New member intro...with problem

[dukester]

Hello Everyone. Here is my FJ40. I got it back in April. I chose this one because it is completely stock. Aside from some typical oil leaks I haven't had any problems until yesterday. After some research I am just about convinced I have a bad exhaust valve on #5 cyl. What I am wondering is how this happened. The spark plug on #5 had a piece of ceramic chipped off of the electrode that I could have damaged the valve. Also, I just happened to see on the SOR site that a bad brake booster can damage #5 & #6 valves. I have performed the test SOR has described and I am still not sure is the booster is bad. My brakes seem to operate fine. There is quite a bit of pedal travel before brakes engage but it doesn't require excessive force to stop the vehicle. I was wondering if anyone has had any experience with damaged valves due to bad brake booster. How big of a job is involved here? I don't have a whole lot of experience with engine work but am willing to give it a try. Comments? Suggestions?

 

[Romer]

Welcome dukester. Please provide us some more info like what is it doing and why are you convinced you have a "bad exhaust valve"?

 

[dukester]

It is running rough @ idle and when accelerating and some loss in power. I replaced the spark plugs (this is when I found the bad #5 plug). The electrode on #5 was also bent if that means anything. The wires tested good. I have good spark to all cylinders. I really don't think its a fuel problem - the choke is working fine. The exhaust note has definitlely changed. Its making a "fwup fwup fwup" sound. It isn't smoking at all. Something I still need to do is a dry/wet compression test.

 

[Romer]

It could be timing. Have you checked the timing? Is there a vacuum hose hooked to your dizzy? Is it still connected? Is that a 76 or 77? How long has it been since you changed/or cleaned and set your points?

It also could be a fuel filter if your experiancing a loss of power at acceleration.

All the above are cheap and easy to check and replace.

 

[dukester]

It is a '78 model. The dizzy is fine (good vacuum, points...). It has a new fuel filter and the timing is good. I checked compression and here is what I found.

#1 125
#2 138
#3 150
#4 145
#5 MAYBE 5 !!!
#6 150

When I removed the spark plugs for the test the #5 plug was seriously dinged up. The gap had closed to less than .020 and the ceramic sleeve around the electrode had broken loose at the base and was moving up and down the electrode. I put these plugs on Thursday night and have driven maybe 40 miles total. Do you think that small piece of ceramic from the previous plug is rattling around in there, damaging the plug and who knows what else? What is really strange is that the ceramic on plug#6 has also broken loose and is moving around the electrode. The gap did not change however. What is causing this??? The plugs are Autolite Platinums if that means anything.

 

[fjbj40]

may sound silly ,,,,,but is it the propper reach plug ? the only way , well not maybe the only way , you will get this type of damage is by the piston hitting the plug or you have a serious case of detonation which you should be hearing while driving if the det. is that bad ! Detonation and pre-ignition will do this to plugs and eventually put holes in your piston! If I were you I would stop driving this thing and figure it out or you are going to kill your engine .
HTH , Daryl

 

[dukester]

The new plugs are dimensionally the same as the old ones. I used the Wally-Mart computer to look up the correct plug. That #5 plug sure took a beating. Somethings definately screwy here. I'll keep looking.

 

[dd113]

Doesnt really matter now what caused it you have big issues. Have you adjusted the valves? Adj them then re test compression. Then do a wet test. If the numbers spike a bunch then look to rings but also do a leak down as it wil tell you a lot about head condition. If number 5 is only a valve issue you will need to pull the ehead and then you might be able to figure out what is causing the plugs to get messed up.

 

[Dave E]

I'd pull the valve cover to see if the valve is fully opening and closing at this point. I would turn the engine by hand though. If there is something in there rattling around, it may be scratching up the cylinder walls. I'n not sure if you can run the piston to TDC on #5 (or close) and look in the plug hole to see if you can see anything. Might try running a small air line in the hole to blow anything in there out. Another way might be to leave the plug out and run the engine, hopeing that the peice will be blown out.

However, if the valve is damaged, there is really no point in all this. The head will have to come off.

Dave

 

[dukester]

The compression on #5 did not change with a wet test. I shined a light into the spark plug hole and there is a lot of "dings" or pitted areas. This really sucks. I guess I'll continue in the morning by pulling the valve cover. Thanks everyone for your help.

 

[warpdriv]

I wonder if you may have a spun crank bearing on number 5. It would enable the piston to travel further up. This happend to me on my GTO and discovered it when the piston was slapp'n the head.

Just a thought...

On another note, much happer, I would like to invite you to the Lone Star Land Cruisers Club Austin chapter. Our web site is :

http://www.lslc.org/austin

 

[dukester]

Not Good!!!!

Bad news. I pulled the head today and as you can see below, the #5 piston has a hole and is badly pitted. Its hard to tell from the pic but the #6 piston is also pitted but does not have a hole (compression is still good). This is looking like a job way beyond my abilities. THe other pic is of the valves on #4 and 5. One thru 4 are dry. Five and 6 are wet. Where do I go from here? Looks like big $$$ to me. I really want to know the root cause of all this.

Oh, all of the bolts except for two on the manifold were loose, maybe hand tight. I guess the PO never went back to retighten. It looks like I'm learning things the hard way.

 

[brian]

WOW, looks like that cyl was running REAL lean.

 

[Velocity2]

remember this.........when in doubt run it FAT!

 

[dd113]

Time for a rebuild

 

[Outback]

I hate to say it Duke, but you should stop everything and pull the head to see what's up with the valves on that cylinder.

You probably have something broken off in there that's causing those probelms. Not what you wanted to hear, I'm sure, but good advice nonetheless. Especially since you have no compression in that cylinder.

Good luck duke...

Jody.

 

[Jetboy]

Hate to say the C word, but at this point your likely money ahead to look for a conversionl I would recomend finding a 4.3 vortec, they are cheep (should be able to find one arround $500) easier to install and easy to find. They are also lighter and have adequate power, plus you'll get better mileage. That's what I plan to do in my 40 when the time comes.

 

[dukester]

I've found a good 2F out of a FJ60 that I can have for $1200 with trade. Any comments on the 4.3 conversion? I don't do any serious offroading with my cruiser - just drive to work and back and an occasional hunting trip. I'm trying to stay positive and look at this as an opportunity to improve my cruiser to better suit my needs. I don't (can't) spend $3000+ on a rebuild. Ideas???

 

[CruisinGA]

A swap to a fuel injected GM motor will cost more and require MUCH more downtime than swapping in a different 2F or getting yours rebuilt-aside from the cost of the motor you much purchase adaptors and engine accessories, and unless you are very skilled and have a good shop, pay for a whole lot of labor.

I would not consider any sort of a conversion a possibility here, unless you have lots of time and money, which i don't think you do.

A rebuilt 2F has an amazing amount of power, you could even put a high comp. head on it and a fancy cam, if you really need more power.

 

[dukester]

I'm not looking for a lot of power. I am most interested in reliability and would love to keep things stock. What is the going rate for a good used 2F? I've also read some discussions on the 3F-E?? $1200 is about my limit here.