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L20 motor dissasembly method


Curt

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There are likely lots of running L engines with cracks. It's stress that has been relieved and where's the coolant going to go anyway? It's sealed by the head gasket and the bolt. If I was building a 'race' engine that saw high RPMs and extreme temp spikes I might care more about them. Sealick welded his up and had the block decked. Looked good. Not saying to ignore them, it's a choice you have to make to ignore them or not.

 

 

 


Thanks for the pics! I have heavyish rust in that exact area... I'll be sure to check it out real good and post pics.

 

This is often from owners running straight water in their blocks or an improper anti-freeze mixture. Rust and scale builds up unseen. Some areas have 'hard water' with dissolved minerals in it that concentrate and plug the rads and block passages as the coolant evaporates. Buy distilled water or use rain water.

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Ive taken apart lots of engines where the cylinder walls were rusty. Most of them cleaned up around 30 to 40 over..

You may have to put the engine on a bench without the crank in it, find a rod that will reach the pistons, and hammer them out.

Please dont hammer on the connecting rods :)

 

If you dont mind putting good gas in it, id say put flat tops in it at wherever the bores clean up at, use your l18 head on it.

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Now why don't you just take it easy, Group Captain, and please make me a drink of grain alcohol and rainwater, and help yourself to whatever you'd like.

DrStrangelove2.png

 

"Do I look all rancid and clotted? You look at me, Jack. Eh? Look, eh? And I drink a lot of water, you know. I'm what you might call a water man, Jack - that's what I am. And I can swear to you, my boy, swear to you, that there's nothing wrong with my bodily fluids. Not a thing, Jackie."

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I've got the pistons already. .030 over.  I'm rebuilding basically to stock. I haven't pulled the A87 on the L-18 to see if its closed or not yet.

The w-58 that was on it is a closed chamber with larger valves than the early A-87 (I think) so I will rebuild the w58 if the A-87 is open chamber.

 

3 of the 4 pistons are out. Only the 1 is still in there stuck pretty good. Soaking for a day or two.

 

As with all of this stuff, feel free to correct me or give advice. I know just enough about this stuff to really get in trouble.

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Fair enough, im not a fan of those exhaust liners but if its closed chambered and has the bigger valves in it.. Sweet.

 

Do those w58's have those bronze material intake seats in them?

 

If its an open chamber a87, it may have the big valves too? The one i have does..

 

In stock form these things are nice and simple, but when you really start frankensteining them it can get a little frustrating.

I dont think ill start another lz frankenstein from scratch again, theyre was alot of headscratching and machining done to make parts work together properly.

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Do those w58's have those bronze material intake seats in them?

I have no idea...My knowledge is pretty limited. I'm just going to have one of them rebuilt after I pull the other head. I

 

Hainz-  I'm gonna have a shop check it out this week. It was pretty rusty so all I did was tear it down as gently as I could.

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The other thing too, is how far down does that crack go. I've seen those on many blocks where they barely go 30 thou into the deck. Was that bolt rusty as hell when it came out? If it wasn't, coolant probibly didn't get through it, and I'd say that's fine for what your doing. If your worried put a bit of rtv on your bolt on re assembly

 

Some cracks are also so fine they may not show up till after surfacing, I've seen that quite a few times.

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Beside the exhaust liners on the W58 the exhaust ports are round and not square like the L16/18 heads. I would rather have the A87 because the L16/18 cast iron header can be used on it.

 

Pretty sure all seats are all hardened. The tetra-ethyl lead  that used to be in the gas was also a good lubricant for them. Not sure when makers began running hardened valve seats (late '60s?) but they are HARD to grind with lapping compound.

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Scooter, yes that bolt was rusty. I'm dropping it off at a shop Monday.

Mike, I thought you could run round port into the square collector. I'll totally be running that a87 if that head is closed anyway. I was going to run the intake and exhaust manifold from the l-18. And the oil pan too I think. Since the L20-b was from a 720.

 

Question. What other parts do I need to swap that motor in? Are the motor mounts different?

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Update- I dropped off everything at the shop, get it back in a week or so. The block needed to be decked .006 to take out the water damage in said head bolt location.

 

Question? Can I take both timing tabs (the one that mounts to the timing cover and the plate behind the cam gear) and pulleys off of the L-18 and swap it onto the L20b and have it be accurate? <- I hope that makes sense. I want to axe out the clutch fan and the crank pulley on the l20b. they are heavier and in worse shape.

Pics of the rusty ole beast.

HPIM4346_zpsc54d4e47.jpg

HPIM4348_zps493d9943.jpg

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The plate behind the cam gear is the same on all engines. But the crank pulley should match the pointer. I always verify TDC after I install the pointer anyway. And yes, the L18 crank pulley should work just fine on the L20B. Just make sure it isn't worn out on the I.D. or cracked or bent. And I assume you know how to remove it without breaking it...?

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How do I check for wear? I'm not familiar with how much wear is acceptable. Last time I just tapped it off very carefully with a rubber mallet moving around it in circles so it wouldn't bind. It was on the stock engine so it was running fine with it as far as I could tell.

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No wear on the crank pulley, but the front oil seal may leak or have worn a small groove in it. New seals are usually thinner front to back and press in further so they run on un-grooved surface.

 

To remove the crank pulley, I just tap forward on the back of it with a hefty 27mm socket. Takes a while but each tap moves it forward and off. Watch for the woodruf (half moon) keys in the end of the crank and save them.

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No wear on the crank pulley, but the front oil seal may leak or have worn a small groove in it. New seals are usually thinner front to back and press in further so they run on un-grooved surface.

 

To remove the crank pulley, I just tap forward on the back of it with a hefty 27mm socket. Takes a while but each tap moves it forward and off. Watch for the woodruf (half moon) keys in the end of the crank and save them.

 

By allmeans, save those woodruff keys!  You will never find out if they were metric or SAE if you loose them!

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Actually I look for wear on the inside of the pulley hub. If the bolt ever came loose and someone didn't catch it in time, the pulley can rock around and wear the key slot and also the ID of the hub. If it comes off too easily, like without any tapping, or if it rocks back and forth I would look for another.

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I looked and couldn't find much info.. Does anyone know the cam profile for an L series cam that is stamped with a C on the rear journal? Also, I read in the rebuild book that there are two "brackets" that mount on the bottom of the block that a bolt runs through to the bell housing on the lower most holes. There were none on the motor when I pulled it. Did someone remove them and not install them back in? Or is it something that was on earlier L20bs?

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The cam is most likely a U20 "C" cam. There were A, B and C cams. I think the C is the one you want. I don't have specs though.

 

The brackets you are missing are block stiffeners. Most people remove them over time to save weight or just ditch them because they don't think they need them. I wouldn't worry about them.

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  • 2 weeks later...

Update: I went to check out the progress the other day at the machine shop. Block was shot peened to clean it up. Crank was polished and ready. I went ahead and had them assemble the bottom end. They charged me 80 for assembly and ring fitting etc. I figured I couldn't argue with that as I would have had to buy some tools to do it myself anyway.

 

Grand total so far in parts and work is around 700 for the bottom end. I'll probably end up somewhere around 2k counting all the stuff I bought previously for the L18. I got a really good deal on a nos cam, rockers and springs so that saved me a ton of money. Add to that another 700 or so for new exhaust and clutch stuff. I'm pulling the L18 this weekend so I can get the head going. I'll post up some pics when I get it back.

 

What is the best way on the cheap to go about transporting the block back from the shop? Like for cleanliness.

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