R16 engine

[Tynan]

Well... while these engines are relatively straight forward in design, it will need to be dissasssmbled and then evaluated by someone who knows engines. From what I see the head will likely need significant work/complete rebuild. If a valve has contacted the piston it has likely caused damage that may require a replacement piston, and all pistons may be worn out. If they are you may need to go to the next size piston, which means the cylinders need to be bored to the correct size by a machine shop. It will at least need to honed (cylinder bores surfaced and prepared for new rings). If things are really bad then the block itself may be damaged beyond repair...

So, I know Dave sent a PM... He knows his stuff and may be making recommendations on next steps or resources. It would be great if someone on the list is close by and can come spend some time and remove the head. Everyone who builds an engine starts with their first one, so this is not something you are incapable of doing. It is however like being a new mountaineer about to do his first climb... you're going to need a lot of new equipment (tools), a path to follow (manual and some basic knowledge), sherpas/guides to set the ropes and climb with you, and the $ to fund it. Most importantly THE DESIRE. First one is a steep climb, but you CAN do it. Start with reading the manual in our tech wiki about this engine, seeing the drawings of internals and developing an understanding of how it works together. This is helpful even if someone else builds the engine, you'll have some understanding and may opt to do some or all of the assembly yourself with guidance. If you're honestly not mechanically inclined or just don't have the desire to learn about this stuff and build an engine that's totally cool... Doesn't mean you have to give up on the car, but now you're back to locating a replacement in good shape that you can learn to maintain like any other car of its era. The U20 is a desirable engine and even if broken it may have use able parts others may need.
Hope that helps!

I'm not saying money isn't a problem but I have expendable income for tools etc. first thing first is im going to remove the head (or at least try). Most likely going to take it to machine shop. I'll post pictures to get a better opinion from you guys.Which manual would you recommend I'd prefer a hardback. It's just overwhelming. I'm located in mid Missouri if you know anyone close

[Gregs672000]

Yep, off with the head! The head bolts use a special socket with an Allen head (ask the list for the size as I don't recall, 8mm? I'll see if I can find mine later). You'll remove the access plate on the front of the head, then remove the chain tensioner (spring loaded). Then, once the cam gear is unbolted and then secured using a small bolt to the L shaped piece right in front of it (and what it's there for), you'll start on one end or the other, break free the two head bolts then go to the other end and break free the two there, then back to the other end etc, progressively moving to the middle... this reportedly helps to guard against head warping. Oil may fill the bolt holes as you remove them, totally normal. There are three other 10mm small bolts to remove (front of head and chain guide), and of course the intake and exhaust should have already been removed. Then some rocking back and forth, maybe some smacks with a RUBBER mallet and the head will break free and you'll lift it over the chain/cam gear.

I think you can print out pages of the manual in the tech wiki we have here, or someone may have one available for sale? Do start with reading some before digging in.

A good set of metric hand tools (sockets and wrenches, extensions), screw drivers, torque wrench, feeler guage set, flexible putty knife to scrape gaskets should meet most of your needs for now. You're not likely to hurt anything by disassembling things except as noted above. Once the head is off we'll known a lot more. It's a learning process but that's how everything is, eh?

[FergO2k]

Perhaps I am superstitious (and definitely over-cautious), but I always felt there was almost as much opportunity to warp a head in removal as in installation.
So just as Greg outlined, but they recommend torquing the head down in 2 steps (example: take them all to 30, then all to 45), so then use same method in removal.
Crack them all, then take them all to 2/3 or 75% of final torque, rotating pattern as Greg outlined. (end to end, and zig-zagging whenever possible)
Then take them all to 50%.
At this point, some are probably hand loose, so amount and pattern makes little difference from here on out.

[Tynan]

Damn I didn't see the head removal tips. But I cracked all of them loose I assume it was easier than normal since my mechanic was already in there. I'm going to keep reading and print some how tos for the u20. Get the head off and we have a very reputable machine shop here in town with all the high tech machines etc and see what they have to say about it

[FergO2k]

Good deal, sounds like you found a good resource.
First thing they will do is put it on a granite inspection table to check for flatness. Fingers crossed for you there.
That is when to consult with the U-20 experts (like Dave Premo), as U-20 heads have some limitations that need to be known by the machine shop when considering "next steps".

[Tynan]

Good deal, sounds like you found a good resource.
First thing they will do is put it on a granite inspection table to check for flatness. Fingers crossed for you there.
That is when to consult with the U-20 experts (like Dave Premo), as U-20 heads have some limitations that need to be known by the machine shop when considering "next steps".

Thanks a bunch guys hope it's in tolerance

[Gregs672000]

Could very well be Fergus! Always better to err on the side of caution, eh?! From what I understand, it has something to do with releasing tension or stress out of the head via the ends so it doesn't "banana" or warp. The head guy I hung out with talked about it, and as I recall there were some heads/makes that were more susceptible to warping during disassembly. Always good to know!

So Tynan, looks like you're headed in the right direction! It's a friendly bunch here who enjoy helping people with their Roadsters, so don't hesitate to ask questions. Many of us have been on this journey and remember what it was like. We'll try to give you the best advice or perspective from a variety of experiences. You won't find a bunch of folks with big egos here, just options and opinions, as we all learn from each other.

Welcome to the Family!

[Tynan]

I downloaded the u20 manual. I got crankshaft pulley bolt off. The manual says remove it. Doesn't really say how. Do I just pull it off with the shaft or...

[FergO2k]

Hmmm. If not sure how far this teardown is going to go, not sure you need to remove crank bolt at this point when current goal is to inspect / evaluate the head. Cam bolt would be a Yes, as the head shop is going to expect it removed when you bring it to them. The manual might be outlining steps to a complete teardown, not "investigative surgery". If the timing gear teeth are really worn, then removing crank bolt is an eventuality. No harm done either way.

[Tynan]

Can you take the head off and leave the timing chain and cover on. I'll find another book as well. Pretty good manual on the u20 I was pleasantly surprised

[david premo]

Yes you can leave the timing cover on and pull the head. I recommend you take the cover off and inspect the timing chains guides and everything else.
Dave

[Tynan]

Top Timing chain sprocket looks good to me. Hope I can get into more this weekend. I assume the chain is relatively new. Since that's what they were changing in late 80s early 90s before disaster struck.

[david premo]

The tensioner foot in your picture is pretty far out, so either the chain is very stretched or something else is wrong. With the tensioner foot that far out it the chain could skip timing if left like that.
Dave

[Tynan]

The tensioner foot in your picture is pretty far out, so either the chain is very stretched or something else is wrong. With the tensioner foot that far out it the chain could skip timing if left like that.
Dave

A valve broke in half when a piston hit it

[Tynan]

We are making progress I have some flash rust in 2 cylinders from some rain on the drive home from the mechanic. At the time I didn't care because I was thinking about just scrapping the engine anyway.

Pulled the head though. Now do I take it to a machine shop? Thanks for all the help