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93 4d lx, z6,ported, port matched, compression bumped, balanced, manual swap
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Yes! Especially with a zinc additive, don't limit yourself to 10w30, if its still topping out early you can go down more, 10w20 racing oil through several brands is a thing and there are maybe 15-20 builds I need to run it in currently, they make a measurable amount of whp over 10w30 and the oil stays good longer. As I said there are so many variables that it becomes a balancing act.
 

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Discussion Starter · #82 ·
Yes! Especially with a zinc additive, don't limit yourself to 10w30, if its still topping out early you can go down more, 10w20 racing oil through several brands is a thing and there are maybe 15-20 builds I need to run it in currently, they make a measurable amount of whp over 10w30 and the oil stays good longer. As I said there are so many variables that it becomes a balancing act.
Ahh okay thats fair. Ill admit I was a bit weary to go with a thinner oil because in 2020 I drove the car (then stock) on the Autobahn. Topped 200kmh and the oil went over 115C. Not that bad but hey, 20yo me didnt know better, the gauge alarm went off.
After that Ive had bad oil pressure, even after oil changes. 5 to 6psi idle with a warm engine. When I did the build I noticed the crank bearings were pretty shot at the edges. Crank was fine just the bearings were done for. I thought the 5w30 may have been too thin. I might give the thinner oils a shot and maybe I'll see some dyno results. Aiming over 170hp on the crank. Currently at 158 with stock airbox and muffler
 

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Discussion Starter · #83 ·
Another update regarding the engine. Took the crank pulley off (had to wait for the locking tool) and to my surprise the front main is good. Now I feel really dumb cause all that oil mustve come from the top. I did some tracework looking on the insides of the timing belt covers and it looks like it mustve come from the rocker arm assembly that bolts to the head. I think the slight rtv that I put on the surface mustve not been correct. Either too much or too little. That and maybe the cam seal failed too, who knows. Replaced that with an OEM Honda one.

Currently waiting on the head to come back from the shop. Hoping for the best
 

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Discussion Starter · #84 ·
Final update for the time being.

Installed the head, installed the belt, did everything. Cranked without plugs till I had oil pressure. Car started on the 2nd crank. It ran great, never this good. Valvetrain really quieted down after the adjustment and maybe the guides had something to do with it, probably not. But it ran great, until it didn't

For some reason the belt snapped at idle. It was idling like normal until I heard 6 ticks while the engine shut off. Those ticks were the #2 exhaust and #4 intake valves getting kissed by the pistons.

I don't get why it snapped. I didn't do anything differently from the other times that I've taken this thing apart. Followed the exact procedure, the exact torque for the belt tensioner and I did the belt twist test (see if the belt can twist +-90deg )

But now I'm back at square one with no motivation to continue in the car for the forseeable future. Maybe this winter, but not now.
I just hope it didn't trash the head. I like to think that it didn't since it was at idle and the stiffer springs might've instantly stopped the cam from closing any bent valves into the head.

When I get it back running again I will post my oil burning results. If this thread is closed I'll see what I can do to update you guys, but for now I'm done.

Thanks for all the help, it really helped me learn a lot more about engines.
 

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Discussion Starter · #88 ·
Odd, sorry to hear about that, it can be frustrating, maybe pick up a head to re work, drop it in at your convenience.
Gonna take the head off thisnweekend or so. Gonna see if its done for or not. Hoping for not.

My hope is that the cam instantly stopped turning since it has stiffer springs and it was at idle. Thus far onky saw those 4 valves being bent. Gonna recheck the guides and hopefully the valve seats aren't hit. Spark plugs havent 'self gapped' so thats a good sign I guess?
 

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93 Civic HB SI, 95 Civic HB CX
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That is a very odd failure for a new belt, but it sure looks like it reached a pull fatigue limit.

Could have been a manufacturer defect too, but are valvesprings upgraded in this thing? If so, what kind? What is advertised seat pressure?

Were you able to rotate the cam gear pretty freely before the valves bent? Short of normal spring pressure resistance, anything feel like it was binding out of normal when you rotated the cam gear?

Did you readjust valves before start up? If not, ALWAYS readjust your valves!! Dont think the machine shop did it, dont adjust it on the workbench either. Always loosen valve adjusters all the way on the workbench, install head, check cam rotation, then adjust valves.

That is something I always do after torquing the head down. Make sure you lube the heck out of the cam journals and lobes during head reassembly, install the head, and torque studs down, then rotate crank so pistons are all at mid cylinder (no P2V interference possibilities), then before adjusting valves use a rubber strap wrench around the cam sprocket or a turning tool that grasps the spokes of the cam gear, and rotate the cam a few times looking for binding. If good, adjust the valves, then try again and see what it feels like.

You're feeling for binding when the springs are compressing before tension release (to make sure your valve springs arent suffering coil bind), as well as for any dragging after spring tension release (the valve springs will "throw" the cam, and spin it automatically after the max point of spring compression as the lobe ramp is on its way down... make sure it can "throw" it and rotate freely, and that it isnt struggling to rotate when its in this state).

If you have a binding feeling at any point other than what normal spring compression typically feels like, you need to figure out the source. If none, then you may just need a beefier belt.

Gates is Honda OE supplier (over in NA at least) for timing belts, they make great stuff. I might even recommend you pick up the Gates blue racing belt next time for added fatigue strength, part number T224RB. Any parts store worth its salt can order this for you, its nothing special, Gates still makes them and is in their catalogs. Or try ebay or amazon looking for sellers who have them closer to you.


An example of a vendor selling this:



Ebay has them all over for very reasonable:

Font Electric blue Packaging and labeling Multimedia Advertising
 

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Discussion Starter · #92 ·
That is a very odd failure for a new belt, but it sure looks like it reached a pull fatigue limit.

Could have been a manufacturer defect too, but are valvesprings upgraded in this thing? If so, what kind? What is advertised seat pressure?

Were you able to rotate the cam gear pretty freely before the valves bent? Short of normal spring pressure resistance, anything feel like it was binding out of normal when you rotated the cam gear?

That is something I always do after torquing the head down. Make sure you lube the heck out of the cam journals and lobes during head reassembly, install the head, and torque studs down, then rotate crank so pistons are all at mid cylinder (no P2V interference possibilities), then before adjusting valves use a rubber strap wrench around the cam sprocket or a turning tool that grasps the spokes of the cam gear, and rotate the cam a few times looking for binding. If good, adjust the valves, then try again and see what it feels like.

You're feeling for binding when the springs are compressing before tension release (to make sure your valve springs arent suffering coil bind), as well as for any dragging after spring tension release (the valve springs will "throw" the cam, and spin it automatically after the max point of spring compression as the lobe ramp is on its way down... make sure it can "throw" it and rotate freely, and that it isnt struggling to rotate when its in this state).

If you have a binding feeling at any point other than what normal spring compression typically feels like, you need to figure out the source. If none, then you may just need a beefier belt.

Gates is Honda OE supplier (over in NA at least) for timing belts, they make great stuff. I might even recommend you pick up the Gates blue racing belt next time for added fatigue strength, part number T224RB. Any parts store worth its salt can order this for you, its nothing special, Gates still makes them and is in their catalogs. Or try ebay or amazon looking for sellers who have them closer to you.


An example of a vendor selling this:



Ebay has them all over for very reasonable:

View attachment 142739
Supertech valve springs, so yeah they're upgraded. I mean I put the belt on and rotated the crank and around every half a turn it felt some resistance but thats what I expected. I coated the cam and springs fully in oil since I don't want stuff to run dry. When having the rocker arm assembly installed rotating the cam is extremely hard. I dont have a rubber strap wrench sadly. And its seems odd that it didnt shred the belt before, since especially the last couple of months the care barely ran and was just started a couple of times. I think the belt was too weak.
Me and my dad had a thought, maybe the resistance from the upped compression and the stiffer valve springs were too much load for the stock belt to handle reliably. But thats just a thought. Gonna look into it more
 

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When you have the head off next, you'll probably want to get a strap wrench to turn the cam in the head, for inspection purposes. They're cheap! Or, you can use your old broken timing belt and a big box end wrench for free lol.

Do you have an upgraded cam with higher overall lift on the non-VTEC lobes as well?

The machine shop "should" have tested all of this if they were the ones who installed the new cam/valve springs, but check for spring coil bind with the head fully assembled and valves adjusted to spec.

You need to turn the cam with a turning tool of some kind, not using the crankshaft and belt installed to turn it all for leverage. You cant sense minute tightness and binding via the crank sprocket, you'll just turn right through it no problem!
 

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Discussion Starter · #94 ·
When you have the head off next, you'll probably want to get a strap wrench to turn the cam in the head, for inspection purposes. They're cheap! Or, you can use your old broken timing belt and a big box end wrench for free lol.

Do you have an upgraded cam with higher overall lift on the non-VTEC lobes as well?

The machine shop "should" have tested all of this if they were the ones who installed the new cam/valve springs, but check for spring coil bind with the head fully assembled and valves adjusted to spec.

You need to turn the cam with a turning tool of some kind, not using the crankshaft and belt installed to turn it all for leverage. You cant sense minute tightness and binding via the crank sprocket, you'll just turn right through it no problem!
Stage 2 Comp Cams 59300 camshaft. Ill do the box end wrench trick. Hopefully I can sense the binding if there is any. Ill report back
 

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Discussion Starter · #97 ·
Damage assesment update. Took the head off just now. Set a new record of 37 mins! I might have been lucky and only the 2 exhaust valves on cyl 2 are done for. Cyl 4 still has that tiny mark on one of the valve reliefs but the valve itself looks untouched, its like the top bit of carbon just got scraped off. Taking it to the shop that put the guides in to see what he says about the damage. I'll also let him diagnose any coil binding as I dont want to take any chances
 

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Discussion Starter · #99 ·
Fingers crossed for you buddy.
Well ouch I think @robgoof was right after all. Didn't take the valvetrain apart as I'd like the more trustworthy shop to do it and he told me the cam seized as well.. Middle cam journal looks beat up. He's going to try and fix it to see if it can be reused. If not, I'm in the market for a Z6 head. Preferably ported, haha.

I'm honestly stumped as to how this could happen. I'm starting to think that I'm crazy and missing something obvious. I rechecked the oil holes inside the engine and didn't see anything notable. Maybe something got stuck inside the rocker arm assembly?
 

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I had a cam journal do that on one I put together a few weeks ago 😖 , all it takes is a tiny piece of trash, little bit of dust, or uneven torque on the caps as the clearances are so small. In my case it was damaged threads that came out with the bolt on the front cap, dont think it was improper torque as the wrench is new and was calibrated less than 2 weeks prior, and tested fine the day after.
 
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