Z24i timing maxed out.

[freddy770]

I've got an 86.5 D21 with the efi and computer controlled ignition. I just put a new crate motor in about 1500 miles ago and all the sudden it started pinging. I checked all mechanical timing parts and all tune up parts to find nothing wrong. Stuck my timing light on it to find the timing at idle to be between 25 and 30 deg. WOW... not sure what's forcing it to advance that far. checked out the tps and it seemed to test ok, but I still think it could be the culprit. Any other thoughts???

[Rev_D21]

Oil pump and distributor are off a tooth.

[freddy770]

I've already been through that, it's good. This thing has ran flawlessly for over 1500 miles and suddenly falls on it's face. I don't think the problem is mechanical I think it's electrical.

[PhillyHardbody]

Just because it ran well before doesn't mean your mechanical timing isn't off, I would triple check that it is timed mechanically, then after you're 150% sure you can move on to trying to track down other issues.

[freddy770]

Yeah, I've been all over with the mechanical portion of the timing. I've pulled the distributor and reindexed with the crank to try and get back to 5 deg base timing but it wont run there. Right around 25 deg is the only place it will even run. Unless the cam and crank are out of time, I don't know where else to look. The timing chain is tensioned correctly so I don't think that could've jumped time.

[mrecoolgar]

I had a similar situation and the cam spoket was off a tooth.
Set to top dead center and verify the cam gear keyway is at 12:00.
Use the crank to cam centerline as the vertical.

[freddy770]

Ok. I'll give that a try. Thanks

[freddy770]

Blown head gasket, between cylinders. Causes some misleading scenarios when troubleshooting.

[Novajoe]

I'm suprised a crate motor blew a head gasket that fast.

How did a blown head gasket set your timing that far advanced?

what crate motor did you go with? so I know never to buy from them :p

[freddy770]

I don't know what the deal was. I think the outfit that did the motor was called ATK engines, but I'm not sure. it blew the gasket out in two different places between 1 and 2 cylinders and between 2 and 3 cylinders. from the looks of it they just used crappy no name gaskets. both surfaces are very flat with a very slight texture so there is no reason this gasket should've failed other than the gasket quality itself. I'll throw a new one in this weekend and she'll be back in business. as far as the timing, I have no idea. I'll change the gasket and see what happen with the timing. I'll keep ya posted on the outcome.

[freddy770]

New Fel Pro gasket in and adjusted the timing advanced about two degrees from where it landed the last time I had the distributor out and it runs like a top. Timing acts correctly and it idles good and makes good power. Strange strange things I guess. thanks all for your input.

[Novajoe]

sorry to hear you had that much trouble out of your brand new crate motor, but I'm glad you got it fixed and it's good now.

I've seen this happen with head gaskets before, but I never understood why it causes the timing to go crazy like that. I'd love to get an explanation from someone that might know, if nothing else just for my own personal knowledge.

[massey461]

i love this forum! learn so much. i had my 89 z24 pu start knocking and didnt get any suggestions from anyone and assumed that there was rod bearings goin out. so i pulled the motor and pulled it apart to find that the head gasket was blown inbetween 1 and 2 cylinder so im pretty sure that was the cause of the knock, because the bearings were fine.....and reading this thread has pretty much made me certain that was the cause! thanks for eveyones replys!

[Rev_D21]

Glad NICO is helping you out. Welcome!