bowtierebel

Hey guys. I have a question NOT ABOUT HOW to do a leak down test, but something that I haven't seen mentioned in the posts that tell how to do it. I was wondering that if, for example, I were to do a leak down test and I hear air coming from the intake then that is supposed to indicate that the intake valve on that cylinder is leaking. Well, I am learning these trucks and I thought that if that piston was not at the top of the stroke, couldn't one of the valves be at least partially open allowing air to pass around the valve?
This is why I ask... I have an '86 22R engine. 165,000 miles, so the odometer says. It smokes a little at idle, but it's not easy to see. When the engine is revved up and the gas pedal is let off of, it smokes quite a lot. The PO put a weber wanna be 32/36 DGEV on it and I have the idle mixture screw at 1 1/4 turns out from seated. the idle speed screw is barely touching the throttle lever and idle is at 900-910 RPMS. Manual calls for 950 RPMS at hot idle, but that seemed a little high. Timing is at 0* per the manual for this truck/engine.
I thought it may be running rich. The plugs are new factory spec NGKs. They have maybe and hour of run time on them and they are pretty dark, but not carboned up. Gapped at .031". I ordered a redline rebuild kit and cleaned it up. The engine idles very good. Revs good, but when I turn it off it continues to "run" or turn over for a few seconds and "cough" back through the carb. BTW, I went ahead and bought a true Redline weber 32/36 that I'll install later. I am not running a fuel pressure regulator yet or gauge either. Factory style mechanical fuel pump. I'm thinking that without the regulator the pump is pushing excess fuel through the carb and when I shut it off it is burning the fuel that has been pushed past the float needle and on into the carb throat. I did check for vacuum leaks too.
All that said, I did a compression check. Here are the results of each cylinder on a hot to warm engine after 10 revs with throttle fully open. I checked several times so of course the engine was cooling down.

#1- 138 psi
#2- 145 psi
#3- 138 psi
#4- 148 psi

My Haynes manual says that 171 psi is normal and 121 is low. My other manual more like a factory manual, but I'm not sure that it really is, says 171 psi is normal and 140 psi is low.
I rechecked the compression after adding some 10w40 in each cylinder, but no change in readings. I suspect the valve train. BTW, the truck sat for at least a year and a half and it is not drivable right now, but I can start and run it. It starts pretty easy too. I was thinking I need to do a leak down test after reading threads, then popped the question I asked earlier. I don't know for sure if I am looking at a rebuild or if I can do a less costly repair at this point. Any help pertaining to any of these problems will be appreciated. It's late and I may have left out some info that one of you may want to know. Let me know and I'll get that to you if I can. Thanks.

bowtierebel

BTW, when I typed this up I had better paragraph spacing. I don't know why it didn't come out that way in the post. Also I forgot to mention that that smoke that comes out when I let off the throttle is blueish colored. I don't notice any coolant loss either. Oh, and when I bought the truck I changed the oil and filter and the fuel filter too. I added the oil and checked and it showed full on the dipstick. After I had ran the truck at idle for a long time working on a temperature problem, I thought I'd check the oil again well after cooled down. It showed about a half a quart low. That kinda puzzled me because I was pretty sure I had filled it up correctly. I topped it off. I have ran the truck for a pretty good while off and on while I was tracking down the temperature problem. I forgot to check the oil level again just to see if it's low again. If it is low again, then that's a lot of oil to be lost only idling and an occasional rev here and there.

millball

Any cylinder that is under leakdown pressure testing must be very near TDC on compression stroke, or the test is meaningless.
I do'nt think that a leakdown test will help you much though.
Your pressures are pretty even and slightly low.
It does'nt sound like you have been able to run your truck enough to determine its oil consumption, but your smoke symptoms likely point to worn rings, although hardened valve stem seals may contribute.
Your 'dieseling' on shutdown is probably not related to high fuel pressure, but more likely to hot carbon deposits on the pistons.
All that said, a better carb and fuel pressure reg can't hurt.
Have you adjusted the valves??
.

bowtierebel

Thanks, millball. No I haven't adjusted the valves. Never done it on one of these engines. Is it very easy?

millball

Valves are easy to adjust. Just need feeler gauges and few wrenches.
Any repair manual will tell the procedure.
The factory manual calls for adjusting them hot, but I usually adjust cold and set them a couple thousanths looser. To each his own. A little slack is better than too tight.

bowtierebel

Gotcha. I am going to install the true Weber this weekend if I get a chance. That's the plan. I am looking at fuel pressure regulators and liquid filled gauges now. I'm looking at the Holley 12-804 and looking at which gauge I want now too. I guess the easiest way to know if the piston is at TDC is to just put a screwdriver in the spark plug hole and turn over the engine over till the piston is at the top.
In the past I have used this procedure to "steam clean" the carbon from the pistons. Get engine to normal operating temp and slowly trickle regular water down through the carb. Of course this will create plenty of white smoke out of the tail pipe. I have done this before and it seems to work pretty good. I can see the carbon on the top of the pistons.
Another question that I have is that I have no oil pressure showing on the gauge. I went through the troubleshooting process and everything checked good. Including ohming the gauges themselves. I went ahead and bought a new oil sending unit since I felt that the one that I had was stopped up and bad. (I did the SR5 cluster swap). I put Sea Foam in the oil before I changed it and the filter the first time, but I'm concerned that the oil is still too dirty to install this new sending unit since the truck sat for so long. I think I will put some more Sea Foam in the oil and run it some more, maybe even a couple more times to help clear up the oil some more before I install this new sender. I don't want to ruin it. They aren't cheap, ya know.
Thanks for your help Millball. I work for U.S. Special Operations at a base in N.C. so I don't always get the time that I want to work on this truck. I am considering having the engine rebuilt, but since I'm trying to restore this truck I'm trying to save as much money as I can and still not cut corners. It needs a new clutch too. That's why I can't drive it at all. I bought a cheap clutch kit from Advance Auto, but I am wondering now if I should go ahead and return it and get a OEM kit due to the amount of work that is involved in removing the transmission. I've heard good and bad things about the cheap kits vs the better OEM kits. The better kits cost twice as much as I spent on the Advance kit. I have an account at Advance Auto so I get much better pricing there than retail prices.
Anyway, thanks again! I have so many things that I'm having to do to this truck, but I feel that it'll be worth it later.

millball

The water method is an old school trick for de-carboning pistons that works very well.
I have used it on many engines over the years. It can be dangerous though, if too much water is aspirated too quickly, causing hydro-lock damage to pistons and con rods. It takes experience and a steady hand, but it works great if done correctly. I used to use a Coke bottle with my thumb over the top and my other hand on the throttle. Might have to be a little creative to get the water into the horizontal 22RE intake. (Hint -engine won't stay running with the intake air pipe disconnected)
I would urge you to upgrade to a top shelf clutch, if you plan to keep the truck.
Temporarily pipe in a mechanical pressure gauge and find out what your true oil pressure situation is.

EDIT!! Duh-- don't know what I was thinking-- You have 22R carbed engine!
So, no worries about horizontal intake, or keeping the engine running with air pipe off.

bowtierebel

You're right. Slow n easy with the water. I just did this 5mins ago and when I shut it down, no dieseling. I also ordered a Holley 12-804 regulator. I'm not sure which gauge to get. Liquid filled or not. It still smokes some so I guess I'll need to adjust the valves. If nothing else at least that will be done. I actually surprised that this engine runs pretty dang smooth. Idles smooth, revs smooth and not much noise from the valve train. I hear a tick, tick every now and then. I had to back the idle down after "cleaning" the carbon out some. The idle increased by about 150rpms. Not sure why.