timing chain guides

[coopab]

I'm in the middle of reassembling my 4.0 OHV with new heads and before I put it all back together I want to replace the timing chain guides. I bought a set including a timing chain and guides, but don't want to unnecessarily change the valve timing (Up to this point the engine is in exactly the same position it was in when I took the old heads off.)
I've read (on this forum????) that the tick_tick_tick that many of these 4.0 engines have on startup is due to collapsed timing chain guides, so I'm thinking I might be better off just replacing the guides without messing with the timing chain.
Expert opinions welcomed, valued, and applied. Other opinions, not so much.
coopab

 

[downer]

not an expert, but much of the ticking on the OHV is due to poor oil flow to the rocker arm/pushrod contact points. takes a while to get oil up there after startup.
timing chain noise with the 4.0 SOHC engine is much more common than on the OHV.
i think the timing chains are reliable on the OHV engines, but whether to change it would depend on mileage. opinions will vary. if you are over 200k and you're at a good spot with assembly then do it.

 

[adsm08]

Yeah, timing chain noise is all but unheard of on the OHV. Almost 100% of startup and ticking type noises on the OHV are related to the lifters and pushrods.

 

[bobbywalter]

ohv or sohc? there is a geometric difference between the two engines.


you say ohv. ohv if the engine was using a valvoline type of oil at 3-5 k change intervals i would expect 250-300k out of system if kept in half ass tune with plugs and fuel filters.

the sohc engines are a pain in the ass to deal with. if there is issues with the guides and or cassettes i would pull the engine and do it all if the vehicle is to remain a driver for the long term. get a book for it.

 

[coopab]

not an expert, but much of the ticking on the OHV is due to poor oil flow to the rocker arm/pushrod contact points. takes a while to get oil up there after startup.
timing chain noise with the 4.0 SOHC engine is much more common than on the OHV.
i think the timing chains are reliable on the OHV engines, but whether to change it would depend on mileage. opinions will vary. if you are over 200k and you're at a good spot with assembly then do it.

Well that is my situation. I've been taking my time doing this and since I already have the parts I might just as well do the timing chain and guides.

 

[RangerSVT]

If you're not removing the cam, or pulling the crank, you should be able to rotate the engine til the timing marks line up on the gears, pull the cam bolt, remove the timing chain set as one unit, then install the new set...

SVT