- This topic has 8 replies, 4 voices, and was last updated 10 years, 2 months ago by .
-
Topic
-
I have a very very strange problem with my Saab 9-3 Aero. I will try to explain…
Engine is 2.0 turbo 16V, stock 205 Hp, it has the following mods done:
-Stage 2 tune to 260 Hp/380Nm (this map is on the car for about 2+ years now.)
Stock boost is 0,8 bar, now it is on 1,1 bar.
-3″ custom downpipe with stock cat modified to 3″ (this DP is on the car for about a year)
-Forge diverter valve + silicone vacuum hoses(1 year on the car)
-Intake muffler removedWell the problem that first happended about 2 months ago is that car bends a single exhaust valve…
First time it happened:
I floored it in first gear and shifted to second at around 4000-4500 rpm range…As soon as i shifted to second i heard a noise and the car started to run on 3 cylinders. We took everything apart and there was only one bent valve on cyl number 2. That valve was replaced + hydraulic lifter.
At that time it was also checked that timming chain is OK, tensoiner is OK, camshafts are OK, timming is spot on, head was never lowered…
Engine was put back togheter and i drove it for about two months but never really floored it properly since because i had a strange feeling it would happen again…
Well two weeks ago i wanted to show a friend how a saab goes and guess what! In third gear at around 5000-5500 rpm range the same noise happned and car once again ran on 3 cylinders!
Engine was taken apart AGAIN and this time its one bent exhaust valve on cyl number 3…
I am clueless… Only thing i can think off are weak valve springs or only a single weak spring that was mixed by my mechanic and put on cly 3 this time…
I ordered a set of valve springs and i just sent one new and one old(taken from bent valve) to testing to see if there is any difference in tension between them.
There are no harder or stronger valve springs for these cars on the market, they use stock springs in racing aplication saabs that have a redline at 7000 rpm or more… Stock redline is around 6200 rpm, i never ever run it to the redline because boost droops rapidly after 5000 rpm and it pulls better if you just shift it in the next gear. I ve been with this car on the track two times before and had no problems with it at that time and same mods.
Any suggestions, ideas? I can’t find similiar problem anywhere on the net, no mechanic i ask have a clue or heard of anything like this…
Thanks.
- You must be logged in to reply to this topic.