Not to prove you wrong, but LSA DEFINETLY applies if you're trying to calculate DCR based on rod length, adversized duration, and LSA

How else would you calculate it if you didn't know the IVC @ ABDC?

I was kind of skeptical of the correct value of IVC since he made the typo, so I was going to use the other values of rod length, adv dur, and LSA

Mike

 

There are some good suggestions in this thread on how to advance/retard the cam without messing with the programming due to the optispark:

http://web.camaross.com/forums/showt...ght=retard+cam

Like I said before, though.... I doubt it has anything to do with detonation problems due to high SCR/DCR. I was running 11.8:1/8.5:1 on 93 in 95* weather/100% humidity with minimal knock retard.

I'd check things like optispark failure, cam installation errors, etc, before I went that route.

Mike

 

check install first. it sounds similar to my problem, way down on power and detonating like crazy. my timing chain was off by a tooth on the crank gear. got that fixed and the car ran great after that.

 

I think I will have to check into this, and if I find nothing wrong here I think I will try to retard the cam a few deg. Worst case is I find out nothing and I'm out a few gaskets...

Also I was reading a bit about how to degree the cam, and was wondering what options there are if the cam, crank, or the timing-set off? I wouldn't think you would want to mess with the crank key. And can you even do this with the heads on? (Not knowing exactly where the piston is) Unfortunatly this is a step I did not do when I put err back together

 

Ya should be able to set the cam ya have dot to dot with NO problem. The .50 something quinch ain't helping either. I am running 12.98 static on pump gas and no rattle with a 9.2 DCR so no way for your set up to rattle on account of DCR(unless ya running 86 octane)--- look somewhere else.

 

IMO ya can't move the cam in an opti engine with a offset key,offset bushing or multiple keway sprockets.
If your intake centerline is off it means the drive pin or bolt pattern was not installed(made) in the proper location--ie.Ground on a 112*LSA and installed on a 108*ICL means the cam has 4* advance in as to drive pin location and bolt pattern. If the ICL isn't 108* as the card says ya need to send it back and get the cam that matches what ya want. End of story-------
OBTW degreeing a cam is just a check to see where the cam is located. Altering the cam ICL is another operation and that's all ya can alter on a cam(but not on an opti engine) the rest is made that way and has to be remade to change anything.Same as bolt pattern and drive pin location on an opti engine.

 

you are only running the hot cam so nothing fancy really has to be done. if i were you just check the timing chain. maybe it was a little too taugt on one side and skipped a tooth, or you just put it together in a hurry and didn't pay perfect attention. when you take the crank pull and then its little balancer 3 pronged thingie you will see its "keyed" it has like a dot. just line the dots up. put a bolt with some washers in there and turn it over with your wrench

i think that might be what it is. i was a tooth off on the crank, so 16 degrees. thing detonated horrible and sounded like some really loud weird thing. it also made no power (with tooth off it dynoed at like 220rwhp with 6 of its cylinders as some of my injectors weren't plugged all the way in) and at higher rpms the a/f ratio was unsafe. and make sure the injectors are all the way "clicked" in and that they didn't work themself out or anything

 

From everything I have heard, it sounds like I have a few things I could do.

1) Pull the heads an throw on thinner gaskets to get my quenched distance down to .041". (Although that raises DCR everyone seems to think It should run fine) Also noting that this will probably not fix the problem!

2) Pull the timming cover and degree the cam to verify that it was manufactured correctly, and installed properly.

3) Put a set of headers on it. (Needs done but probably not the issue!)

4) What about running a colder plug? (Probably just a waste of money?)

5) Pray that I will find something wrong with this setup, so I can get past this...


Thanks For all your help

 

1--Yes
2-yes, don't have to degree just make sure it's dot to dot.If ya have a name brand chain and sprocket set chances are it's OK,but won't hurt.
3- yes but not necessary to get to run right,just run better.
4-No help
5-AMEN

 

i think its the timing chain install. your symptoms are exactly what i had.

 

I agree with the above post.

Sorry, but I believe it is installer error. ALWAYS check, verify, and check again the basics.

 

It very well could be but when I installed it I remember checking that the marks were in-line and the crank sproket was straight up... I just didn't bother to degree it becuase it was a standard off the shelf cam.

Hopefully I will find that this is the problem though. (Kinda agervating paying for a car you don't drive)

 

Yeah I know that feeling, but mine was because of insurance issues. Out of the 5 years I paid on my TA, it spent 3 of them in a garage, "resting". Meanwhile I paid $300/mo. for her, and kept basic comprehensive on it which was like another $60/mo. That sucked @ss but hey, at the rate I was going I would have either ended up in jail or dead. As much fun as beating the crap out of these cars is,.....ya forget that they're not just toys, and alcohol and fast cars dont mix, unless you're talking funny cars. I like to think someone was looking out for me, and it was all fate. Anyways, hope ya get yer **** straightened out, it does sound like you have the cam timing off to me. Maybe you got the wrong cam, or it was mispackaged, it does happen.

 

I agree about the timing chain. My engine builder was putting together an engine late one night because the guy needed it the next day. They installed the engine and they couldn't get it to run at all. The tore it down and there was a flaw in the finish of the cam gear of the timing chain set that looked like the dot you were supposed to line it up with. They put it to the correct dot and it fired right up and ran great.

 

To bring this post back... I finally got the cam degreed. Here is what I found from the number one cylinder...

INTAKE

Lobe Lift 0.328 in
Lobe_CL 109
Open @ .006 Lift 31 BTDC
Open @ .050 Lift 5.5 BTDC
Close @ .006 Lift 69 ABDC
Close @ .050 Lift 43 ABDC

Dur. @ .006 Lift 280
Dur. @ .050 Lift 228.5

EXHUAST

Lobe Lift 0.328 in
Lobe_CL 115
Open @ .006 Lift 77 BBDC
Open @ .050 Lift 53 BBDC
Close @ .006 Lift 31 ATDC
Close @ .050 Lift 3.5 ATDC

Dur. @ .006 Lift 288
Dur. @ .050 Lift 236.5

CAM CARD

Int/Exh
Lobe Lift 0.328 0.328
Lobe_CL 109/ 115
Open @ .006 Lift 27 BTDC/ 75.5 BBDC
Open @ .050 Lift .5 BTDC/49 BBDC
Close @ .006 Lift 65 ABDC/25.5 ATDC
Close @ .050 Lift 38.5 ABDC/1 ATDC

Dur. @ .006 Lift 272 281
Dur. @ .050 Lift 219 228

Someone may have to check my math. (I think it's correct though) If you notice the advertised duration on the cam card and what I found is up to 10 deg off. Also when I took the intake off I noticed that the intake runners were pretty black where exhaust gases have been. (Is this normal for the hot cam?) Maybe I'm jumping to conclusions here a bit early, but I don't think that these numbers are anywhere close to the hot cam numbers... Also when you calculate the Exh_CL Using both lift values, it is 113 using the .006 lift duration and it is 115 using the .050 duration values. I still need to check the other 7 cylinders, but does anyone else see this as being my problem?

To recap!
Int. Dur (.006/.050) 272/219 ----- Actual 280/228.5
Exh. Dur (.006/.050) 281/228 ----- Actual 288/236.5

Any coments/corrections are welcome!