Motor has bad tick/knock in upper end!

[kingmatt16]

Just got the bad news that the upper end of my 89 360 with 150k is toast. Low compression in 3 cylinders. Guy suggested to send the heads out to be done over ($500) and $500 labor to take everything apart and put it all back together when the heads are done. Is this reasonable? Any other suggestions? I appreciate any and all advice.

Thanks,
Matt

[Bob Barry]

What you describe is just as likely a worn camshaft with rounded lobes as a need for a valve job. And, if the cam is gone, the bearings are usually not far behind, if they're not leading the cam out the door in the first place.

In general, if the top end of a GW's engine is ticking, what you're hearing is the timer running down for an engine rebuild. That $1000 you would spend for a head job would go a long way toward rebuilding the entire engine. I'd be afraid that you'd have to follow up that initial investment with a shortblock rebuild in order to solve the problem.

You can have the mechanic check the physical lift of each cam lobe with a dial-indicator; if the cam is worn (and I'd bet a core 360 on the side of my driveway that it is), then a rebuild is in order. This is just one of the peculiarities of our AMC V-8's.

[kreb]

i would say go ahead and get the whole thing done. if you plan on keeping her you would be much happier in the end

benjamin

[Jeepzilla]

Don't ever do just a top overhaul on a high mileage engine. The increased compression will just blow everything past your already worn out rings. Not much benefit. Don't forget about the possibility of a collapsed lifter. Just taking off the valve cover and watching the rocker arms move will reveal this. Sometimes a tick is just poor oil circulation, too. Plugged pushrods, head drains, and bearing holes. Try a motor flush and see what happens. Pull your oil pan and look at the amount of sludge you have--clean out your oil pick-up screen. Simple, cheap stuff like this can make a big difference. But then, if you really wanna rebuild that motor, the just do it!

[RichCal]

Noises or not, low compression in 3 cylinders, and 150K mi..it's time for an overhaul. Repairs at this stage are not cost effective.

[bigchief79]

before looking into a rebuild, check jasper for prices. Depending on who you go through it will be different prices. I got a $2800 quote from them but my mechanic could get it for 2400. I went for a local rebuid and it ended up being $2500 for the engine plus 2 mos wait. Also i only got a year unlimited mi. waranty, whereas jasper had 3 yr 36000 mi warranty plus a quick turnaround time. Having to do over, woulda went w/ the jasper. Just my $.02