Mauitrailguy Posted August 2, 2011 Share Posted August 2, 2011 So heres a long story made short. The stud for the timing belt tensioner broke while running. Pathy died. I towed it home and did a timing belt and fixed the stud. Put it all back together and now....no compression on cylinders 3 and 4. All others is 180 Kpa. I have heard we have "interference" engines. Haven't taken the valve covers off and looked and whats going on. It still runs, but like @!*%. What do you guys think? Link to comment Share on other sites More sharing options...
OldSlowReliable Posted August 2, 2011 Share Posted August 2, 2011 I know bikes primarily, but are you sure your timing is right? 0 compression definitely sounds valve related, and its possible you bent some valves..... just my observations though.. Link to comment Share on other sites More sharing options...
Tungsten Posted August 2, 2011 Share Posted August 2, 2011 Straighten out those valves with a screwdriver and try again. I had no idea those studs could snap, I never replaced mine not even doing the timing belt. Link to comment Share on other sites More sharing options...
Mauitrailguy Posted August 2, 2011 Author Share Posted August 2, 2011 Straighten out those valves with a screwdriver and try again. I had no idea those studs could snap, I never replaced mine not even doing the timing belt. How do I straighten a valve out with a screwdriver...? Link to comment Share on other sites More sharing options...
sewebster Posted August 2, 2011 Share Posted August 2, 2011 I think he means after you pull the heads. Probably I would put new valves in if I was going to do that. But anyway, yeah, if you are absolutely sure your timing belt is on properly (because if it isn't then that could be why you have no compression) then likely you damaged something bad inside and need to pull the heads etc (at least). I hope my stud doesn't break! I'm guessing it could be caused by excessive timing belt tension? Link to comment Share on other sites More sharing options...
Kingman Posted August 2, 2011 Share Posted August 2, 2011 Take the heads off and throw some new valves in. The tensioner breaking isn't unheard of either. Link to comment Share on other sites More sharing options...
Joel97R50 Posted August 2, 2011 Share Posted August 2, 2011 My tensioner shred in my R50. the bolt did not break but it made for a real loud clanking noise. I was lucky enough to not snap the belt. These motors are interference motors like you mentioned. You slapped pistons into valves and bent them. Bent valves = 0 compression. Heads will have to be gone through. Sorry to hear about it. Link to comment Share on other sites More sharing options...
Mauitrailguy Posted August 2, 2011 Author Share Posted August 2, 2011 Guess I just gut "Unlucky". Im thinking about just having the whole thing rebuilt. Any one have any suggestions to make it more cost efficient? Link to comment Share on other sites More sharing options...
sewebster Posted August 2, 2011 Share Posted August 2, 2011 Guess I just gut "Unlucky". Im thinking about just having the whole thing rebuilt. Any one have any suggestions to make it more cost efficient? I rebuilt mine myself and spent way too much money Doing a full rebuild is going to be significantly more work than just doing the heads. But you need to check for piston/cylinder damage to know if your block is still good. When I rebuilt mine with 185k miles I replaced all the valves, rockers, rocker shafts, and lifters. I also had the valve seats recut and had the heads faced. You should also check if the valve guides are good, and replace the valve stem seals. Theoretically you should check the springs and the lifter guide plates too... plus cam clearances etc etc Anyway, rock auto is pretty cheap for this stuff, but I can't really imagine paying the prices a shop would want for all those parts. And that's just the top end... Link to comment Share on other sites More sharing options...
JUNN Posted August 2, 2011 Share Posted August 2, 2011 i just recently rebuild mine and spent about 420 in piston rings rod bearings 5 valves the head work and the gaskets etc.. Link to comment Share on other sites More sharing options...
frozenrotors Posted August 2, 2011 Share Posted August 2, 2011 i just recently rebuild mine and spent about 420 in piston rings rod bearings 5 valves the head work and the gaskets etc.. Was that in USD? LOL Link to comment Share on other sites More sharing options...
Mauitrailguy Posted August 3, 2011 Author Share Posted August 3, 2011 So I have an 87 that I was parting out. Compression is 160 all around. Going to swap it in and then rebuild the current one as a spare but wit 300 zx parts. The 87 has 156xxx miles on it compared to the 227xxx on my current engine. plus no cost to me to do the swap except for some gaskets ETC. Link to comment Share on other sites More sharing options...
Mauitrailguy Posted September 18, 2011 Author Share Posted September 18, 2011 Did the swap. Went smooth. Much more power now to. I also took the open diff axle. so now I have the option of a detroit for about 300 dollars less. Link to comment Share on other sites More sharing options...
Tungsten Posted September 18, 2011 Share Posted September 18, 2011 Good to hear that! What I meant by straightening valves with a screwdriver is you take the rockers off and jam a screwdriver into the valve hole and pry the valves straight. It's a controversial method but worth a shot if you ever bend valves. 1 Link to comment Share on other sites More sharing options...
Mauitrailguy Posted October 11, 2011 Author Share Posted October 11, 2011 thanks for that ill remember that in the future. might be a good "get me home trick" Link to comment Share on other sites More sharing options...
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