Help! Changed timing chain - did I crunch my valves?
#22
Registered User
i know you got it fixed (nice distributor gear) but im pretty sure i read somewhere (dotn remember where) but iirc most toyota motors half valve reliefs cut into the piston so if the chain breaks you dont mash valves, correct me if im wrong
has anybody ever had this problem. when i replaced my timing chain i bought it from orielys and the dots on the gears were way off (just did it the old fashioned way by putting the crank at tdc then rolling the cam till it was on its commpression cycle then put the chain on) plus i didnt hit the valves when i was turning over the crank while doing it with this method
has anybody ever had this problem. when i replaced my timing chain i bought it from orielys and the dots on the gears were way off (just did it the old fashioned way by putting the crank at tdc then rolling the cam till it was on its commpression cycle then put the chain on) plus i didnt hit the valves when i was turning over the crank while doing it with this method
Last edited by Dreidel; 02-06-2013 at 02:44 PM.
#23
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I'll definitely be doing a couple of oil changes in the next 1000 miles. I changed out the oil to get most of it, but don't like the thought of little metal bits floating around in my smooth running engine.
how 'bout that gear, huh? It's going into my fubar'ed parts HOF. In fact, that should be a thread with a sticky, somewhere!
As far as the question on whether or not the engine has valve relief cuts in the pistions, I don't know. But I followed these instructions, http://www.4crawler.com/4x4/CheapTri...ingChain.shtml, along with my FSM.
The 4Crawler post had this to say:
CAUTION: The 22R line of engines are an interference style engine.
Meaning if the valves are open when a piston is in the up position they will collide.
Therefore you must be VERY careful and keep the cam gear and crank perfectly aligned.
I don't know if he's correct, but he seemed to get everything else right.
how 'bout that gear, huh? It's going into my fubar'ed parts HOF. In fact, that should be a thread with a sticky, somewhere!
As far as the question on whether or not the engine has valve relief cuts in the pistions, I don't know. But I followed these instructions, http://www.4crawler.com/4x4/CheapTri...ingChain.shtml, along with my FSM.
The 4Crawler post had this to say:
CAUTION: The 22R line of engines are an interference style engine.
Meaning if the valves are open when a piston is in the up position they will collide.
Therefore you must be VERY careful and keep the cam gear and crank perfectly aligned.
I don't know if he's correct, but he seemed to get everything else right.
#24
Registered User
oh well i must of read that about some different engines dont remember which though
edit: you were right turns out its just rare because in order to hit the piston has to be at perfect tdc at the same time as one of the valves being at its lowest point in the cc at the same exact time. so it can hit but usually wont coresty of 22rekid from race-dezert.com to better explain
[quote] The 22R/RE is an interference engine for future reference. 9 times out of 10 there is no interference so it is rare, but the valves will hit the piston given the right circumstances. It's got nothing to do with the later or early pistons. The early 22R pistons were dome shaped and the later moder pistons have a dish in them, but not where the valves will hit. There is valve reliefs cut into the pistons but they will still hit. When the block or head is milled there is an even greater chance of interference but it happens on stock deck heiths too, it's just rare. [quote]
ps i do like looking over that guys site seems to really know what he's doing and does a good job explaining stuff and using pics
edit: you were right turns out its just rare because in order to hit the piston has to be at perfect tdc at the same time as one of the valves being at its lowest point in the cc at the same exact time. so it can hit but usually wont coresty of 22rekid from race-dezert.com to better explain
[quote] The 22R/RE is an interference engine for future reference. 9 times out of 10 there is no interference so it is rare, but the valves will hit the piston given the right circumstances. It's got nothing to do with the later or early pistons. The early 22R pistons were dome shaped and the later moder pistons have a dish in them, but not where the valves will hit. There is valve reliefs cut into the pistons but they will still hit. When the block or head is milled there is an even greater chance of interference but it happens on stock deck heiths too, it's just rare. [quote]
ps i do like looking over that guys site seems to really know what he's doing and does a good job explaining stuff and using pics
Last edited by Dreidel; 02-09-2013 at 12:02 PM.
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