Strange sound from rebuilt engine...
02-11-2013, 06:09 PM
#122
Rennlist Member
oil pressure.
hello, first off i not a 993 engine expert. but very mechancal inclined.
1. did you have good oil pressure before the top end?
2. you said you had the lifter reground, did you blow the oil hole in the rocker to clear debre? if not that could clog and hinder the lifter from pumping up.
3. also were the rocker rebush/ new bushing?
4. if the lifters are collapsed and not pumping up this can be verified by running the engine, not long and then pulling one distributor cap and looking at what cylinder its closes to firing on and remove that valve cover and checking for rocker play, you do not want to turn the engine over. the rocker should be tight if not completly on top dead center . a excessively loose rocker mean they are not pumping up.
5. like i said im no 993 expert, but the supply oil for lifter comes from head and transfer via the rocker crossbar, is it possible you dont have these installed correctly.
6. did you use any sealer on the bridges ?
7. did you have any work done on the cam towers?
8. cant you remove the lifter and prime by hand?
1. did you have good oil pressure before the top end?
2. you said you had the lifter reground, did you blow the oil hole in the rocker to clear debre? if not that could clog and hinder the lifter from pumping up.
3. also were the rocker rebush/ new bushing?
4. if the lifters are collapsed and not pumping up this can be verified by running the engine, not long and then pulling one distributor cap and looking at what cylinder its closes to firing on and remove that valve cover and checking for rocker play, you do not want to turn the engine over. the rocker should be tight if not completly on top dead center . a excessively loose rocker mean they are not pumping up.
5. like i said im no 993 expert, but the supply oil for lifter comes from head and transfer via the rocker crossbar, is it possible you dont have these installed correctly.
6. did you use any sealer on the bridges ?
7. did you have any work done on the cam towers?
8. cant you remove the lifter and prime by hand?
02-11-2013, 06:39 PM
#123
Rennlist Member
low oil pressure.
i forgot
i know this mAY SOUND STUPID BUT DID YOU INSTALL THE LIFTER UPSIDE DOWN, DONT KNOW IF POSSIBLE BUT COULD CAUSE LOW PRESS AND LIFTER NOISE.
i know this mAY SOUND STUPID BUT DID YOU INSTALL THE LIFTER UPSIDE DOWN, DONT KNOW IF POSSIBLE BUT COULD CAUSE LOW PRESS AND LIFTER NOISE.
02-11-2013, 07:22 PM
#124
Burning Brakes
Thread Starter
hello, first off i not a 993 engine expert. but very mechancal inclined.
1. did you have good oil pressure before the top end?
Yes.
2. you said you had the lifter reground, did you blow the oil hole in the rocker to clear debre? if not that could clog and hinder the lifter from pumping up.
No. but they were fine prior to the rebuild.
3. also were the rocker rebush/ new bushing?
The surface facing the cam was re-bushed. I re-used the cross-bar pieces.
4. if the lifters are collapsed and not pumping up this can be verified by running the engine, not long and then pulling one distributor cap and looking at what cylinder its closes to firing on and remove that valve cover and checking for rocker play, you do not want to turn the engine over. the rocker should be tight if not completly on top dead center . a excessively loose rocker mean they are not pumping up.
OK.
5. like i said im no 993 expert, but the supply oil for lifter comes from head and transfer via the rocker crossbar, is it possible you dont have these installed correctly.
No, they can only go on one way.
6. did you use any sealer on the bridges ?
No Sealer in the bridges. Only DOW 111 on the small o-rings. I just had the left side bridge off and stuck a piece of plstic into the hole running up over the chain housing. Oil was present in there as well as in the bridge.
7. did you have any work done on the cam towers?
No. I only cleaned out the SAI passages and otherwise just cleaned everything.
8. cant you remove the lifter and prime by hand?
I suppose so but I did soak them overnight before putting them in the rocker.
1. did you have good oil pressure before the top end?
Yes.
2. you said you had the lifter reground, did you blow the oil hole in the rocker to clear debre? if not that could clog and hinder the lifter from pumping up.
No. but they were fine prior to the rebuild.
3. also were the rocker rebush/ new bushing?
The surface facing the cam was re-bushed. I re-used the cross-bar pieces.
4. if the lifters are collapsed and not pumping up this can be verified by running the engine, not long and then pulling one distributor cap and looking at what cylinder its closes to firing on and remove that valve cover and checking for rocker play, you do not want to turn the engine over. the rocker should be tight if not completly on top dead center . a excessively loose rocker mean they are not pumping up.
OK.
5. like i said im no 993 expert, but the supply oil for lifter comes from head and transfer via the rocker crossbar, is it possible you dont have these installed correctly.
No, they can only go on one way.
6. did you use any sealer on the bridges ?
No Sealer in the bridges. Only DOW 111 on the small o-rings. I just had the left side bridge off and stuck a piece of plstic into the hole running up over the chain housing. Oil was present in there as well as in the bridge.
7. did you have any work done on the cam towers?
No. I only cleaned out the SAI passages and otherwise just cleaned everything.
8. cant you remove the lifter and prime by hand?
I suppose so but I did soak them overnight before putting them in the rocker.
02-11-2013, 07:23 PM
#125
Burning Brakes
Thread Starter
02-11-2013, 08:12 PM
#126
Rennlist Member
it would really help you out if you run the car briefly and and pull the cap to see which cylinder is just about to fire and just pull that valve cover and see how loose the rocker is.
also you never stated if you verify the right tensioner orientation unless i miss it. you did say you checked the left.
i can tell you this that a tensioner will pump itself up with just an idle only takes a minute or two. i read on other rennlist poster that even new lifter required a spirited drive to pump up. but if you can run briefly and check the cylinder thats a bout to fire and see if those lifter are loose at least you will know that that the problem.
also you never stated if you verify the right tensioner orientation unless i miss it. you did say you checked the left.
i can tell you this that a tensioner will pump itself up with just an idle only takes a minute or two. i read on other rennlist poster that even new lifter required a spirited drive to pump up. but if you can run briefly and check the cylinder thats a bout to fire and see if those lifter are loose at least you will know that that the problem.
02-11-2013, 08:28 PM
#127
Rennlist Member
you stated that the valves heights were ground to compensate for the cam reground so standard lifter could be used. ok. do these lifter snap into the the rockers or just slide in. if they just slide in and they are not primed all they way up i could see why they are a bitch to prime on their own.
so lets say that the geometry is off and even if they are fully primed and the gap is too large, they are going to rattle like crazy.
i know your stressing, but the oil pressure thing althogh im portant i thinks thats fine.
when you installed the rockers on a pacticular cylinder hopefully at top dead center. was there play??
if you look on rennlist you can see what a lifter look like when primed and extended.
so lets say that the geometry is off and even if they are fully primed and the gap is too large, they are going to rattle like crazy.
i know your stressing, but the oil pressure thing althogh im portant i thinks thats fine.
when you installed the rockers on a pacticular cylinder hopefully at top dead center. was there play??
if you look on rennlist you can see what a lifter look like when primed and extended.
02-11-2013, 09:10 PM
#128
Burning Brakes
Thread Starter
it would really help you out if you run the car briefly and and pull the cap to see which cylinder is just about to fire and just pull that valve cover and see how loose the rocker is.
Yes, I can do this. Which rocker panel, Exhaust (lower) or Intake (upper)?
also you never stated if you verify the right tensioner orientation unless i miss it. you did say you checked the left.
I have not checked this one yet. It is harder to get at and I would have to drain the oil - the right one is pointing down. It has a heat shield over it. So, this tensioner is still a suspect.
i can tell you this that a tensioner will pump itself up with just an idle only takes a minute or two. i read on other rennlist poster that even new lifter required a spirited drive to pump up. but if you can run briefly and check the cylinder thats a bout to fire and see if those lifter are loose at least you will know that that the problem.
Yes, I can do this. Which rocker panel, Exhaust (lower) or Intake (upper)?
also you never stated if you verify the right tensioner orientation unless i miss it. you did say you checked the left.
I have not checked this one yet. It is harder to get at and I would have to drain the oil - the right one is pointing down. It has a heat shield over it. So, this tensioner is still a suspect.
i can tell you this that a tensioner will pump itself up with just an idle only takes a minute or two. i read on other rennlist poster that even new lifter required a spirited drive to pump up. but if you can run briefly and check the cylinder thats a bout to fire and see if those lifter are loose at least you will know that that the problem.
02-11-2013, 09:30 PM
#130
Burning Brakes
Thread Starter
you stated that the valves heights were ground to compensate for the cam reground so standard lifter could be used. ok. do these lifter snap into the the rockers or just slide in. if they just slide in and they are not primed all they way up i could see why they are a bitch to prime on their own.
Peter: The machine shop did NOT know the cams were being ground. The cams were re-ground at a different shop. Both the machine shop and the cam shop say the geometry should be fine.
so lets say that the geometry is off and even if they are fully primed and the gap is too large, they are going to rattle like crazy.
Peter: See above.
i know your stressing, but the oil pressure thing althogh im portant i thinks thats fine.
Peter: Yes, others have stated the oil pressure could be Red Herring.
when you installed the rockers on a pacticular cylinder hopefully at top dead center. was there play??
Peter:
Here's what I did:
1. Installed solid lifter on no. 1 intake.
2. Brought no. 1 to TDC Rotated cam to dot up position.
3. introduced .1mm gap at lifter end. Tensioned Chain.
4. Installed pin to lock cam, tightened cam nut.
5. Set up dial gauge, pre-loaded dial on spring retainer and set dial to zero.
6. Rotated crank about 350 degrees and dial starts to move.
7. Continued rotation until dial read 1mm.
8. removed locking pin.
9 rotated crand a couple more degrees to TDC.
10. Re-inserted pin.
11. Torqued cam nut.
Repeat other side. But first rotated Cam to dot down position.
At no time was the lifter loose. No Play at all.
if you look on rennlist you can see what a lifter look like when primed and extended.
Peter: The machine shop did NOT know the cams were being ground. The cams were re-ground at a different shop. Both the machine shop and the cam shop say the geometry should be fine.
so lets say that the geometry is off and even if they are fully primed and the gap is too large, they are going to rattle like crazy.
Peter: See above.
i know your stressing, but the oil pressure thing althogh im portant i thinks thats fine.
Peter: Yes, others have stated the oil pressure could be Red Herring.
when you installed the rockers on a pacticular cylinder hopefully at top dead center. was there play??
Peter:
Here's what I did:
1. Installed solid lifter on no. 1 intake.
2. Brought no. 1 to TDC Rotated cam to dot up position.
3. introduced .1mm gap at lifter end. Tensioned Chain.
4. Installed pin to lock cam, tightened cam nut.
5. Set up dial gauge, pre-loaded dial on spring retainer and set dial to zero.
6. Rotated crank about 350 degrees and dial starts to move.
7. Continued rotation until dial read 1mm.
8. removed locking pin.
9 rotated crand a couple more degrees to TDC.
10. Re-inserted pin.
11. Torqued cam nut.
Repeat other side. But first rotated Cam to dot down position.
At no time was the lifter loose. No Play at all.
if you look on rennlist you can see what a lifter look like when primed and extended.
02-11-2013, 09:40 PM
#131
Rennlist Member
I for one definitely do not think that the oil pressure issue is a red herring... Even if you're engine was totally quite, if you were only getting 1 bar of pressure, and a low pressure light after 20 minutes, that would be a no no... I bet that if you track down the pressure issue, you'll stop your noise.
02-11-2013, 09:47 PM
#132
Seared
Rennlist Member
Rennlist Member
Herr Vorsicht,
Subscibed, as I'm eager to see what you find.
This thread clearly shows what a wonderful community the 993 board is.
Andreas
Subscibed, as I'm eager to see what you find.
This thread clearly shows what a wonderful community the 993 board is.
Andreas
02-11-2013, 09:47 PM
#133
Burning Brakes
Thread Starter
I for one definitely do not think that the oil pressure issue is a red herring... Even if you're engine was totally quite, if you were only getting 1 bar of pressure, and a low pressure light after 20 minutes, that would be a no no... I bet that if you track down the pressure issue, you'll stop your noise.
Any ideas on HOW to track down the pressure issue? What would cause that light to come on after 20 min?
02-11-2013, 09:51 PM
#134
Burning Brakes
Thread Starter
02-11-2013, 10:26 PM
#135
Rennlist Member
Peter, until you have good oil pressure I would not high rev the engine as suggested. If the posters who follow this theory are willing to pay for and rebuild your engine then go for it. Turning the engine over without it firing should still build reasonable oil pressure.