colby72olds

iTrader: (7)

Alright, this is one of my friends engines so I'll try to explain as much as I know. First of all, the engine is in a 1986 chevy 4x4 with 40" ground hogs. A couple of months ago he was headed home and heared a "POP", he said it would run fine for a couple secs then "POP", run fine then "POP", etc..

He tore the engine down to discover ONE lifter broke, and about FIVE lobes ground off the cam. There was no metal shavings in the oil, complete bottom end looked fine.

One of his friends gave him a used cam, lifters, push rods from a 350. After he got the motor back in the truck and tried to start it, it wouldn't start.

It acts like the battery is dead when the spark plugs are in, but as soon as you take the spark plugs out it it turns over fine. Now the guy is saying the used cam, lifters, and pushrods could possibly be from a 327. He says he's going to order a new cam now and thinks that's the problem, but he doiesn't really have any idea IMO. He said the PTV clearence is fine but that's all he said, so IDK what they've actually done to try to diagnose the problem. He just knows I'm on ls1tech all day and wanted me to ask for him. Anyone have any input, anything you can come up with from that little amount of info?

Thanks

jg04222

is he sure the starting system is in good condition? starter is good? battery? battery cables? if he offroads this thing the starter might be toast from being submerged in mud/water. i would check all those things first.

fast01

iTrader: (16)

I agree with the above post, check the starting system. It sounds like the starter doesn't have enough torque to turn the engine when it's building compression. Also, double check the distributor. If the timing is too far off you'll have problems as well. There is one other thing that bothers me though. If your buddy got a cam/lifters etc. from a friend and they are used, the lifters MUST go back in the engine on the same cam lobe they were removed from, unless it's a roller cam. A flat tappet actually wears itself in to it's corresponding cam lobe and if things are moved around the engine won't run 5 minutes before it wipes out the camshaft again, then you're back to square one! You can however, run a brand new set of lifters on a used cam and be ok.

Oh yeah, it doesn't matter if the cam was from anything from a 262-400, all small block Chevys can share camshafts. The specs may be a little different, but piston to valve clearance will not be an issue with a stock cam.

slvr98camaro

iTrader: (1)

did he put the distributor back in correctly?

having an engine that is slow to start means a few things: the timing is too far advanced, there is something wrong with the wiring/starter (weak starter, bad connection, bad ground), or the battery is just dead

the camshaft doesnt matter what kind of car it came from, as long as it is a standard SBC cam (which i can almost guarantee it is)

he really needs to buy a timing light, find TDC of number 1 piston and hook a timing light up, rotate the engine by hand and wait for the timing light to turn on, and see where the engine is compared to the timing tab

i have a feeling the distributor is off a little bit and the timing is so far advanced the spark is trying to push the piston back down.

colby72olds

iTrader: (7)

Awesome! Thanks guys. I just talked to him on the phone and he thinks his starter and battery good. He said he's going to try using the timing light tonight, the timing HAS to be way out of time because it would try to turn over easier when they was twisting the distrubutor. Also he's probalby screwed about the lifters... He just pulled them out of an old motor, soaked them in oil and threw them in his engine.

So new lifters on a used cam is fine....but used lifters/ used cam is bad if the lifters aren't on the same lobe as they were in the other engine? More than likely he is going to be getting new lifters if so.

andrew69_04

iTrader: (148)

might be too late if hes been cranking the **** out of the motor. also, did he line up the cam dot to dot? seen motors where its off many times where people swore it was right on

slvr98camaro

iTrader: (1)

* with number 6 cylinder at TDC

monkihead

I had a customer do a cam swap and had me look into it. It nearly drove me nuts not getting it to start. Turns out the idle adjustment screw came out of place and closed the butterfly's not letting it get any fuel. So, check the plugs for raw gas or fouling to eliminate a carb issue.