87 with 68k original miles. should I replace timing chain while its stripped?

[weider1717]

Just stripped it down and replaced the water pump and thinking DANG I should have went a step further and replaced the chain.

think it would be a waste of time at 68k miles or no? i plan to drive it more from now on.

it's still stripped manifolds etc off just due to wanting to restore them so I have plenty of room trying to see if I wanter to yank that pump back off and do it or not.

will I have to drop the oil pan and change that gasket if I do?

thanks

[jetmech85]

I would based on what my 67,000 mile motor looked like. Clean inside indicating proper oil/filter changes, rod and main bearings original and perfect, good compression, lots of timing chain wear and cam bearings showing wear on the lower half of the bearings. Replaced cam, lifters, cam bearings, timing set, seals and gaskets. I understand cam bearings may be impossible with engine in the frame but I would at least do the timing set if it were me. I also did front and rear seals and front transmission seal while the engine was out but my old ones were not leaking. Use the one peice pan gasket and if there is sludge a new oil pump and pick-up.

[jlk]

If you don't mind doing the work and buying the parts is not an issue then I would go ahead and do it. No, you don't have to drop the pan. Is it a small block? Buy a quality set i.e. Sealed Power, etc.

You could take the distributor cap off and rotate the balancer back and forth a bit and see how much the rotor moves. If you turn the balancer much and the rotor doesn't move then the chain is stretched a bit.

[cadillac_al]

It's not a fun job with the oil pan on and it's a tight fit getting that timing cover back on. Some people even trim the ends of the timing cover around the seal to get it back in with the oil pan on. Then if you get it back on without leaking that will be a small miracle. I always prefer to remove, or at least loosen the oil pan so I can get it sealed up good. That's hard to do on a Camaro and most GM cars for that matter. I don't think the C10's have that much more room but there is slightly more room to loosen an oil pan. I would verify how loose it really is before deciding. It would be nice to do it but it's not a simple remove and replace operation imo.

[gmachinz]

You need to drop the pan a couple inches. The lower timing cover lip is not going to want to go into place because it'll get bound up on the crank shaft snout. Put it this way:can you remove the timing cover without dropping the pan? Yes....with a little effort. Can you "slip" it back on the same way? No, not very easily at all. And there is no sense in breaking the pan seal and then NOT replacing it. You can completely remove the pan with the engine still in place so I would drain oil, pull pan, replace oil pump and screen, then use a Fel-Pro 1-piece pan gasket and then replace the timing set.
The issue is that the OEM link chain wears much faster than aftermarket double roller chains and, the stock cam sprocket gear has a nylon coating (for a quieter running engine) which wears off pieces of plastic over time and that furthers the progression of timing chain slack and clogs up the pickup screen-effectively reducing oil pressure. So, with everything at stake, it very much worth the effort and since its mostly tore down anyway-I'd say jump in and do it! That motor will run soooo much better you'll be glad you did it!

[weider1717]

Ok,

Since I plan to keep the truck I might as well so a couple questions.

1. should I go to GM dealer and get a "timing set"? I like oem or is this an area where not to go with oem?

2. by timing set you mean you replace the gears and chain correct? (sorry never done this) had in my mind I was just replacing the strecthed chain but thinking about it and the nylon is on the gears so I think I know the answer but making sure.

3. what is the recommened timing set / brand you guys have came across as being good? ex sealed power etc..

4. gaskets I will use felpro, and maybe the slightest smearing of permatex #2 or something (any suggestions)

thanks, and I hope this helps the idle it isn't GREAT and I suspect the chain may be part of it.

[BigBlocksRule]

Was GM still using the plastic chain then? If so, definitely replace it. Vortecs run a true roller and I haven't seen excessive stretch in those.

[bnoon]

Replace it with a double roller. Super cheap from Summit/Jegs/PAW/etc. and way better than the stock single chains.

[gmachinz]

I deal with performance parts besides my harness work so I prefer certain brands and am partial to DynaGear-HD double roller (not just double rolled-get the HD version-much stronger chain links!) If this is your first time doing a timing set replacement, you will want a couple tools-some are required, some just make life easier.

1.) Pull LH valve cover off....make sure both #1 valves are closed.
2.) You need a harmonic balancer puller AND installer tool kit (parts store rent them)
3.) If ordering parts from Summit, also grab a crankshaft socket for a SBC.
4.) Buy a HD 3-jaw gear puller (or rent one) from parts store
5.) After removing balancer and timing cover, carefully flatten out cover edges so it will re-install perfectly flat-and carefully tap new seal in place.
6.) Use your crankshaft socket to rotate crank so that your gear marks are aligned at 12 and 6.....then remove the cam sprocket, pull chain and use gear puller to remove crankshaft gear-you should still have both #1 valves closed and marks should line up pretty much dead on but could be slightly off due to worn chain-but thats OK at this point. DO NOT bump engine over for any reason.
7.) Now reinstall new timing set making sure marks are aligned at 12 and 6. Clean the cam bolts on a wire wheel and dab some blue loc-tite on the threads before torqueing down. You need to hold the cam gear in the chain up in place while using a large socket over the crank snout to "gently" tap the crank gear on-as it seats, your cam sprocket bolt holes should line up. If slightly off, use your fancy new crankshaft socket to slightly rotate crank so that the cam sprocket holes line up-paying attention to your timing marks.
8.) Reinstall new timing cover and balancer. Then, reinstall pan.

[weider1717]

Originally Posted by gmachinz

I deal with performance parts besides my harness work so I prefer certain brands and am partial to DynaGear-HD double roller (not just double rolled-get the HD version-much stronger chain links!) If this is your first time doing a timing set replacement, you will want a couple tools-some are required, some just make life easier.

1.) Pull LH valve cover off....make sure both #1 valves are closed.
2.) You need a harmonic balancer puller AND installer tool kit (parts store rent them)
3.) If ordering parts from Summit, also grab a crankshaft socket for a SBC.
4.) Buy a HD 3-jaw gear puller (or rent one) from parts store
5.) After removing balancer and timing cover, carefully flatten out cover edges so it will re-install perfectly flat-and carefully tap new seal in place.
6.) Use your crankshaft socket to rotate crank so that your gear marks are aligned at 12 and 6.....then remove the cam sprocket, pull chain and use gear puller to remove crankshaft gear-you should still have both #1 valves closed and marks should line up pretty much dead on but could be slightly off due to worn chain-but thats OK at this point. DO NOT bump engine over for any reason.
7.) Now reinstall new timing set making sure marks are aligned at 12 and 6. Clean the cam bolts on a wire wheel and dab some blue loc-tite on the threads before torqueing down. You need to hold the cam gear in the chain up in place while using a large socket over the crank snout to "gently" tap the crank gear on-as it seats, your cam sprocket bolt holes should line up. If slightly off, use your fancy new crankshaft socket to slightly rotate crank so that the cam sprocket holes line up-paying attention to your timing marks.
8.) Reinstall new timing cover and balancer. Then, reinstall pan.

thanks! very good info. Looked at the pan and cover up close after work today looks like I can infact remove and replace the timing chain cover WITHOUT touching the oil pan.

I'll replace the gasket between the two and I should be good to go of course along with the cover gasket itself.

I'm sure it's a 2 piece gasket so the gasket between the pan and timing cover should be individual being it's stock and never messed with so I think my plan not to have to remove the own should work.

[gmachinz]

Well...try it out but, keep in mind that the lower timing cover seal is pretty thick and it requires you to install it at an angle however-the fact that the crank snout is in the way AND you still have to align the timing cover dowels too-it looks easier to do that it actually is without dropping the oil pan.

[weider1717]

Well, I ended up giving the timing chain a good check by rotating the crank and feeling and also looking at when the distributor rotor started to turn.

Did this several times and the slack indicated 5 degrees and looking online 3-5 is normal and 10+ means to replace it and some say replace it at 7 degrees.

Anyway, looks like it's not needed at this time so I'll leave it as is and probably whenever it hits around 125k or so just pulls the engine and go through it completely.

if you think about it when you also think about the little play in that 5 degrees the distributor gears are worn 5 degrees of slack area isn't bad not to mention the amount of human error because the plugs were in so it would want to JUMP when turning it and yet still only averaged 5 degrees of slack..not too bad I didn't think so probably less than that is what I'm saying but thats per the timing tab.

thanks for all that helped on this, much appreciated!