spacecadet

Hello, after selling my 84 4runner a couple years ago i have regreted it ever since.

2 days a go i found a 85 truck on craigs list, supposed rebuilt engine 10k miles ago, 38's flat bed, pretty junky but kind of also right up my alley. I checked the dip stick, nice dark oil, dark enough to know it was not just dumped in to cover something but was no like a milk shake or anything. Owner started it right up, i took it for a test drive, when comming to a stop or clutch in you had to give it gas to keep it running, i thought it was just an idle or fuel screw issue. so i ended up buying the truck driving it home and trying to get the idle right.

Checked the timing with the vacum capped off, it was way past 12* wtf? so i rolled it back to 0 and it just dies.

So from there i thought must have skipped a tooth, so i got a stick put it in spark plug hole found top dead center and timing mark lined right up with 0* and dizzy was right on #1.

So then i poped the bolt of the balencer to make sure the key and the timing mark were aligned, they were.

So then i thought it was a spark issue, checked the wires, 2 of them were bad so i replaced all the wires, the rotor the cap and the plugs.

still wont run at 0*

then i checked soemthing i should have done first thing when i went to look at it, the radiator cap. pulled it off this is what i see:



So then i did a compression test:
#1 89psi
#2 89psi
#3 90psi
#4 88psi

i also pulled the valve cover, the timing chain/guides look in good shape, if someone told me they were only 10k miles id belive them.


anyway, is it pretty safe to assume this thing needs a head gasket?
any other ideas of what i can check?


thanks for any input.

yotaman85

your name isnt cameron is it?

spacecadet

no sir why do you ask?

yotaman85

never mind, a buddy of mine uses the name spacecadet for everything...

ill check some things out and try to help you with your problem. but if your running 88-90psi in your compression test in all cylenders its worse then a HG.. if i was you i would flush the hell out of the motor and radiator. then pull the spark plugs and put a small amount of oil in each cylender then do the compression check again, if its better your rings are leaking, if not, it might be your valves. check to make sure your valves are adjusted correctly if it is not the rings.

well go from there..

spacecadet

sounds good.

I drained the coolant, pulled the t-stat, jammed a hose in there and flushed it out good then filled it up with 50/50.

Will try to start it up later to warm it up and perform the wet test, tried earlier but start made a dreaded click

spacecadet

wet test done, pressures went up maybe i mean maybe .5 psi, not really enough difference to measure accuratly.

are my rings so ˟˟˟˟ that oil just flys past them? i would think my plugs would look like ˟˟˟˟ and i would be able to feel/hear that kind of problem.

going to check valves now, never checked valves on anything thats not a motorcycle i sense alot of fail about to happen.

spacecadet

all valves check out in spec.

inspected lobes on rockers to ensure they were neutral at TDC, they were.

Not sure what else to look at here before i rip the head off.

spacecadet

so im assuming it has to be head/valve related so im pulling the head.

peow130

Probably your best bet.
Inspect your cylinder wall for glazing or scoring.
Maybe they ran a synthetic and the rings never wore in, like they should have.

spacecadet

got head off:


cylinder look good, still have a nice cross hone visible, not scored look good:
only question is should there be a small gap at the top stroke of the piston in the cylinder?? the piston does not come up flush with the top of the block, i assume to prevent damaging valves but i dont know for sure:



if the pistons have flat heads does that mean i have an 85+ block? i ask because i do not have the mickey mouse on the side and there is a head local for 85+ so id like to know.


here is the head:

i am not sure what to look for or check with this, or should i just take it to a machine shop and have them inspect it?


summary:
should the small gap exist at the top of the piston stroke in the cylinder?
Is the block an 85+ because it has flat pistons? it does not have the mickey mouse on the exhaust side


Thanks for any help you can give

spacecadet

i think that the guy rebuilt it with the wrong pistons.

The head is an 84' no pear exhaust ports, and the block has no mickey mouse on the exhaust side so i assume its an 84, yet the pistons are flat topped which im pretty sure 84 pistons are doughnut style.

I guess i need to find a tape measure and measure my block height to verify.

spacecadet

no laser stamp on the side, head has round exhaust ports and the gap at the top of the stroke in the cylinder just look wrong.

so im about 99% sure that these are the wrong pistons for the block, which i think would explain the low compression. it is bored .02 over but even then i would imagine a higher compression on the test.

Could anyone confirm if the pistons should travel higher in the block?

thanks

spacecadet

im about 99.5% sure now. after searching build up threads and pictures all 84 blocks i see have doughnut pistons that dont sit nearly that far down.

Can i just drop some .2 over 84 pistons in with just re-honing or do i need to pull the block and measure the new pistons and get it bored?


Thanks for any help/input you can give

spacecadet

well engnbldr confirmed i have the wrong pistons.

Took the head to the machine shop, turns out the PO put the cam journal caps on backwards, pretty much destroying the cam and head.

got a replacment head from yoda jims, machine shop confirmed its rebuildable, now im just trying to decided if i just want a basic rebuild job, or to send it off to engnbldr for OS valves and a 261 cam hmmmm

EFI85

dont mean to butt in but it might be worth it to have the bottom end checked out as well With the looks of it who knows what might have been done to it by the PO . Also how much you gonna have into a new used head and having it rebuilt ? Might wanna consider a brand new engbldr.com stock or HP head and one of their cams .(i have stock style and cam and love them). $348 for a new heads is pretty reasonable . I bet if the bottom end is good you could get everything from engbldr.com and have it back together for a reasonable price . just my .02 good luck

spacecadet

ty for the concern!

I checked the crank/crank bearings and plastigauged everything, everything checked out. so im happy with how the bottom end is.

as far as a head goes, no one re produces the >84 heads so you have to find one used and have it built, the head was only 50$ from yoda jims and 20$ to have the machine shop give it a once over. Engnbldr quoted me 350$ to rebuild the head OS valves/guildes/seats so i figure if i want to go that route thats my best bet

EFI85

My mistake I thought he had heads for all years .. Either way I sounds like you got a handle on things .. Be n let us know how it turns out !! Good luck

spacecadet

Got pistons rings HG bearings ect, threw the engine back together.

Ended up getting a weber 32/36 from wcd on ebay.

picked up what i belive is a thorley header off craigslist, welded up a custom exhaust dumps out right behind the cab routed inbetween the bed mounts, no cat, thrush muffler.
I can register where emissions are not a problem and all i can say, i think emissions systems are great for the environment and hell most are good for your car, but getting rid of that vaccum nightmare feels sooo good.

got a tach, and a actual oil pressure gauge.

got everything set up, oil in, coolant in, weber on pulled the plugs cranked it over for about 15-20 sec, watched the oil pressure climb, start getting gitty.

put the plugs in hook up the dizzy, turn the key, starts up really quick super exciting.

runs really smooth, although all i did was zip tie the linkage for 20 min @ 2k rpm to break in the cam but just sooo much better than before, im really stoked about it.

i forgot to tighten down the heater hoses so had a little leakage, nothign major.

shut her down, change the oil, check the valve clearance, retorqued the head bolts. everything looked great!!!!

rworegon

It's always great to hear an engine come back to life. Nice work!

SR25JD

I Had The Same Problems,W/My 22 RE Dropped Allot Of Money ,I Really Don't Have.I Changed Out The Map Sensor,And Replaced A Set Screw On The Trottle Plate And Changed,The Timing Chain.Starts Right Up ,Idle's Fine.Still Have A Little Lifter Noise,Need To Get The Right Lifter Adjustment's/Spec's And Torque Spec's And I Should Be Ok MAP SENSOR Part #22250-35020 Second Set Of #'s197100-2470 ID HIPPOMDENSO /7 Prong Inlet W/Wire Clip.Hope All This Was a Help T You,I Had To Find Out By Trial and Error.....God Bless Joseph