914-6 Valve Adjust, 914-6 Valve Adjust Procedure, Hot vs Cold Spec Options

[Movin6]

Valve Adjust Cold vs hot clearance Question / Discussion
A question and a discussion topic.

Finally reassembling my 914-6 after the Dr Evil transaxle rebuild a couple years ago... and all the 'while you're at it things'... New clutch, shifter bushings, painted the original modified muffler, etc. 

Adjusting the valves and talking to my 80 year old cousin and expert old-time chevy small block racer / engine builder. He raises the question about  0.004" being a tight spec (compared to his experience w American, mostly push rod engines) and brings up the point that this gap will likely be smaller when the engine is hot. I assume Dr. Porsche compensates for this? Also that this spec is for a new engine, ours are certainly no longer new, most even if rebuilt, were done some time ago, if not that many miles ago. 

My #1 exaust was tight, it was firing up through the carb. I could not get the .004 gauge into the gap.

I also, stupidly didn't check for proper marks on the flywheel when I had it machined. I replaced shortly after buying the car ~1990 when the starter chewed some teeth after hydralocking. (I installed watershield air cleaner covers after that...) 
So I do not have a "Z1" mark, just a red mark where it is stamped 35. Maybe it is a 911 flywheel? 

So my valve adjust question: Can I simply rotate the cams to where the lobe is 180 degrees away from the valve and measure? (via turning a wheel with the other locked). i.e. do exaust 1-3, then exaust 4-6, lower the car then repeat for intakes. Should not matter that it's not intake and exaust for same cylinder at the same time, right. 

Thanks in advance for the sanity check!

[aharder]

http://www.914world.com/bbs2/index.php?showtopic=28758

[ClayPerrine]

http://www.914world.com/bbs2/index.php?showtopic=28758

That is the Captain Crusty's directions on how to adjust valves on a /4. OP is asking about a /6.

Yes, Just make sure the rocker is touching the base circle on the cam. The firing order is 1-6-2-4-3-5 so if you are adjusting #1, make sure the ignition rotor is pointed to #4. You are sure to be on the base circle then.

And just an FYI... I normally drop the motor to adjust the valves on a six. Do it in conjunction with an oil change. It is much easier to do out of the car where you have more room to get to the valves.

Clay

[GregAmy]

http://www.914world.com/bbs2/index.php?showtopic=28758

Came here to post that link...RIP Cap'n!

OP is asking about a /6.

Then OP may want to edit his thread title.

EDIT: And thus OP has made that adjustment...

[sixnotfour]

Push Rod engine versus Overhead Cam....

[fixer34]

Valve Adjust Cold vs hot clearance Question / Discussion
A question and a discussion topic.

Finally reassembling my 914-6 after the Dr Evil transaxle rebuild a couple years ago... and all the 'while you're at it things'... New clutch, shifter bushings, painted the original modified muffler, etc. 

Adjusting the valves and talking to my 80 year old cousin and expert old-time chevy small block racer / engine builder. He raises the question about  0.004" being a tight spec (compared to his experience w American, mostly push rod engines) and brings up the point that this gap will likely be smaller when the engine is hot. I assume Dr. Porsche compensates for this? Also that this spec is for a new engine, ours are certainly no longer new, most even if rebuilt, were done some time ago, if not that many miles ago. 

My #1 exaust was tight, it was firing up through the carb. I could not get the .004 gauge into the gap.

I also, stupidly didn't check for proper marks on the flywheel when I had it machined. I replaced shortly after buying the car ~1990 when the starter chewed some teeth after hydralocking. (I installed watershield air cleaner covers after that...) 
So I do not have a "Z1" mark, just a red mark where it is stamped 35. Maybe it is a 911 flywheel? 

So my valve adjust question: Can I simply rotate the cams to where the lobe is 180 degrees away from the valve and measure? (via turning a wheel with the other locked). i.e. do exaust 1-3, then exaust 4-6, lower the car then repeat for intakes. Should not matter that it's not intake and exaust for same cylinder at the same time, right. 

Thanks in advance for the sanity check!

Small block Chevy, pushrod (iron block, water cooled) is a whole different animal than Porsche overhead cam (aluminum/magesium, air cooled). These engines 'grow' a little when hot, so the gap increases. Intake and exhaust 0.1mm/.004in, cold. Much wider than that and you get rocker clatter. The good Dr knew what he was doing.

Is the engine in or out of the car? Doing the exhausts with the engine installed is a real character builder. By any chance did you install 'turbo' valve covers on the lower/exhaust sides? If you did, please check a couple threads on here (if you haven't already) about machining some of the fins on the covers. Otherwise you will not be able to get them off and will have to lower/drop the engine.

I see Clay answered about using the distributor to help with finding the right spot, but some more clarification for your above question. The cam lobe should be 180 degrees from the flat side of the rocker, not the valve itself.

[nditiz1]

If you have a good eye and some light you almost don't need to worry about the z1 mark. What you need to reference is 180 out of the top of the cam lobe for that valve. You will know the valve is fully closed.

If you are having trouble getting them adjusted with engine in situ you can try the snapgap product. It is easy to use and accurate.

[Movin6]

Thanks! Yes, wishing I dropped the engine, LOL But it is on a lift, so there's that...
Is there a similar shortcut like the Captain's for a 6? Maybe not due to not just 1 cam on a 6?

Can I do another cylinder at same time?

Some progress, all valve covers are off, found TDC, #1 exhaust was tight. Hence the popping up through the carb.

[Movin6]

Valve Adjust Cold vs hot clearance Question / Discussion
A question and a discussion topic.

...

Small block Chevy, pushrod (iron block, water cooled) is a whole different animal than Porsche overhead cam (aluminum/magesium, air cooled). These engines 'grow' a little when hot, so the gap increases. Intake and exhaust 0.1mm/.004in, cold. Much wider than that and you get rocker clatter. The good Dr knew what he was doing.

Is the engine in or out of the car? Doing the exhausts with the engine installed is a real character builder. By any chance did you install 'turbo' valve covers on the lower/exhaust sides? If you did, please check a couple threads on here (if you haven't already) about machining some of the fins on the covers. Otherwise you will not be able to get them off and will have to lower/drop the engine.

I see Clay answered about using the distributor to help with finding the right spot, but some more clarification for your above question. The cam lobe should be 180 degrees from the flat side of the rocker, not the valve itself.

Thanks for the sanity check, the 'engine growing' as it warms up makes perfect sense. At least Dr Porsche didn't write the procedure to check valves on a hot engine, LOL (I think that's the only step that would make it more difficult! LOL)

I do have turbo valve covers, believe I installed them with engine in, but the left one was tight getting it down. My Chevy mechanic friend suggested shaving off one thread on those two studs, but not sure if I want metal flakes around open valve covers...

I have headers, no heater boxes, so a bit more room to work on exhaust valves.

Appears my replacement flywheel has a TDC mark and a 35 degree mark. Just not stamped Z1 (Should have asked the machine shop to properly mark when they resurfaced, LOL)

So doing valves at 180 from the cam lobes should be easy, my cousin brought over go / no-go feeler gauges, they help a bit, although not as easy to get into the gap as the bent angle one made for the job.

Thanks for all the replies!

[Movin6]

One more question: Gasket recommendations? I bought a set of old skool Victor Reitz, but have seen recommendations for 'silicone'. Thoughts and where to source silicone?

2nd question - The rubber / washer 'seals' under the lower valve cover nuts, I assume those are a replace item? Where to buy them?

Thanks!

[ClayPerrine]

One more question: Gasket recommendations? I bought a set of old skool Victor Reitz, but have seen recommendations for 'silicone'. Thoughts and where to source silicone?

2nd question - The rubber / washer 'seals' under the lower valve cover nuts, I assume those are a replace item? Where to buy them?

Thanks!

Most of the Porsche parts houses supply valve adjustment kits that come with the gaskets, washers and new nylock nuts for the valve covers. I would get one of the kits.

[Retroracer]

FWIW on gaskets: I've had good experience with the red silicone (reusable ones) with non-turbo OG lower covers. The paper ones seem hopeless when the covers heat up and deform, but the silicone has more "squish" to adapt and retain the seal. Make sure they are installed evenly before torquing up, and use a torque wrench that can accurately get you to the range specified - and you should be good to go.

FWIW on adjusting: I follow the Dempsey book procedure: it might help to duplicate the "120 degree" marks on the flywheel with a sharpie, just so you can follow the firing order easily as you rotate the crankshaft through the TDC positions (when viewed from the top of the engine). If the car is on a lift, you hopefully can see the front crank pulley too?

- Tony

[mb911]

I have victor reinz on mine now but bought some "real gaskets" from the place TN that makes them for next time. I have used silicone before with good results.

[Sway Bar]

Silicone gaskets work well....hard to get a feel for torque and don't overtighten since they'll cut.

My gaskets of choice on all my 911 motor's and builds are the standard gasket with a silicone bead for the bottom ones. With a clean uniform surface I've never had leaks and you can give them a little more torque over time.

[porschetub]

Silicone gaskets work well....hard to get a feel for torque and don't overtighten since they'll cut.

My gaskets of choice on all my 911 motor's and builds are the standard gasket with a silicone bead for the bottom ones. With a clean uniform surface I've never had leaks and you can give them a little more torque over time.

(IMG:style_emoticons/default/agree.gif) yes I found that out and only buy those ones as opposed to the plain gaskets,be aware if you have magnesium valve covers its a good time to resurface them,all of mine were warped,if you don't do this no gasket will stop the leaks.
I have 930 exhaust covers that I will fit next time I reset the valves.
I found the feeler gauge that Pelican sell is good to use and you can fit replacement gauges to them,I found because they are thin they wear out fairly easily.
I did two full rotations. and rechecked clearances again a found a couple were slightly off.
Good luck.

[fixer34]

Veering a little off the original topic, but since valve cover gaskets came up (and potential leaks), I want to put a plug in for a Rothsport oil check valve if the car will be sitting for any length of time. I see you are in New England area and have headers/no heat exchangers, therefore I'll assume you won't be driving it much late fall thru early spring. Oil WILL seep back from the tank into the crankcase and can spill over to the return tubes and lower valve covers. They seem to leak more when cold.

[Movin6]

Silicone gaskets work well....hard to get a feel for torque and don't overtighten since they'll cut.

My gaskets of choice on all my 911 motor's and builds are the standard gasket with a silicone bead for the bottom ones. With a clean uniform surface I've never had leaks and you can give them a little more torque over time.

To clarify, do you mean the standard gasket, such as the Victor Reitz that I already have, with an added bead of silicon, that you add? I'm leaning this way since I have the gasket already and that's what was there, but with not added Si.

[Movin6]

These are the 'washer seals' that were under the nylock nuts and washers on my exhaust valve covers. Seemed to work well.

They do not appear on the version of PET I've looked at, does anyone else use them or have a source?

[nditiz1]

You can discard those, shouldn't be needed/be used. Each cavity behind the cover is sealed with the gasket. Simple metal washers go underneath the nylon lock nuts. If these were needed to keep oil out then the covers themselves may need to be trued and or the cam tower face.

Also there are only certain areas behind each valve cover that actually have oil, where the rockers are. The cavities in between are to open air. If you see oil in those cavities then most likely your rocker shafts are leaking and need to be addressed.