DTT_Eruc Posted August 11, 2019 Author Share Posted August 11, 2019 5 hours ago, NEO25T said: Did you hold the intake cam on the hex with a spanner while removing/installing the cam gear? If not it might be jammed advanced and could probably cause something like this yes i did that remove it with a spanner in place to remove the vct gear Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7913290 Share on other sites More sharing options...
NEO25T Posted August 11, 2019 Share Posted August 11, 2019 Do you know why it bent valves in the first place? Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7913295 Share on other sites More sharing options...
DTT_Eruc Posted August 11, 2019 Author Share Posted August 11, 2019 3 hours ago, NEO25T said: Do you know why it bent valves in the first place? thats a long story but thats not what am worried about Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7913299 Share on other sites More sharing options...
NEO25T Posted August 12, 2019 Share Posted August 12, 2019 Last thing I can think of, my fuel map need adjusting after tightening the valve clearences but it still ran and idled Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7913304 Share on other sites More sharing options...
DTT_Eruc Posted August 12, 2019 Author Share Posted August 12, 2019 5 hours ago, NEO25T said: Last thing I can think of, my fuel map need adjusting after tightening the valve clearences but it still ran and idled you know whats funny now.... i checked the cam specs card to see whats the clearance of tomei 262 should be and it fell within the range the clearance of it and i personally wanted it to be in nissan specs so thinking i have it at a tight valve when tomei requested it to be so without me even realizing it....now it have me wondering it can be really something else geeezzz Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7913322 Share on other sites More sharing options...
DTT_Eruc Posted August 25, 2019 Author Share Posted August 25, 2019 Ok buddies... i have finally got the time to check the timing and did a compression test and so far on the timing its on spot so far , the compression test showed the same value for the cylinders 2-6 of 125 but cylinder 1 was a bit lower but thats due to valve 1 of the intake being 0.011 when the others are 0.012.... so my last check is to do a proper smoke test.. what yall think? Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914280 Share on other sites More sharing options...
Ben C34 Posted August 25, 2019 Share Posted August 25, 2019 Cam timing or ignition timing checked? Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914281 Share on other sites More sharing options...
DTT_Eruc Posted August 25, 2019 Author Share Posted August 25, 2019 2 hours ago, Ben C34 said: Cam timing or ignition timing checked? cam timing is on spot but havent checked the ignition timing...also what i forget to mention is that the compression tester took a while to build up the reading so it have me wondering that its looking like a valve seating issue... could be wrong ? Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914288 Share on other sites More sharing options...
DTT_Eruc Posted August 27, 2019 Author Share Posted August 27, 2019 On 8/24/2019 at 10:04 PM, Ben C34 said: Cam timing or ignition timing checked? lolllll i came to harass my sau buddies once again..... finally took of the head saw nothing to really say A BIG issue.... Took some gas and put it on all 6 chambers of valves and all seems to be well sealed except for one but very slow .... so now am left to believe due to the shim clearance settings i got for intake and exhaust can be causing the problem... Intake - 0.012(Nissan) Tomei Requires - 0.018 Exhaust - 0.019(Nissan) Tomei Requires - 0.015 what i currently have is the intake side of nissan and the exhaust side of tomei so am wondering to have the intake of tomei to see if it makes a differences ..... Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914449 Share on other sites More sharing options...
GTSBoy Posted August 27, 2019 Share Posted August 27, 2019 Sigh. It won't be the clearances. Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914454 Share on other sites More sharing options...
DTT_Eruc Posted August 27, 2019 Author Share Posted August 27, 2019 27 minutes ago, GTSBoy said: Sigh. It won't be the clearances. what could it really be.... wouldmt it be from the clearance that changes the overlap? Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914457 Share on other sites More sharing options...
GTSBoy Posted August 27, 2019 Share Posted August 27, 2019 There is no way that slightly tight clearances can cause NO vacuum. Slightly less vacuum perhaps. But not none. You definitely have something very weird going on, and in my experience of these threads, it always turns out to be something that no-one could have guessed. Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914458 Share on other sites More sharing options...
DTT_Eruc Posted August 27, 2019 Author Share Posted August 27, 2019 3 minutes ago, GTSBoy said: There is no way that slightly tight clearances can cause NO vacuum. Slightly less vacuum perhaps. But not none. You definitely have something very weird going on, and in my experience of these threads, it always turns out to be something that no-one could have guessed. ok let me say again..... its very hard for the engine to idle at 1000rpm so high rpms it idles but with no vac... if it trys to go 1000rpm its gonna cut off sure.... did a compression test and it took long for the results to build up wasnt like the first pulse it jump to a 60-90psi reading and then settle to another high number... Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914459 Share on other sites More sharing options...
GTSBoy Posted August 27, 2019 Share Posted August 27, 2019 Let me state again.....how the hell can slightly tight clearances cause the effect you're seeing? It's just wrong to think that they can. The problem is elsewhere. Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914460 Share on other sites More sharing options...
DTT_Eruc Posted August 27, 2019 Author Share Posted August 27, 2019 Just now, GTSBoy said: Let me state again.....how the hell can slightly tight clearances cause the effect you're seeing? It's just wrong to think that they can. The problem is elsewhere. am moving away from the "tight clearance" cause i saw it still wouldnt cause that issue, what i really wanna know what IF the clearance settings i posted a little while would cause a change in overlap .... am not no genius in this cause currently search results is limited to my question so i hadda fetch from all over and then put it together to see if it makes sense .... Timing correct,did a smoke machine test no BIG leak, compression test done(but slow build up) Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914461 Share on other sites More sharing options...
GTSBoy Posted August 27, 2019 Share Posted August 27, 2019 Will change overlap, but only by a tiny amount. I'm thinking that something really big is wrong and you should take it apart. This is generally how these threads go. Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914464 Share on other sites More sharing options...
DTT_Eruc Posted August 28, 2019 Author Share Posted August 28, 2019 22 hours ago, GTSBoy said: Will change overlap, but only by a tiny amount. I'm thinking that something really big is wrong and you should take it apart. This is generally how these threads go. Well i did and so far i havent seen anything wrong,valves are sealing properly..... so just for a piece of mind i did the intake clearances to tomei spec and so is the exhaust.... now its just to time the engine and am not even gonna start just run a compression test again and see whats popping...am starting to wonder maybe the engine was just a tooth off and could of been part of the issue even doh i checked a million times if that doesnt work welllllllllllllll idk lol Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914563 Share on other sites More sharing options...
DTT_Eruc Posted August 28, 2019 Author Share Posted August 28, 2019 On 8/11/2019 at 2:43 AM, NEO25T said: Did you hold the intake cam on the hex with a spanner while removing/installing the cam gear? If not it might be jammed advanced and could probably cause something like this And yes i held it in position in removing and installing.This might be my last bet.. If its stuck open it will create much more overlap = low vac. Correct me if am wrong. How can i tell if my vct is stuck..... Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914612 Share on other sites More sharing options...
Ben C34 Posted August 28, 2019 Share Posted August 28, 2019 2 hours ago, DTT_Eruc said: And yes i held it in position in removing and installing.This might be my last bet.. If its stuck open it will create much more overlap = low vac. Correct me if am wrong. How can i tell if my vct is stuck..... Still won't cause what you are experiencing. Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914621 Share on other sites More sharing options...
DTT_Eruc Posted August 28, 2019 Author Share Posted August 28, 2019 6 minutes ago, Ben C34 said: Still won't cause what you are experiencing. Thanks... brb until i continue the assembly of the engine... Link to comment https://www.sau.com.au/forums/topic/478240-no-vacuum-at-lower-rpm-rb25det-neo/page/2/#findComment-7914622 Share on other sites More sharing options...
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