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Rb25det both cams off by 4 teeth. Damaged head?

Joey J

By Joey J,
in General Maintenance

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Joey J Apprentice

Joey J

Posted
Posted

So I’m replacing a few maintenance items and I noticed the cams are both off by 4 teeth. The car will turn on and run for like 30 seconds before shutting off if I don’t give it gas. 
 

i thought the issue might be the tune but now I’m not sure. Could there be damage to the valves?

55AC7947-29AC-4036-909A-79C70FFA37B7.jpeg

B3984533-0736-4C67-B2FA-9A0D45556C21.jpeg

Ben C34 Grand Master

Ben C34

Posted
Posted

It depends on the direction they are off if it may cause damage. A comp test with the cam timing wrong isn't very useful, a leak down test would be better.

I would just set cams to correct position while crossing fingers and try starting it again. No real need to waste time testing when you could just fix it and see

 

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Ben C34 Grand Master

Ben C34

Posted
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43 minutes ago, Joey J said:

Working on fixing it now. Balancer is off and mark on crank lines up with tdc marker. I will update once done. Probably won’t finish untill tomorrow night. 

That’s ok I can wait 👍

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Joey J Apprentice

Joey J

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  • Author
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Balancer looks good. When I pulled it off the crank gear mark lined up with the timing mark on the block.
 

Im assuming below is why the cams are both off by 4 teeth. Not sure. Between those 2 teeth was that crud had pretty much turned into a rock. 
 

I don’t know how the car was dyno’d at the shop and no one noticed the timing was off. Is it possible it was set like that on purpose? I don’t see why that would be done. 

A51DECD7-AC36-4373-A75A-2722DA8DD310.jpeg

tridentt150v Grand Master

tridentt150v

Posted
Posted
2 hours ago, Joey J said:

I don’t know how the car was dyno’d at all................FYP

A51DECD7-AC36-4373-A75A-2722DA8DD310.jpeg

I honestly can't understand how the car could even do dyno runs........surely it would have had trouble revving out?

And what is the crud made up of?  road gravel? metal? old belt?

Blakeo Rising Star

Blakeo

Posted
Posted
2 hours ago, Joey J said:

Balancer looks good. When I pulled it off the crank gear mark lined up with the timing mark on the block.
 

Im assuming below is why the cams are both off by 4 teeth. Not sure. Between those 2 teeth was that crud had pretty much turned into a rock. 
 

I don’t know how the car was dyno’d at the shop and no one noticed the timing was off. Is it possible it was set like that on purpose? I don’t see why that would be done. 

A51DECD7-AC36-4373-A75A-2722DA8DD310.jpeg

Hi Joey, I'd definitely be pulling the crank gear off and giving it a good clean (especially between the teeth so the belt can get good engagement) as well as cleaning up the general area down there. 

I can't comment in this case because I don't know what has been done to the car in regards to its history. But I do know my timing has been adjusted using Tomei adjustable timing gears, as my head has been decked a couple of times as well as the block has been decked. 

Unfortunately we couldn't accurately make up for the loss material with a bigger head gasket, so we had to degree the engine after the rebuild to ensure tdc was still correct as per the marks on the rear timing cover (they weren't), so the timing gears were used to take up this slack. 

Could be the same in this case, but I'd really be asking your tuner as they may have had a valid reason for doing this. 

Ben C34 Grand Master

Ben C34

Posted
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3 minutes ago, Blakeo said:

Hi Joey, I'd definitely be pulling the crank gear off and giving it a good clean (especially between the teeth so the belt can get good engagement) as well as cleaning up the general area down there. 

I can't comment in this case because I don't know what has been done to the car in regards to its history. But I do know my timing has been adjusted using Tomei adjustable timing gears, as my head has been decked a couple of times as well as the block has been decked. 

Unfortunately we couldn't accurately make up for the loss material with a bigger head gasket, so we had to degree the engine after the rebuild to ensure tdc was still correct as per the marks on the rear timing cover (they weren't), so the timing gears were used to take up this slack. 

Could be the same in this case, but I'd really be asking your tuner as they may have had a valid reason for doing this. 

Nah man, adjustments for facing head and block are a few degrees, one whole tooth is 16 from memory. One whole tooth is way too much

Blakeo Rising Star

Blakeo

Posted
Posted
28 minutes ago, Ben C34 said:

Nah man, adjustments for facing head and block are a few degrees, one whole tooth is 16 from memory. One whole tooth is way too much

Ok, I dare say that's not the issue then my bad. 

I'd say OP is extremely lucky if it hasn't done any damage. 

Also Ben do you still have a RB or have you gone to the dark side? 

 

Joey J Apprentice

Joey J

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20 hours ago, tridentt150v said:

I honestly can't understand how the car could even do dyno runs........surely it would have had trouble revving out?

And what is the crud made up of?  road gravel? metal? old belt?

They had sent me a vid when it was getting dyno’d. Sounded fine.
 

The crud was dirt and gravel. No metal. Old belt actually looked good. No teeth missing. Didn’t appear to be old at all. 

19 hours ago, NZ-GTT said:

Exhaust valves could be bent but as mentioned a leak down test will reveal any damage. 

I hope that’s not the case. I don’t want to have to deal with pulling the engine. I don’t have space to do all that. I’d have to ship it to a shop. I really want to avoid that. 

 

I got everything back on today but I ran out of time. I’ll check all the bolts next week end and refill coolant, check for leaks and give her a crank. I had replaced the water pump and thermostat since I was there. The gasket maker says it needs 24 hours to cure.

I’ll report back next week. 
 

Thank you all for the responses. Much appreciated! I feel I’d be lost without this forum. 

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