Soren

Sold my 91 Pickup 5 years ago when I moved from NY to CT. A month ago a coworker mentioned he was getting ready to donate his 91 pickup since it was beyond repair (e.g. leaking rear, bad brakes, engine miss, bad tires, etc...). So of course I took it. The price was right. In CT emissions tests are done every 2 years and vehicles 25 years and older are exempt. I have one more emissions test on this truck before it is exempt. And no I'm not planning on defeating the emissions equipment, but I do have a 2001 3.4L sitting on a stand in the corner of the garage ready to go in.

The previous owner stated that the truck failed the last emissions check for leaking fluids, and bad exhaust. They didn't bother testing the exhaust. I would like to get a little more out of the truck before the 3.4 swap so I decided to tackle some of the issues.

With the truck running pulled each plug wire and diagnosed that #4 was not firing. Did a compression test with my cheap HF tester and found that 5 cylinders were around 140 and #4 was at 40. I pulled the valve covers and sure enough #4 exhaust have had no clearance and all the other exhaust haves were tight out of spec. All the intake valves were good.

Next I pulled the heads:




You can see that #4 was not firing. Also a lot of carbon buildup. A little more background: I work with both previous owners. The truck has the head gaskets replaced in '97 and the truck has 308k miles on it. Doesn't owe anyone anything. Frame is good. Body rot is typical.

I got a cheap full gasket set, but all a set of victor reinz graphite head gaskets, new exhaust valves, water pump/timing belt kit. I've cleaned up one head so far to get the sludge out of it, cleaned up the valve seats, and pressed new valve stem seals on.





I put the valves in and cam to check clearances once again, I'll need to shims on the exhaust valves but the intake are all still fine. Checked head warp and I'm within spec.

Block looks good, cylinders look pretty good, you can see a little crosshatch from '97. Negligible ridge at the top of the cylinder.



Only have $300 in the engine parts so far so I'm not too upset.

Now my real question. Any please don't yell at me for putting any money into my 308k mi 3.0. There is some pitting on the cylinder head. Will the graphite gaskets seal? The graphite gaskets that were on it were working fine. I don't think I can get the heads decked because they were probably decked back in 97 when the HGs were replaced. I've read you can basically only do it once. Also decking the heads would add additional $$$ to an engine that is destined to be a boat anchor in a year or so. I can try to get another pic of the pitting if you want to see it better.

This truck will not be a daily driver, mostly for dump runs, lumber yard trips and dolling a few small cars from NY to CT.

oldblue

if it were a truck you were going to drive more/care about more, i'd say drop the heads off at a machine shop and see what they say about milling them down. and have them do a proper valve job while they are at it. but if its just a spare work truck, just do what you're doing right now and hope for the best. a new knock sensor harness and even new sensors would be good while you are in there. it'll at least run better with all cylinders firing properly, and be leak free for a while to help you pass inspection.

scope103

I'm with oldblue. The pitting doesn't look "too" bad to me, but I haven't done enough head gaskets to really say much about what works and what doesn't. I would be inclined to have a machine shop grind the valves and seats (lapping them is probably not worth the time). Particularly when you might have had an exhaust valve propped open and could have been damaged.

BUT: the tricky part of any head gasket job (heck, ANY job) is knowing when to quit. A trip to the machine shop will cost some money. You might be "good enough" right where you are now.

Soren

Thanks for the input guys. I think I'll clean them the best I can and throw them back on. Thanks for the reminder on the knock sensor, the insulation fell right off when I touched it. As for the valves, I'm confident that my valve job will at least be better then it was. All the exhaust valves were pitted and burned. It's amazing it still ran and drove. I used a set of newway cutters and an 8mm arbor that goes in the valve guide. The cutters cut nice concentric seats that need no lapping. The exhaust valves are new and the intakes had nice clean seating lines, so I think I'm alright. Now hopefully the bottom end doesn't give out on me when it starting running on all 6 cylinders again. The first thing I'll do is get that inspection done.

That being said, for that 3.4 in the corner, I'll do a better job. The history isn't known, so I'll do a tear down and have a shop do the heads and maybe the block for me so I know what I'm starting with.

Thanks again.