Honda D Series Forum banner

1 - 16 of 16 Posts

·
Registered
89 CRX si
Joined
·
71 Posts
Discussion Starter #1
I have my newly built 1989 D16A6 running well and have accumulated 2300 miles at the present time. I went with forged CP pistons at .020 overbore and stock rods. The head was freshened up as well and milled .010 and I have a Y8 head gasket to increase the compression. After the initial break in with Penzoil conventional oil 10w 30 I have put in Mobil 1 10w 30 synthetic for the past 2K and have changed oil 4 times with no particles in the oils. I have a concern with a knock I cannot identify even with a stethoscope. The knock I'm hearing is well after warm up and after a short trip and is only at idle rpm. It seems to be up top the best I can tell even though I know noise can travel and I have ruled out timing belt slap. At this point I think it could be the rocker shaft bridge or the cam cradle. Is there a possibility that either of those area's are expanding due to heat after extended operation and creating wider clearances for either the rocker shaft or the camshaft?
 

·
Registered
89 CRX si
Joined
·
71 Posts
Discussion Starter #2
Anyone?
 

·
BATSLOMAN GIVES NO FUCKS.
Joined
·
4,525 Posts
why haven't you checked the valve lash to see if theyre in spec?
 
  • Like
Reactions: EFB055

·
Registered
89 CRX si
Joined
·
71 Posts
Discussion Starter #4
I have the valve lash set to spec. The noise doesn't sound like valve/rocker noise to me but.....
 

·
Formerly weebeastie
Joined
·
1,059 Posts
Could be piston to wall clearance. You are running forged pistons, correct? They will sometimes make a "knocking or clocking" sound. How loose was the motor built? N/A or FI later?
 

·
Registered
89 CRX si
Joined
·
71 Posts
Discussion Starter #6
Engine was honed to specs supplied by CP. My experience with forged pistons has been they get quieter after warm up but these low silica pistons may behave differently. ?
 

·
Registered
89 CRX si
Joined
·
71 Posts
Discussion Starter #8
.020 over.
 

·
Registered
89 CRX si
Joined
·
71 Posts
Discussion Starter #10
I don't feel the need to transplant another engine. At least that is what I think you said. ???
 

·
Registered
Sloppy Jalopy
Joined
·
1,380 Posts
A motor is the path toward emptying a vehicle's extraordinary engine and overriding it with another. This is done either by virtue of disillusionment, or to present a substitute car engine. This article is based on swapping-in an other engine that is even more predominant, and typically one that is progressively present day. Progressively prepared engines may in like manner have an insufficiency of additional parts, along these lines a propelled substitution may be even more viably and cheaply kept up.
I like the way you think.

but seriously Slo needs to get that shit outta here!
 

·
BATSLOMAN GIVES NO FUCKS.
Joined
·
4,525 Posts
I like the way you think.

but seriously Slo needs to get that shit outta here!

listen, give me time to get home.


better now mom?
 
  • Like
Reactions: robgoof

·
Registered
89 CRX si
Joined
·
71 Posts
Discussion Starter #13
Ok, back on point. The engine is running great with awesome oil pressure but has the low idle warm engine knock. It has forged .020 pistons. I have 3k on the fresh rebuild now and the rockers have been adjusted and readjusted after several miles of driving but the noise never sounded like rockers or valves to me. I have also eliminated timing belt slap. I'm thinking cam cradle or rocker bridge wear but I cannot confirm at this time. Thoughts ?, Suggestions ?, Lude comments?
 

·
Registered
93 Civic HB SI
Joined
·
806 Posts
Ok, back on point. The engine is running great with awesome oil pressure but has the low idle warm engine knock. It has forged .020 pistons. I have 3k on the fresh rebuild now and the rockers have been adjusted and readjusted after several miles of driving but the noise never sounded like rockers or valves to me. I have also eliminated timing belt slap. I'm thinking cam cradle or rocker bridge wear but I cannot confirm at this time. Thoughts ?, Suggestions ?, Lude comments?
If you think it's those things, then the best thing to do will be pull the valvetrain apart and inspect all of those item clearances against the service manual specs.

Do you maybe have video/audio of the sound from multiple points around the engine when the problem is occurring?
 

·
Registered
89 CRX si
Joined
·
71 Posts
Discussion Starter #15
I have a suspicion it could be the cam cradle or rocker bridge but I do not have the tools to measure the clearances. I started this thread with hopes that someone might have experienced these same symtom's but I must be having a rare occurrence. At the present time it seems like a no issue problem but if it should progress I will go forward with a solution. Sorry, no video.
 
1 - 16 of 16 Posts
Top