4 Degree Offset Key Install Questions

[AJT944]

I've got my 4 degree offset key for my 8V NA 944, and hoping to install it in the coming weeks. Also purchased a 10mm 12point tool as well. I understand the basic procedure, but my question is around getting the timing belt off to pull the cam gear off. Is it possible to not remove the balance belt, just un-tension the timing belt, and slide it off to remove the cam gear, install the key, put back on the cam gear and then slide the belt back on? The previous owner already did a belt and water pump change, so I don't need to get too in depth into replacing those things. Any photos or help here would be greatly appreciated.

Thanks,

[wildcat077]

Post your question in the Rennlist 944 section , i'm sure Spencer ( V2Rocket ) can chime in and give you the best advice !

[AJT944]

Thanks - Yeah, I was hoping that guy would chime in. I posted there as well. His name always comes up when I try to search these things.

[Monkey Wrench]

i'd post the car's date as well as 8 valve. mine is early 85 and I believe it is adjusted with eccentric bolt(s) I think ones made later than mine may have a spring loaded tensioner. 16 Valve cars are all different again. Someone else will know these details better.

[AJT944]

Good call. It's a 1986.

[TibetanT]

Hello there
I would not do this

You will need to lock the flywheel and set your cam gear at TDC .Then loosen your balance shaft belt and go through the entire procedure described in Clarks
Garage for a belt change.

Hope this helps

[Monkey Wrench]

can't argue about following the correct procedure as per the shop manual.

outside that, I think if you just make sure you don't change the relationship between any belt teeth and the belt, for example set the engine to TDC, find the marks as described in the manual and then use three different colors of paint pen to carefully mark the belt tooth and corresponding pulley divot then you should be back to the same timing. That pulley could be perhaps mistakenly flipped but otherwise it is keyed , the others probably do not need to come off. it sounds like you mainly need to remove the belt to get the toothed pulley off to change the key, then put it back together without changing any timing.

if the manual refers to marks on the belt, I'd check if they are still present. If you have lost the original belt markings then don't pull the belt off until you have new marks.
If the belt is a year or two old it might be worth putting a new one. Im not sure about the difference but for mine a new gates belt is only about 30 bucks or so. might as well renew it if it's cheap? I did see "racing belts" for around 100 dollars too. I consider Gates to be Ok quality, not the best or worst. some may spring for OEM or the racing quality level of belt because it is so important that it never fails.


when done yes you should recheck the timing as per the manual, I just think it may help to use marks so as not to get things further confused than necessary.
you now that making a mistake in the timing can cause a lot of damage so this is very important. I would also turn the engine over by hand with the plugs out just as a final check that it isn't interfering.

whether or not you really need the thousand dollar or so tension guage to tension the belt or if reasonable judgement is ok , That's hard to say, You might get differing opinions. Best to use the right tool if you have access and the procedure will describe that.

sometimes I work on machines and there is no real procedure and timing is critical on toothed belts. one trick is to put a little clamp on the pulley to prevent the belt from lifting out of the teeth it was in. you know if you haven't removed the belt from the pulley and it hasn't shifted then it's still in the same tooth.

Im not sure if the shape of the pulleys supports it but can you leave the belts on other than the timing belt where it drives the cam and clamp the other pulley and belt locations in place with a small C clamp or similar? maybe you can sneak the belt off the cam pulley enough to remove the pulley without changing any other timing, then change the key and put the belt back on without opening any other cans of worms?

sometimes if I renew the belt I will then transfer the paint pen marks from the old belt to the new belt, with care.

point is , if you dont loose the position you should be able to keep things right, but I'd still verify per the manual, It just helps to start in the right tooth and avoid confusion rather than pulling the belt off without marking anything and then sorting out the subsequent confusion.

as you pull the belt off there may be weight or tension from the valves that wants to shift the position. The manual may refer to removing the starter and using the special flywheel lock tool.
If you have others in the area it might be good to share these tools , best to have them, Likely some have found improvised ways in the absence of access the right tools. some will twist belts and use that to judge tension but this experience is hard to write into a manual so the factory finds ways to make them hard to misinterpret. More accurate to use the tensioning tool than just an experienced twist of the belt and good judgement. As things warm up and stretch and normalize it might change a little and the tension may be different if the engine is at operating temp as compared to cold.

with my volvo , it has a spring loaded tensioner, you loosen a bolt an it applies the right tension then lock it again. after break in you are supposed to loosen that bolt again so the spring applies the pressure a second time, that's because of stretch. once that bolt is tight the spring does nothing as the idler/ tensioner isn't able to move.
This car uses a different system but if the belt stretches over it's break in, it makes sense that a recheck may not be a bad idea. The Volvo however will roll to a stop if you break the belt , whereas it can kill a Porsche engine and ruin your day because this is an interference engine.

if you had a mechanic do a belt swap, would the mechanic ask you to run the car 500 miles and bring it back to retension? It may be set with stretch in mind and not intended to be rechecked to prevent owners needing to return their car to the dealership after a run in. If you are doing the work it's time, not money, to do a recheck.

[OK-944]

...just make sure that when you get to the point of loosening that central bolt (can be very difficult to remove), you firmly support the surrounding nut with a wrench set against something solid on the engine...to prevent any excess movement of the camshaft during this procedure.

...and I will be very curious to learn about changes in your car's performance with the offset key - so do let us know!

[AJT944]

Thanks for all of the helpful info! I really appreciate it. I think I'm going to dive in and see if it's possible or not. Seems like it's mostly dependent upon the belt tensioner. I'll do my best to document along the way and report back. I'm hoping to do a MAF conversion as well as this 4 degree cam key kit all at once, as well as lighter wheels and tires. I'm sure the car will feel like it has a little more "Go" after all of that. Spent the last year getting it healthy and in good running shape - now it's time for the fun stuff!

[Monkey Wrench]

Id do one, drive it a while, and then do the other , otherwise you dont really know which "upgrade" made the differences.
looking at spec sheet and whatnot are nice but I agree, hearing about your real experiences will be interesting.

from what I learned about it there are different maps to choose from with your new performance chip, so you may want to adjust that . If you know you are doing the offset key then maybe you'd want to play with those choices with the new key installed, otherwise you might be trying to choose the best one over again, after it is installed.

Is changing the cam for one with more duration or more lift another valid street level upgrade?

im not sure if it's just some models, or all of them but there seems to be a timing mark in a little window that you need to locate and it can get rusty. I'd locate the mark and pant it in before you get too far, just so that isn't hampering progress when you have it apart.

sometimes with machinery , they will require a degree wheel to be bolted on and a pointer fashioned. somethign like a scrap of metal band from a lumber bundle might do ok. easy to bend about until it points to the degrees.

I suppose you could do a cylinder leakdown test with one installed and then you might be able to do the same with the new offset key, You might be able to see and record valve opening times by pressurizing cylinders etc.
I'm not sure you will get a lot from that other than it may be interesting. If you just make a printout of a 360 degree compass you can paste that to a piece of round aluminum or similar to fashion one. it need not be super complex, then you might also learn how well the valves are sealing , if any are leaking, etc. Not essential but it might be fun to do, only if that is interesting to you.

I knocked the guts out of a spark plug and stuck a tubeless tire valve inside and that works fine for pressurizing the cylinders, If you chose to do that, you can turn the engine and hear it exhausting and know how many degrees it happens at.

so you are changing the cam sprocket to change the cam by 4 degrees. and some say you can go between 2 and 4

I have to wonder , if the belt were intentionally installed one tooth out, how many degrees would that change equate to? I think the answer would be the number of cogs on the pulley divided by 360. I assume one tooth would be more than 4 degrees. if the pulley had 90 cogs then that would be 4 degrees per cog, but I doubt it has that many, otherwise it would be possible to intentionally install it in the wrong tooth.

I wonder if the 4 degrees is a reference to the number of degrees of change on the "engine" or is it the number of degrees on the "cam"?

the cam goes twice around to every rev of the crank , I think.. unless I'm thinking about it incorrectly..

[AJT944]

Originally Posted by Monkey Wrench

Id do one, drive it a while, and then do the other , otherwise you dont really know which "upgrade" made the differences.
looking at spec sheet and whatnot are nice but I agree, hearing about your real experiences will be interesting.

Is changing the cam for one with more duration or more lift another valid street level upgrade?

No cam change. Just installing the 4 degree offset key on the cam gear to advance it by 4 degrees. Puts the power more in the useable low end range, from what I understand.

[OK-944]

I'd also like a bit more oomph lower down the rpm range - especially seeing as how I rarely go much above 4K rpm's.

Now the question...having read the recent posts about performance chips (the Sawyer in particular), would it be "guilding the lilly" to install one of these chips...in addition to the 4 degree offset? Or would there be some redundancy in this? Or maybe the way the chip is mapped would just serve to cancel out benefits?

Thing is...I'm actually liking my engine as is - but having more on the low end would be nice, so AJT, do chime in to let us know what's what after the install - and in the meantime, good luck!

[AJT944]

Originally Posted by OK-944

I'd also like a bit more oomph lower down the rpm range - especially seeing as how I rarely go much above 4K rpm's.

Now the question...having read the recent posts about performance chips (the Sawyer in particular), would it be "guilding the lilly" to install one of these chips...in addition to the 4 degree offset? Or would there be some redundancy in this? Or maybe the way the chip is mapped would just serve to cancel out benefits?

Thing is...I'm actually liking my engine as is - but having more on the low end would be nice, so AJT, do chime in to let us know what's what after the install - and in the meantime, good luck!

From all of the research I've done and posts I've seen from Josh at Rogue Tuning and V2Rocket (User on this forum), it sounds like the MAF kit with the appropriate chip and the 4 degree key work really well together. I kinda like upgrades like this too, as they aren't too out of place and don't look all that different from an OEM set up. It's like OEM+. I'll for sure report back. I have the 4 degree key already, and the MAF kit and chip show up hopefully soon too.

[AJT944]

Originally Posted by OK-944

I'd also like a bit more oomph lower down the rpm range - especially seeing as how I rarely go much above 4K rpm's.

Now the question...having read the recent posts about performance chips (the Sawyer in particular), would it be "guilding the lilly" to install one of these chips...in addition to the 4 degree offset? Or would there be some redundancy in this? Or maybe the way the chip is mapped would just serve to cancel out benefits?

Thing is...I'm actually liking my engine as is - but having more on the low end would be nice, so AJT, do chime in to let us know what's what after the install - and in the meantime, good luck!

Also - Just to clarify. I'm not doing a performance chip. Just the LR (Former F9T) 28 pin chip that allows the DME to process the MAF. From what I understand, the ARP and Sawyer and LR performance chips only work with an OEM AFM, and do not work with a MAF. I opted for the better airflow and modern-ness of the MAF, and my AFM is pretty worn out anyways. I mostly just want my engine to breath nicely and remain healthy for fun driving.

[Monkey Wrench]

so when the engine was designed they thought about the clearances between valves and pistons, and the timing is important so they clear each other. there would be some room for error for a safety factor but maybe its unlikely that things in there, like clearances change much, perhaps a little due to wear of parts, replacing head gaskets, variations in valve adjustment, head planing etc.

Now the key will advance or retard? all the valve operations. The opening times, closing times will change , the dwell and lift will be the same but the relationship between valves and pistons is being changed. is this all happening sooner? (advanced) or later ( retarded)

the question in my mind is does adding this key cause more risk of the valves and pistons colliding, for example if the belt comes a bit loose and the timing is further offset through lash? is adding that key also changing the margin of safety for the clearance of these parts?

Im wondering if changing the aspect of the original design is actually an improvement. Porsche engineers could have changed that easily, maybe it was just all about fuel economics and passing thresholds, but maybe there is also some degree of "valvetrain collision safety factor" that we are playing around with?

fuel economy we can accept, no big deal , easy to change back. if the trade off is more torque but if it increases engine failure risk, that may be another factor in the consideration.

[v2rocket_aka944]

I always come up on this topic because of how amazing it was on my car...


Advancing the cam will really wake up the car - you will wish you had done it sooner.
It makes the valves open and close sooner relative to the pistons going up/down than the factory setting. Essentially this gets a little more air into the cylinder and keeps it in the cylinder rather than pushing it out as the piston comes up (intake valve closes earlier), so a small bump in effective compression and it makes a nice bump in torque across the range.

There is no tradeoff at the top end, the advanced stock cam makes more power everywhere.

The MAF conversion is a night/day difference in driving responsiveness - I can't compliment it enough.

The only difference between the two runs on this dyno chart below is the red one has the cam advanced 2 degrees - 4 degrees would be even more pronounced.

[v2rocket_aka944]

And this chart below is a summary of 100% stock (blue) vs a Rogue MAF kit (tuned for 91 octane) with the 2* cam advance.

[Monkey Wrench]

I think with mine the chip will be the lesser number of pins as it is an early 85. I have heard mention of an update to make it take the larger chip but Im a bit in the dark with the costs of such a conversion.

changing the cam key sounds pretty straight forward and I have never actually started the car as I want to change a bunch of parts first , mainly the timing belts and fuel related parts, tank has a lot of tar like gunk, may pull the tank. i dont know if 2 or 4 degrees is "best".
Would I be wise to do the cam key and the belts at the same time and start there?

it doesn't seem likely to cause a no start issue but of course I'd rather run the car before messing with E-prom changes. The car was in a no-start state 10 years ago and sat since but it' may just be a DME relay issue , or bad pump or similar. The previous owner is a friend and I know it didn't die of a valve crash.
I thought I'd do the belts , some hoses and stuff, plugs, plug wires, rad flush, brake fluid, fuel pump etc and then try to get it fired up because I dont want to trust the aged timing belt mainly. I ordered lots of parts and I'm ready for nicer weather.

Im thinking it might be ok to do the key ( or adjustable toothed pulley) change along with my new belts since I'll be in there doing the belts , maybe seals, and it could be changed back if there is reason to. At first I thought I better not get ahead of myself, because I know I bought the car with a no start issue and expect some sort of mystery issue. I certainly dont wish to create another no start issue on top of the one I bought it with.

It means opening the same places twice to delay it. Now I'm thinking well others aren't having issue with the cam key, causing any problems for them , that I've heard of.

If I go ahead now I wont have a comparison , just presumably a bit more torque from the get-go. I dont see it as worthwhile to do it twice just to get to feel the comparison.

You guys should be in sales ;-)

[v2rocket_aka944]

may as well do the key while doing the belt.

[AJT944]

Originally Posted by v2rocket_aka944

may as well do the key while doing the belt.

Quick Update.

Installed the MAF this weekend, which opened up a whole new can of worms. Engine starts, gets tach bounce, and then dies immediately and especially dies quicker when I give it gas. Felt like it was either an electrical thing or a fuel thing, but my whole fuel system is all brand new (Rebuilt injectors, new fuel rail, new fuel lines, new regulator and damper, new fuel filter) and I was getting great pressure (I have an adjustable one set at 35psi). Set the fuel quality key to stock position on the DME as well, and swapped out a few different DME relays.
Tested my coil, and turns out it wasn't quite getting full voltage and has a ton of resistance. Have a new one on the way (Went with an MSD 2 Blaster, High Vibration, which hopefully sorts everything out. I suppose that also kinda explains why I was having a rough idle beforehand (Even after replacing vacuum lines) and hard starts. The coil looks original (Holy cow!)

Once I get it up and running reliably, I'll look more into installing this cam key.