J-Dog

Howdy,
Picked up a 95 4Runner with suspect head gasket failure. Motor had been partially stripped by previous owner, then parked for 12 months.
Motor has 286,000km / 177712 miles on it. The Interior and exterior is in pretty good condition, motor runs on duel fuel (LPG and Petrol). Just tidying this ride up to cart my work dogs around. I average around 130,000km a year driving so prefer to give motor a complete rebuild so I can cruise on the highway.

How it started



After a few hours



Main and big end bearings look like new, even with 286,000km on them.
Plan is to measure up crank before re-grind, re-bore and deck block, completely recondition both heads with new everything. Need to hunt around for a set of new cam shafts.

cbr600rx7

Looks like your elbow deep already. Keep us up to date on your progress.

hippystyle

getting ready to do the same maybe I can catch up lol

cbr600rx7

What's wrong with your current cams?

J-Dog

One camshaft was left on the bonnet in the open for 9 months whilst the other was exposed to condensation. Both cams have a lovely patina of heavy rust. I will get the shop to have a look at them and see if they will clean up but not counting on it!

cbr600rx7

Send them to Crower they can spec and grind them if needed to what ever duration, LSA, and lift you want. $175 for the pair and you know they will be right.

J-Dog

So started cleaning the block out, the amount of rust and crud in the water galleries was amazing. I've decided to drop the block into the molasses bath for a couple of weeks before having it hot tanked. Looks like some heavy pitting in the no 6 bore, up the top. I will inspect is when I pull the block from the tank but looks like initially will have to test bore to see if it will clean out at 20 thou under or just I will have to re-sleeve it.





New parts are slowly rolling in like the full gasket kit, welsh plug kit, have ordered new oil pump, timing belt kit, water pump ect. Will measure crank during the week, but looks almost like new so anticipating a good clean and linish and a new set of STD bearings.

J-Dog

Update - So pulled block out of molasses mix after 7 days..... Bugger all effect on the heavy rust inside the water chambers / channels so decided to have it professionally dipped and cleaned before dropping it off to the engine shop for a re-bore. Block was test bored to 40 thou over as I had a brand new set of pistons on the shelf. All the bores came out perfect except one, so opted for a re-sleeve then a re-bore to match the pistons.
Crank has been re-ground 10 under and thrust faces have been kept as standard.

I've managed to clean up the cam shafts and are in really good condition. stripped both cylinder heads down and on inspection, plenty of corrosion on the Right head directly on top of the bore with bad pitting. Looks like it may have been leaking coolant into the cylinder for some time before it decided to let go. The valve seats on the centre inlet and exhaust seats on right hand head have dropped slightly from the block, most likely due to getting hot I would imagine, so these will be replaced and re-set into the head. Everything else looks good.

Pretty much have all the parts here now for when the block is ready for picking up, so can get straight into the clean and re-assemble.

Stay tuned for more action! (AND PICS)

cbr600rx7

Check your valve spring pressure. Especially since yours is high milage and was exposed to weather. Odds are they will need to be replaced.

coopster

Lots of fun. Or work. Two sides same coin. I gotta ask altho it exposes my stupid, but what is the molasses bath?? Are you down under somewhere?

J-Dog

G'day,
Yes, from Australia. The molasses bath is and old school method of cleaning up rusted metal parts. If you google molasses rust removal, plenty of stuff on the interweb about it. The only problem is it can take a few weeks depending on how rusty the part is, the size of the part, you mix ratio ect. Can be very effective and cheap if you have the time and patience.

J-Dog

Cheers Mate,
Never even occurred to me to check the spring pressure! Hopefully engine shop will do it but will make sure they do.

J-Dog

Well finally picked up the block, crank and the rest of the new parts.



Unfortunately the heads are a little worse for wear! One head is extremely warped and most of the valve seats have dropped slightly. The other head is slightly warped. Looks like I need to buy new heads...........

cbr600rx7

That sucks. The deck looks good. Are you considering MLS head gaskets or just OEMs?

J-Dog

I've got MLS head gaskets on the shelf so will be using them. Have decided to purchase 2 brand new complete heads rather than messing around with second hand heads and hoping that they are not warped plus the wear that the valve train already has due to the 290,000 odd km already traveled on them makes brand new re-manufactured heads seem more appealing.

Just waiting on some freight prices but should have both heads landed for around $640US dollars. Will need to add a little extra as will get my engine shop to double check all the valve shim clearances ect, they are advertised as straight bolt on heads but from experience, this is never the case.

cbr600rx7

Very true

J-Dog

So engine is on its way to being re-assembled, got held up on other engine jobs. Need to give the block a nice lick of paint.


Literally everything has been replaced with new parts or recondition items. Brand new heads are on the way, hopefully here by next week.



The dead parts bucket is filling up quickly

J-Dog

Finally the new heads arrived, a quick trip to the machine shop to measure and check them over, a few mods and they were ready to go. Engine is now pretty much re-assembled, just waiting on a couple of parts which will arrive in a couple of days. Looking forward to finally getting it in and fired up.

mattyboi

Good job, would love to learn how to rebuild engines one of these days! What do you do that gets you 130,000km a year on the odo?

J-Dog

I travel around 65,000km for work, then the rest is usually road trips, and driving around looking for old cool stuff!