Fresh gsr making banging noise!!
 

I just finished buiding a gsr for a friend. The motor has type R crank and rods with pr4 ls pistons. Everything if new Bearings, rings, water/oil pump. The head is a p72 with skunk 2 valvetrain, ctr cams and a fresh valve job.

The problem is when the car revs to 3000rpms it starts sounding like there is a socket in the valve coverand then the sound goes away above 3500 and comes back when the rpms drop threw that 3000-3500rpm range. We had this same problem with his old B16 with this same head, Toda spec B cams and the same valvetrain. The head just got back from the machine shop getting a valve job and checking everything out. The machine shop said the head looked good and there was nothing wrong with it.

Has anyone had this problem before? the compresson is good and all the valves are straight. we visualy checked out the head before we put it on and did not see anything loose or worn. Other than between 3000 and 3500 the car seems to run really smooth and has no valve noise.

Thanks for the help

steve

Re: Fresh gsr making banging noise!!
 

I would start with the easy visual stuff, make sure everything was tightened down. Do you think its the valves? maybe clearnances?

Re: Fresh gsr making banging noise!!
 

We checked all the visual stuff and everything else is torqued to spec. All of the valves were checked out by the machine shop and were said to not be bent. The thing is this is the second motor and second set of cams that we have had this problem with. I visualy check all of the rockers. I am kind of lost on what could cause this and not see any wear or anything broke.

steve

Re: Fresh gsr making banging noise!!
 

No, I'm pretty sure he meant valve lash...did you guys do a valve lash adjustment? Every time the head is taken apart it needs the valve lash adjusted. Tightening down all the head bolts and slapping everything back in even if properly torqued isn't going to have the same lash as when you pulled it apart. ::)

Re: Fresh gsr making banging noise!!
 

yeah we ajusted the valves and it still did the same thing. so last night we swaped the head out with a type r head and a edelbrok manifold. I am going to take the gsr head back to the machine shop tommorow.

Re: Fresh gsr making banging noise!!
 

so when you swapped the head it stopped?

Re: Fresh gsr making banging noise!!
 

when we swaped out the head, it already had some scaring on one of the cam jurnals. so we think that one of the CTR cams is bent. So we put the new head on with some old gsr cams and still had the same banging noise. It turned out to be the vtec solenoid. Vtec was going on and off when the car was reved. Swaped that out and now it's running good. i want to let everything break in for a few hundred miles before we really get on it.

steve

Re: Fresh gsr making banging noise!!
 

the solenoid only turns on when voltage is supplied to it, so you may want to be looking at the vtec signal to make sure its working correctly.

Re: Fresh gsr making banging noise!!
 

There is also a spring inside the solenoid itself that keeps tension on the plunger that opens and closes to allow the oil through for vtec. Probably either broken, or some idiot pulled it out. The first crx I bought had a mini-mi, and the douchebag pulled the spring out so he could always have vtec without wiring it up. ::) Check that out too.

Re: Fresh gsr making banging noise!!
 

Ok we got vtec to work and the noise to go away when swaped the vtec silenoid but now the engine bogs and studders when you put a load on it above 3500rpm. The motor will rev fine when there is no load. If you take off from a stop and floor it, it will pull good untill 3500 or so and then fall on its face. I have tried a couple of diffrent computers and it has not changed. It is not throwing a cel or anything. I have swaped out the plugs, wires, dizzy, tps, and map sensor the problem hasn't changed at all. Has anyone had this happen before? thanks for the help.

steve