leek157

How necessary is it to change the timing chain sprocket on the crank, i am buying a new timing set. and if it is how do i get it off. second question my motor was rebuilt about 10k miles ago by the previous owner and im hoping the lifters were replaced, i know he said he reused the cam but if the roller lifters are all in good shape is it necessary to replace them, other than that i think the camswap has gone pretty smoothly so far. O yea its a 87 l98

Orr89RocZ

iTrader: (20)

If the lifters are good and clean, then dont replace them. Else you can get cheap but good lifters from GM, the LS7 lifters. They are the best bang for the buck for 120 bucks i think these days. May require longer pushrods since the cup sits in abit more than stock lifters. NO big deal, should replace rods anyway with the cam swap.

If your buying a new timing set, which is needed, then use the complete set. To take off that bottom gear you will need a puller. A harmonic balancer puller with some long bolts and a nut on the end can be used to pull the timing gear off the crank. You can get a puller like that for 12 bucks at a auto parts store.

leek157

cool, i planned on putting new rods in i really didnt want to spend a couple hundred more on lifters if they were all in good shape, but since the sprocket has to be pulled off do i need an installer to put it back on like a balancer or something

Damon

You can reuse roller lifters if they are in good shape- even reusing them with a new cam (which you can't to with flat tappet lifters).

A gear puller will take the bottom timing chain gear off. Installing the new one is as simple as getting a sufficiently large piece of pipe to fit over the crank snout and drive the new gear home with a few modest hammer blows. They often go on without much difficulty. I've even done it with a big screwdriver and a hammer, tapping around it at various points until it's home.

Orr89RocZ

iTrader: (20)

its a press fit but you can get a large piece of pipe that will cover the crank snout and put it against the sprocket, and hammer it on with a mallet. Thats what i did

EDIT: i see above posted before me: agree on the pipe or tapping around edges method

leek157

cool, thanks for the help

leek157

it doesnt look like this rubbed for long but is this normal??

pandin

Roller cams need a button on the cover for the cam to rub against. Flat lifters push the cam back into the engine, rollers don't.

Read up on roller cam covers.

ssxmac

iTrader: (1)

How do you tell if the lifters are bad? Any specific thing to look for?

And where do you get those GM LS7 lifters from?

Orr89RocZ

iTrader: (20)

inspect the pushrod plungers to see if they are easy to push in. If so they may be weakened and require new springs or just new lifters period. Also make sure the roller tips are smooth rolling and dont have alot of play to them when you wiggle them side to side.

LS7 lifters from Scoggin dickey is where i got mine.

Also roller blocks should have a cam retainer plate. They dont need a button if you use a cam retainer plate like factory has done

leek157

since this is an 87 roller block how come there isnt a button on the cover

Damon

Factory roller cam setups used a cam retaining plate on the front of the block that kept it from moving forward. Cam buttons are for aftermarket roller cam conversions.

If your engine is stock then you should see it right behind the upper timing chain gear. No way to pull the cam forward with this plate in place. If somebody forgot to reinstall it during a previous rebuild...... well, that's a problem- the cam would walk forward and scrape against the timing chain cover, which is definitely NOT supposed to happen. You would need to buy a replacement (along with the special screws that hold it in place).

So, NO, that's not normal.

leek157

k, i havent pulled the chain and sprockets off yet, the motor was rebuilt and there wasnt a gasket on the cover just rtv sealant, i wouldnt doubt it that the retaining plate isnt there because the person i bought it off of was an idiot and whoever he had rebuild the motor couldnt of been that smart either because last year my flexplate came loose and was on there backwards, and i have had several other problems of things on this car not being put together correctly

leek157

I think i figured out why the can was rubbing on the cover, there was no gasket between the cover and block just rtv sealant.

Orr89RocZ

iTrader: (20)

gasket isnt that thick compared to RTV. I used RTV on my build and it doesnt come close to rubbing. The retainer plate again, keeps the cam from walking out. Maybe your timing chain set/sprocket just was too thick and didnt clear the cover?

pandin

Is the cover OEM or after market? I was wondering about the RTV too.

Lay a straight edge across the cover and then the sprocket. The distance should be able to be measured. Check for end play in the cam retainer.

If you have another cover, you could check for differences.

Also look at the cam bolt heads some are thicker than others, washers under the heads?

Or use RTV and a Gasket.

leek157

o yeah the cam retainer was there, maybe the cover was tapped too hard or something