Timing vs Turbo Spool

schaef_12

schaef_12

Diesel Junkie
Joined
Oct 30, 2007
Messages
248
Ok, I just installed a PDP ported and polished fireringed head valve work and yadda yadda, along with a Helix II cam. When I pulled the vehicle into the shop, it ran great, spooled the turbo (SPS 62) well and pulled hard.

Long story short, after the install the thing is an absolute dog. Turbo will not light until 2000 rpm and only pulls 30 some lbs of boost because I run out of rpm with the 3k gsk. The only other thing that was changed was the lift pump (but there is plenty of fuel), and the timing. Timing was recommended to be set at .241 inches of lift (I don't have a metric dial indicator). Can anyone tell me how much lift (mm) and what degree of timing .241 in is? I wanted it set at 15.5 but I am afraid its much higher than that.

Also, its kind cold outside (30*) and it smokes blue at Idle and the exhaust burns your eyes.

Edit: 1998 Manual Trans, 75hp injectors, 100 plate full forward Gutted afc.

Any help is appreciated
Thanks
Corey
 
U are at 6.12mm=Roughly 18.5 degrees. To get where u want it u need to be at .217=5.5118mm 15.5 degrees.
Brandon
 
You're not seeing as much boost because of the ported/polished head and the cam. When you changed that stuff you basically opened up the airway of your engine. Boost is an indication of the engine's inability to pass the air being fed to it by the turbo. Now with the head being opened up and the cam allowing more air to pass through, it's not building up pressure any more (boost).
 
im curious as to why the turbo wont spool as hard. shouldnt it help spool as theres more exhaust air hitting the compressr wheel
 
It's probably spinning just as fast as at always did, if not faster. It's just not building any boost pressure because there isn't as much restriction anymore. Probably time to put more fuel to it. Slide the pate forward, tweak the AFC spring to allow the rack to move under less pressure.
 
Smokem said:
Do you see a boost increase from 2000RPM to 2500RPM?
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Yes, but I didn't really pay close attention to how much or how fast

PRattenbury said:
It's probably spinning just as fast as at always did, if not faster. It's just not building any boost pressure because there isn't as much restriction anymore. Probably time to put more fuel to it. Slide the pate forward, tweak the AFC spring to allow the rack to move under less pressure.
Click to expand...

I just got back from a good 30-40 mile drive and I think you are exactly right. It just starts to pulling hard, cleans up the exhaust then levels out. I am starting to think 75hp injectors and bigger turbo's do not get along real well. Guess I'll order some DDP4's on Monday.
 
Yes the cam was set on the correct centerline. I dont think it is a 24v grind?? I was going to say it has the lobe for the lift pump but I guess all the Helix cams do?
 
definately get some good injectors... DDP4's are the cleanest, best spooling injectors I've run. I just replaced mine with stock injectors, and the truck smokes more and doesn't spool up as good.

an improper cam grind or improper installation can make the truck a serious dog!

it might be that everything is right, and you're not getting that "smack" of hard boost coming on after lagging... IE, the truck is actually pulling better down low and you're not getting that hit when the turbo finally comes on
 
Does that mean the keyway on the cam was not in the right spot, but the timing marks where still lined up on the cam and crank?
 
Forrest Nearing said:
definately get some good injectors... DDP4's are the cleanest, best spooling injectors I've run. I just replaced mine with stock injectors, and the truck smokes more and doesn't spool up as good.

an improper cam grind or improper installation can make the truck a serious dog!

it might be that everything is right, and you're not getting that "smack" of hard boost coming on after lagging... IE, the truck is actually pulling better down low and you're not getting that hit when the turbo finally comes on
Click to expand...

That's the main thing it's lacking, it doesn't hit hard. But so many things changed at once that its hard to pinpoint to what it is. Its very smokey on the bottom end and very clean on the top. Once it hits around 30 psi it just levels out and quits pulling. Before it would keep pulling, but I have never had any experience with an aftermarket cam or ported head so it may be normal. More smooth. Guess I'll add more fuel :rockwoot:
 
Only fueling changes made was a new lift pump.

Ported polished, 5 angle valve job, and Timing were the only things changed.

The motor sounds fine

I lined the marks up on the crank and cam gear. Also the timing pin in the case lined up with the cam gear. Keyway was at 12 o'clock. What are the chances it is a 24v grind? How do I tell?
 
schaef_12 said:
Yes, but I didn't really pay close attention to how much or how fast



I just got back from a good 30-40 mile drive and I think you are exactly right. It just starts to pulling hard, cleans up the exhaust then levels out. I am starting to think 75hp injectors and bigger turbo's do not get along real well. Guess I'll order some DDP4's on Monday.
Click to expand...

That's a good pick for injectors. I had them with a PS-62 and a 215 pump. Worked nice. You might want to get a different GSK. 3k isn't gonna do it for you.
 
I just used the pin as a reference, the head was off when I put the cam in it.
 
Smokem said:
I had a similiar issue with a camshaft that the cam gear was installed 5° retarded from stock centerline.
Click to expand...

I did this because I was told it would work better....epic failure, and it sounded just fine too.

Jim
 
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