Ran cold comp test today, Ugh-followed with leak down test..double Ugh Options

[76-914]

so I check #2 first and get 60psi. On #2 no less. This ain't good. Got the same readings +/-2 on cyl's #1 & #3. I got 70 something on #4. I'm thinking the jugs are coming off (and maybe they are). About then Dave stops by to check out my new toy and says start it. I came up with some lame excuse for not starting it but after he left I thought "screw it"! 60 psi..........how much could I Fngngn it up. So I poured a little gas down the throttle body and it started and died. I did this 2 more times and it farted and started and ran roughly. It wanted to die under 2500rpm. This was about a 15 sec run. I get out of the car and see this:


These two elbows are leaking like sieves. They're swole up like a Boy Scout at a Pancake Dinner. OK, it's coming out.


Then I thought I should check the valves. The PO might have over tightened all of them, equally. Could that explain the equally low compression and part of the rough run? Possibly. (IMG:style_emoticons/default/confused24.gif) Otherwise it's tear down time. So I'll check the valves tomorrow and if I find they were too tight I'll give it a 5 - 15 sec run, shut it down, re check compression and so on. Either way it's coming out so I can freshen up the Hell Hole area and attend the engine and drive train.
I found some notes from the previous owner from 1999. The PO wrote that it would run for about 3 min's then inexplicably die. I'm thinking CHT sensor problem and found the spade connection was indeed exposed (it's plastic cover gone) and laying against the tin, hmm? BTW this GC is one of the 1st 100 built. #93 or something.

[silver74insocal]

(IMG:style_emoticons/default/biggrin.gif) im glad it didnt continue to run!! that could have got ugly real quick. it looks like the injector seals are bad. i may have some you can stick in there if you want to try again..but for gods sakes man start it while someone is watching with an extinguisher! let me know bud...Dave

[SLITS]

Injector seals don't leak gas, just air ...

The bent rubber elbows from the fuel rail to the injector do. Get some REAL 7mm FI hose and replace them ... In fact, replace all the rubber lines - PERIOD. I buy 12' at a time for a car. If you want the preformed elbows, check the usual suspect vendors .. Pretty sure AA had them made.

You can get the real Deutscher braided line from CarCraft in Riverside (and maybe some other places).

Also, after adjusting the valves, shoot a shot of oil in each cylinder and see if the compression comes up.

[Krieger]

(IMG:style_emoticons/default/agree.gif) Fix the fuel leaks first. If your fuel pressure is too low (big leak) your car won't run right.

[76-914]

(IMG:style_emoticons/default/biggrin.gif) im glad it didnt continue to run!! that could have got ugly real quick. it looks like the injector seals are bad. i may have some you can stick in there if you want to try again..but for gods sakes man start it while someone is watching with an extinguisher! let me know bud...Dave

No, it's those elbows leaking, badly. They're pretty swollen. I won't let it run more than a few seconds to see if a valve adjust was the key.

[76-914]

(IMG:style_emoticons/default/agree.gif) Fix the fuel leaks first. If your fuel pressure is too low (big leak) your car won't run right.

Thx for the comfirmation. I suspected that, also.

[SLITS]

Come by the shop ... I should be there at 8 today and I'll give you the fuchin' fuel line. If I don't have any, I'll go buy you some.

Car will not run correctly with leaking lines .. insufficient fuel pressure at the injectors.

[76-914]

Injector seals don't leak gas, just air ...

The bent rubber elbows from the fuel rail to the injector do. Get some REAL 7mm FI hose and replace them ... In fact, replace all the rubber lines - PERIOD. I buy 12' at a time for a car. If you want the preformed elbows, check the usual suspect vendors .. Pretty sure AA had them made.

You can get the real Deutscher braided line from CarCraft in Riverside (and maybe some other places).

Also, after adjusting the valves, shoot a shot of oil in each cylinder and see if the compression comes up.

Every one of them gets replaced. I have a "new" set of injectors w/ the elbows so that shouldn't be a problem.

[underthetire]

Just a FYI if you want to do the injector seals at the same time I got a set at auto zone for about 8 bucks. It was a unerversal set that had seals for the older injectors like ours, and the smaller ones for the newer cars. Perfect fit. Might want to do the filter while your there.

[Dave_Darling]

Results with the engine cold can be fairly different from results with the engine warmed up, which is the preferred way to do them. So you might try another test after you get the fuel leaks fixed up and after the car has run for a while.

--DD

[tod914]

How many cranks did you do to get the compression up, and did you have the throttle body wide open? If closed, could explain your low numbers.

[r_towle]

I would suggest you fix the fuel leaks and get it running and warm, then do a compression test again.

Rich

[76-914]

I would suggest you fix the fuel leaks and get it running and warm, then do a compression test again.

Rich

OK, that might be tomorrow. Do you expect it may raise above 90?

[VaccaRabite]

If you are getting ~70 cold with the car in poor tune I bet you will be fine with it tuned up and warm.

Do your valves. fix the fuel line. remember that compresion tests need to be done with the engine warm and throttle wide open. Crank it until the gauge does not go up any more.

Cold engine, unknown valves and a closed throttle are going to give you poor results on a compression test.

Zach

[sean_v8_914]

they are all very even, right? that is a good thing.
valve adj
open throttle
re-test
remove all plugs for test crank
watch needle while cranking
10 - 12 wa-wa-wa-wa-wa cranks each
needle should level out after about 6
run a jumper hot wire to the solenoid so you dont have to use the key to crank it if your alone

[r_towle]

I would suggest you fix the fuel leaks and get it running and warm, then do a compression test again.

Rich

OK, that might be tomorrow. Do you expect it may raise above 90?

It will be a significant jump....the rings and pistons need to expand to really give you an accurate reading.

If it was me, I would spend the time to fix the leak, get it running then do the compression test again before I bothered to take out the motor.

The motor will stay warm enough to get good readings for at least 30 minutes, so get it hot, then remove all the plugs and test all the cylinders.

That is if you wanted to run that car as is.....if you already planned to rebuild it, dont bother, just pull it out.

I never trust a cold test on a aircooled motor...there is just to much expansion that needs to occur to have any relevant numbers.
A leak down will tell you more in the long run, but a good warm compression test will inform you if you really need to rebuild it today, or if you can run it for a while.

Its not going to really show you rings that are worn, but it will show you if you have a leaking head or valve seat issues.

If the valves are set too tight, the compression test will look poor, so loosen up the valve adjustment so you know they are seated really well, then you can re-adjust them once you get it all tested.

Wire the throttle body open, remove all the plugs and like stated above, crank it over for about 20 seconds per cylinder test...

RIch

Rich

[76-914]

OK, a quick update. I checked the valves today and all but one were dead on. The tranny has issues so I ended up using a remote start switch fusing w/ the Cap't. method. It's a good thing that I received an extra tranny in the deal. I'll need it for parts I'm sure. The Dr Evil DVD will be used once again. Does that mean I'll own him again? I had some 7mm left over from the 76 project so I fashioned 2 elbows to correct the leaks at the injectors. I prime the TB, start it up and run it about 15-20 sec's @2000rpm to smooth it out. Then backed off and shut it down. Gave a quick once over and found no leaks nor smelled any. I restarted it and let it idle. The tach didn't register at low rpm but I'm guessing it was around 1300. I felt the end of the hose feed going into the AAR and it was pulling alot of air. I had found some notes by the PO saying it would quit after a few min's so I figured it was AAR related. And as sure as God made little green apples the AAR begins to close and the rpm drops noticebly until it dies after being starved for air. I thought the CHT sensor might be the problem so I put the variable resistor in line to find out. It wouldn't think about starting so I gave it a shot a gas and still nada. I'm thinking it is flooded out and that after the AAR begans to close the unit is going to a full rich. I've disconnected all vac lines except the dist and MPS. Fuel pressure was a constant 28psi indicated and was holding 15psi 10 min's after being turned off. I'll try again tomorrow w/ the resistor in line to check it. BTW, the plugs were black when I pulled and gapped them. Thought's?

[VaccaRabite]

black plugs means rich, but you knew that already. Clean them off before you put them abck in and it will make the engine easier to start (until they get all cocked up again).

Zach

[76-914]

I finally got around to doing a leak down test, yesterday. Double Ugh! It was done cold but it wouldn't start. Read the results and I think you'll agree it's time for an extraction.Results are as follows:
#1 - 60% leak down/crank case noise level= 5/exhaust noise level=5 1-10 scale
#2 - 34% / =10/ =2
#4 - 38% / =10/ =2
#3 - 48% very loud hissing in head area. cracked head or cyl?

[VaccaRabite]

I finally got around to doing a leak down test, yesterday. Double Ugh! It was done cold but it wouldn't start. Read the results and I think you'll agree it's time for an extraction.Results are as follows:
#1 - 60% leak down/crank case noise level= 5/exhaust noise level=5 1-10 scale
#2 - 34% / =10/ =2
#4 - 38% / =10/ =2
#3 - 48% very loud hissing in head area. cracked head or cyl?

Well, thats not good.
I don't recall - did you check all your valves? A valve open even a little will ruin leak scores.

Leak in the crank case is rings (probably).

Leak at the exhaust is either a failing valve seat, or a valve that is not properly adjusted.

Loud hissing at head could be a seat dropping, poorly adjusted valve, register collapse (as was the case on my engine), or some other issue.

Do a spray test in conjunction with leak. At the leaky cylinder, spray it with soapy water and look for when the bubbles are forming. This will tell you where you need to be looking the hardest.


Zach