Domaas

So it was time to replace the timming chain. it had too much slop in the chain, almost 12 degrees of rotation before rotor movement.

anyhow, i tore down the front of the engine and set the timing at tdc compression, verified tdc and rocker postion, all looked good, till i looked at the timming marks on the gears, the gam gear was 180 out. triple checked everything 3 times..yup, it was on spot. the only way to get the cam and crank gears to line up was at TDC on the exhaust stroke.

yeah yeah, enhine rotated over hundereds of time to check. form the looks of it this engine has been torn down before by the PO..mis match fasteners and what not throughout. I ran good before, so best i can tell is the cam pin dowel was in the wrong hole at some point, since the engine can not run with the cam 180 out.

btw its a 88 renix.

anyone else ever see this?

freegdr

valve timing and ignition timing are two different things distributor not removed set valve timing correct your good to go

sthon

Was the dist installed 180* out?

Domaas

nope, this was a runner, set dtc, on the piston, then verified with the dizzy..all is well. this cam has two, dowel pin positions 180 off of each other. If i pull the dowel and set in other position then the cam marks will line up.

Domaas

Im guessing the cam dowel was placed in the wrong hole on the replacment cam.

freegdr

motor was running correct your just replacing timing chain correct dist and cam have not been removed ?

Domaas

as was stated in first post, mottor wan great, chain was trashed. rolled motor to tdc compression verifying both pressure(thumb) then actually tdc(aluminum tig filler rod down plug hole) to check actual TDC. dizzy was at #1. THEn tore down front of motor, marking crankshaft location NOT balancer(those like to slip)

tore down, double check alll the above..then notice cam gear dot on the top..whent through and check another 30 times or so( i have changed lots of cams before SBC,cat, cummins, deutz, handa bmw..ect) and thought , thats wierd. from all acounts cam dowel was miss installed. already set timming, gonna button it up and forget about it.

edit; dizzy was not removed.

freegdr

as long as it was put back same way it came out you good

Domaas

thats what im thinking, may be awhile though, upgrading the radiator,trans cooler, head light harness, and adding the triple fan kit and wiring while im in there.

freegdr

heard mixed issues with bigger radiator and three fan set up good luck

Domaas

yeah, i heard kinda the same thing,but my fan clutch was trashed, and the original fan shroud..missing..original e fan..cracked. so i quess it couldn't be much worse than that?

Domaas

just an update, buttoned up the front end, crank, crank, then fired right up! some 180 on the cam pin it was..go figure.

jebbie

Domaas - i went to replace my timing chain/gears . mine is a 1988 jeep wagoneer 4.0. i found the same thing. my cam gear was 180 off. i was confused . i was at tdc on #1 comp stroke and rotor at #1 post. i was kinda afraid to take off the chain/gears as i thought i had something wrong. when the timing marks lined up it was in exhaust stroke on #1 and rotor pointing at #6 comp stroke. so yes this is happening and isnt a freak thing. i just wonder if jeep by mistake put the cam pin in wrong hole. my new set of timing chain/gears are the same way. it was running good before i started to replace so i guess il just put it back together and hope it runs. i was confused for a while but i bet jeep for some reason put that pin in the wrong hole as this is all i can figure! others please chime in and let us know if you have run into this before. im still looking for that post that says jeep knows about this issue and says tdc is with cam gear 180 off. i called local jeep dealer and asked to talk to the best timing guy in the shop. he has not heard of this and said they dont do much with these motors as they are great motors. i guess thats a good thing!!!! once again mine is a 1988 motor 4.0 . thanks

jebbie

domaas - i forgot to say i didnt touch the distributer and #1 post is at about the 8 oclock spot with screw down screws at 5 and 11 oclock looking at it from the front of jeep. thats where my dist. sits as i post this. thanks

Domaas

glad you got it figured out!, I hoe that anyone else that comes accross this post, it will help them as well. Mine is running great after the new chain, and some basic tune up goodies.