What problems should I expect running 9-out-of-10 head bolts on an L20b?

[Justin]

Hey ya'll!

So, for those that don't know, I punched a hole in my L16 block and am (desperately) trying to slap together another L series to get it back on the road-

And, I keep running into problems-

 

I snapped a 1 of the 5 flywheel bolts on the L18... took it as "a sign" and moved onto the L20b-

 

Found out it's been bored .50 over (so it's pistons WON'T work in my other stock L20b block that has no pistons) and the 2nd from last rear head bolt hole has been stripped out. So that means if I run that L20b I'll be running 9 out of 10 bolts and JB Weld/gasket maker or some stupid nonsense in the 10th so I'm not overly-panicked about the thing all the time.

 

***Unless I remove the L18 pistons from the connecting rods and remove the L20b connecting rods from the over-bored pistons and slap said stock pistons onto correct-length connecting rods BUT I have no idea which side is the entry side and which side is the exit side (and, it says in the book pistons must be separated from connecting rods by using a press and not hammering, so that kinda stops me there too)

 

 

It's actually pretty funny because the L16's head was merely cracked before the head-swap;

And now that I've switched to an L20 I'll likely still be dealing with (the same)*similar issues.

 

 

I'm pretty sure the CORRECT way to fix this would be to take it to a machine shop and have them heli-coil up the hole and re-tap it, but none of my other vehicles run or are licensed right now so I don't see THAT happening (and price is a factor 'cause hey, it IS a Datsun)...

 

 

So yeah, any info on better solutions/options or any idea what kind of problems I'll be facing if I run the motor with only 9 of the 10 headbolts?

 

Or (**better option**) is it possible to separate pistons from connecting rods at home?

 

Thanks! 

[BlackBird620]

Blown gasket

[LeviGideon]

 

All or nothing. Leave one out and you'll do it all over again in a week. No amount of jb weld or gasket maker can withstand the heat and pressure generated by an engine. Take it to a shop, it will be cheaper than having the head milled next week.

[]2eDeYe]

One of three things, most likely all three... Oil leak, coolant leak, low compression in one cylinder.

 

You'd also be lucky if you don't warp the head after a while.

[MicroMachinery]

Look forward to more work/expense than if you'd just done it right the first time.

[datzenmike]

Get a $10 drill bit and do it yourself. Maybe it's in the heli-coil kit. Why pay $100 for a mechanic to do what you can do yourself? Get-r-done!

 

I broke all the flywheel bolts off once. Black and Decker hand drill, (borrowed) drill bit, tap and 6 new grade10 bolts came to $30 back in the mid 80s. Couldn't save the bolts, or get them out so I drilled to an over size. The holes weren't very straight but it worked and I was on the road in a weekend.

[metalmonkey47]

Hell, maybe just look for another engine core? If that's an option for you. L series shouldn't be too hard to come by over there. 

[bananahamuck]

Installing Heli-coils is pretty straight forward ,,,, you can do it.   Just take your time and read up on a few the internet articles on the subject ,, maybe watch a You tube video on it... take your time,, you can do this.

[K_trip]

- removed -

[laotsu]

I have an L20b short block I could be persuaded to part with. Got a 280 Zx oil cooler? If you can get one I will deliver.

[Justin]

Hahahaha, okay, okay! Never messed with heli-coils before, don't know!

 

No 280zx oil cooler laotsu (but there's one on ebay now for $75 shipped, FYI), and I DO have an extra L20b block, just only one set of connecting rods on the over-size pistons.

 

I guess maybe I should be wondering how to separate the pistons from the connecting rods/how to tell which end is the small end?

 

Or where to buy heli-coil and what type to get?

 

 

Thanks guys.

[]2eDeYe]

Any hardware store should have heli-coil kits. Get the one that fits your head bolt threads :)

[MikeRL411]

Head bolts have very healthy torque requirements. I think I would use a "Threadsert" insert [check the name, that's how I remember it, doesn't mean it's correct]. You drill and tap like a helicoil, but the insert has two vertical slots and hardened steel rectangular drive pins. You thread it into the block and give the steel pins a good smack with a small sledge, driving the 2 steel pins into the head and pop off the "bridge" connecting the pins. An anti-retation device.

[laotsu]

No 280zx oil cooler laotsu (but there's one on ebay now for $75 shipped, FYI), and I DO have an extra L20b block, just only one set of connecting rods on the over-size pistons.

 

That one on E-bay has only half the lines and no adapter, but thanks for looking out.

 

FYI a "short-block" is: the block, crank, con-rods, wrist pins, pistons and the various bearings, bolts, and seals that hold it all together. I'm not pushing it on you, just passing on info that I have picked up.

[Draker]

Timeserts would be recommended here. Basically the same as above, but can handle the torque.

[q-tip]

For head bolts I would go with a thread insert before a helicoil but that's just the machinist in me....

 

...a helicoil would work for you situation but its just a good band aid not a permanent fix.

 

You could also just go up to the next size thread on the bolt,(stongest optoin and what i would do) don't know if there is clearance in the hole in the head though.

 

As for finding out which end of the wrist pin is the small end go to harbor freight and get you a set of $10 digital calipers, they are good enough for garage use.

 

 

Good luck!!!

[datzenmike]

Never heard of large and small ends. I just went out and measured one of my many L20B pins. 0.826" My FSM says 0.8265 to 0.8267" so close enough. No mention of taper. I just recently pressed 8 pins out of the rods.

[wayno]

Just put a heilcoil in it, and use an ARP stud kit, no issues since. :)

ARP 202-4201

[Ranman72]

Just put a heilcoil in it, and use an ARP stud kit, no issues since. :)

ARP 202-4201

what wayno said 

If you leave it out you will be doing the same job again sooner then later 

if you arp stud it that bolt will never have to be removed 

do it right or do it twice   your choice