'68 & 74 Eldorado's

[Viator Trudeau]

A few years back in 07 I replaced the timing gear set on my '68 W/O dropping the pan.  Worked out very well.
I plan to change the timing gear set on my '74 the same way.
I have not gotton into the '74 yet, but are the engines front ends the same, will the gear set be the same and the front end lay out be the same??  I don't have it apart yet, nor have I checked on chain slop yet.  Can some one give me a heads up on this.
Thanks.
V. Trudeau  # 8697
I have not looked for parts yet, that should tell me a lot about the '74 change.

[TJ Hopland]

The front of the engine is basically the same.   There were slight changes to pulleys and such.   Also changes in the overall front layout of the car with the core support and radiator location so the space you have to work in may be different.

Chain is the same 68-81.  Everyone says get a Cloyes brand.   They have a stock type link belt chain that is fine.  They also have roller (bicycle) chain options if you want to spend a few extra bucks.   I hear bad things about other brands especially stories of the crank sprocket shattering.   The basic link belt one does not have the alternate timing key slots.  The rollers do.

Same process if you are choosing not to drop the pan (which in an Eldo requires you to separate the engine and trans one way or another).   The trick is to drive the 2 big pins into the block enough to clear the cover , this lets you lift it off the front of the pan.   Once its out you can drive the pins the rest of the way through the block being sure to catch them, not let them drop into the pan.  Once you get the cover back on and hooked on the front of the pan you drive the pins back into their original depth.   Down sides to this process is you don't have as good a chance of being leak free as if you drop the pan.   Chance of dropping parts in the pan.   Don't get a chance to clean the bits of timing gear and valve guide seals out of the pan and oil pickup tube.   For some it may be worth the risk because the alternative is to remove either the engine or transmission.

While you have the timing cover off its a good idea to weld a couple nuts on the inside where the 3? small 1/4-20 (7/16 head) water pump bolts thread into just the cover.   More often than not these holes are stripped or almost stripped from someone over tightening those little bolts, its easy to do since the others are much larger and can take a lot more torque.  Also that is the only spec given in inch pounds, the rest are in foot pounds so your brain kinda goes on auto pilot and tries to torque them to 115 foot pounds which obviously aint gonna happen with that size bolt and only about 1 1/2 thread thickness in the cover.   If they don't look stripped now I would still do it so that way it won't ever be a problem.   It really stinks to have a slightly leaky water pump and go to give em a little more and suddenly you have a big leak.    Its easy to do regular nuts will work.   Thread a bolt in the front then thread the nut to the back finger tight and weld it.   Can be stick, mig, tig, whatever.   Its steel.  Plenty of clearance.  Can't see it from the outside so no one will ever know.   

Before you ever do anything related or that could be related to timing its always a good idea to get your timing light out and take some readings at various rpms with and without vacuum connected.   Write down those readings.    Its always nice to know where you started from.   Take pictures.   Take notes.   Mark wires.   

[Viator Trudeau]

To  T. J. Hopland   
From  V. Trudeau
Subject   ' 74 timing chain.

Thanks for the advice, it will give me a heads up on the job.
On the '68 I could turn the engine W/ a wrench on the power steering pulley nut,
The '74 is much harder to turn over so it will take some one on the crank nut and some one looking at the timing tab.

V. Trudeau

[Viator Trudeau]

T.J.  you commented that the" crank gear" in some replacements  cam gear sets can disintegrate.
Are those gears made of powered metal?  That process cannot be as good as one machined from round stock.  I do not know what the powder make up is.

V.Trudeau

[TJ Hopland]

Not sure what or how they are made.   Just know I have read several reports where either the sprocket breaks on installation or shortly after starting.  They were all store brand OE style sets.

[Viator Trudeau]

Thanks again for the advice on timing gear set change on my "74 eldo.
Comments on crank sprockets W/ three key way adjustments, what would be the benefit of using another key way , will it improve power on this 500 C.I. D. engine if I go to the next adv. timing key way?
Which key is for standard operation?
On the crank sprocket breaking, it the crank  O. D. is on the high side and the powdered sprocket in on the low side of clearance the extra press fit could fracture the powered metal sprocket
just in getting it on the stub.
V.Trudeau  #8697