2000 U20 Engine Rebuild + Mid Atlantic Machine Shop Recommendations

[mschel]

Thanks. I believe I found a broken one so will compare the threads. Didnt want to just run a tap to see if it fits since so much metric and sae mixed on this car.

'Also thanks for the reminder on marking driveshaft.

I would suggest using/replacing with head studs anyway (via vendors) as they are reusable vs the original which are "true stretch bolts". I dont know the pitch but pretty sure the block threads are metric. I have used a strong S hook bolted to the engine with a long transmission-to-engine bolt and a big washer in the back, and one of the alternator mount-to-block bolts up front. It works with enough chain and connectors. You may want to put a chalk or similar mark on your drive shaft ends where they bolt as they are balanced and (assuming they were right before) should go back on the same way later when reassembled (if already off, no problem as we can direct you as to where to find the factory marks). If you're lucky you may find the original "engine pulling" hook that used the upper two rear intake manifold bolts to provide a lifting hook in your "head/manifold nuts/parts" bin, but that won't help you here with the head off. Nice to have for later if you find it.

I don't see any risk in lifting from a bolt in a head bolt hole.

[mschel]

I went through the box that came with it and found the following.

The heads are around this thicknexx:

2023-09-27 21.13.09.jpg

The cam towers are all there but were in a box. They have marks on them with numbers but none are sequential. I.E there are 5 of them but some twos some 3s a 4 no 5. And the caps don't seem to match the towers. Probably all mixed up. There is light wear on the cam towers inside hole but not deep grooves. I assume they are the wear surface for the cam or should I have some cam bearings?

2023-09-27 21.38.43.jpg

Should I have sequential numbers on the towers or are they for something else?
I have read about shims but dont have any in the box.

I believe the nuts are in the nuts/bolts box but should they be a special type/grade?

Two of the rocker arms were in a separate bag but rusty. Not sure if they were bad or just got rusty in storage. It appears all the other arms are new or very clean. Looks like a valve job, some new valves, new springs.

Two of the guides/wearsurfaces that go between the rocker ends and the valve tips are missing completely.

Anyone have 2 spare rocker arms and 2x the other part for the valve tips?

Still on track to get this motor pulled later in week. Got sidetracked on looking at brakes and other stuff on it.

2023-09-27 21.13.09.jpg

2023-09-27 21.17.04.jpg

[david premo]

Well the first and fifth towers are unique, now you just need to sort out the other three.
Dave

[mschel]

I saw some had the bolt hole on different sides but how do I figure out what the order is for rest? Why would I have multiple 2 markings etc?

I have them mocked up ok just don't know the markings thing.

I wish I had an assembled one next to me to compare to. Do they need bored/shimmed? I added a pic of some of the inside surfaces of the cam holes.

thanks.

Well the first and fifth towers are unique, now you just need to sort out the other three.
Dave

[david premo]

The easiest thing to do is put in the first and last towers and torque them down. Then install the others one at a time using a straight edge on the side until you find the correct order of towers.

[mschel]

Great thanks for the tip. Will try that

The easiest thing to do is put in the first and last towers and torque them down. Then install the others one at a time using a straight edge on the side until you find the correct order of towers.

[Gregs672000]

Head looks pretty good to my eye. Exhaust seats have been changed to stainless, brass still for the intake (that's fine). Does not look overly cut. At the very least the cam and rockers should be surfaced (see previous post). You will probably be OK with stock lash caps (the part that goes between the rocker and the valve tip) but I believe that depends upon the valve assembled height and how much the cam has been cut (looks uncut), so surfacing won't change things, but you mentioned wanting another cam grind and that probably will change the thickness of the lash cap needed... the only way I know to determine this is to install the cam and rocker (once surfaced and desired cam profile ground) with the rocker's pad colored by a sharpie and adjusted close to stock lash/gap, then spin the cam around a couple times to wipe the rocker so you can see where it's wiping in the pad... the thickness of the lash cap determines where the cam wipes on the rocker pad (center is desired, wiping off the pad one end or the other is a no go). Vendors have different thickness lash caps available. The rocker arms came in two versions, one piece and two piece rocker arms that have a separate pad. You have two piece that may still have enough surface/arch to surface... Otherwise they will need replacing and are not cheap. Determining the correct thickness of the lash caps can/will be one of the last things you do once the engine is back together as its much easier to rotate the cam against the resistance of the valve springs via the crank IMHO. I also have a recommendation on a tool used to compress the valve springs with the cam in place using the cam as leverage that will make doing your testing (that requires installing/removing/testing/reinstalling/etc) of the rockers and lash caps easier. If the cam is installed with all the rockers in place you'll be fighting the springs on a few as the cam lobe will be pushing against the rocker. All of this is not hard, but knowing what needs to happen and what tools you need makes all the difference.

Regarding cam towers... they can be finicky. It’s my understanding these were "line bored" at the factory and using non-original to that head does require some careful assembly to keep the cam from binding or even breaking. They are pinned. As Dave said, two can only go in one place so install those and confirm the cam turns by hand, then add the other towers and caps one at a time, making sure the cam does not bind and can be turned by hand (no rocker/spring tension of course). If one binds, try another and so on until you find the set up that has the cam turning without binding (with assembly lube). Progressively tightening and loosening then re-tightening the nuts, light taping etc on the towers to find the sweet spot, and maybe a little light emery cloth work on the bearing surfaces as a last resort (there are no shells like the crank/rods) should bring success. This may take some time and patience. I don't believe the nuts are anything special, but do note that the washers on the small nuts for the cam caps can sometimes protrude past the edge of the cap and impair the head studs or your socket when you go to install the head.

Regarding tower shims, they are used to maintain the "geometry" and to keep the cam chain correct (others can explain with more knowledge than me) but thickness is based on how much the head has been cut (again, other input needed here based on what you posted).

Really, so far so good. I'm a little concerned about the rockers but they may clean up fine, but they must be done correctly... I know Delta Cam in Tacoma and Isky in CA can, some vendors offer exchanges if yours are good cores, but at a cost. How do your gears look?

[mschel]

Thanks for all that detail. Very much appreciated!

I need to process it all and will try all in the next week or so.

The cam gear looks like newish condition on quick inspection.

Any idea on the numbers on the caps and the bases of cam towers? Should they match in some fashion?

Head looks pretty good to my eye. Exhaust seats have been changed to stainless, brass still for the intake (that's fine). Does not look overly cut. At the very least the cam and rockers should be surfaced (see previous post). You will probably be OK with stock lash caps (the part that goes between the rocker and the valve tip) but I believe that depends upon the valve assembled height and how much the cam has been cut (looks uncut), so surfacing won't change things, but you mentioned wanting another cam grind and that probably will change the thickness of the lash cap needed... the only way I know to determine this is to install the cam and rocker (once surfaced and desired cam profile ground) with the rocker's pad colored by a sharpie and adjusted close to stock lash/gap, then spin the cam around a couple times to wipe the rocker so you can see where it's wiping in the pad... the thickness of the lash cap determines where the cam wipes on the rocker pad (center is desired, wiping off the pad one end or the other is a no go). Vendors have different thickness lash caps available. The rocker arms came in two versions, one piece and two piece rocker arms that have a separate pad. You have two piece that may still have enough surface/arch to surface... Otherwise they will need replacing and are not cheap. Determining the correct thickness of the lash caps can/will be one of the last things you do once the engine is back together as its much easier to rotate the cam against the resistance of the valve springs via the crank IMHO. I also have a recommendation on a tool used to compress the valve springs with the cam in place using the cam as leverage that will make doing your testing (that requires installing/removing/testing/reinstalling/etc) of the rockers and lash caps easier. If the cam is installed with all the rockers in place you'll be fighting the springs on a few as the cam lobe will be pushing against the rocker. All of this is not hard, but knowing what needs to happen and what tools you need makes all the difference.

Regarding cam towers... they can be finicky. It’s my understanding these were "line bored" at the factory and using non-original to that head does require some careful assembly to keep the cam from binding or even breaking. They are pinned. As Dave said, two can only go in one place so install those and confirm the cam turns by hand, then add the other towers and caps one at a time, making sure the cam does not bind and can be turned by hand (no rocker/spring tension of course). If one binds, try another and so on until you find the set up that has the cam turning without binding (with assembly lube). Progressively tightening and loosening then re-tightening the nuts, light taping etc on the towers to find the sweet spot, and maybe a little light emery cloth work on the bearing surfaces as a last resort (there are no shells like the crank/rods) should bring success. This may take some time and patience. I don't believe the nuts are anything special, but do note that the washers on the small nuts for the cam caps can sometimes protrude past the edge of the cap and impair the head studs or your socket when you go to install the head.

Regarding tower shims, they are used to maintain the "geometry" and to keep the cam chain correct (others can explain with more knowledge than me) but thickness is based on how much the head has been cut (again, other input needed here based on what you posted).

Really, so far so good. I'm a little concerned about the rockers but they may clean up fine, but they must be done correctly... I know Delta Cam in Tacoma and Isky in CA can, some vendors offer exchanges if yours are good cores, but at a cost. How do your gears look?

[Gregs672000]

I'll have to go look at my motor to be sure and clear so I don't give incorrect info, and that may not happen until sunday... Dave said 1 and 5 are unique, and the other three are the same. Numbers may match up but who knows... what's gonna matter is that they play well together!

[theunz]

What matters most is that the cam turns freely once the towers and caps are torqued down. In your case it’s just going to have to be by the trial and error method.

[Gregs672000]

Ok, I was looking at the head pics you posted... I see stamped numbers between the two holes on the caps, 1, 2 and 3 and they are not in the right spot. Are there numbers stamped on the towers?. I would ignore the cast numbers on the caps.

[mschel]

The towers also have numbers but not sequential either.

Ok, I was looking at the head pics you posted... I see stamped numbers between the two holes on the caps, 1, 2 and 3 and they are not in the right spot. Are there numbers stamped on the towers?. I would ignore the cast numbers on the caps.

[mschel]

Thanks. I guess there are only so many combinations

What matters most is that the cam turns freely once the towers and caps are torqued down. In your case it’s just going to have to be by the trial and error method.

[Gregs672000]

I would match cap numbers to tower numbers if possible.

[mschel]

Will see if I have matching ones. Probably won't mess with it for a bit. Need to get the short block and trans out and replace Master cylinder.

I would match cap numbers to tower numbers if possible.