Rat-a-tat-Dat's '79 720 rebirthing of 'Helios'

[Rat-a-tat-Dat]

Still waiting for the emulsion tubes to arrive from the UK. Been over three weeks, Covid-19 delays, I'm sure.

 

 

But look what I found in the mean time....

 

Waking by a truck in town, these 6 bolt rims just happened to catch my eye. 15x7's!

They were not in the best presentable state, with exposure to the elements the surfaces were degraded. 

The owner was in good spirits though and parting with them was well, what he said, "It was meant to be".

 

After hours of clean up, elbow grease and more elbow grease, they started to shine, literally.

Unfortunately, half of the rims didn't make it to an acceptable finish. 

 

 

The original finish had been eroded away, leaving only a flatter shine.

Tried several methods of polishing techniques but to no avail the difference between them is quite noticeable.

Maybe pair the rims together, best ones on the right side and the worse ones on the left, lol.

 

Here, you can see the dullness in the top and left rims. Much shinier in the right and bottom ones.

 

 

Thinking that I could Plastic-Dip them into whatever colour works for the truck. Compelled to go with a strong WHITE. Thoughts?

[Rat-a-tat-Dat]

One hell of a wait but they finally arrived, the new emulsion tubes for my Webers are here!

The time for patience is over and before the days light rests in the west, Ol’ Helios’ gallop will quicken.

 

 

[Rat-a-tat-Dat]

Oh my, oh my, what a subtle difference. Hadn't taken too long to install and the throttle response was immediate. Better idling, smoother transition through the rpm's and the overall carb characteristics have improved. A few minor tweaks with the synchrometer and they'll be all set up with these new tubes.

I imagine this step is one of many, but for now, a noticeable improvement for sure. 

Next is figuring out the main jet and air corrector jet numbers.

Q: I did notice on a couple of the jetting tube arrangements (after installing the new emulsion tubes), that two are sitting higher when all are bottomed out (stacked hight). It doesn't seem to affect the performance, so it can't be a serious problem, right? I had removed them to verify proper fitment and checked for restriction but all looked normal.

[Crashtd420]

Glad you saw the improvements I was talking about, I'm always worried about giving advice when it means the person has to spend money to see if I'm right.  It just sucks emulsion tube cost what they do, I feel are an important part that gets overlook due to price....

[Rat-a-tat-Dat]

All good advise, so no worries.

 

Sent me in the right direction so I'm actively engaged now.

But seasonal changes are upon us and thus a cessation in carburetion refinement.

 

Helios is stabled and at rest!

 

Cheers!

[Rat-a-tat-Dat]

Greetings fellow Ratsunites, 

I have had a slight sabbatical in the interim from updating because of experiencing a 'glitch' or a 'slight technical difficulty' with entering any comments on this message balloon. Actually, I couldn't, but problem has resolved itself ( go figure? ).

A transition in living accommodations and relocation coordinates have been a priority in our lives of late, which also contributed to the delay. 

I just unboxed this computer to address an update and disclose said tardiness.

Update:

Helios has been running better this year because of earlier carburetor refinements from last year however, during an outing and feeling very spunky, my right foot suddenly became extremely heavy and from a full stop Helios decided to engage into a gallop. While shifting gears to keep up, something unexplainable occurred to which Helios stumbled and fell into a despondent state. No longer did he encompass the energy of a wild horse but rather that of a half beaten plow horse. A serious foisting impact had been placed upon me during a routine jaunt. 

No matter, we Ratsunites engage when circumstances summon us.

Turns out my heavy foot has found a weak spot in the firewall where the throttle accelerator is mounted ( no rust observed ). The super hard thrust impacted and physically shifted the metal underneath the pedal. It buckled, causing a shorter throttle stroke and choked off the travel to the carbs, hence the half assed response. Me thinks some modification is in order to rectify said condition.

Has anyone else experienced or had this phenomena happen to them?

[Rat-a-tat-Dat]

G'day to you all, I do hope everyone's instauration on their projects has been positive? I've noticed a few Ratsunities have nearly completed their missions, congrats. 

 

Well, I must confess, my instillments on said matters barely scratched the surface due to the insuperability with locating the necessary component to effectively migrate Helios to Island life

.  

My dilemma remains with an unattainable item, referred to as a windshield ( mine will not pass the safety inspection report ) and I've enervated even the most resourceful people in the industry. 

 

Apparently my quest is now shifting to the only places that rarely inhabit these obsolete vehicles, let alone the perfect, unobscured glass.

If any of you kind souls out there are inclined to aid in the scavenger hunt that has now been bestowed upon me, I'd be so grateful for any lead.

 

Take care and stay safe, cheers!

[Rat-a-tat-Dat]

 An update, with regards, to the obligatory windshield. ( The exiguous and somewhat non existent component )

 

During my travels back in Alberta, an unprecedented stop at a glass shop emerged and I had a conversation with the office attendant. Despite the reason for my visit, I couldn't resist the temptation to inquire about aforementioned windshield. With little luck ( no conclusive findings ), as expected, we exchanged contact info. 

After returning to the Island a few days later, a serendipitous incident occurred. I received, via that Glass Shop, an actual place and location to which confirmed the availability of a windshield. OMG! Thank you for your diligence office staff attendant.

 

So now I'm focused and excited to obtain this item. I then called the business to which I had been directed and was disappointed when I heard of their location, too far away to make another immediate trip. Further conversing lead to an alternative plan that would be more doable. It was delightful to know they had other branches across Alberta but only in said Provence. A plan was formulating.

 

With a contact I have near one of their locals, I proceeded to acquire the parts for replacement and ordered them. Given the timeline and nature of my return to that area, we managed to arrange a day where we both could pick up the new windshield and seal. Done!

 

Only one acute disruption interfered with it being in my possession back home, I had flown to that destination. No big deal, it just meant a further delay in repairing the truck.

The windshield was mildly wrapped in perforated cardboard and therefore subject to any incidental accidents. Simple enough, with plenty of access to materials, I constructed a wooden crate that surrounded the glass. This prevented any minor mishaps and gave it an external perseverance with easier handling capabilities.

Unfortunately, my contact lived too far away as well, closer yes but still in Alberta.

 

Oddly, the path of the crate continues, as a transferor accepted responsibility to retain my illusive but well traveled package. This other contact stepped up and it now resides somewhere in central BC, still too distant a trip, some 600 km away.

 

Please don't judge. I'm not in any hurry. Sure, putting it on a transport and expediting it here would be the norm but I enjoy the basic, fundamental execution of a journey, with little to no overcharged transactions, I control the costs.

 

Besides, everyone loves a great storey. Am I right?!

 

Early October is in the works...

 

  

[EDM620]

Where pray tell did you source the windshield here in AB? I had months ago discussed my future needs with a shop, but wasn't ready yet to acquire one.

[Rat-a-tat-Dat]

Well, you're in good fortune my friend. One of their many branches across Alberta is actually in Edmonton. Its location is in the northwest and goes under the name of All West Glass. They expedited it for me the very next working day. When you pick up the parcel it'll be wrapped only once in perforated cardboard. Definitely bring a blanket with you to ensure its safe journey home. My windshield part number was FW00413, dimensions are 55" x 25", for a 1980 720 King Cab. You can purchase separately and DIY or have them install for you for an additional cost. Either method is realtively inexpensive. 

[Rat-a-tat-Dat]

Here's a blunder I'd like to share.

 

Each time I drove Helios, I'd complain about the continuous and constant poor performance of the Webers. No matter how many attempts to correct or tweak the carbs, the same result came back ( carb linkage sticking after it warmed up ). I put up with it for far too long. I finally parked him and neglected to drive him for quite awhile.

 

So after a long absence, I decided that the carbs probably needed a major overhaul, right? and was ready to do it. Started the process of removing the carbs when I came across the throttle sticking even before the engine had been started. New problem? or maybe this time I get lucky and find the actual issue.

 

Yup, as far as I was concerned the carburetors were in fact the problem. How many tries and attempts of having a normal running engine had been accumulated?

Enough to frustrate the hell out of me, that's for sure. Meanwhile, a clear fault and oversight on my part could have been avoided so easily ( hindsight; wink, wink ) by a simple twist or rather a not so firm twist of a fitting on one of the carb linkages. These dual carbs are linked with one pull rod that attaches to each individual carb throttle. So naturally the heim-joint connection points are critical, especially with synchronizing the idle and performance aspects. Each bolt carries two flat washers, one on either side and one ny-lock nut to keep them firmly in place. They're not very big but very important. I thought I had just snugged them up, not with too much pressure. There are four of them to deal with and every time I made an adjustment to the carbs I had movement in each one. Easy, nothing to see here! I even lubricated them too at one point.

 

Nope, when all things seem too easy you can even miss the obvious. Case in point, by just releasing the nut on the sticky carb connection, a hair or two, the throttle linkage was free from sticking. What a revelation, what an idiot! 

 

I was even preparing to rebuild a new heat shield to go under the carburetors too, if it came right down to it.

 

Reset the carbs and they idled smoothly, burped the engine and Helios revved with a new anticipation before descending back to a smooth idle again. Even after running him for quite some time, no more stickiness. Problem solved! 

 

Blunder worth sharing, I hope.

 

 

[Rat-a-tat-Dat]

So, the worst possible dilemma occurred all because I trusted a guy whom happened to own a Datsun 510 truck. Albeit he was going to restore the vehicle and had a collection of parts to install, but who are I kindling, right? I am the one that happened along and spotted these rims in the back of his truck during a walk through a neighbourhood. I am the one who insisted on buying these rims. So naturally, I am the one to take full responsibility.

 

For all you Datsunites and followers, never take for granted any parts that are NOT attached to a vehicle. Measure and double check all your specifications regarding proper fitment to the vehicle those said parts are going to be attached to.

 

Case in point, I picked up these rims and imagined 'they' would look real good on my Datsun truck. Even though 'they' had been IN not ON a Datsun truck and 'they' also had the 6 stud holes matching the description of a Datsun rim. This doesn't necessarily mean they will be a perfect swap over.

 

I found out the hard way, meaning, I bought new rubber for these cleaned up and polished rims, dismounted all four existing tires, swapped over the old to new shoes and when it was time to remount them it became apparent that these rims were never going to fit no matter how hard I tried to push them on, lol. Palm of your hand smacking yourself in the forehead moment.

 

Turns out the bolt pattern is for some GM SUV models, like the Trailblazer and Envoy. Very limited, apparently, 6 x 5" or 6 x 127mm. You guessed it, I have some rims for sale, lol.

 

Have a gr8 day everyone, cheers!

 

 

[EDM620]

That's what we call "buyers remorse" - and the big DUH to learn from...

[Rat-a-tat-Dat]

Well, I thoroughly enjoyed Helios this summer. Lots of driving, with not too many hiccups, was bliss. The occasional mishap happened with a no start but sorted that out as an ignition issue, a poor connection at the matchbox terminal. The climate here, I found, compared to where I was before seems to be more humid and harsher on electronic connections.

It wasn't until the late fall heading home, just before I bedded down Helios for the winter, that he made a loud unhappy noise. Not even a kilometre from home the engine temperature gauge max'd out and all I could do was baby him home, making sure the movement of air would keep the temps down just long enough.  Eureka! 

home at last. 

Stopping and looking behind me my eyes followed a trail of coolant showing where I had come from. I didn't like the looks of this past.

After opening the hood and letting the steam out, I proceeded to investigate our dilemma.

At first I was hoping it was just a coolant leak coming from an old deteriorated hose. Not so lucky, a second closer look indicated otherwise and pointed to the cylinder head gasket. Oh dear!

I let Helios rest and later feed him four litres of refreshment prior to leading him to the stall.

[Rat-a-tat-Dat]

The sad part about this experience, it's the second time I'm repairing this motor for a head gasket issue.

In the beginning; I tore the head off, removed the existing exhaust port liners, sand blocked the head, ported intakes and exhausts, new valve guides, new valves, new springs, timing chain set and related items.

The block itself was within tolerance specs. and I did a mild scrub around the cylinder bore themselves ( took away the lip ). After which the assembly followed.

Some other mod's continued as to help with improved engine performance, attached peripherally in nature.

I did not dive into the bowels of the engine, nor needed too at the time. Internal components felt tight and without any visual concern. A satisfactory Bill of Health.

As I try to stay positive, the outcome of Helios is wavering to be a complete reconstruction and upgrade.

I thought about a transplant but there is no need to overcompensate his abilities. Perhaps refreshing some internals and/or adding a larger lung capacity my be all he needs to perform slightly better.

I'm interested in all ideas that may help but without going extreme, if you know what I mean.

Cheers.

 

[datzenmike]

Try to never overheat an L series if at all possible. Pull over and let cool down, add ditch water if you have to. 

 

Pull the head right away. There's a good chance of warp and coolant getting into one of the cylinders and rusting the rings to the walls. It will if left till next summer. Better to know now if you need to scrap the head.

[Stoffregen Motorsports]

Head gasket quality matters. I hear that most aftermarket gaskets these days come with the graphite coating. Is that true? Are OEM gaskets not available anymore?

[datzenmike]

I think Felpro are graphite coated. These might allow more movement between the two different expansion rates between aluminum and steel. Aluminum expands twice as much as steel. There would be less internal shearing.

[Stoffregen Motorsports]

Fel-pro used to be plain, with no coating. They also had that stupid print-o-seal gasket, which was junk.

[banzai510(hainz)]

https://www.ebay.com/itm/323974767604?hash=item4b6e66a3f4:g:97kAAOSw7WxdxvEH&amdata=enc%3AAQAIAAAA0LUWV1MmJf8QkCqAVRnAw%2BnaqWrymIM%2FMAk40Odwf5cuogModpQsm69r%2BQMccTzpCFVIsmM7w1f0mwOgFrVMop7pJpci69Hst8RMcjaDiOU9k3dLj0rMOSsKu9PbxcPu9INjYsWFyEr8TkQ0bCAx8CvK3ZSoNAFO%2FzJ1oH0u9%2Ff4U3tk96e4LN2OUBHre8TrE6n%2Bf8yocpqwKn96QF3qUmCFrQZLytzViBGhSBEiMUl%2FEY3QDvsRgFjOSurgHpVh40s0MPv%2B%2BNE5Ab5DG%2FBKjNs%3D|tkp%3ABk9SR4SsuJKEYw

 

japan made

grafite ones are the better ones to get. Nissan ones.

I got Durapro from Australia (japan made grafite)

 

Felro headgasket is OK in a pinch esp a L16  L18/20 the bores are close so beware

Edited November 30, 2023 by banzai510(hainz)

[Rat-a-tat-Dat]

Removed cylinder head and found very little tell tale signs of cause. wtf?

The area in question had the usual soft spot and bypass on gasket but cannot find the reason behind it. Possibly a weak head bolt, stretching?

Will clean up the block surface and straight edge for unevenness. The head too, of course.

Found a little wear ( scoring in number three pocket ) but within specs., 3.345"

 

If I were to replace the pistons, say with flat tops and bore each hole 0.010" over, is there going to be any issues moving forward? Should I keep the old pistons? How much can I get away with? What will work in a L20B with a W58 peanut head?

Previous pistons are slightly dished but I'm not sure about the flat tops, especially for valve movement. Don't want piston slap.

 

I'm doing the bottom end at this stage of the game, it just makes sense.

 

Thanks ya'll.

 

 

 

 

[datzenmike]

There were no  flattops in L20B size. Piston dish on the L20B was 11.36cc.

 

The Z20E pistons were flattop but the pin height is higher, meaning you would need the Z20E rods to go with it. 9.95 compression.

'81-'83 280zx pistons are flattop but you need to over bore the L20B block from 85mm to 86mm. 10.11 compression.

 

Only way the valves will hit a flattop is if the timing chain breaks while running. Have never heard of an L series double roller chain breaking. Virtually impossible.

 

Piston slap has nothing to do with valve/piston clearance and is caused by too much piston to cylinder wall clearance, caused by a worn cylinder, causing the piston to rock side to side. It's most pronounced on cold start up and usually goes away. It's often mistaken for rod knock which doesn't go away.

 

None of this is really worth the cost and bother sourcing parts and in the case of the 280zx pistons the machining costs. Block bore is 85mm to 85.050mm, so just hone the cylinders and replace the rings. Ring selection dictates what cylinder finish you hone to.

 

 

[Rat-a-tat-Dat]

21 hours ago, datzenmike said:

None of this is really worth the cost and bother sourcing parts and in the case of the 280zx pistons the machining costs. Block bore is 85mm to 85.050mm, so just hone the cylinders and replace the rings. Ring selection dictates what cylinder finish you hone to.

Can you elaborate on what "Ring selection dictates what cylinder finish you hone to" means? 

If I have a block and its cylinders are within 85mm to 85.050mm, wouldn't I just need a standard ring set?

Thanks

[datzenmike]

The latest chrome  or chrome moly are very hard and will last a long time but for best results the bore must be almost perfect or freshly machined and the finish very fine. Cheap jobber cast iron rings work better on out of round or tapered cylinders and need a rougher hone to break them in faster

[EDM620]

If you are taking the block into a reputable shop to have the machining done, take your assembled pistons and rings so they can mate them up. When you do your assembly work, the pistons will be ready to go