Sealiks Shit

[banzai510(hainz)]

I never seen a 140 lash pad. Maybe you can squek by with a 150, or shave a 150.

 

 

looks good.

 

make sure to use cam grease, prime oil pump and prime carb( i hand pump the fuel pump, gas to fill the carb bowl up) then push on carb to hear squirting.I also pour oil over valves right before startup

 

This motor this weekend I also routed a hose from where the oil filter is I pushed Gear oil80-90 wt to the front cover and filled the oil pump with the same gear oil. Pretty mcuh instant oil pressure. no need to spin it up with w drill motor as others do.

[Sealik]

I never seen a 140 lash pad. Maybe you can squek by with a 150, or shave a 150.

 

 

looks good.

 

make sure to use cam grease, prime oil pump and prime carb( i hand pump the fuel pump, gas to fill the carb bowl up) then push on carb to hear squirting.I also pour oil over valves right before startup

 

This motor this weekend I also routed a hose from where the oil filter is I pushed Gear oil80-90 wt to the front cover and filled the oil pump with the same gear oil. Pretty mcuh instant oil pressure. no need to spin it up with w drill motor as others do.

 

 

I started grinding a pad yesterday.....very hard....might take a while.

Ya...got lube and a device to spin the oil pump.

Just noticed something on the head though.

Doesn't look like a lot of clearance between the underside of the rocker and the edge of the retainer????

It's not hitting and in theory shouldn't...but sure is close.

About .020....it's less if I slide in the .009 feeler gauge....if I was setting the valve lash.

 

[Sealik]

Got the pad down to .139 from .149.....won't work.

Retainer hits underside of rocker.........excellent. :blink:

Would assume now that those Isky retainers are designed for a taller lash pad app.

With those retainers it also raises the installed spring height....which doesn't help matters.

Not sure of the Nissan Motorsport .150-.180 retainers...but their .190-240 also raises installed spring height.

[banzai510(hainz)]

trim underside of rocker. Doesnt look like your gonna hit to me by the photo.

[Sealik]

Has this been done before....?

[banzai510(hainz)]

I havent heard of it.IM winging it now!!!!!!!!!

[Sealik]

I havent heard of it.IM winging it now!!!!!!!!!

 

That's what I figured... :lol:

Definitely thought about 'winging it' though.....

[Sealik]

Think I'm gonna run the stock retainers.

Specialty Engineering say I can get away with .180s...which is what my intakes will be.

The exhausts run .150s...but only half of the pad is in the retainer.....should be 2/3 I believe.

[datsunwizard]

Why are you having to use different size lash pads for the intake and exhaust? Did you or your machinist equalize the valve stems lengths by proper cutting of the seats. If all of the stems are of the same height from the the spring seat, you can use the same thickness lash pads on all valves(If the rockers and the cam lobes are in tolerance). When the stems heights are all over the place it makes the job much more difficult which you are now finding out. Also a little trick, replace all of your springs with light tension springs during the cam setup, helps make the job easier. The valves that the you are having to use the smaller lash pads have the valves sunk to far into the head. Most machine shop that are use to doing Chevy, Fords, etc. don't understand the geometry of the Datsun. You sink the valve in a Datsun head and it changes everything. I would equailze the stems and go from there ( don't grind the top of the stem to equailze !)

[Sealik]

Why are you having to use different size lash pads for the intake and exhaust? Did you or your machinist equalize the valve stems lengths by proper cutting of the seats. If all of the stems are of the same height from the the spring seat, you can use the same thickness lash pads on all valves(If the rockers and the cam lobes are in tolerance). When the stems heights are all over the place it makes the job much more difficult which you are now finding out. Also a little trick, replace all of your springs with light tension springs during the cam setup, helps make the job easier. The valves that the you are having to use the smaller lash pads have the valves sunk to far into the head. Most machine shop that are use to doing Chevy, Fords, etc. don't understand the geometry of the Datsun. You sink the valve in a Datsun head and it changes everything. I would equailze the stems and go from there ( don't grind the top of the stem to equailze !)

 

My machinist is...well...suspect at best......I assumed what he was doing and just dropped the head off.

Not too many options up here....he's about 240km away, round trip.

Already had it back once because 4 guides were installed incorrectly and the valve stem seals didn't seat properly, flush with the head.

He replaced the exhaust valves/ guides and the intake seats.

The intakes are 'fine'.....well.....close anyways....180s-190s ...which gives me about 60+% of the pad in the stock retainer.

I can see that there is more valve stem above the keepers on the new exhaust valves...appox... 30-40 thousands....which is what I'm using in lash pads to compensate.

 

Same size pads in pic

 

 

So....don't cut the top of the stem to equalize?

I'll be taking the head back tomorrow......

 

Thanks

[Sealik]

I havent heard of it.IM winging it now!!!!!!!!!

 

Actually...you are allowed to "correct any interference".

 

..."Use a large sanding drum to relieve the rocker arm from actual contact, plus an extra .015 to .020...then round off any sharp corners or edges on the rocker to prevent generating a stress riser.

Or, use the late-style rockers shown ..."

Quote from How to Hotrod and Race Your Datsun

Think I'll be fine after I take the head back and get some issues corrected....again.

[banzai510(hainz)]

Crap I have that book@home but I use it as a big Coaster for my coffee and drink cups

[Sealik]

Crap I have that book@home but I use it as a big Coaster for my coffee and drink cups

 

I just found mine... :blink: ..forgot about it...Merlin lent it to me last winter.

Some good info.

I'm reading up..... :D

[Sealik]

Well....basically have no clue on what to say to the machinist other than to clip the top of the exhaust stems.

 

Anywho....

Finally got some new (not reconditioned) Beck Arnley injectors....yeah.

My other truck has been running like shit.....very bad gas mileage.

I thought it was the MIA air regulator....but nay....after further inspection. :D

Was losing fuel pressure after the truck was sitting for a while.....draining into No 1 piston...not good.

Should be a noticeable improvement....

Shall install in morn and make the trek...

 

[datsunwizard]

I just found mine... :blink: ..forgot about it...Merlin lent it to me last winter.

Some good info.

I'm reading up..... :D

 

Is your book the 1st. edition or the second? If the 1st. read the entire charter by Racer Brown on cams. It will tell you what you need to know about L series cam geometry. Before you take the mess back to the "The Machinist", You need to find where the problem is or what is causing the problem. Number the valves to the their cylinder, then remove the springs / valves. Measure the length of the valves to each other ( are the replacement valves Nissan OEM or aftermarket? if aftermarket maybe the replacements are longer then stock OEM). The stock exhaust valve is 4.57"/ 116mm in length, the intakes vary depending on what model, but average is 4.56"/ 115.9mm. Are they the same between each other? If they measure ok for length, then insert the valves into the head in the respective cylinder and measure from the spring seat to the tip of the stem and record the measurement. This measurement should be the same for all cylinders, if not then this is where the problem is. The seats and/ or valves are not cut correctly. Look at the seat face width on the valves are they the same on all intakes, same with the exhausts? should be. More likely, is the seats in the head are not the same in height, some are probably cut more than the others. I don't remember if you mentioned if the seats have been replaced? If you need what the specs are on the seats, I can provide. Over the years dealing with machinists , I have found that if you give them the specs on what you are requiring, the better. Machinists like numbers. You need to tell them that the measurement from spring seat to the stem tip is to be the same on all valves and not to cheat and shorten the stems to achieve the measurement( remember that the lash pad seats on the stem and not the retainer), work with only the seats and don't sink the valves. Sometimes the only way achieve the goal is to replace the seat and start over cutting the seats. I hope that this info helps.

 

monte

[datsunwizard]

Was working on my post ,while you where posting. That is the second addition book,no Racer Brown in that copy. I remember that the Racer Brown article is some where on the web, I will see if I can find the link for you.

[Sealik]

The exhaust valves are PN..... 100365, not sure of OE or aftermarket.

By the look of my invoice...no new seats. just valves and guides.

I'll pull a valve out and measure.....I'll bet it's longer than OE specs.. ;) ..give me 6 mins... :D

 

 

Head is a 1975 U67

That book is the revised edition.

[Sealik]

The valves are....(drum roll).....4.621...117.42mm...a tad longer I'd say... :)

 

So...if I get 30 thousands shaved from the stems....good to go.

That's the same amount or difference in intake and exhaust pads.

Give or take.... :)

[datzenmike]

Don't trim too much there's a groove for the keepers.

[Sealik]

Don't trim too much there's a groove for the keepers.

 

 

Ya....I'll confirm that distance prior...in theory that 30 thousands should result in the same config as the intake valves, valve stem above keepers

[datsunwizard]

Those exhaust valves look aftermarket, do happen to have a stock used valve? If so, I would put the the new and used valve on a flat surface and measure the location of the groove on both stems using a height gauge. Just to be sure the stems are not longer between the valve head and groove. If they are the same, you could shorten the stems. This needs to be done in a lathe with a tool post grinder or a valve machine. Be sure to shorten all of the exhaust valves to same over all length. Just for kicks, take one of the exhaust valves and using it, do the measurement on the spring seat to the tip of the stem on all cylinders. They should be the same. This is to see if "The Machinist" did the job right on cutting the seats ( that one seat is not sunk more than another).

[Sealik]

Found the old valves....4.612 / 117mm..........New valves...4.621...117.42mm.

More stem above grooves on the new valves....3.14....old...2.61

No 4 exhaust needed a 140 pad, down from 150s for the other exhaust valves. Still didn't have a centered wipe pattern, most likely needed a 130. Don't have anything to measure it.

 

Do you know the measurement from spring seat to the stem tip?

[datsunwizard]

Found the old valves....4.612 / 117mm..........New valves...4.621...117.42mm.

More stem above grooves on the new valves....3.14....old...2.61

No 4 exhaust needed a 140 pad, down from 150s for the other exhaust valves. Still didn't have a centered wipe pattern, most likely needed a 130. Don't have anything to measure it with but I would assume that valve seat is too deep.

 

Do you know the measurement from spring seat to the stem tip?

 

This is weird, the length is about the same but the groove appears to be father down the stem, correct? If that is true, then the spring pressure on the exhausts is more. What height lash pads are you using on the intake valves? It appears the exHausts are all sunk with# 4 the worst. I will check an see if I can find a measurement that you requested.

[Sealik]

This is weird, the length is about the same but the groove appears to be father down the stem, correct? If that is true, then the spring pressure on the exhausts is more. What height lash pads are you using on the intake valves? It appears the exHausts are all sunk with# 4 the worst. I will check an see if I can find a measurement that you requested.

 

Yup....about the same length...groove farther done on new ones

Intake pads were .180-.190

 

Thanks

[Sealik]

30mm / 1.18 sound familiar?

 

http://preterhuman.net/texts/automotive/Nissan_Model_L20b_Engine.pdf

 

Mike Klotz.....www.THE620.com

Figured Mike should know..... :D