LT5 Assembly Project - Page 46 - ZR-1 Net Registry Forums

LGAFF · 11-26-2011

Spoke to my contact at Mercury...he said that he did not think that the valves or rings would be impacted by using the stand....and he was right.
I tried doing it by supporting the engine and it made 0 difference.

He stated that the engines he referred to as green were low hours/miles....and that he does not recall doing unfired engine.

He did mention that he has seen issues with people not checking to see if the valves were being hung open after valve jobs.

He also mentioned that it was a known problem that the liners did disort at the bottom and it sometimes resulted in piston slap but performance was not affected.

Changing the guides can make it difficult seal the valves also......this is addressed apparently by lapping the valves with varying degrees of compound working through to lighter grits.

In the end, he agreed...if the valves hold fluid....if the bores are round...and pistons are ok...put it together and see what happens.

LGAFF · 11-26-2011

Just for shits and grins I did the factoray cam timing procedure, but did not torque the cam bolts to spec....surprising after a few rotations..the timing held true.

In talking with my contact at Mercury...apparently the cam timing slippage actually occurred at the initial start of each engine...

The #1 exhaust valve still has me very concerned....

Pete · 11-26-2011

Lee,check leak down with cams on,just to make sure no valves are hanging open.

Pete

LGAFF · 11-27-2011

Pete, this is the same valve that I checked last time.....and it leaks air and the other exhaust valve on #1 does not.....odd since both held fluid.

A26B · 11-27-2011

It wouldn't be odd if the valve stem on the leaking exhaust valve was too high or oil was trapped in the lifter.

LGAFF · 11-27-2011

These lifters are new, no oil.....stems were all cut to the same height and when I removed the cams last time it still leaked......will look at it more today

Some day this thread will say....fired up the engine no problems car ran great

tomtom72 · 11-27-2011

Quote:

Originally Posted by LGAFF

These lifters are new, no oil.....stems were all cut to the same height and when I removed the cams last time it still leaked......will look at it more today

Some day this thread will say....fired up the engine no problems car ran great

Man I hope so. Sincerely I do. My brain hurts from reading about all the "quirks" that our motors seem to have. I can't remember ever having this many Q's while assembling my first sbc. Man what a different animal our stuff seems to be.

Lee, straight up, thanks for this thread!

Tom

LGAFF · 12-02-2011

Did the factory cam timing and then used some basic math to set exhaust at 108......I did not lock them down yet. I bought two different dial gauges and none will sit on the lifter.

Once I can get the dial gauge to verify the specs I will lock them in...

LGAFF · 12-03-2011

Checked all my timing, I am at max lift at 114 intake,which is the stock pinned setting, and 108 max lift on the exhaust.

I used a flexible dial indicator from Harbor Freight....remove the flex arm from the vise grip and the arm threads into the IH and other bolt holes.

I had trouble putting the indicator on the lifter. To address remove the small point at the bottom on the dial gauge(it unscrews) cut a piece of coat hanger about 7.5-7.75"long, put a slight curve at the tip(rest it on the lifter)....the coat hanger will slide in nicely against the cam, there is even a small groove it can rest in.

pic of dial mounted ......you can see coat hanger

Wheel at 51 degrees, top cams pinned...

curved bottom of hanger on the lifter:

LGAFF · 12-03-2011

timing exhaust cams:

11-26-2011	#451
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,184	Re: LT5 Assembly Project Spoke to my contact at Mercury...he said that he did not think that the valves or rings would be impacted by using the stand....and he was right. I tried doing it by supporting the engine and it made 0 difference. He stated that the engines he referred to as green were low hours/miles....and that he does not recall doing unfired engine. He did mention that he has seen issues with people not checking to see if the valves were being hung open after valve jobs. He also mentioned that it was a known problem that the liners did disort at the bottom and it sometimes resulted in piston slap but performance was not affected. Changing the guides can make it difficult seal the valves also......this is addressed apparently by lapping the valves with varying degrees of compound working through to lighter grits. In the end, he agreed...if the valves hold fluid....if the bores are round...and pistons are ok...put it together and see what happens. __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

11-26-2011	#452
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,184	Re: LT5 Assembly Project Just for shits and grins I did the factoray cam timing procedure, but did not torque the cam bolts to spec....surprising after a few rotations..the timing held true. In talking with my contact at Mercury...apparently the cam timing slippage actually occurred at the initial start of each engine... The #1 exhaust valve still has me very concerned.... __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

11-26-2011	#453
Pete Join Date: Dec 2003 Location: Chicagoland,IL Posts: 2,680	Re: LT5 Assembly Project Lee,check leak down with cams on,just to make sure no valves are hanging open. Pete __________________ '91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage

11-27-2011	#454
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,184	Re: LT5 Assembly Project Pete, this is the same valve that I checked last time.....and it leaks air and the other exhaust valve on #1 does not.....odd since both held fluid. __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

11-27-2011	#455
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,372	Re: LT5 Assembly Project It wouldn't be odd if the valve stem on the leaking exhaust valve was too high or oil was trapped in the lifter. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

11-27-2011	#456
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,184	Re: LT5 Assembly Project These lifters are new, no oil.....stems were all cut to the same height and when I removed the cams last time it still leaked......will look at it more today Some day this thread will say....fired up the engine no problems car ran great __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

12-02-2011	#458
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,184	Re: LT5 Assembly Project Did the factory cam timing and then used some basic math to set exhaust at 108......I did not lock them down yet. I bought two different dial gauges and none will sit on the lifter. Once I can get the dial gauge to verify the specs I will lock them in... __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 Last edited by LGAFF; 12-02-2011 at 11:21 PM.

12-03-2011	#459
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,184	Re: LT5 Assembly Project Checked all my timing, I am at max lift at 114 intake,which is the stock pinned setting, and 108 max lift on the exhaust. I used a flexible dial indicator from Harbor Freight....remove the flex arm from the vise grip and the arm threads into the IH and other bolt holes. I had trouble putting the indicator on the lifter. To address remove the small point at the bottom on the dial gauge(it unscrews) cut a piece of coat hanger about 7.5-7.75"long, put a slight curve at the tip(rest it on the lifter)....the coat hanger will slide in nicely against the cam, there is even a small groove it can rest in. pic of dial mounted ......you can see coat hanger Wheel at 51 degrees, top cams pinned... curved bottom of hanger on the lifter: __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 Last edited by LGAFF; 12-03-2011 at 04:27 PM.

12-03-2011	#460
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,184	Re: LT5 Assembly Project timing exhaust cams: __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359