pstallard

I blew the head gasket on my ’87 4Runner, and I’m trying to replace it myself… I’ve never done any engine work this involved before, and I’m probably in way over my head, but I’m nearly broke, and desperately need the truck, so I’m pressing ahead…

I got the head off, took it to a shop and had it checked and re-surfaced, bought the gasket kit, and I’m ready to start trying to put everything back together. I have two concerns about the timing chain, though:

1. The guys that cleaned up the head for me noticed that there are a couple of grooves where the timing chain was cutting into the head itself. They said it might not be a big deal, but that I should check the chain, tensioners, etc. for excessive wear and any other problems. The problem is, I have absolutely no idea what to look for, and I’m having trouble finding any info on this. Can anyone give me any pointers on how to check for wear or problems (preferably without pulling any more of the engine apart, and without removing the chain completely?)
2. When I removed the nut that holds the upper chain sprocket to the camshaft I did mark the chain and the sprocket, and also wired them together… But what I didn’t do was make sure to keep tension on the chain, to make sure that it didn’t slip on the lower gear… (Oops.) Can anyone give me detailed steps on how to get the chain set back up correctly once I have the head back on, again preferably without removing anything else? Obviously I don’t want to get it all back together and have the timing wrong, start it up and shatter all my valves or something…

I have to stress again that I’m on a very tight budget here… I’d love to do everything “right” while I have things apart, but I really have almost no money at all to spend, and sadly I need to do pretty much the absolute minimum to get the truck back together so I can use it…

Thanks!

myyota

You need a new timing chain kit, yours is bad. basicly if you pull the head to replace the head gasket you always replace the timing chain at the same time, otherwise you will end up tearing it a part again down the road to do it.

92 TOY

look down more. see if the chain has dug into the timing cover. I bet it did.

the groves on the head won't bother a darn thing. and I would bet your chain is much harder than that had.

BUT.....

see my "THREAD B" in my sig....and you will see what happens when the chain erodes the timing cover.

my opinion is that you probably didn't blow your head gasket at all...or maybe you did....but if you don't have timing chain guides....which apparently you don't any more because they prevent the chain from rubbing....you are heading for trouble.

www.engnbldr.com get he front end kit....cover, chain with metal guides, and if you can afford it, oil and water pumps and you'll be good to go. get the oil pan off and cleaned out from the debris that is likely in there from the timing chain guides.

again....read my thread. https://www.yotatech.com/forums/f116...cement-212688/

crashnburn80

If your chain had enough slack that the tensioner couldn't take it up and it was hitting the head, the chain needs to be replaced.

As the above post mentions, you probably have bits of your timing chain guide in your oil pan. You should drop the pan and clean those out. On my truck, the timing guide remains had nearly clogged the oil pickup, causing low oil pressure at idle. Engnbldr sells a kit with a steel guide to help prevent this problem in the future.

If you don't replace the chain and guide, the chain will saw into the coolant passagein the timing cover dumping your coolant into your oil pan, which will quickly destroy your motor.

pstallard

Thanks everyone. What you're saying isn't good news, but it makes a lot of sense. So I'm starting work on removing the timing chain cover, and after that the oil pan.


"92 TOY", I really want to thank you especially, for the *very* helpful post about your own repair job, and also for the link to engnbldr.com. (That's gonna save me a ton of money right there, wish I'd known about them sooner.)

92 TOY

i do stuff the hard way so you don't have to.....and thanks for the compliment.

nightstalker

Be careful with your water pump bolts, if I remember correctly they need to go back in a the holes they came out of, there all different lengths, my mind is old and feable so someone chime in.....

92 TOY

as I recall, this is true.