check. The truck is pretty unmolested but it could be wrong. Will someone please quickly measure their dipstick and post the results? lol.

 

 

I need a running L20b truck motor to put in there, or can I get a L18 that will work? there's a few 620's on CL right now that are under 500 bucks. I figure I can strip them for what I need and then datsunholic will happily add whats left to his yard for future restore. ;) I've never met someone with more automotive junk of a particular vein.

 

Please point me in the direction of running engines that grow on trees. The thing that sucks is I paid 1500 for this friggin truck. Its damn straight, little rust, new red paint, good rubber, an L20b It was a decent deal, I wanted a red one. Now it's FUBAR. I did not compression check it before I bought it.

[datsunaholic]

Who said anything about restoring them? I just rotate them through commute duty. And I've quit buying/taking on folks parts rigs. Too much hassle.

[banzai510(hainz)]

try to find another L20 other wise youll need another flywheel for a L16/18 since they are 5 bolts flywheels most are 200mm. L20s are 6 bolt most trucks are 225mm setups.

 

 

 

L20 round or square exhaust? I dont know the year break down on these Doug would know

 

Maybe there is NO baffle on the valve cover?

 

 

Oil always comes squirting out of the cam lobes holes

 

 

all you got left to change is the oil pump as a last resort(cause its EZ to change) then I dont know without looking at it or maybe tearing it apart. Make sure you line up the motor before doing this!!!!!!!!!!!!

[datzenmike]

Pthedude: The dip stick tube might not be seated all the way down into the block too. Does the tail pipe smoke too?

 

Hainz, the baffle has like a dozen rivets holding it on, sure woulden't fall off. Maybe excessive oil press?

[banzai510(hainz)]

Mike,

yeah I know the baffle would never come off . Im just reaching here.