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Is this a 4K or 5K head?


Papay
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Have already purchased all the new bolts I could source for the head.  Today I bought valves, valve stem seals, and valve guides at the local parts shop.  They didn't have valve seats in stock, I figure I can get them from the machine shop.  

What else is recommended in a head rebuild?  Springs, keepers, etc?

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Check the rocker faces where they rub on the valve top. If they get a groove worn in them by the valve then you will never be able to set the tappets accurately as the feeler gauge will go across the top of that groove. A thou or two would be fine, but otherwise you can get the rocker tip re-machined if the groove is deep. I've never had a problem with springs, keepers or collets.

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It does, if you mill enough off you'll have the rocker tip start to slide off the edge of the valve. I doubt 0.5mm will worry it, but you can check when you get it assembled.  Worry about it when you're fly-cutting 1/2moons into the pistons to allow the valves to open without hitting them!

Its nowhere the problem of skimming an overhead cam setup, there it upsets cam timing as well.

I don't think the pushrods can be machined, I'd expect to space the rocker pedestals upwards the same amount.

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  • 1 month later...

Update, have the head ready to install.  I went ahead and refurbished an intake manifold and dual plane exhaust mani, including all new hardware.  Pulled the old head today, man what a mess.  It was corroded between the water passages and the edge of the cylinder chamber in a couple of places.  Right now I am searching for the torque spec for the head bolts.  

A word of advice regarding heads and intake manifolds.  My ports in the head were at least 3-4mm smaller than the intake.  Now, I did acquire them from different sources.  They aligned perfectly to the bolt holes and guide pins, so its possible that Toyota used different port diameters in different years or markets.  I took the time to make my own gasket and port match everything to ensure perfect alignment.  The exhaust lined up rather well.  But there again, the off-the-shelf gasket I originally bought was absolute rubbish, blocking at least 4mm of the exhaust ports.  Hopefully the homemade gasket will hold up.  I used the 'proper' material as recommended by everyone around town.  Being Philippines, I'm keeping my fingers crossed.    

Edited by Papay
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66NM for head bolts. The manifold bolts are 30NM and the rocker pedestals 24. Make sure the bolt holes in the block are really clean all the way to the bottom, same with the head for the manifold bolts.

I took about 3mm off the head around the ports to match the gasket, I think most stock ports are small. I could send you this gasket if you need one in the future, they're about $10 so mailing will cost more than the gasket I expect!

478748462_CFHeadported.jpg.bfa40b09da4411c0a9049b5f1b32a2cf.jpg

Are you going to tip the block over and get all the rust scale out of it?? It really collects around the back of the block and stops it cooling very well, especially if no-one uses coolant in the 'Pines. I just scraped it out with a bit of wire and a screwdriver. I've done a couple of blocks now.

343449729_CHblockrust.jpg.7eae9983fd0ec661ac7d43cdce8b2331.jpg

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Bless you for posting the rocker stand and manifold torques.  I couldn't find them anywhere!  As far as the block, no it is still in the van, this is just a top end job only.  Old head was totally FUBAR.... not only were most of the passages at the block stopped up with dirt and scale, the aluminum had corroded right up to the edge of the cylinder chamber in a couple of places.  One corner of the casting itself around the front left head bolt (the exposed bolt) was either broken or corroded off as well down where it meets the block.  Before I got started I procured the necessary taps and dies, so I have been re-tapping all the critical holes as I go.  Its amazing how much crap is down there.  

Earlier we had discussed the 2-3mm step in the chambers of this cylinder head.  The shop ended up shaving it twice, totaling about .75mm so I still have plenty of relief in there.  Now here is what is interesting:  Both this head and my old one have a casting mark '100'.  The old head has been shaved much more, you can barely see the former step in a few places.  This is interesting because of our discussion about the pushrods.....knowing the mechanics around here, I can almost guarantee whoever worked on this engine before just re-used the stock pushrods.  So at least with this newer head, it should take me a step toward correcting the rocker geometry rather than making things worse. Gonna take some measurements today during install.

I need to dig through here and find the rocker adjustment procedure. 

rebuilt-head.jpg

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" not only were most of the passages at the block stopped up with dirt and scale, "

Sound like the block should definitely come out and be cleaned out.. it will be just as bad inside there as in the head & it will kill water flow. Also, check your new head gasket, some of those holes do not go through at the front to force circulation to the back, so they would be blocked at factory.

" I have been re-tapping all the critical holes as I go. "   Great idea!

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42 minutes ago, altezzaclub said:

" not only were most of the passages at the block stopped up with dirt and scale, "

Sound like the block should definitely come out and be cleaned out.. it will be just as bad inside there as in the head & it will kill water flow. Also, check your new head gasket, some of those holes do not go through at the front to force circulation to the back, so they would be blocked at factory.

" I have been re-tapping all the critical holes as I go. "   Great idea!

I had the shop weld up 4 of the holes in the head where the new gasket had omitted the passages.  But the block will have to wait until later.  I'm planning to pick up a spare and rebuild it for when its needed.  

Regarding rocker adjustment, my engine is a 5K, but the rockers look like this.  Actually both heads I have are like this.  So I'm assuming there must at least be a zero-lash adjustment needed, even though the forum here seems to indicate that only mechanical lifters have adjustable rocker gear. 

rocker.jpg

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Hit a snag.  Two of the 8 rocker stand threads look like they had been previously stripped and maybe heli-coiled.  Did not notice this on disassembly, and they tapped normally when I ran the taps into all the bosses.  Now they will not hold the torque of the bolts.  Went to all the normal parts shops here and no-one has even heard of heli-coils.  So it looks like I'm going to be drilling these oversize unless I get a better suggestion.  Fortunately, the old head I removed had 4 such oversize studs....maybe this is a common problem in these engines.  Sucks though, I should have installed the rocker stands prior to installing the head.  

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Pulled the head again this morning, drilled the two offending holes oversize and re-tapped them.  I was a little iffy about doing it with a hand drill, but it worked out fine.  I had my old head to practice on to make sure I wasn't going to bugger up the new one.  So now the rocker stands have 4 bolts and 4 studs.  It is what it is. 

I'm torquing down the rocker stands right now and setting the initial rocker clearance.  It occurs to me that all I have to do is check each rocker in the closed position, to make sure there is no clearance.  Should be simple enough to rotate the engine through a few cycles until I can get each valve to close.  The hydro lifters will pump up and do the rest.

If I'm measuring right, the old head was 3MM thinner!  Now I'm feeling nervous about these pushrods.  They measure 186mm, I'll throw up a picture here in case it looks wildly off to some of you.  This is my first K motor, so I don't have a comparison. 

EDIT:  Ok there is a little sticker in the fender well specifying intake and exhaust clearance, so I will follow that.  

Edited by Papay
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So the pushrods should be 3mm too short, which is fine if you can take that up with the adjusting bolts.  Do some research on the arc the rockers must swing through and check that they don't run onto the edge of the valve at full open. I can't find a picture on the net to demonstrate it, and its hard to draw.

Try this-

What clearances do they list?

Edited by altezzaclub
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