That's frustrating. Same thing happen to me 2 years ago. We took out the engine from mtlsp (a member here) and got it to a Porsche specialist for a rods replacement...This guy do mostly air cooled engines. After we reinstall the engine we had cam sensor fault ;-( Later we found out he made a mistake timing the cams.... Strange because I ask him at the beginning if he had the plates to time the cams and he show me the exact Porsche tool!!!!

 

if you make an investment into plates, buy the OEM ones and not the Baum ones. they are a bit more.

 

Ok, after thinking about it for a while this morning I believe the mistake is that we tightened the intake cams at 110 degrees as called for at the fully forward position in the variocam. This must be incorrect, it must be 110 degrees at the fully back or retarded position. I'm positive that they were set properly at their respective marks, I inspected them myself with the tools so I don't think it was a mistake of that nature. Here is tim's thread of him setting fixed GT3 cams (no vario) and he sets his intakes at 110.

https://www.6speedonline.com/forums/...your-cams.html

I assume for a top end power car like his he would want them set at the retarded timing position to optimise his cylinder scavaging at high rpm. I set mine fully forward here, which (correct me if I'm wrong) leaves me with severely retarded timing (full retard! you never go full retard!). This would leave my intake valves hanging open a bit while the piston is ascending on the compression stroke and would likely cause my overboost issue. I am going to pull the motor and have my shop reset my intake cams, they already said they would re do them if they were wrong. They were acting on information from Jake Raby who is a well respected builder. He told them full forward but I think he was thinking in terms of using the timing plates which uses a full forward position, that must be the source of the confusion.

 

If the cams were way off wouldn't we have a crappy running engine at best and mechanical interference at worse? Is it possible to install these 180 degrees out the wrong way?

 

With the dials you can set the camsat 110 with the vario full forward or full back and it is not obvious what you should do. We picked the wrong way. When my car is at low rpm or idle the the cams are fully advanced for low rpm power and emissions. During this low rpm operation my cams sit where they should be when at high rpm. The GT3 without variocam runs in this position full time. When I ramp up the power the variocam moves the intake timing back farther than it should go causing my pistons to push air out of the intake valve if my theory is right.

 

Well I'm not going to buy the plates now that I know how we screwed up. I'll use the stomski again and this mistake wont cost me much.

 

You have gone from outsourcing timing in the beginning to now learning enough from your mistakes and doing it yourself to be a pro. Good for you! It is easy for some of the other keyboard experts here to fret too much about doing their own build and just throw money for someone else to do it. But to face the risk and learn like this is real.

 

Tôi đoán không có gì ngoài thành công của bạn

 

Did a bit more research. Looking back at the Stomski video he sets the intake cam right in the middle of the variocam play at around 112, which is a common setting for GT3s. It looks like this is what I was supposed to do at 110, rather than having the cams fully forward of the variocam play. I can't believe I didn't catch this earlier, I should have been more careful. I am going to use this picture of the plates as a reference for when they are set.

 

Looks like I am off by 15 degrees. Not sure how this affects where I need to set them. 15 degrees advanced and I am on?

 

I just read that the variocam can swing 30 degrees. Since I am 15 degrees off that confirms the cams should be set at 110 degrees right in the middle of the variocam range.

 

I just got off the phone with Stomski. He says he doesn't touch the sprockets in the video, so that would indicate that the cams are set at 110 in the back of the variocam range. My parts will be here on the 1st of next month so I will see how things look.

 

Just finished reading this whole thing. I'm a little bummed you never finished the story. What happened?

 

I pulled the engine early last year to re do the timing. I compression tested it and checked things over. I found one cylinder to have 20% leak down while the others were perfect. I let it sit while I thought about what to do about it. I'm pretty bad about finishing stuff when I get sick of it, so I wasted 2018. I'm back at it now, I pulled off the weak cylinder and found the two piston rings to be lined up. I read that this can cause you to have low comp temporarily, but I'm not sure if the rings just didn't seat properly. They cyl and piston are in good condition. I decided to re ring that cylinder as the pros on Pelicanparts do this when they rebuild nikasil lined Porsches. They just put new rings in the old cyl if it is in good shape, just clean up the cross hatches with scotch brite, no re hone. I'm putting it back together now and should have it done in a few weeks. This is taking me way too long, I know.

 

Don't sweat it man. It's easy to get discouraged, but you did some pretty amazing work on this. I wish I had the ***** to try. I think I may buy something cheaper to build, and someday work my way up to something like this. Wish I had an expert nearby...