924Board.org

JBTurbo · Joined: 19 Mar 2007 Posts: 30

Posted but it would not take before so I hope it is not up 2 times...
I did all that I was told and set the timing belt up with the dot on the back, checked with the cyl being up on TDC, plus had checked the compression stroke by preasure, Flywheel marks dead on and also the pointer is dead on, even looked at the intake valve open then close as the timeing mark cam up to it's point leaving both valves intake and exhaust closed. I had turned the engine over by hand very careful to make sure I was not 180 out and re checked several times, even the books shows it correct!!!! But now that it is in time it moves about 50 to 60 degrees and it goes against something as I turned it by the crank before trying to start it, and in reverse rotation it hits at about 30 degrees rotation. All feeling like it is coming in contact with a valve, and not on number one cyl as I can see it plainly through the oil filler cap.
Are these an interference engine, being that the valves will hit if they are the slightest out. Like I said I had rotated very carfully with the cam in one position and had no contact, but now it comes against something feeling just like a valve is open on another cyl and this car had strong compression and did run, but badly with the timing lined up by the front mark done by the guy I bought it from. Interference engine or not, Even if I could possibly be 180 out I do not think a valve would hit. Both valves on number one are closed when it does this, and it does it just past the compression stroke being there (#1) with the exhaust being ready to start opening, about 50 to 60 degrees, so what am I missing here??? There should be no valve touching anywhere and it has been checked so many time by the REAR dot in the valley of 2 teeth on the back of the sprocket and is right on the line on the fly wheel, If I move it up to the 24 degree mark on the flywheel she spins fine, but then it is not timed right. I am not going to hit the starter until it is set correct or someone give me and idea of what I could possibley missied on this. I have not bent a valve because I have not put any real presure on it when I tuned it by had to check it first, so it is safe, just missing something somewhere. Done according to everyone here and the book and the old school way of watching the valves........ I know there has to be something simple that is off just enough, I am going to try and double check the 180 out while I hope someone solves this or gives me the answer from above.
Please tolerate my crude typing all, and now a grease spotted key board,
Thanks
John
We will conquer all, I feel like marathin man now>>>8:45 EST[/i][/b]
_________________
Cars owned now, 924 Turbo, 944 Turbo, Mid 80's Big Block Camaro, ++ Dailey driver....

Paul · Posted: Wed Apr 11, 2007 11:12 am Post subject:

Yes all stock 931s are interference motors.

Did you verify that piston 1 was at top dead center when the marks are lined up?

You are not 180 out if number one's exhaust valve is closed.

The next valve to hit a piston would be 2's exhaust valve.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

PORSCHEV · Posted: Wed Apr 11, 2007 11:14 am Post subject:

You have a turbo...so YES IT IS AN INTERFERENCE ENGINE. I wish I could help you out to tell if you have done any damage. I am not sure how close the valves run to the pistons, or if it can do damage when turned over by hand.

Someone will chime in here soon I am sure.
_________________
1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

PORSCHEV · Posted: Wed Apr 11, 2007 11:16 am Post subject:

Paul beat me to the punch line....

_________________
1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

Paul · Posted: Wed Apr 11, 2007 11:27 am Post subject:

BTW it is impossible to be 180 off, the camshaft determines which cylinder is on the compression stroke. So put number one at the exact top of its bore (ignore the marks on the flywheel and crankshaft pulley), and align the cam to its mark.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

JBTurbo · Joined: 19 Mar 2007 Posts: 30

I was very careful tuning by had so I know I did ot hurt it, but I did do the TDC with the number one, and setthe cam right on the mark. And I know the cam makes it the commpression strodke on it and it is set right on the mark. All I know to do is set it again, but at TDC on number one the flywheel is right on the mark,and my cam gear lines up perfect. All i know to do is time it again and do it just like it is but check it until I am passed out, even have another set of eyes here looking at it and they are baffled. I go lossen the tension and put everything in position on it but it wil be like I have it unless maybe this time I spot a mistake I amy have done worng. It is so simple that makes it the problem, it is either in, or it isd out... Right now it lines up perfect
My 944 Turbo I know is an interference engine and they will not tolerate more that about 2 teeth out and you bought the farm on it, but I check it regulaly for tension and maintain it re well, and have had no problem timing it at all, so off to this again, more post coming in, thanks guys for your help, I'll try this 20 minute re time real fast
JB
_________________
Cars owned now, 924 Turbo, 944 Turbo, Mid 80's Big Block Camaro, ++ Dailey driver....

Paul · Posted: Wed Apr 11, 2007 11:50 am Post subject:

You are using the mark on the firewall side of the cam gear, correct?

You are feeling this resistance with the plugs out, correct?

The car is out of gear, correct?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

JBTurbo · Joined: 19 Mar 2007 Posts: 30

Yes I am, the dot facing the fire wall, it's mark is right on the pointer on the valve cover, and TDC is correct by the straw type test, with the mark on the flywheel coming up correct at that point also. But yes, I am using the mark facing the fire wall and the gear is not on back wards or anything of that sort....I am going to recheck and set it now, about 20 minutes
10PM EST

JB
_________________
Cars owned now, 924 Turbo, 944 Turbo, Mid 80's Big Block Camaro, ++ Dailey driver....

Paul · Posted: Wed Apr 11, 2007 11:57 am Post subject:

Don't bother, if its correct, its correct.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Wed Apr 11, 2007 11:59 am Post subject:

The tranny is in neutral, correct?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

JBTurbo · Joined: 19 Mar 2007 Posts: 30

Yes it is in nuetralm that ws the first thing I asked my partner here if he had put it in gear in between us working on it.

So his answer to me was do you think I am 4 years old!!! At least we are still at the point of being able to joke about it a little......
Pulled spark plugs and tried to listen with my stethescope with the long point on it to hear what cyl it may hit at while tuningit by hand, but no noise or tap of any sort so far. I have not cranked this engine with the starter at all, I always do a check by hand no matter how sure I am that I have it right, so ther4 is no way that it is damaged and it may not be hitting a valve, we are looking now for any thing that could possibly cause it to not want to make a rotation, even pulled the distributor out to make sure it had not been on a bind or something, but it is definately coming up against something that is solid, but I have never tried to force it by hand to try and go past the spot it hits both ways, and I see no valves stuck down at all now, plugs out and all. It has to be something very simple that is making it complicated.......I am still in the hunt,,, Please more trouble shooting no matter how far off the mark any of you may feel it might be, I am open to anything to check and not hurt this engine before I start it. It does have a real stop spot in both directions, 60 degress maybe in the running rotation, and about 30 in the reverse rotation.....

JB
_________________
Cars owned now, 924 Turbo, 944 Turbo, Mid 80's Big Block Camaro, ++ Dailey driver....

Paul · Posted: Wed Apr 11, 2007 1:00 pm Post subject:

Tell us more about the history of this car and everything that has been touched since the last time it ran.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

JBTurbo · Joined: 19 Mar 2007 Posts: 30

The car would run bad, then I cleaned the fuel system out and it ran pretty good but would not idle at low RPM's and lacked response and power, then I discovered the previous owner had installed the nnew timing belt using the 0 on the fron of the pully making it about 20 to 24 degress advanced, so I saw the problem and set it in time, Between this I did do a compression test and a leak down test and the engine came back much better than I could have hoped it would, so it had good valve sealing and rings held good, The engine appears to have been rebuilt at oner time and for it's age has low miles, and was also never driven hard. So the engine is a very solid engine and still makes good compression, nothing hurt by turning it by hand, I have put air into each cyl now a shor hour ago to make sure they did all seat good and after a fast test they held. But basically I set the timing right and now it does not run, or I will not start it up until I find the bind it is hitting or the problem. Going for the 90 degre setting on the crank now, and checking thevalve train again just to make sure that they are all moving properly, though I have done nothing to cause a problem there/ It is strangfe how it ran at about 24 degrees out, though low on power, but now timed righ there is a problem......I may find it now, I am leaving no stone untrned on it as we set it up now at 90 degress on the crank, so I'll seee what this show in a few minutes, It will get noarowed down with all the help I am getting from all of you. Good group here, hope I can return the help someday soon.
Thanks,
JB
_________________
Cars owned now, 924 Turbo, 944 Turbo, Mid 80's Big Block Camaro, ++ Dailey driver....

Lizard · Posted: Thu Apr 12, 2007 1:07 am Post subject:

at this point in time I would recommend that you drop the oil pan and make sure there is no binding in the bottom.

The other thing is you could put the timing belt back on how the PO had it and see if the engine binds.

I would be verifying that Cyl #1 is at TDC with that mark on O again, do it with a straw or screwdriver etc,

the other thing I would do is to put the car in 5th gear have one person hold the clutch in and the other spin both the CV joints to spin driveshaft in the torque tube, eliminate that the stop is not in the clutch or driveshaft area.
_________________
3 928s,

JBTurbo · Joined: 19 Mar 2007 Posts: 30

I have checked the clutch and also the botom end spins freely, also there are no bent valves and that has checked out, and I have come to the conclusion it is not hitting a valve becase at the 6o degree position no piston is een up far enough to hit one, and at 30 degrees the other wya they are all down below where the could poosibly hit. So now that I know everything is not binding in the engine valve train or clutch or anything there I am going back to timing it straight up as before and spin it by hand and look for anything that could make it bind, even checking to see if the starter had somehow engaged and had it binding up, But there is nothing hold either end from spininning freely when the4y are separate so I may find it is something real simple here today when I align it up all over again I am EST at about 2:45pm right now. As I told Nick please for give y typing because I do have a loss of sight that is supposed to be temporay andis coming back but I have trouble seeing up close at all though it is coming back, so I have a lot of bad spelling mesitakes and such.
But I will know shortly here what it is I think because I just know it is simple and over looked somehow, I even though I may had the belt a little tight or I may have extra fuel in a cyl and the compression is real strong on a cyl or 2 from the extra volume in it, so every thing is getting cleaned out and start from the beginning, But any and all ideas are more the welcome because I am going to when this battle. It has to be a simple fix. I will updater afterr I get it together and who knows it may be the positive, Thsnkd to you and all that have helped give me ideas of checking everything on this, it has been a big help, more than a big help!!!!
JB
_________________
Cars owned now, 924 Turbo, 944 Turbo, Mid 80's Big Block Camaro, ++ Dailey driver....