79 620 King cab, Cali Import now in the UK

[Stoffregen Motorsports]

17 hours ago, datzenmike said:

But lobe minus base circle times rocker ratio still gives the lift. The L20B cam

 

Yes, that's true.

[datzenmike]

 

This is my Isky cam. Obviously a Nissan casting that has been chucked in a lathe and the rough surfaces trimmed off. The original casting finish is around those square knobs in the middle.

[Danalive]

pulled the engine, found the bottom part of a piston in the oil pan, it came of off no.4 piston which strangely was the only cylinder with good compression when tested

 

a friend pulled it apart and sent me these photos, 

 

 

 

 

 

 

i took the head to work with me and started stripping it, the head is bowed, with a straight edge along the mounting face you can see a big ol' gap easily, ill measure it with some feeler gauges when i get a chance, after removing the rocker arms the cam was still too stiff to turn by hand, which makes me think the head is bowed beyond being useable. 

 

still debating the best course of action, engine swap is too much hassle for me, i havent had any luck finding a l20b or l18 over here, im leaning towards having the block bored to fit 280zx pistons and trying to source another head at this point, 

 

 

 

[datzenmike]

 

Can't see where the missing piece goes on the piston. Looks like maybe #1 piston?

 

Try loosening BUT DON'T DISTURB the cam towers. Start with the front an see if the cam turns then. Then loosen the rear and see. If still tight I doubt the head is so bent that the middle two are doing this. At all costs try not to remove any cam tower. See what results you get.

 

Warping is almost from severe over heating. Usually the area between cylinder 2 and 3 lifts up or puckers here. 0.004" (0.1mm) is the limit, probably you can get away with 0.006" (0.15mm) I had one at 0.015"!!! (0.38mm) I got a thick sheet of glass and glued sheets of 180 grit emery cloth to it and pushed/pulled the head lengthwise across it. Every 20 blow the aluminum dust off and change ends. Tool less than an hour and cost me two sheets of sand paper.

 

 

 

 

 

 

 

Finished with 220 grit

[Danalive]

 

the bit that broke off is this part highlighted in red, missing off the otherside of that piston. 

 

 

got the feeler gauges out on the head and the gap is  .020 so i think thats stuffed. 

[datzenmike]

0.020" is a new record! Someone really over heated this. Were the rings broken? They usually expand so much the ring gap closes and the break and or break the pistons and score the cylinder bores.

[Stoffregen Motorsports]

At .020", the cam will almost certainly not turn. You would need to surface the top and bottom of the head, and use shims under the cam towers to get the rocker geometry back to where it should be.

 

Also, with broken bits floating around the block, I hope you removed the baffle and screen in the block to clean it.

[EDM620]

Well that broken piston skirt and warped head are not a good thing at all, time for an engine swap...

[Stoffregen Motorsports]

Yeah, do something crazy!

 

[EDM620]

Thinking.... IF you were to go that way, and with what powertrains are more readily available to you, what kinda flavour you might be persuaded to spice with...

I'm always admiring the unconventional though my budget tends to dictate otherwise

[Danalive]

Had time to go look at the disassembled block, piston rings are still intact, Rods are rusted, bores are in surprisingly good shape, will take the block to an engine shop for a check over. 
 

Still trying to source a replacement engine, we never got the l20b in the uk only the l16 & l18, even those are hard to come by, if I can track down a replacement head then I’ll have the block checked over, bored and rebuild it myself.  
 

engine swap would be fun however I don’t have a garage to work on a swap, storing it at a friends business in the yard and wrenching on it outside atm, though he’s given me a corner in a store room to work on the engine. 

 

swap wise though there’s the sr20, they tend to go for about 2k here plus another 1k for the gearbox. 

we also had the ca18det that came in the s13 here, cheaper than the sr20.

we didn’t get the ka24de in anything, I can see that’s a popular swap over there in the states.
 

miata engines are cheap and plentiful, a buddy has a 70s ford courier, the Rebadged Mazda, with a engine and trans from a miata. 

The swap that is a bit unusual and over the top, if it would fit would be a jaguar aj30 v6, similar to the duratec v6 I believe, you can pick them up dirt cheap, super durable and 240bhp. 

there’s also a few ford 4 cylinder rwd options but I don’t know much about those. 
 

or - Honda k24, cheap and plentiful engines but the costs seem to add up with the rwd conversion

[Danalive]

thought id update as ive dropped the block off for a rebore and a few bits,  got some 86mm small dish pistons from SW motorsport in Australia, sourced a closed chamber w53 head, new old stock, never used, few weeks and i'll start to put it all together hopefully.

 

managed to get a right side wing mirror, it was plastic where as the left side one that came on the truck was chrome so painted them both to match, also filled and painted the steering wheel, it had some big gaps in it where the plastic had cracked and shrunk, the gear knob was missing the top, got a simple h pattern off ebay that fit perfectly, also the D logo was missing from the center of the steering wheel, so i had some datsun logos printed up to size in a gel domed sticker. 

 

[Ooph!]

I know this is late to the party since you obtained a replacement head but since parts are so scarce there you might want to attempt to straighten that original head. This was done on the head in my pickup about 1985. Any competent machine shop should be able to do this.

 

[Stoffregen Motorsports]

I've straightened aluminum heads before, but it's hit or miss. You can also break the head in half.

 

A new W53 head will be awesome. Not just because it's new, but the little things, like having all new threads that aren't stripped.

 

Oh, and the steering wheel looks great.

[Danalive]

called a few places and looked online but i couldnt find anywhere near that would straighten a cylinder head like in the video, might not be something that is done over here, could of had it skimmed top and bottom but that adds more complications. 

 

[banzai510(hainz)]

If a L series head what they can do is shave the top of the head also. But you got to remove the rockers arms ect...and what ever stuff on top.

then get head saver cam shims to put under the Cam tower to get the stock height back

Edited March 22, 2023 by banzai510(hainz)

[Danalive]

 

got an exhaust manifold to match the square exhaust ports on the w53 head im picking up later this week. 

 

 

 

im assuming these are the remains of some studs, these will not be fun to sort out. 

 

[banzai510(hainz)]

I watch those Do it yourself car shows . They make it look ez taking them out

 

I had to have a machinist do mine.  They say a 50/50 mix of acetone and automatic tranny fluid works good to soak it. then heat for a small torch

 

when I ut the nut on I used antiseize compound but hopefully thats 20yrs later from now( put I have a spare with new studs ready to go.

Edited March 28, 2023 by banzai510(hainz)

[Stoffregen Motorsports]

Judging from the amount of rust pitting, those studs are likely completely fused to the manifold by now. You could heat and try to unscrew them, but your best bet is to grind that whole surface flat and zero in on the center of each stud to drill it out and attempt to use extractors.

 

You may end up having to drill it larger than 8mm and use oversized studs, like 10mm.

[bottomwatcher]

Man those are going to be fun. My first swing at those would be to weld nuts on them. Don't go cheap on the heat. Let them cool then you have something to grab on with a wrench. Try your snake oil of choice, smack em with a hammer and try to "tickle" them out. If you get movement go back and forth a little working in the juice and letting the rust grind down a little. Good luck.

[Danalive]

Havent attacked the exhaust studs yet, but ive recently picked up a mig welder so i'll have a go at welding a nut on and hope the heat works its magic.

 

Engine is still at the machine shop, 2-3 week estimate has turned into 5 weeks, hopefully get the block back this week and the rebuild can begin.

 

in the mean time ive replaced all the ball joints, new discs, pads, brake lines and bearings up front, going to attack the rear drums tomorrow so it'll be ready to stop when it finally gets running.

 

theres a localish show in a few weeks called retrorides, which had been my initial goal to have the truck road worthy by, might still be possible if everything goes to plan. 

 

been looking for a set of steel wheels, found a set of 4 15x6.5 steel wheels from an isuzu Dmax, 5 minutes from my house, brand new wheels and tyres, got taken off a new pickup as they swapped the wheels and tyres. got all 4 for £122, which is an absolute steal. 

 

 

I'm going to have a go at 3d printing a hubcap/nut cover, something like this but with a datsun logo in the middle. 

[Danalive]

update time, 

 

pulled the rear drums, nothing inside, no hand brake brackets / forks, no springs, 

 

in a stroke of luck a chap messaged me as he had a 620 he was breaking for parts, it was definitely beyond returning to the road but i managed to salvage most of the break bits i needed for the rears.

 

the only bit i was missing / couldnt get was the centre spring in the photo above, which is the top spring for the rear brake shoes, the silver one on the right is for an isuzu trooper/rodeo, which is a bit short but just about fits. 

 

 

Engine came back eventually, painted it up,found a little brass plaque on it i hadnt noticed before saying remanufactured

 

 

 

rebuilt the block, was quite fun, everything went pretty smoothly, threw it in: 

 

 

throwing everything back together, still a few bits to do before firing it up 

 

 

Edited June 20, 2023 by Danalive

[Stoffregen Motorsports]

Looking great. You're going to have the nicest 620 in the UK.

 

The new shorter brake springs shouldn't be a problem, as long as they clear the axle shaft and other parts they aren't supposed to rub on.

[EDM620]

somewhat redefines the statement "no brakes" 😁

[Danalive]

ive been working through a whole bunch of little jobs on the truck, which i have no tasty photos of but here it is finally running & idling, ready for its first drive.