sr cam timing messed up?

[gameeffect]

so i have recently build my head 272 bc cams, springs retainers and a 1.1 head gasket. I pulled the head off when it was at TDC did everything like the books say. I put it in with the cam lobes facing out 10,12 and the 5, 20, 8 chain count. I was able to start the car it ran fine until i started to tune it. My compression is really low 80. I checked the piston rings by putting a little oil in and it read the same compression rate. SO im thinking my cams are not aligned right or my valves are sticking open or something.

It sucks i have to be at asb at the end of the week and my shit is not running. Any help would be cool.

oh my normal user name is MRBELLS

[HalveBlue]

The most common problem with setting timing is aligning the CAS correctly. Follow the procedure in the book and make sure the mating marks on the CAS are alligned correctly. Best way to do it is with the valve cover off. It's annoying as fuck but it'll allow you to make sure the marks are set correctly.

Also, I have found that when I set the timing with the timing gun, DON'T use the loop on the back of the coil pack harness, contrary to what the FSM says to do. I've found that doing so will not set the timing correctly resulting in a loss of power and all sorts of bogging issues. Connect the gun to the wires running from the #1 coil pack instead.

Good Luck!

EDIT: Oh yeah, this applies to S13 SR's. I haven't worked on an S14 SR so I don't know if the above information applies.

[SoguRacing]

i'm sure that setting the timing on the s13 is the same as the s14 SR. As for the compression.. you do have more valve over lap due to bigger cams but i wouldn't think that compression would be 80 but it would definitely be lower. also take into consideration the size of your head gasket. both of these will lower overall compression.

[mrbells]

I know i was going to have lower compression i just didnt think that low. Anybody else have same set up? whats your compression?

as far as the timing goes on the CAS i know about the marks and all that.

also when i was running my car the vacume was really low too like 10. So thats why i figured i had the cams like a tooth off. I checked and its good. Well see what happens tomorrow im going to mess around with it some more.
Thanks

[SoguRacing]

well the sr is a lower compression engine. and you have a thicker headgasket, huge cams so i wouldn't worry.

[mrbells]

what about the vacume then... All my lines are good i checked with the soapy water. At first my intercooler was leaking so i tossed it, and put a solid pipe to just bring the vacume up make it run at least but nothing.

[HalveBlue]

80 psi is like half of what your supposed to be running.

I really doubt that the upgrades you would lower compression that much.

[mrbells]

ya thats what im thinking im going to check the cam alignment again. Hopefully i figure it out soon

[mjjstang]

bc cams have been known to be some degrees off. A lot of guys run gears to adjust for the sloppy manufacturing. as a hypocrite, I myself bought a set of bc's today on ebay since msn is running the 20 percent off deal. I have had enough trouble with timing before when I was simply cleaning the rust off my original set of cams, so I know now to spend the most time of the swap making sure that everything is absolutely the same as it came out. I hope I dont have this issue, since I will not be purchasing gears, they are a pain in the ass and I dont like bolts backing out.

[aNskY]

Also, I have found that when I set the timing with the timing gun, DON'T use the loop on the back of the coil pack harness, contrary to what the FSM says to do. I've found that doing so will not set the timing correctly resulting in a loss of power and all sorts of bogging issues. Connect the gun to the wires running from the #1 coil pack instead.




If you trace the loop at the back of the harness, you'll notice that it IS the signal from #1. I think your issues were unrelated.

[fliprayzin240sx]

80 PSI is too damn low even with the overlap. If you used the chain marks to line up the cam gears, how sure are you that the chain marks are dependable? If the chain have skipped, then the chain marks would be off.

Maybe you can use this picture as a reference and count some chains to make sure...
http://www.roastedpavement.com/assemble2/15.jpg

[aNskY]

would the car even run @ 80psi compression? maybe your compression tester is f'd?

[mrbells]

the car ran and runs on 80psi i guess, could be a possiblility my compressoin tester is messed up (lets hope so and have my compressoin be 140). MY cams marks look like the ones in the picture, i just dont have the dark (or silver) links on the dots so i will do that tomorrow see if that makes a difference lets hope it does

[fliprayzin240sx]

Make sure the engines back on TDC, exhaust cam dowel pin at 12 oclock, then count the links and make sure there are 10 full chains between the exhaust and the intake cam. The cam gear teeth by the dot should be in the middle of the chain...
http://www.frsport.com/writeups/poncams/poncam_2b.jpg
Then count 10 chain links...
http://www.frsport.com/writeups/poncams/poncam_10.jpg

[aNskY]

well the marks only line up @ tdc on compression stroke, as long as you lined up all 3 dots when you installed the chain you should be good.