Blown head gasket? Video

[Techspy]

Good advice. I will pull the plug wires one at a time then do a compression test. Man I hope I don't have to pull the head again.

[Vulcan Grey]

Plug wires often get damaged by pulling them off. You may have a bad one.

And yea, do a compression test.

[Techspy]

Zero compression cylinder 4. Bent valves I guess. Just my luck. Pulling the head again. Are you able to re-use a head gasket that has only been on a day? What about the head studs? They are good for 2-3 times correct?

[Sparky]

I'd be double-checking valve clearances first!

[Techspy]

Good point. I will check that before pulling the cam towers. I could have screwed that up but I checked so many times and had everything within the specs. Just removed the covers so that will be next tomorrow.

[Chillidoggy]

Fingers crossed it's a shim issue.

I wouldn't reuse the cylinder head gasket once it's been compressed, but that's just me. If it seals, fine. If it doesn't you're gonna be really pissed off.

[jonwat]

1 hour ago, Chillidoggy said:

Fingers crossed it's a shim issue.

I wouldn't reuse the cylinder head gasket once it's been compressed, but that's just me. If it seals, fine. If it doesn't you're gonna be really pissed off.

I agree, it's just not worth the risk of all the extra work & my money is on one of the shims being too thick on cylinder four.

Good luck. 

Edited March 26, 2018 by jonwat

[Techspy]

Well, the rear most intake valve was too tight to get a gauge in. Pulled it off and went from a 113 shim to a 107 and will be seeing how that does. I just don't understand. Maybe some sealant or trash got between the cup and shim? Nothing looks out of the ordinary on the cup or shim like any strange wear marks. I put the shims on the valve towers and the cups in the cam tower and install. I must have checked that valve clearance 6 times or so. I guess I will find out when I put it on with the 107. I also looked at the intake valves from the intake ports and they seem fine. No signs of being bent (as best I can tell from that view anyway)

Thanks for all the advice guys. I hope this is the issue! I will report back.

[snowrx]

Fingers crossed here for a good result for you. That small a change should not result in valve/piston contact.

[Techspy]

Ok, good news I think. With the smaller shim I have clearance (a bit too much so will be adjusting). The great news is that I connected a leak down tester to that cylinder and rotated until the hissing stopped (all valves with clearance between the cam and cup). Inserted a hose in teh intake and the exhaust, and the other end to my ear and no blow by around the valves! I guess that means no bent valves! Compression test on the other cylinders was in the 120s so I guess I am good. Still confused on how I ended up so off on that one shim. If I end up back to needing a 113 (what was in there), I can only assume some trash or sealant got between the cup and shim. Anyone ever had this happen?

Also, does anyone have any ballpark HZ I should be shooting for when tensioning the gates blue belt?

Thanks again guys. Hopefully my next post will be with vids of her healthy and running. Glad I didn't pull the head already!

[Sparky]

I can't see 6 thou making that much difference.  If you did the shims off-engine, did you check again after fitting head and towers?  I can only imagine a shim wasn't seated.

[Techspy]

Thanks for your help everyone!

 

[Bibs]

Enjoy your upcoming driving

[jonwat]

Excellent work, well done & congratulations. 

[Glyn Harper]

Great news. I wonder if your shim issue was because the head changed shape slightly when it was bolted down to the block. As was mentioned earlier in this thread, slightly warped heads will clamp flat when bolted down. That could cause clearance issues with valve shims.

Top job though. I would have spent a week just moaning if my head gasket blew, before even ordering any replacement parts!

[Glyn Harper]

A question.. Your engine sounds a bit rattly for a few minutes after start-up then seems to quite down... mine sounds exactly the same for maybe a minute or so. I take it that's normal? Mines always been like this so I've never worried too much about it but I'd like to know if it's normal.

[Techspy]

Thanks and I have no idea what caused the issue. I suppose it could be a warp in the head but the rest of the valves on that cylinder were fine. I had a 113 on that valve and ended up with a 111 for approx .0065 clearance.

BTW, since there is not a whole lot of data on the Gates belt tension;

Started with 95 Hz but slipped a couple teeth on first startup. Then went to 170 Hz knowing it was too tight but didn't want to slip any teeth again. Yep, it was too tight and whined when driving. Dropped it to 130 Hz and no whine and "feels" right. I am able to twist it approx 60 degrees each direction and can make the belt "slide" on the cam sprocket with a bit more than moderate pressure. This is how it felt when I had it rebuilt awhile back where the builder stated;

" After putting enough tension where it cannot be twisted to a 90 degree angle at its longest run, its tight enough, then I rotate the engine a few times them push hard on the long run and make sure it is just right to turn 90 and no more no less"

When I was at approx 95 Hz I could twist to approx 90 degrees but that is subjective I guess. It could be different for different people and how much pressure they apply and I imagine it depends on if you are doing this engine out (as the builder was) or laying on top of the engine. Then there is the experience level of the tester.

Anyway, hopefully this will help others.

Also, just went for an extended drive around town and on the interstate and all is well. BUT, I am listening so intently on every little sound while driving! It is going to make me nuts.

Oh yeah, Mine does sound "rattly" until it warms up. I think they "all do that sir". Actually, I was just pondering what all the different stages are during the warmup of the 910 engine. It has so many distinct stages of sounds as it gets to temp. Just curious what those are from. Cams? Different electronic valves changing the intake/air flow? Mine has always sounded kinda "pop-corny" at first startup. Kinda like bubbly sounding.

Edited March 28, 2018 by Techspy

[Glyn Harper]

Few, I'm glad to hear they all do that! I guess the valve clearances probably change slightly once the valves warm up which is maybe where the rattles are coming from. That's what I assumed.

Without hydraulic cam followers, there's probably no way to avoid this.

I used to have a Ford Escort RS Turbo that had hydraulic followers so it was very quiet, whereas the Escort RS1600i had solid adjustable followers so it used to rattle a lot. Ford actually had a different cast aluminium rocker cover on the RS1600i just for this reason.. to keep the noise levels down a bit!

[Sparky]

I never do clearances unless the head is bolted to the block. This improves accuracy and helps avoid an issue like John's.  I'm convinced the issue here was an unseated shim, as a few thou shouldn't have zeroed compression.

Yes, they do all sound like that!  A fair bit of that noise is in fact bottom end.

[Glyn Harper]

Rattly bottom end? Don't tell me that!

Glad they're all the same though!

[snowrx]

6 minutes ago, Sparky said:

Yes, they do all sound like that!  A fair bit of that noise is in fact bottom end.

I was afraid to say that, so soon after the top end went together.

[Sparky]

I don't mean "bottom end" with air sucking through teeth and shaking of head, just "bottom end" as in, it's a feature. Tolerances change as it warms up; everything's peachy!

[Chillidoggy]

My engine sounds exactly the same, it has that kind of chirping noise going on until it warms up and gets quieter.

[Glyn Harper]

18 minutes ago, Sparky said:

I don't mean "bottom end" with air sucking through teeth and shaking of head, just "bottom end" as in, it's a feature. Tolerances change as it warms up; everything's peachy!

Ah yes, I get you now.

[andydclements]

37 minutes ago, Sparky said:

I never do clearances unless the head is bolted to the block. This improves accuracy and helps avoid an issue like John's.  I'm convinced the issue here was an unseated shim, as a few thou shouldn't have zeroed compression.

+1 here.

The clearance isn't so small that a few thou takes up all of it.