Camshafts/Cylinder Head - Rabbit Hole!

[EwanG]

Hi, looking for considered advice here...

So in my ongoing quest to get the engine started for the first time since who knows when (no history), I have gone down the next rabbit hole. On taking the Cam cover off for the first time in my ownership (3 months) with the initial thought of having a quick look and checking clearances etc I am now seeing things that are suggesting to me to keep going and remove the cylinder head. So far :

1. There was a washer lying about beneath one of the camshafts (thankfully one of those little orange rubber ones) but it certainly tingled my spider senses
2. The Cam cover gasket was missing in places and despite my recent oil change its "grubby". No sign of water and oil mixing though.
3. I believe, the Camshaft bearing caps are incorrectly sequenced on the Exhaust side according to my reference manuals - running from 5 to 10 starting from the timing chain end (is this a fundamental flaw and do I potentially replace as is or correct?)
4. The valve clearances seem incredibly tight on the Inlet side
#1 0.002", #2 0.002", #3 0.003, #4 0.005
5. The Cam lobe between #1 and #2 Cam bearing caps is incredibly close to touching the head (right hand front edge). I can just squeeze my smallest feeler gauge 0.002" between the edge when cold (car won't start so don't know what happens when hot . The lobe isn't marked so I guess its missing but its close. The other lobes all have decent clearance
6. The Cam lobes seem to be in good condition. No scratches. Smooth. Well rounded - classic teardrop - no flat spots
7. I've removed the Inlet Cam and carefully marked crank, cam pulleys, camshaft to pulley alignment from TDC etc and taken lots of pictures
8. Camshaft bearing shells have some scratches but no major gouges and I don't feel any "high" spots
9. Before I go too much further down the next rabbit hole, I'm seeking advice...

I am a relative novice but can carefully follow instructions and apply caution and care as I go. I had not intended to proceed to head removal but based on the evidence of what I am seeing so far I'm concerned that some of this has not been set up correctly and that on an engine that I have never started it may make sense to proceed to check and correct other issues? Once removed and inspected I can then make a decision to refit or seek expert cylinder head refurbishment based on what I find. I can also check out pistons, bores, rings etc...

Thoughts? Recommendations? Some images below:

IMG_3473.png (133.32 KiB) Viewed 885 times

IMG_3476.png (134.54 KiB) Viewed 885 times

[mbell]

3. I believe, the Camshaft bearing caps are incorrectly sequenced on the Exhaust side according to my reference manuals - running from 5 to 10 starting from the timing chain end (is this a fundamental flaw and do I potentially replace as is or correct?)

My engine and I thinks factory not a rebuild thing, has the cap number stamped on the caps and cylinder head. The cylinder head is just under the cam cover gasket near the spark plugs. As the cam cover gasket needs replacing you may as well remove it and see if your head is stamped.

[EwanG]

Thanks mbell - I will take a look tomorrow - learning new things every day!

[nmauduit]

The first thing that comes to my mind is taking your time when it comes to reassembly at timing: it is quite easy to bend a valve by mistake. Books (e.g. Miles Wilkins's Lotus Wintcam Engine) and this forum can be studied to get familiarized with the engine internals so that to avoid pitfalls.

[EwanG]

The first thing that comes to my mind is taking your time when it comes to reassembly at timing: it is quite easy to bend a valve by mistake. Books (e.g. Miles Wilkins's Lotus Wintcam Engine) and this forum can be studied to get familiarized with the engine internals so that to avoid pitfalls.

Thanks nmauduit - will do. I am certainly taking my time disassembling and marking as many items as possible. Finding it impossible at the moment to identify original timing markings so at this stage I'm marking how it was but will need to take extra care reassembling. Patience!

[512BB]

'1. There was a washer lying about beneath one of the camshafts (thankfully one of those little orange rubber ones) but it certainly tingled my spider senses

I take it you mean a fibre washer. That shows complete carelessness with maintenance or assembly by whoever, which would cause me concern.

2. The Cam cover gasket was missing in places and despite my recent oil change its "grubby".

I thought exactly the same but cannot tell from your pictures if the 'dirtyness' is in fact an assembly paste, such as graphogen, which makes a lovely clean cylinder head look dirty. Good stuff though.

3. I believe, the Camshaft bearing caps are incorrectly sequenced on the Exhaust side according to my reference manuals - running from 5 to 10 starting from the timing chain end (is this a fundamental flaw and do I potentially replace as is or correct?)

Your cam caps are correct. Number 5 is the frontmost cap on the exhaust side.

4. The valve clearances seem incredibly tight on the Inlet side
#1 0.002", #2 0.002", #3 0.003, #4 0.005

Yes, they are to tight. Should be .005" - .007". On a new build, I always set them 1 thou over max, so that when things bed in, they will reduce to within spec. and hopefully that will prevent me having to reset them after the bedding in stage, which it normally does. On an engine that has a few thousand miles under its belt, I set to middle of spec and then hopefully it will not require further messing.

5. The Cam lobe between #1 and #2 Cam bearing caps is incredibly close to touching the head (right hand front edge). I can just squeeze my smallest feeler gauge 0.002" between the edge when cold (car won't start so don't know what happens when hot . The lobe isn't marked so I guess its missing but its close. The other lobes all have decent clearance

I have never noticed a cam lobe running so close to the head before, but I would certainly relieve the head a little, taking care to not let any material fall into the head.

9. Before I go too much further down the next rabbit hole, I'm seeking advice...

I am a relative novice but can carefully follow instructions and apply caution and care as I go. I had not intended to proceed to head removal but based on the evidence of what I am seeing so far I'm concerned that some of this has not been set up correctly and that on an engine that I have never started it may make sense to proceed to check and correct other issues? Once removed and inspected I can then make a decision to refit or seek expert cylinder head refurbishment based on what I find. I can also check out pistons, bores, rings etc...

Only you can make that decision, but if you have concerns, that seems like a good way to go, you will learn a lot and then be confident in your engine.

Good luck with it.

Leslie

[rgh0]

With replacement cams and especially high lift ones I have seen this problem. The cam lobes on replacement cams cann sometimes not be in the precise location to centre them on the cut outs. High lift cams also run closer to the cut outs depending on the lift and base circle.

For competion engines I routinely mill the cut outs in the follower bore to a larger diameter and a little deeper to avoid this issue.

cheers
Rohan

[EwanG]

Thanks Leslie. Extremely helpful. Yes a fibre washer. The camshafts seem to be in good condition and if so I will look at relieving the head a little as suggested. I will perhaps validate their origin / authenticity as part of the process.
I failed to explain the Cam Cap Bearing sequence question properly. Based on the actual photo the Exhaust side (from the timing chain) is running a sequence from 6-10 (and manual says it should be 10-6). Is the car or manual correct? The Inlet side matches ok on a 5-1 sequence (from the timing chain).

On balance I think I will feel more confident and learn a lot in the process by continuing to remove the head and appreciate your insights.

[EwanG]

With replacement cams and especially high lift ones I have seen this problem. The cam lobes on replacement cams cann sometimes not be in the precise location to centre them on the cut outs. High lift cams also run closer to the cut outs depending on the lift and base circle.

For competion engines I routinely mill the cut outs in the follower bore to a larger diameter and a little deeper to avoid this issue.

cheers
Rohan

Thanks Rohan - great info. I will check the markings and do some measuring to try and assess their origin / authenticity as they seem to be in good condition. Good to know that milling the cutouts is a known solution.

[Craven]

From memory cap 10 has the narrow ½ width bearing.

[draenog]

As others have stated, your cam cap ordering is correct. Here's some pictures I took when I adjusted the valve clearances a couple of years ago. You should be able to see the numbers stamped into the head, hidden on your picture by the cam cover gasket. On the exhaust side, from the timing chain, the sequence is 6 - 10.

[2cams70]

If your cams lobes are almost touching the cutouts the root cause maybe that the slot in the head at the front of the cam is worn. This slot takes the thrust load from the cam location face. Wear in this area doesn’t normally cause problems unless really bad but that’s probably where the issue is originating from.

[rgh0]

"5. The Cam lobe between #1 and #2 Cam bearing caps is incredibly close to touching the head (right hand front edge). I can just squeeze my smallest feeler gauge 0.002" between the edge when cold (car won't start so don't know what happens when hot . The lobe isn't marked so I guess its missing but its close. The other lobes all have decent clearance"

It appears to be just one lobe that has the small clearance which suggests its not wear on the cam thrust groove which would be causing all the lobes to move and be close. Careful measurement of the cam lobe locations versus the cut outs locations will tell if its the cut out that is poorly postioned ( seen that) or the cam lobe that is poorly positioned ( seen that also)

A simple quick check is to swap the cams and see whether the issue moves with the cam or not

cheers
Rohan

[2cams70]

It’s a 2 second job to visually check the groove to see if it has a step in it caused by wear so for the effort involved it’s worth doing

[EwanG]

From memory cap 10 has the narrow ½ width bearing.

Caps.JPG

Thanks Craven, I still need to painfully scratch off the "goo" that the partial gasket is attached to and will hopefully reveal the underlying numbers too. Thanks!