how replace '94 valve springs w/o dropping valve

[raxley]

I don't have a TDC mark on dampaner. The timing pin is too stiff to get in, even with WD-40. I don't have any help.
How do I tell the piston is high enough so I don't drop valve into engine? Can I tell from my valve action about where my piston is?
Like, after the exhaust valve is closing, right at the point where it stops moving and the intake opens (engine is turning normally clockwise) is that where it is at TDC? Also are pistons in pairs, like 1 & 6-you can install springs on 1 & 6 at same time?

 

[Stox5225]

Force the cam pin out. F the retaining ring, and remove the plug. Get your finger in there and feel for that dimple. Feel the dimple, find compression TDC. Just what I would do.

A quick Google would give you the answer to the latter.

Have you worked on these trucks before? Or used any sort of resource to repair things?

 

[Joseph Donnelly]

Just turn over the engine until either #1 or #6 has one valve almost closed and the other just beginning to open. That is TDC, or close enough. Now you can change those valve springs and the valves can't drop more than about 1/16". Mark the damper vs. something close to it that does not turn. 120 degrees and 240 degrees of rotation are the other TDC's.

 

[Joseph Donnelly]

BTW, I cut a slot at the end of a piece of 3/8" water pipe to fit over the end of the timing pin. I can spray WD-40 through it to get it onto the pin area. Also, I can use it to pop the pin in and out much easier than trying to get my hand in there.

 

[GAmes]

Remember the pistons at TDC at the same time equal 7. 1-6, 2-5 and 3-4

 

[GAmes]

It is a preference thing but I only do one cylinder at a time, the one at compression TDC. The valves have to be adjusted anyway, so I complete one, turn the engine 120, do the next, etc.

 

[raxley]

Thank you for the replies everybody. I was finally about to get the old timing pin out, feel around (with a nail, couldn't get a finger in) with a nail, and then put it back in and pop it in to get #1 at TDC. I made a mark, but will probably modify it when I also do the moving of crankshaft on both sides, 'creeping' up with a dial indicator(I heard that was more accurate for permanent mark on dampener). Today I got a set of 60# springs in for #1. I will get the rest in tomorrow.
With my springs in (60 #) and my 4000 governor spring kit in, I'll be set for going over 3200 rpm, right? It's set at stock timing, I have a Power Driven Diesel timing kit, and plan to move timing to around 19 degrees BTDC. I never carry anything in truck besides tools for work. (and I have a EGT and boost gauge) I won't be getting any improved performance until I'm able set the timing and also increase the boost from 21#, I guess. I have a adjustable boost elbow that I will put in soon. I need to rebuild my transmission (although it's good at the moment) with my parts from my fairly strong (input, flex, goerand TC, shift kit) 2005 48re transmission or get a $2000 Suncoast (also think there is another brand too) kit to shift my transmission. I haven't done the KDP yet, that needs to be installed soon. I got the cheapest fix for that, I think it's a tab 'thingy' that bolts in somewhere and you put the tab over the KDP. It was only like $10. After that, (eventually as finances allow) I'd like to get some kind of twin kit, I'm looking at Power driven Diesel's kit w/ Borg Warner K27 over Borg Warner s369SX-E

 

[raxley]

I finally got the springs on #6 in (along with #1 yesterday) it was difficult to get 'back there'. I wish that damned insulation isn't there on the firewall above the cylinder, even though I stuffed rags into the pushrod holes and TRIED to vacuum all the 'fur' that came down, I don't like the idea of any of that stuff getting into my valve train. Maybe before starting I should have taken a razor knife and cut away all insulation above that cylinder. I'm glad I did this myself rather than paying for it to be done (although if I was working and too busy I probably would have had to) the valvetrain isn't as 'mysterious' to me now.Another question, can I crank down on the rocker arm assembly instead of loosening up the valve adjustment nuts? Games said they have to be adjusted anyway (altho I did it last week) Otherwise it seems like I will have to tighten down the rocker arm assembly and compress the springs somewhat while doing it. Unless somebody says I can do that, I think I will loosen up the valve adjustments like for my first cylinder, I'm not wanting to take any 'short cuts' when I have doubt.
Joe Donnelly-about the 120 degree, 240 and 360 degree comment-do the cylinder pairs fire exactly the same time? (1&6, 2&5 and 3&4)?

 

[GAmes]

First it is capital G, capital A, first initial, last name. I've never replaced the valve springs with the piston at exhaust TDC, it seems like a recipe for disaster. The pairs do not fire at the same time. Suck, squeeze, bang, blow. The #1 is at the top of the squeeze, the #6 is at the top of the blow.

 

[raxley]

Sorry GAmes. I re-read your post above and now understand the firing is 120 degrees apart, first 3 cylinders in one complete revolution (1, 6, 2) other 3 cylinders (5, 3, 4) in the second revolution. I guess doing it in pairs are 'close enough' to replace springs and lash but I will do it your way.
I will set the cylinders valve lash and spring replacements at the top of each cylinder's compression stroke. I have a magnetic degree wheel that I will use to find those 120 degree marks after using timing pin for #1.
That furry stuff is obviously fiberglass, my wrists were itching all night. Probably extremely abrasive too. I think I will plug (as best I can) the space around the pushrods and try to squirt it with some fast drying stuff and soak it up with rags. And razor out the insulation too, after it's 'buttoned up'.
Did you fly helicopters in VN?

 

[GAmes]

I was a helicopter mechanic in VN. The war ended while I was in flight school.