I recently bought a project VR-4 that had a supposed knock in the rear head. I ran a compression check on it today and obtained the following results on a cold engine (don't want to run it yet):
Damn good numbers if you ask me for a cold engine. However, something still isn't quite right. There is a strange sound coming from cylinder number 6 when this thing is cranking over. Almost sounds like a popping noise, but I'm thinking it may be piston on valve (although the compression wouldn't have been so high). Anyway, take a look at my youtube video and tell me what you think. Sorry I didn't get over top of the number 6 cylinder...I didn't realize it was that making the noise until after I took the video.
I started the same project last year with the same issue. when i did my compression test cylinder 2 was at 161, where yours is at 160. the sound is the same as mine, a spun bearing on cylinder 2. the reason for the higher number is there is no bearing in the rod allowing more movement, reason for higher reading. easiest check is to drop the tc and remove the trans support brackets so you can drop the oil pan. then you can reach the rods to check for play. willing to bet whats left of cyl 2's rod bearing is in the oil pan and the rod has lots of play.
I started the same project last year with the same issue. when i did my compression test cylinder 2 was at 161, where yours is at 160. the sound is the same as mine, a spun bearing on cylinder 2. the reason for the higher number is there is no bearing in the rod allowing more movement, reason for higher reading. easiest check is to drop the tc and remove the trans support brackets so you can drop the oil pan. then you can reach the rods to check for play. willing to bet whats left of cyl 2's rod bearing is in the oil pan and the rod has lots of play.
sorry to be the bearer of bad news
Someone had to do it
You said you had a similar sound, but was it coming from the number 2 cylinder? My sound is definitely coming from number 6 as I can put my hand over the intake runner and you can barely hear it.
If it is a spun bearing, oh well...this car was meant to be a project and that's exactly what it may become
Have you tried to put everything back together and start her?
I have not. The previous owner said he had it running and it was making a knocking noise, which appeared to be coming from the rear head. When I went to look at the car, we couldn't get it started, but the fact that I could hear the engine hitting on all 6 cylinder when we were cranking it over was reason enough for me to believe the engine was good.
You said you had a similar sound, but was it coming from the number 2 cylinder? My sound is definitely coming from number 6 as I can put my hand over the intake runner and you can barely hear it.
If it is a spun bearing, oh well...this car was meant to be a project and that's exactly what it may become
mine was on cyl 2, rear bank closest to the timing belt. but the video you posted was the same sound i heard.
you have a fun project ahead of you. building an interference motor is interesting and nerve racking when its time to turn the key. the guy that owned mine before me did not have a clue as to what he was doing. it cost me more than it should have, but she purrs like a kitten now with forged internals, 8.3:1 pistons, balanced and blueprinted. well worth the effort in the end.
mine was on cyl 2, rear bank closest to the timing belt. but the video you posted was the same sound i heard.
you have a fun project ahead of you. building an interference motor is interesting and nerve racking when its time to turn the key. the guy that owned mine before me did not have a clue as to what he was doing. it cost me more than it should have, but she purrs like a kitten now with forged internals, 8.3:1 pistons, balanced and blueprinted. well worth the effort in the end.
Just seems odd that even though my number 2 cylinder (rear bank closest to timing belt) has the highest compression (isn't the number 2 intake runner also the closest to the EGR pipe?), the sound is definitely coming from the number 6 cylinder (rear bank furthest from timing belt).
yes cyl 2 is close the egr return pipe. it may be cyl 6 but from where the cam was recording it sounds like 2. but that sound is what pretty unmistakable.
yes cyl 2 is close the egr return pipe. it may be cyl 6 but from where the cam was recording it sounds like 2. but that sound is what pretty unmistakable.
Yea, I'll take another video tomorrow if I get some time and I'll show you what happens when I place my hand over the number 6 runner....you can barely hear the sound anymore. Doing the same with all of the other cylinder has no affect on the sound. In the video, it does sound like it's coming from number 2, but I assure you it's not. I didn't figure out where it was coming from until after I brought the camera inside and uploaded the video.
Regardless, I'm going to drain the oil and cut open the filter and look for chunks of metal tomorrow.
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Help me diagnose this sound (with video)
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