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-   -   No compression #4 after head change (https://www.northamericanmotoring.com/forums/r60-r61-stock-problems-issues/340315-no-compression-4-after-head-change.html)

cudamank 06-30-2019 09:21 PM

No compression #4 after head change
 
So I had a bad exhaust valve on cyl 1 , no compression 125k motor. Pulled the head machine shot checked it, pressure test, surfaced and replaced 1 valve.

Replaced timing chain and reassymbled engine. Miss fire cyl 4, compression test shoes 0. 210 on other 3 cylinders.

I used to crank and cam locks , guessing leakdoen is next , but unless someone has a suggestion on something I missed, pulling head is going to happen.

Let me know.
.

MiniToBe 07-01-2019 05:48 PM

if you take the valve cover, can you physically see the valve rollers in place and sung nicely?

how much did the shop take out from the head when resurfaced? did you compensate that in the head gasket?

cudamank 07-05-2019 10:14 PM


Originally Posted by MiniToBe (Post 4480051)
if you take the valve cover, can you physically see the valve rollers in place and sung nicely?

how much did the shop take out from the head when resurfaced? did you compensate that in the head gasket?

They did surface the head, and I went with the thicker head gasket to compensate.

Question. When I put the cam lock tool on, should exhaust valves on cyl 4 open? I had to move the exhaust cam to get the tool on flat and it engaged the exhaust valves.

MiniToBe 07-06-2019 06:25 AM

looking at my pix when i did my CM, the exhaust valves on cyl #4 (towards the vacuum pump) are pressed.

https://cimg6.ibsrv.net/gimg/www.nor...e113d3d97d.jpg

cudamank 07-06-2019 05:03 PM

Leak down test done today. 80% loss through exhaust.

So really bummed (that isn't quite strong enough). I pulled this head for no compression on 1, and found a burnt valve. Had machine shop inspect, pressure test and surface head. When I originally took it there I planned on all new valves. , But after they inspected I went with their recommendations and only changed the one.

Will be pulling head tonight or tomorrow night as it's about 100 hear today.

I figure I need to pull timing chain, and replace crank bolt, cam bolts, head gasket, tensioner? And I'll most likely change all exhaust valves.

Any suggestions? Or things I don't need or need to change? (Other than my luck?)

MiniToBe 07-06-2019 05:17 PM

since you're raking it back to the shop, negotiate with them a new price and let them know they screwed up somehow, if they actually did, and have them do the stem seals. no need to replace the crank bolt. if the tensioner is the 78mm, I would upgrade that to 82mm. if the timing chain rails look rather burned, I would replace it.

cudamank 07-06-2019 05:27 PM

Brand new guides and chain so that is good.

MiniToBe 07-06-2019 05:35 PM

if you end having access to the turbo oil feed line, I would replace it with Detroit Tuning style. also, oil filter housing gasket....budget wise, it an additional $50 for both, the cheapest.


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