JCan

Video is at the below link. http://http://youtu.be/rc-TE_wGupM

BAD NEWS! I added a thicker head gasket and the noise continued. Therefore I believe the noise is coming from the head and specifically from the valve train somewhere. I took a video and appreciate your ideas as to what to do next. (noting I have a backup N42 head, but I would prefer to use my completely rebuilt P90 head) Here is what I know. I believe the noise is related to only one piston and not all 6 The sound comes from the valve cover, I removed the cover using my hands when it was running (oil leaking everywhere) and the noise was not attenuated Cam - Isky My plans are as follows: Wait till sunday, then regap the intake/output valves to 0.006/0.008 intake/Output and re-run the engine. On monday, I plan to call Isky cams and ask them for ideas. If isky has no ideas, I plan to swap out the existing cam for the old cam inside the N42 head. If that does not solve the problem, then I plan to remove the head I spent so much money on and re-install the N42 head. Attached is a video of the noise. Thanks for your advice. Jim

Tuff Z - So close! Now we live in on opposite side of the country. Near misses don't count! either way, I'm sure your kids are having fun in their Z. It is a great fun car to drive. JSM. I expect fender benders. Reasoning comes from the frontal lobe in the brain and it starts developing at 6 years old and does not stop till around 24 yrs old. Best of luck!

I read your blog. You really did a nice job! I especially liked your box of newly sandblasted and plated 40 year screws and bolts. So many questions. I have 3 kids, my first two (girls) both crashed their car when they were in HS and are now off to college. This is my son's car.... did Jade last through hs without any collisions? I expect brian (my son) to get in a fender bender or two. I have to take this position now to prepare. Either way, Jade looks great. We make memories and I'm siure your rebuild with your kids is a great memory. One last thing. My wife grew up in Greece near you her maden name was Lamberty and her dad worked at kodak. A long time ago. Thanks for the encouragement. Jim

Next steps we temperarily installed the dash and checked out the electrical connections using the harness, This took 3-5 days and answered several questions I had as to how to properly connect things up. We were even able to get the intermittent wipers to work! (however we have a problem with the park location which I hope is an adjustment located ontop of the wiper motor).. We next removed the dash, insulated the firewall, installed petals, heater and fan, and reinstalled the dash. Lastly we installed an exhaust system (used themotorsport package, I think it hangs too low and will mostlikely add a flange and have the exhaust modified as it hangs too low at the 2-1 pipe under the car (we have a 6-2-1 headers). The car started up easily, however thre was a tapping, that I am debugging now (another thread) Added rims and took pictures.

time for an update. We got the car back from the body shop on thanksgiving!. The body is beautiful. (pictures below). First came installing the wiring harnesses (front and rear) Then the undercarrage, cleaned up gas lines (3), ran new break lines, checked rear bearings and re-torqued suspension (just to be sure), installed breaks, gas tank, pump in rear, and vent lines. Last was the rear end and half shafts. Just before xmas we mated the engine to the transmission and installed it.

time for an update. We got the car back from the body shop on thanksgiving!. The body is beautiful. (pictures below). First came installing the wiring harnesses (front and rear) Then the undercarrage

Josh. No. I pulled the plugs and measured compression. My compression was 230psi at #6 down to 190ps1 at #1 The compression seemed to drop evenly as I moved from #6 to #1 (making me think the reason for the difference was that the car was not level and #6 got more oil than #1). During this measurement. There was no sign or sound of any tapping. The tapping did sound like a loud valve but only on one cylinder. FYI the new head gasket is in fedex now. Hope to have an update fri eve. Thanks for your good idea. Jim

Wiki D - Are you going to make me say it.... (sweating...). Ok. I looked up my cam angles and found to my surprise...on my mild + cam the intake starts opening a full 62 degrees prior to the exhaust valve closing. Madness!! I guess that the piston only moves +/- 14% of its vertical distance (cosine of the angle of -31deg to 31 deg) as the crankshaft moves from the exhaust stroke to the intake stroke. I am also guessing that momentum is the primary force at work during this time at higher RPMs. This fogs my perception of the difference between a medium cam and a mild cam. As I look at progressively more agressive cams I notice that the duration increases only by 8-10 degrees with each step and now I believe the only reason for the additional timing (overlap) is to accomodate for larger and larger valve lift as cams get more agressive. I guess one must close a valve and there is probably a maximum valve closing rate (thus causing the valve duration to increase) My perception of reality has been shattered... I'll never be the same!

With me holding the cover up by 1 inch and moving it around the Noise stayed the same. thanks

Wiki D - You know, next time I have my front cover off, I'll take the time to accurately measure and build one that more accurately fits in the space. When I do it I will add the exact dimensions to this site. Mr Obvious... I also like the screwdriver idea, but since I have no experience with it I didnt want to risk the new tensioner spring slipping out of it's socket and my having to pull the front cover... I've done enough rework on the engine. (hate rework) Thanks! Jim

What a mess that was! I unscrewed the rocker arm cover with the engine running and lifted it up. No the noise did not stop and yes I needed a beach towel to mop up the oil mess under the car. Needless to say, that was not the problem. Thanks for your suggestion. Jim

Okay. Lots of things to consider. I am not sure of the history of the motor or the car as I just purchased the car from a guy who had it on a farm in stockton for 11 years.... Background. I tried to be careful in measuring clearances during engine re-assembly (see below picture of excel spreadsheet). On my setup, the piston rises above the deck by 0.025" and with a 0.049" gasket this leaves 0.024" of gap between the top of the piston and the head. the first spreadsheet shows my measurements and calculations during initial assembly. The second spreadsheet shows what I will have after I install the custom head gasket (0.063"). You comment is accurate. I may be barking up the wrong tree! My brother thinks the problem is with the cam and lashpads. I know I can repeat the noise (not as loud) if I tap the rocker arm onto its lash pad (when not engaged with the cam). Regarding timing. I think I timed the engine correctly, but how can having the timing cause a loud tapping noise each time the engine turns a revolution? I will certainly recheck my timing. Regarding rocker arm cam. I took the head to the guys that built it and they said it looked ok. Their suggestion was to call isky and talk to them regarding the geometry. Again, I will report my findings this weekend when I install the new head gasket and completely eliminate the piston to head clearance as being a problem. Brian (my son) and I are looking forward to show the car at the motorsport west coast show. Thanks Jim

I am not sure that the piston to head gap is the problem I am having (see quote from Braap below). However it is the best idea I have. See quoted text below. Jim

Hello. I know most of you have a chain wedge, however I found myself needing one and could not find the dimensions on the web easily, so I thought I would remedy the situation. I built my timing chain wedge out of hard wood I had laying around my garage. I installed it using the straight side along the drivers side of the motor. Check out the pictures and dimensions are provided below. Enjoy and good luck! Jim

Guys. Thanks for your feedback. I think we are on the right track getting a custom gasket which would ensure my piston to head gap is 0.035". As soon as I get the new gasket and install it, I'll write up my results. thanks again Jim

NewZed When I removed my head, I used the compressed gasket (The thickness was 0.050" as measured with calipers). I used a metal straight edge and spanned it across the gasket/piston such that the edge was down and the flat part was perpendicular to the piston surface. then I slipped a feeler gauge between the piston and the straight edge. FYI - Jim

Alright... bad idea. Of course there is no way I can add an extra 1.25mm under the head without stretching the new timing chain and chain guides.... I tried! Regroup! New plan. I am going to purchase a custom head gasket which is 1.6mm (old gasket 1.2mm). This should give me a piston to head gap of 0.035" (sorry for mixing units) instead of my current 0.024". I found a shop close to me (Pasadena CA) Gasket Works USA LLC. Unfortunately, I will have to wait a week for the new gasket. Thanks for your support I really appreciate it. Jim

Okay. I am reassembling the engine now with two head gaskets 2.4mm and will start the engine. If it rattles, I will take video and audio. I will also take more pictures. Guys thanks! I really appreciate the help!!! Jim

John. - I think it is one per revolution. Update. I made a mistake! When I was cleaning the head with acetone I noticed a very small collision in cylinder no 3 (pictures below) It looks like a very small piece of sand was on the piston and crashed into the head and made a divot. I have decided to place two head gaskets on top of each other and reassemble the engine and start it to see if the rattle goes away. If it does, it means that my clearance between piston and head is too close. If it does not, then the problem is probably the cam/rocker arm/ lashpad area.

John. - I think it is one per revolution. Update. I made a mistake! When I was cleaning the head with acetone I noticed a very small collision in cylinder no 3 (pictures below) It looks like a very small piece of sand was on the piston and crashed into the head and made a divot. I have decided to place two head gaskets on top of each other and reassemble the engine and start it to see if the rattle goes away. If it does, it means that my clearance between piston and head is too close. If it does not, then the problem is probably the cam/rocker arm/ lashpad area.

update. I removed the head and have the following update. Good news - there are no signs of the valves crashing into the pistons and there is no evidence the pistons are hitting the head. I was able to take some measurements. Using a metal straight edge and a feeler gauge. I am measuring a piston to head clearance of 0.023. My previous measurements (using a different head gasket) during assembly measured 0.027 inch. Next steps. Take the head back to valley head service and have them determine if they can find a problem with the valve train. If they say it is ok then the only option I have is to assume the pistons are hitting the head and increase the gasket thickness from 0.050 to 0.070. I took a stethescope and put it on the valve cover, it was loud. When I put it on the head below the valve cover, it was much quieter. I am stumped. Thanks for your inputs. Jim

I used a screwdriver as a stethescope and the noise is metal against metal. Thanks for the input!

When I was a kid, my brother and I ended up assembling a 2.8L motor and inadvertantly dropped a washer in #6 cylinder. It made a very loud noise. This sounds more like a really bad valve job to me, however when I turn over the motor using the starter with no spark plugs, the valve train seems to work perfectly with no noises... Tomorrow I take off the head. Thanks for your support Jim