FRporscheman

Tim, I've checked about 5 times (lol), the belt timing is dead on. I did the HG and valve job, oil cooler job, belts, made a new cork gasket for the distributor cap, battery tray repair with por15 por-patch, welded the floor pan (seat bolt mounts were cracking - I removed the battery first), installed new gauges in the center speaker grill (volts and oil temp, with the oil temp sender in the oil drain plug, and both gauges' power is tapped off the radio's key-in power), painted the cam tower and intake manifold (but taped over every threaded hole and gasket surface, lol), had the injectors cleaned at witch hunter, replaced the passenger door handle, replaced all 5 gauges with nicer spares I had, I think that's it.

Ross and others, Yes they painted the underside. It didn't occur to me that paint got into the oil passages, now I'm really pissed. However, they painted it BEFORE resurfacing it, so the head gasket surface was clean and raw.

I don't know if it matters but I did use copper gasket spray on the head gasket.

Bob, I removed the spark plugs (I've driven the car maybe 10 miles) and they appear ok but what do I know. This project has made me broke, so I won't buy new plugs unless I know I need them. I do have a set of used plugs I could try I guess.

Spencer, yes, they did mess up other things. There was paint on the gasket surface for the cam tower! I cleaned it off obviously. There were lots of gouges like from a screwdriver all over the cam tower gasket surface of the head! Dude, wtf! I used copper gasket spray on the cam tower gasket to mitigate any issues caused by the gouges (and it's not leaking thank God). Lastly, they broke off a chunk of aluminum when taking out one of the exhaust valve guides. They just put a new guide in and gave it back to me. I took it right back (once I noticed) and told them to fix it or replace it, they took out the guide, welded some filler there and put the guide back in. Oh, the variables with this one - warped head, warped or messed up guide causing valve not to seat, etc.

kev, Doc, I think I took pics of the head because I knew people wouldn't believe me, lol, I'll try to find them and post them.

JoKa, when it comes to the cylinder head, I agree completely! I'll take it au naturel, with all the stains, rough surfaces, and armpit hair as was intended.

pettybird

haha point taken

FRporscheman

OK, some more data.

I don't know if it's related, but the fuse for the rear wiper, reverse lights, and side mirrors keeps blowing as soon as I turn the key. I didn't touch the reverse lights or the rear wiper, and I'm certain I put the mirror switch back the same was as before, and just as a precaution I unplugged it and it still blows.

The oil pressure never gets as low as it used to at operating temperature. I always use castrol 20w-50 but right now it's running 10w-30 because the first day I fired it up it was making loud lifter noise so I switched to lighter oil to help it out. It used to get to 2 bar at hot idle, now it only goes to 3 (on the gauge).

I just remembered when I did the oil cooler job, I did not use an OPRV alignment tool. FWIW.

I cleaned the spark plug seats in the head. I was very careful and didn't let anything fall in. The misfire is the same, or only slightly improved if at all.

I did a warm compression test followed by a leakdown test. Compression is 140, 165, 155, 152 using a compression tester from Kragen. I did it with all plugs removed, and about 7 rotations.

Leakdown is 64%, 3%, 15%, 43%, using my homemade leakdown tester which is composed of an air pressure regulator set to read 0.5psi with my blow gun blowing, and a donor hose from some compression tester with the check valve removed. The tests were done at firing TDC for each cylinder. For cylinder 1, the leak was mainly blowing out spark plug hole 2. Cylinder 3's leak was coming out the dipstick tube. Cylinder 4's leak was faintly coming from spark plug 3.

I used a jumper cable to connect the battery negative to various parts of the engine to see if it improved, implying a bad ground, and it did not change at all, so I believe all the grounds are good.

If it matters, the car was sitting for 5 months. The battery was still showing about 12v so I just trickle charged it for 3 hours to bring it up to 13+. The battery performs well, it turns over very strong.

PorscheDoc

More then likely you have a wire cut and shorting out in the door jamb (where the wires go from the interior to the door opening in regards to the fuse issue (not related to the running issue). When you open and close the door, over time, the insulation of those wires gets rubbed and will short out. You will just have to pull that section of the harness apart and find the short.

FRporscheman

I started all the work because the headgasket blew around cylinder 4 and water was getting in the cylinder causing hydrolock on cold starts. I don't think the rod got bent.

The fuel is 5 months old... could that cause the misfire? I've used older fuel before without issues...

I washed the engine bay with simple green and water, I was careful not to get the engine itself wet, but I'm sure I got water all over the coil. I figured the cap would protect it, and that was like 2 weeks ago so it must have dried off....

Also, I noticed the #3 spark plug was black and sooty when I had the plugs out yesterday. The other 3 were still clean.

JohnKoaWood

stuck fuel injector could be the cause of misfire... move #3 injector to another position, clean the plugs up, run it and pull the plugs again.. if the position you moved the injector to is now soot covered that injector is stuck open... or not completely closing..

it is possible to have them cleaned, and tested, but would also be a decent idea to drain that old fuel out and start with fresh clean fuel..

I am fresh out of turbo injectors, or I would send a set out to you for testing...

give the injectors a good look, it is possible the pintle pin (head side of the injector) got damaged somewhere along the line...

You could also install that other set of plugs you have, but swap that injector to another position... (this will rule out wiring as the problem)

Let me know if you would like to borrow (for lack of a proper one out there) a longacre leakdown tester... your numbers are WAY off where they should be, likely as a result of the tester rather than the motor...

JohnKoaWood

OK, just re-read this... #1 is cross leaking to #2, #2 is OK, #3 has blown rings, and #4 is cross leaking to #3?

Did the shop that rebuilt your head do any NDI inspection of the head?

944Ross

I don't see how that's possible that #1 leaks to #2, but #2 is tight? But overall, if this home-made gauge is working right, you've got significant problems.

V2Rocket

64% leakdown?

FRporscheman

hey honestly, I don't trust the leakdown tester I made. I followed a few diys I read online for making one myself, and as far as I can tell I did it right, but like y'all said, how CAN these numbers be right? Remember, the car runs smoothly (the misfire is steady) and runs/drives pretty well but for the lack of power. I just don't know. Maybe the tester is good and I'm just doing it wrong.

I have 951 injectors, 55# siemens injectors, and 1989 2.7 injectors. Who can tell me which ones would be safe to swap into my 1984 944? I hope I didn't waste the money on witch hunter if 1 or more of these injectors are now bad.

First I will try swapping injectors 1 and 3. And I'll drain the fuel.

944Ross

I would for sure try your old plugs. The paint may contain metallic compounds that can be plated out on the insulator and causing the misfire. If you have a spark plug sandblaster try cleaning them, but the insulators can absorb some compounds permanently. Aluminum paint may well contain bits of aluminum.

Tedro951

Whether you trust the leakdown tester or not, if you are putting air in #1 at firing TDC and its coming out of the #2 spark plug hole, I think you'll be taking the head off this weekend. Ouch

F18Rep

I would not have thought I would be happy if the heads came back being painted but take a look at these 928 heads, I had them done last spring. I think he first hit them with walnut shells to clean them up, then a mist coat of gray then some scuffing to see if there were high spots. After all that, the broken studs and freeze plugs were removed and the machining was done. This might actually be a good approach, note how the crack that was caught before the machining phase started... just a thought... Bruce





PS...btw, 2 heads cost me only $200 for a shave and 3 angle valve job. Hard to beat that.

FRporscheman

I tried a trick I read about online - to disconnect 1 spark plug wire at a time while the engine is running to identify the missing cylinder. So the engine runs worse when I disconnect cylinders 1,3, and 4, but it doesn't really change when I disconnect cylinder 2. It hardly gets worse at all. Hmm.



I tried another trick, to watch the engine run at night, looking for arcs. Man, it's arcing everywhere. Wires 2, 3, and 4 are arcing to the fuel rail. Wire 1 is ok but when I wiggle it closer to the coolant gooseneck, it arcs to it. WTF?! This set of wires was a good used (very low miles) set, by Bosch, with Beru ends. Should I buy a brand new set, and what brand? Is there some wire insulation magic trick I can try?

It wasn't doing this before I did the head gasket job... I wonder what changed. I really hope once I fix this arcing issue it will run right. As far as the bad leakdown results, I'll just gear up for a rebuild next year if I can put it off that long.



John, what's an NDI inspection? I seriously doubt the shop did any kind of inspecting.

daveo90s4

NDI = non destructive investigation. Maybe they just did the DI and left out the N?

But seriously you've got lot's going on there. You need to stop the spark lead arcing one way or another. The good used set of wires you have unfortunately aren't that good. As a temporary measure you may be able to move them far enough away from whatever to stop the arcing, but really I think you need a new set.

About the leak down, this sort of test has to be done so that you have confidence in the results, be they good or bad. From the leak down test you / we still don't know if the problem is the tester or the engine itself.

Now, when you pull plug lead no. 2 it makes no difference. Could be the spark lead, could be the plug, could be the cylinder. Change one thing at a time, and start with the simple things 1st. Swap no 2 and another plug lead over (at both ends!!) and see if the problem stays with No. 2 or goes with the lead to the other cylinder. If the problem migrates then you know that that lead is at least one of your problems. Fix that. If not then put the ;eads back to thier original position and change two plugs over - ditto above logic. Then I suggest doing a leak down test using a known reliable tester - and if you can get someone else to help - maybe the leak you hear is not coming from where you originally thought.

If you really do have air coming out of no.2 spark plug hole when you pressurise no.1 you really do have major problem - blown head gasket (but if that is the case why is the compression not getting into the coolant and blowing the radiator cap - or is it??), or cracked head. But maybe the air is leaking out of no.1 itself and you are hearing it moving through the exhaust / inlet manifold by listening at the open no.2 plug hole. Are you sure you are doing all this at TDC on compression firing stroke and not the other TDC at the end of the exhaust stroke? If on TDC at firing stroke do you have a valve that is not closing properly - filled with old burnt paint even possibly??

Can you beg / borrow / steal a borescope and have a look inside each cylinder?

Good luck