i am confused.

sylvesterkitty · August 20, 2016

i am rebuilding my 350 in my 91 k2500 i got the truck cheap. so far it has two blown head gaskets and a pretty sloppy timing chain. and the radiator looks clogged,lets face it the truck was abused,but the engine was changed who knows how long ago and a few parts were missing like the temp sensor on the head and the dipstick and the thermostat. bought two rebuilt heads and a gasket kit and a new water pump and timing chain. the only problem i am having is the timing chain where do i set it ? do i match dots or are they both pointing up and how do i get the bottom gear off it is on there tight the rest is pretty simple. i've tightened the head bolts to 69 ft/lbs and i need to adjust the valves. do i tighten them just until i start to feel resistance and no end play then 3/4 turn more. i want to do this right and not screw it up and i have heard lots of different ways to do these proceedures so i am confused.

grampadirt · August 20, 2016

You need a repair manual,all those specs and procedures are in there.

j-ten-ner · August 20, 2016

I think I remember that the dots have to match.
Better get a Haynes Manual or similar, as grampadirt pointed out already.

You need a gear puller to get the gear off. Refer to the repair manual, what type of puller you need.

so long

j-ten-ner

O_J_Simpson · August 20, 2016

Most match the dots. That said, you better get a manual with all the specs. You are in over your head without it.

ifixedit · August 22, 2016

For correct (and easiest) timing chain / gear install the #6 cylinder needs to be at top dead center, the crank gear dot will be at the 12 o'clock position and the cam gear dot should be at the 6 o'clock position. Many think the #1 cylinder is supposed to be at TDC and then the dots align as I describe above, that is incorrect, you will be off 180 degrees and you'll have pistons slamming into valves, not good.

Although the link I provide here isn't for a 1991 truck, it's still the same and is still a small block Chevy. For a visual, scroll down to where he installs the timing set, you can see the #6 cylinder is at top dead center in the picture and how the timing marks are to be aligned.

http://www.70chevellecaliforniadream.com/2013/06/15/how-to-assemble-a-chevy-engine-part-2/

As far as how to adjust the valves, I've used this procedure many times and it works perfectly. I go with half turn past zero lash but 3/4 turn is also fine, no need to go to 1 turn as that's too much and may make for a rough idling engine.

http://berlinetta.info/Lash.htm

I hope this helps!

By the way, is this a roller cam engine or does it use the regular flat tappet hydraulic lifters? If it uses flat tappet lifters you are going to want to make sure you use the proper oil to break in the cam (Valvoline VR1 is a good choice) if you are installing a new cam, you will also want to go through the correct cam break-in procedure. DON'T use regular off the shelf motor oil or you will be replacing the cam again in short order!

j-ten-ner · August 23, 2016

Allow me one more advice.

After you've put everything back together, turn over the engine for two full turns. By hand. W/o the spark plugs installed.

so long

j-ten-ner

ifixedit · August 23, 2016

Allow me one more advice.

After you've put everything back together, turn over the engine for two full turns. By hand. W/o the spark plugs installed.

so long

j-ten-ner

Yes, I thought of that afterwards and is very good advice. Just to be sure you have things installed correctly, don't just rely on things and assume, the last thing you want to do is try starting the engine and finding out you have something off and pistons are banging into valves, that will make a very serious mess of things in a hurry. Once the engine is assembled you can rotate the engine by hand using a crank socket tool. Comp Cams makes them, I bought mine at Advance Auto Parts and well worth the $30 asking price vs. a damaged engine. You can also use it while you rotate the engine to set the valves / rocker arms. It's not advisable to try turn the engine by hand off the balancer bolt, you may end up breaking the bolt or worse, stripping the threads in the end of the crank snout.

sylvesterkitty · November 12, 2016

so it set the two dots together for valve timing then turn it 1 turn so no. 1 is on top for ign timming, is that right ? because no.1 and no.6 are companion cylinders i had a 72 chrysler that threw a push rod through the valve cover out in the middle of noware so o took the valve covers off and took the remaining push rod off that cylinder and the two off the companion cylinder and hammered the hole in the valve cover with a rock put the valve covers back on and drove the remaing 100 miles home the car ran fine just not as much power

ifixedit · November 14, 2016

Sounds like you did it right. For correct distributor installation you want #1 at top dead center and both valves on #1 closed. If either valve is open with #1 at top you are 180 degrees off. Once you have established the correct positioning of #1 drop the distributor in and it should be pointing just a hair past the #1 spark plug tower on the distributor cap, of course you can rotate the distributor either way to get this positioning. If it seems you really have to turn the distributor one way or another to achieve this you are likely off one tooth on the distributor and I'd re-install it to most easily achieve getting the rotor cap to just be past the #1 spark plug tower on the distributor cap. This will likely involve turning the oil pump shaft one way or the other in order to get the distributor to drop where you want it. Once you have this part correct then it's time to try start the engine. If it bucks and kicks back while you crank you are too far advanced, turn the distributor clockwise to retard the timing some, on the other hand if the engine seems to not want to start or is sluggish to start, you are likely too far retarded on the timing and you will want to turn the distributor counter-clockwise to advance the timing. Once you have it running set the timing per the specs with a good timing light. I hope this helps.