ZCar Forum banner
Status
Not open for further replies.
1 - 2 of 2 Posts

·
Registered
Joined
·
107,695 Posts
Discussion Starter · #1 ·
This time the problem is with my son's 78 280Z. He is running a 280 block with flat top pistons, a big valve E88 head, a .500/.280 cam, triple Weber DCOE 45's, and Motorsport Header+Exhaust. We rebuilt his engine about 3 years ago and did all of the mods at that time. It runs strong. He recently noticed that when you get off the gas from 3500 or more RPM and let the engine coast down to idle, whether moving or not, there is a sort of whining sound which seems to be coming from inside the engine. My son think it sounds like the timing chain has too much slack in it and it is sort of slapping around in there while coasting from higher RPM. We put on a new chain and sprockets when we rebuilt the car. We don't know what it is and it doesn't seem to affect performance, but we would like to fix it, any ideas?? By the way he did advance the cam / sprocket relationship from 1 to 2 with no affect. Thanks Bill
 

·
Registered
Joined
·
100 Posts
> This time the problem is with my son's 78
> 280Z. He is running a 280 block with flat
> top pistons, a big valve E88 head, a
> .500/.280 cam, triple Weber DCOE 45's, and
> Motorsport Header+Exhaust. We rebuilt his
> engine about 3 years ago and did all of the
> mods at that time. It runs strong. He
> recently noticed that when you get off the
> gas from 3500 or more RPM and let the engine
> coast down to idle, whether
> moving or not, there is a sort of whining
> sound which seems to be coming from inside
> the engine. My son think it sounds like the
> timing chain has too much slack in it and it
> is sort of slapping around in there while
> coasting from higher RPM. We put on a new
> chain and sprockets when we rebuilt the car.
> We don't know what it is and it doesn't seem
> to affect performance, but we would like to
> fix it, any ideas?? By the way he did
> advance the cam / sprocket relationship from
> 1 to 2 with no affect. Thanks Bill
Bill, i'm no expert on all the cams and stuff. My car (81 zx) has developed a whine coming from the front of the engine as well. It goes with the engine speed whether idling or under power. I was listening to it and wondering if it could be the fan clutch going. If you have an electric fan, this is certainly not the problem. Just a guess.

Anyone have any other ideas on this?

Rbest
 
1 - 2 of 2 Posts
Status
Not open for further replies.
Top