Ugh! Just finished putting my 20R/22R hybrid together, it's taken months to get all the machine work done, so I was super stoked to have everything finished.

However, after assembling the long block, I turned the motor over by hand to check everything out. It turned over smoothly but came to a sudden STOP! I backed it up, tried again, and STOP. Uh oh. I took everything apart and had 4 nice little nicks in each (new) piston and the number 4 intake valve was visibly bent, and no longer seating. (I think 4 was bent the worst because the I had the tappets on the rockers all backed off about half way, but # 4 was a little tighter than the rest) Didn't think I was wrenching on the thing that hard, but apparently enough to bend valves!

I measured the block (83 22r) and have a height from main cap to deck of 9.100 (lc engineering says stock is 9.120)

I measured the head (80 20r) from the lip for the valve cover to the head surface and got 3.929 (not sure what stock is)

I measured the height of the pistons below the deck which is 0.010 and the height the dome rises above the deck is 0.250

I used a stock victor reniz gasket which i forgot to measure, I'm guessing around .040

I'm using a crower stage 1 RV cam intake 270 degree duration, exhaust 276 degree duration, lift for both is .432 and lobe separation is 108 degrees

The head has engnbldrs OS valves which I think are 44mm intake and 36mm exhaust (almost same size as 22r)

So. I'm thinking one of two things. One I had the cam off a tooth, which is technically possible, because I didn't check after I realized I had a problem (dumb mistake) BUT I did check to see everything was lined up before I turned the motor over, so its not likely.

Or, taking a little off the block, a little off the head, putting in a little bit bigger valve, using a little bigger cam with a little longer duration added up to having no clearance? I hope not, but I really can't think of anything else it might be.

Any ideas?

 

No one?

 

i'm not too familiar with these engines yet, but from other motors (v-8s) i don't think the piston will hit the valves if you are just one tooth off. it may be harder to time, but you shouldn't get any interference. a few teeth, sure... but not just one. are you sure you were at tdc and couldn't be 180 out when you reassembled everything?

Al

 

in stock form the valves whond hit pistons when you are a tooth off. infact they will even run! shatty but they will run. with what you have done with valves, pistons, and cam, it is possible. nut somewhere in the neighborhood of 2 or 3 teeth off

 

Yah, I didn't think being of a tooth would cause that much destruction, and I don't think I was off a tooth. Does anyone know how much clearance a stock set up has? I don't think my combo is that wild. I haven't gone back out and second checked everything cause I been busy and don't have the money to repair it right now anyway.

Thanks for the posts

 

Being a tooth off will not produce bent valves

 

when you torqued the head down , were the adjustment screws on the rockers backed off ?

If not , damage could occure right off the bat , this would bend 2 valves



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Yah all of the valve tappets were backed off. Even if they weren't, I'm not understanding how that would bend valves. If the cam timing is right, it either has interference or it doesn't. The tightness of the head bolts shouldn't matter.

Thanks for the comments though, everything helps!

 

I think u just had ur rockers too tight, but u would have really had to torque it hard to bend a valve using a rachet on the crank, i bent three valves and broke one by cranking mine out of time

 

timing chain isnt installed untill AFTER the head is torqued .. so if your adjusters arnt backed off when you "adjust" the bottom end , and cam to the propper 0 deg. for the timing chain adjustment , everything is "floating" .. you'll bend valves ..


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Cool. I'll check that out. I know for a fact though that all the tappets were backed way off. I'm planning on re-assembling everything monday and really thoroughly checking everything over before I go complaining to the machine shop