cam change

[newbie17]

1987 R30/5.7 TBI
Exhaust valve cam lobe on #7 cylinder worn off.
Going to replace cam/lifters. My GM Service manual says to "Remove
front engine mount bolts and raise engine"-but it does not say how high.
Can't go very high or the rear of the engine will hit the firewall. Has anyone out there
done a cam change on a '81-'87 with engine in truck? I realize I have to
remove the A/C condenser, radiator and grill.

 

[Ricko1966]

Does your ac work? I ask because if it has working A/C the time to R&R the condenser and evac and recharge the A/C is more than it takes to just pull the engine. And if you pull the engine you can do some more preventative things such as check/ change rods mains and oil pump. Just my .02 cents. If you are going to do the cam in car I'd pull everything in the way, undo my mounts and use my eyeballs and common sense as to where the engine needs to be to clear whatever.

 

[newbie17]

Thanks Ricko1966. I am going to have my A/C system emptied with a recovery unit. The engine has only
40,000 mi. All else is o.k. Last week the engine felt like it had a miss at idle. I changed spark plugs-no improvement. Wires all good. Removed rocked covers-ran engine-noticed #7 cylinder exhaust valve rocker arm not moving much. No lifter noise. Going to pull intake and remove/check-out lifters and cam.

 

[Ricko1966]

If you pull the engine you don't have to break the A/C open. Unbolt it leave the lines attached and bungee it out of the way.

 

[SquareRoot]

I swapped cams in my 85. The vertical metal brace in the center of the core support prevented the cam from coming all the way out. At that point I was already pissed off so I just sliced i and moved it to the side. Afterwards, I mig welded it back together like it never even happened. It was frustrating though.

 

[wazzadakka94]

If one of the cam lobes was whipped out it is highly recommended that you pull the engine out and tear it down to clean out all of the metal shavings that are now in the oil.

 

[newbie17]

Thanks SquareRoot, I changed the cam 28 yrs. ago and I cut the vertical brace and welded it back in place when done. Been so long my memory took a walk!!!! Don't know why the Serv. manual said to raise engine. Thanks wazzadakka94 I will be cleaning the inside.

 

[bft305]

If you removed the whole front end and hood, except the front fenders. This was to install a new engine cause my truck is too high to go over. Though it would work for a cam swap as well.

 

[Ricko1966]

Thanks SquareRoot, I changed the cam 28 yrs. ago and I cut the vertical brace and welded it back in place when done. Been so long my memory took a walk!!!! Don't know why the Serv. manual said to raise engine. Thanks wazzadakka94 I will be cleaning the inside.

So have you decided to pull the engine and remove the pan? Do you know how to spin in New mains without engine teardown? Just asking/saying because if the engine was out if it was mine I would at least pull the pan and inspect mains and rods. Personally I'd change them and the oil pump and the timing set and feel pretty good I had a bottom end that was going to treat me well for a long time. An extra hours work for a ton of confidence.

 

[peats]

i agree with a teardown. 1 cam lobe equals a lot of metal floating around in the engine

 

[Ricko1966]

i agree with a teardown. 1 cam lobe equals a lot of metal floating around in the engine

The metal is in the pan the pump screen and the oil filter and has been for 100s if not thousands of miles. I was suggesting mains, rods,oil pump and timing kit because it's quick cheap and will give him a solid foundation lower end.I wouldn't do a complete disassembly over a flat cam.

 

[idahovette]

I wouldn't be willing to take a chance, there is gonna be metal left over in every nook and cranny inside that engine. My opinion.... YMMV.

 

[Ricko1966]

I worked flat rate too many years and saw too many flat cams. I have to agree total disassembly clean everything, pull the galley plugs clean the passages, new rings, rods, mains, cam bearings, etc. While we've gone this far he'll you really should bore it and have the heads valve jobbed. Most people don't have that kind of time and money to invest on a flat cam. Everyone saying the right way is total disassembly, actually is correct. But I'd stick a cam in it lifters, rods, mains and an oil pump and not be afraid for a minute especially if this came went flat over years. Remember any bits still in there have to make it through the screen, through the pump and through the oil filter to get to a bearing.

 

[idahovette]

There's a LOT of splash involved here. Most people notice a lobe going pretty quickly if they are in tune with their engines. Not all of it is gonna be filtered out. Sure maybe if this is a long term failure, but by then a flat cam is probably the least of your worries!....kinda what a lot of the guys on here say "Buy once, Cry once"

 

[Ricko1966]

Oh! Wow it's amazing how many things we do and forget. One of my trucks wiped out a cam before 2016 I know because it was before the ex left. Junk truck ,junk motor thinking just need the truck for the weekend and its being parted. I put a cam in it changed the oil and filter and I'm still using that truck didn't even drop the pan. Damnit now I have to, because I remembered it.