Should I replace the head on my 3rz?

The truck:
1996 Tacoma 4x4 2.7L 3rz-fe with 215k on it. Has got consistent gas mileage for the year that I've had my 33's. Takes a few extra cranks to start when it's warm and power kinda of drops off after 3500rpm.

I pulled a P0302 code when my CEL came on and decided to replace the cap, rotor, plugs, and wires. The truck was missing at idle slightly and replacing those components did nothing to fix it. I then ran a compression test and got 175-75-150-170. Put a little oil into cylinder #2 and it was still 75. Today I was driving and the CEL started blinking. When I rescanned I got the P1300, in addition to my P0302. Could this be due to the low compression in the #2 cylinder?

After a bit of research it sounds like I may have a burnt exhaust valve considering that the valves have never been adjusted on the engine. (I wasn't aware that they needed to be adjusted until AFTER this ordeal)

The truck is my daily driver and the only vehicle I have aside from my motorcycle, so it can't be down for much longer than a weekend. At this point should I buy a new or rebuilt head (prices vary from $550-$650) or would it be worth my time to tear down the motor a little to actually check to see if it's the valve?

I don't think I have enough time to have a machine shop go through my head, so if I bought one has anyone had good luck with a certain shop's heads that have been rebuilt or a vendor selling new heads? Another question-if I do replace it, should I replace the timing chain? I was thinking of doing the water pump while it's torn down since I heard they last til about 250k.

I've replaced head gaskets on other vehicles, so I'm somewhat comfortable doing the work myself..

 

just my opinion but if I was looking at spending nearly $500-$650 I would just get a salvage yard 100k mile engine that has good compression and runs and drop it in, then you are done.

a new complete ready to install head will run you around $1000 and weather you pull your head or buy a used one you will still have to spend the time and money having a shop redo the head before you can install it or your just asking for problems.

most times once you pull a head it gets more involved ten that especially time wise so if you need the vehicle to drive and don't want to pay a shop to "do it all" for you at shop prices, I would drop in another engine

 

What if I manage to get my hands on a vehicle, so my truck an be down for weeks if needed? Would removing my head and taking it to a reputable machine shop be the best bet then? I don't have an engine puller and I'm not so sure that I have enough clearance in my garage to even pull a motor out of my truck. (Lifted on 33's with a low ceiling in my garage)

 

You could always jack up the truck, remove the wheels, then lower it onto some stands

 

yes that would be my first thought would be to see if they can first determine if your head is in good condition to be reworked and if so then have them rework it BUT with 215k miles on the lower end of your engine I must consider the strong possibility that while still good, the lower end of your engine has a LOT of miles on it and personally I wouldn't sleep well knowing I didn't just rebuild the whole engine at that point. hence why I said sourcing a good fully working engine with low miles from a wrecked salvage yard truck (wrecked means you know it was running and driving at the time it was wrecked so the engine "should" be good) so the salvage yard engine is the cheaper and easier way to get you where you need to be in the long run.

whenever you have the time and money to rebuild your own engine, that is always the "best" solution for long term ownership of the truck but you would have to hold onto the truck for another 10-15 years for that investment of money (usually ends up reaching the $4k-$5k price from a shop or about half that to do it yourself by the time its all said and done) to balance out. trouble is, you cant forget the truck value is only going to be a set amount and adding a new rebuilt engine doesn't make it worth 1 penny more to a buyer when its time to sell it so if you drop $2500 or $5k into a truck that it's book value is only $5k or $6k then after spending that money its still only worth $5k or $6k.

as for pulling the engine, im sure you can get a local shop to pull your engine out and put the salvage yard engine in for you at "moderate" cost of a few hundred dollars

this is why its hard to decide for someone else what is best to do, it depends on so many factors such as honesty on how long you will keep the truck, how much money you want to put into it, how much mechanic skill you have as well as help to do things, and in the end, everyones situation is different, so that's why most engine repair advice on forums brings contradictory opinions based on who is answering the post

 

It may just be time to sell the truck then...

 

well that's why you need to add up all these considerations but for about $400-$500 you can get a used good running engine from the salvage yard and for another $400-$500 have it installed for you so your looking at about $1000 to have your truck running great again.

or fot that same $1000 pull your head and have it reworked and reinstall it and just roll the dice that the rings and cylinders are still good for another 200k miles.

both choices are equally good ones but the least desirable choice, in my opinion, would be to sell it, I think the truck is worth saving but its what you value the truck at that's the key.

 

at least call these guys and see what they want for an engine http://sacramento.craigslist.org/ptd/5264691614.html

also shop around your area for the best prices on used engines with warranty

 

Random question....is it at all possible I have a stuck valve, which has a possibility of being remedied with seafoam? At this point if I seafoam my truck will I screw anything up? I need the current engine to last me til January at least because that's when I'll have a commuter to hold me over while the truck is down...don't want to screw anything up until then. The truck drives alright, but loses a ton of power past 3500rpms, so it's manageable.

 

the only way I know of valves to get stuck is from being bent and in those cases the only "fix" is a new valve and valve guide as well as sometimes the seat needs replaced as well.

if you feel up to the task you can try reworking the head yourself by following this video to relap the valves, then you just measure for all the new valve tappets you need to buy to get the right valve clearance and put the head back on the engine. you can probably do all that yourself and spend a few hundred dollars (and maybe a month of weekends and a few weeknights) to get it back running fine again

look art the process involved in relapping the valves:
https://www.youtube.com/watch?v=_d-eNJtnawI

 

Great resource. I was looking at this thread as a starting point. Like you said I can probably replace 2 valves, lap them myself, get a new headgasket and studs and do it all for under $300. I'm leaning towards this now..doesn't seem TOO bad. I just need to do research on properly on R/R of the valve springs without binding them.

 

My experience with rebuilding heads is the bottom end always fails soon after the head is rebuilt. Best to rebuild the whole engine.

 

have you considered a leak down test?

 

Didn't my adding oil to cylinder #2 with no increase in compression # already kinda let me know that it was a valve?

EDIT: I also can't find any information on removing the valve springs. Is there a special tool I will need? I know we have shim over bucket designs, so it's different than say a SOHC Honda engine.

 

You're right on your hunch but considering your compression numbers and your delima atm it wouldnt hurt to know more. Also im curious about how you did your comp test. ie removed all spark plugs or only one cylinder at a time, fixed number or cranks vs cranking for max reading etc..

 

Engine was cold and I removed 1 spark plug at a time and cranked for approximately 5 seconds for each cylinder. Also for the #2 cylinder I did a trial where I cranked for longer to see if the compression would go over 75psi and it didn't.

 

as suggested by others, I would get a replacement motor and swap it out over the weekend.

 

My 3rz was similar. I dont remember the numbers but the leak down indicated more leaks then I originally thought. The cost to rebuild a DOHC head properly cost more than I wanted to invest. It was more cost effective buying a new made in china head at about 5-600. You can find used long blocks on craigs from a private party for the same amount but you're taking a big gamble. Recycle shops in Rancho will charge you around 1000 +/- and will offer some type of iffy start up warranty. I went with a china head and rebuilt the bottom since it was overheated. If you know your bottom end is good then I would get a new head. If its bad then I would rebuild or find a used long block depending on how long you intend to own.

 

you can make your own valve spring compressor with a big "c" clamp and a simple spacer that gives you access to remove and replace the valve spring keepers. I used a 1/2" pipe fitting union that I cut out so it was a 3/4 circle so I could reach in to remove and reinstall the keepers to hold the cap on.

when you do the valves you need to relap every valve so they all seal the same and you don't have "issues" with another valve in 6 months

this video will show you what I replicated with tools I had on hand
https://www.youtube.com/watch?v=Hof8Aiw1cdo

or just buy this tool http://www.amazon.com/XtremepowerUS...178&sr=8-118&keywords=Valve+Spring+Compressor

 

A good used 3rz is easy enough to get. An engine swap sounds like a good way to go. Then rebuild your old motor as time allows and you have a great spare engine or sell it.