Rb25 Rookie timing mistake , damaged ?

[Frozengrip]

Hello all sau community, unfortunately I’m writing this here today for a rookie mistake I have done. Or so atleast i think. 

I was adjusting my Cam timing , as I was turning the Cam gears I noticed a sound (that I know now is where I f’d up) and didn’t think too much since this was my first time. Anywho got both cams set on the timing marks and went to go check on the valves. I found metal shavings and this is when I realized what I had done smfh.

I then proceeded to take off the head to see if any pistons or valves where damaged from underneath and nope. All pistons had no scuffs and valves where good besides the shavings on the inlet ports. 

I clean the shavings out but should I consider this a damaged valve or should I be good to put it all back together?

thank you guys, I’m gonna get some heat but hey it’s for the best haha

[Frozengrip]

Anyone ? Wanna go work on it asap, but need a honest opinion before I assemble again lol

[Ben C34]

So the engine was on a stand rotated by hand with the cam timing set to some strange position, and a piston hit a valve, but aside from the piece of swarf in a strange spot there are no signs of any damage?

[Frozengrip]

14 minutes ago, Ben C34 said:

So the engine was on a stand rotated by hand with the cam timing set to some strange position, and a piston hit a valve, but aside from the piece of swarf in a strange spot there are no signs of any damage?

Yes, so I got the block and head back from the machine shop. I got it back with #2 piston and #5 piston at tdc. I then set the head on it , torqued it down and adjusted the camgears to the marks on the marks but did feel it force and clunk. Unfortunately that’s when it clicked to what was going on and yup. Found those shaving in the head ports. But no damage to pistons or valve surface. Just those shavings on the valve stems. Will update with some pics a little later..

[admS15]

I don't see how you'd get a shaving like that from what you've done and since you say the head came back from a machine shop, I'd be thinking it's swarf the shop has left behind or somehow got there another way. 

[Frozengrip]

29 minutes ago, admS15 said:

I don't see how you'd get a shaving like that from what you've done and since you say the head came back from a machine shop, I'd be thinking it's swarf the shop has left behind or somehow got there another way. 

Well thing is it’s not only that valve that has those shavings. It isn’t all but I really think i made the valves bounce down on the pistons as I was turning the cams or I was forcing the valves down with the lobes on the cams. Ah im just worried i messed up bad. 

 

Another question, should I position #1 and #6 piston to be at tdc ? Or is it fine how it is ? Thank you this just has me wishing for the best haha

[GTSBoy]

You always assemble any engine with #1 at TDC firing. Anything else is just asking for trouble. If the head is going back n with cams installed (where that is possible) then you also need to set the head up to match the engine angle. Or, when you're putting cams back into the head with the head on the block, then you need to install the cams at a compatible position to the engine position. Otherwise you're likely to drive valves into the pistons somewhere.

In this case, you were turning the motor by hand and cannot see any places where the valves have scraped metal off the pistons, etc etc. That means that you simply haven't done the damage (created the swarf) that you see. So stop worrying about that. But.......Now you have to wonder why there is swarf in the head, when there absolutely shouldn't be. Whoever worked on it has not done a good job of cleaning up after themselves. I would not put it back together without a surgical inspection.

[admS15]

Exactly what gtsboy has said is your best course of action.

[Frozengrip]

15 hours ago, GTSBoy said:

You always assemble any engine with #1 at TDC firing. Anything else is just asking for trouble. If the head is going back n with cams installed (where that is possible) then you also need to set the head up to match the engine angle. Or, when you're putting cams back into the head with the head on the block, then you need to install the cams at a compatible position to the engine position. Otherwise you're likely to drive valves into the pistons somewhere.

In this case, you were turning the motor by hand and cannot see any places where the valves have scraped metal off the pistons, etc etc. That means that you simply haven't done the damage (created the swarf) that you see. So stop worrying about that. But.......Now you have to wonder why there is swarf in the head, when there absolutely shouldn't be. Whoever worked on it has not done a good job of cleaning up after themselves. I would not put it back together without a surgical inspection.

Thank you for this important piece of info gts! I always saw engines being assembled with #1 tdc but didn’t think to much of it till recently. But with that known I’ll be postining #1 at tdc today. 

As for the head , I was planning on putting in with cams since I never took them off. But yes I do have to angle to the pistons positioning now. How do I go about it or should take cams off and postions the lobes on the corresponding place? 

And I hope it was, just cause when I was turning the cam gears it was clunks and hard. But yes no scrapes on Pistons or valve surface. 

Is it possible that I could have hit a valve with a piston and forced the valve to go up a little ?? 

 

Thank you guys for all the critical help! 

[GTSBoy]

Cam position is easy. #1 firing is simply set up with both intake and exhaust lobes on #1 pointing away from the lifter. They are independently rotatable. They don't have to be exact - just pointing as close to directly away as you can eyeball them. Then all the other valves will be open (or closed) to safe positions wrt their pistons.

The other thing you can do is put #1 piston at TDC then back it down by, say, 10mm before putting the head on. This just gets the pistons well away from TDC on all cylinders as you put the head on, so that even if you have your valve angles a bit wrong, you shouldn't be able to hurt anything. Then, when it comes time to set up the timing, you just roll the crank that bit to bring the piston back to TDC and keep them cams as close to the right spot as you can and then throw the chain on it.

The main thing with this just to work slowly and carefully enough with as much double checking as you feel is necessary at each step to make sure you're not leaning on it wrongly. Experienced assemblers of engines rapidly get past even having to think about it. Novices just need to know and apply the commonsense rules.

[Frozengrip]

On 6/27/2021 at 7:05 PM, GTSBoy said:

Cam position is easy. #1 firing is simply set up with both intake and exhaust lobes on #1 pointing away from the lifter. They are independently rotatable. They don't have to be exact - just pointing as close to directly away as you can eyeball them. Then all the other valves will be open (or closed) to safe positions wrt their pistons.

The other thing you can do is put #1 piston at TDC then back it down by, say, 10mm before putting the head on. This just gets the pistons well away from TDC on all cylinders as you put the head on, so that even if you have your valve angles a bit wrong, you shouldn't be able to hurt anything. Then, when it comes time to set up the timing, you just roll the crank that bit to bring the piston back to TDC and keep them cams as close to the right spot as you can and then throw the chain on it.

The main thing with this just to work slowly and carefully enough with as much double checking as you feel is necessary at each step to make sure you're not leaning on it wrongly. Experienced assemblers of engines rapidly get past even having to think about it. Novices just need to know and apply the commonsense rules.

Wow gts can’t thank you enough for this drop of knowledge! Honestly was in a rut and was wondering if shot myself in the foot but happy to have people like yourself help out!

with that said , would it be the safest option to set #1 lobes away from lifters and set piston 10mm down? Or is that too much? 

And when I’m pointing the lobes up do I have to unbolt the clamps holding the cams down ? Thank you ! 

And it’s my first engine build so getting familiar with everything but enjoying the process nonthless! Making the best engine shine in the us !

and oh! Took some extra pics to show that verything is fine (valves/Pistons) and I think the metal shavings were definitely from the machine shop

[GTSBoy]

1 hour ago, Frozengrip said:

would it be the safest option to set #1 lobes away from lifters and set piston 10mm down?

That's totally safe. If the piston is down the bore a bit and the head is set up very close to where it should be for TDC, then there's no chance of hitting anything further down the row of cylinders. You can eyeball the protrusion of the valves and the height of their pistons before you drop the head on, and you should be able to feel them make contact if you have managed to get it wrong, long before you try to bolt it down.

You just have to remember that you wound the engine backwards before putting the head on, so that when you try to put the chain on, you know that you have to wind it forwards. The TDC marks on the pulley can help, even though it won't be fully fitted up before you've got the timing cover on. Just fit it temporarily and make yourself a pointer that will help you mark TDC.

1 hour ago, Frozengrip said:

And when I’m pointing the lobes up do I have to unbolt the clamps holding the cams down ?

If the head is fully assembled and off the engine, then you can just turn either cam by hand to put it wherever you want. No need to back off cam bearings, and in fact, that wouldn't make it any easier anyway.

 

Edited July 1, 2021 by GTSBoy

[Ben C34]

Building an engine is at least 80% cleaning and checking things!

[Duncan]

Damn straight....the machine shop should do it but I always treat it as though they haven't....

Just one thing to add to the approach above. When you put the head on, the crank should be at (or just before) TDC, and the cams should also be set for TDC. You can determine that from the pin on the front of the cams or if necessary just put the cams gears on temporarily.

Once the backing plates / timing covers are in  place it is then ready for timing belt straight away

[Frozengrip]

Hey guys !!! Sorry been super busy with work and some rather odd shitty weather that managed to take a touch of something’s. 

Unfortunately a storm hit and flipped my Canopy over and managed to get my head wet but my block is fine ! 

Surface rust embedded on the cams and surrounding areas 😞 

 

but just got back to work on this beast , and set the pistons 10mm before tdc and set the  the first pair the lobes up? 

Look good ? Thanks guys for all the help really do appreciate it !

 

one last to mention I did like a newbie torque both cam gears before adjusting back when I first made this post.. should I untorque and then set lobes up ?

[Frozengrip]

Hey guys! Any thoughts ?

[Ben C34]

Those cams are f**ked. What's your plan there?

[tridentt150v]

Umm....a machine shop may be able to 'polish' the rust off, but it doesn't look good.  Depends on hardening integrity and the the type of build you want.

Take 'em out and get them to a shop.  They will know.

[tsuokun]

Oh my god that head looks horrible. I would just disassemble it and clean everything up and hope there is no corrosion on the lobe surfaces. It does NOT look promising, and what about the rest of the valve train; the springs, lifters etc..

A couple of thoughts (and personal opinions, others may or may not agree):

- I hope you are using some assembly lube or at least motor oil when putting that thing back together.

- If you leave it sitting for a while, protect exposed surfaces with something, WD-40, CRC 5-56, motor oil (and clean up when continuing) Those machined surfaces can catch rust in minutes.

- Just as Duncan said, always assume there is some shit left over from the machine shop. Always do a proper, thorough check with a good lamp for any left over swarf etc.

I found pieces of the old valve guides in an oil channel by shaking the head and hearing rattling noise. Scary shit.

 

[GTSBoy]

Those cams be f**ked.