free hit
counters
Blown head gasket? Video - Page 3 - Engine/Ancilliaries - The Lotus Forums Jump to content
Techspy

Blown head gasket? Video

Recommended Posts

Thanks Guys. I use Mobile 1 15w50 and was more asking about the flush procedure after having oil and coolant mixed.


John
94 S4

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Well apparently I have screwed something up. Got everything done today, set timing belt tension to around 94 hz. Seemed the same tension as before. Started, it stuttered and wouldn't run. Pulled plugs, had fuel. Checked plug wires=correct. Turned to TDC and found that the intake had jumped 2 or 3 teeth. Checked cylinder heads with my borescope, no signs of valve collision. Loosened belt, put intake cam back, tightened to about 120hz. I know that may be too high but I haven't been able to find a HZ setting for the gates belt. Figured if it whines it is too tight and I will adjust. Tried again. It runs but is very rough. To me it still sounds like timing but I confirmed all marks line up and are exactly like before I started the teardown. See picts. Does it look like I am off a tooth on both? Looking at the picture it kinda looks like the dots need to go up one tooth. Video shows how rough it sounds. With the plugs out and turning it with a wrench by the crank, everything feels smooth. Pretty low at the moment. I hope I didn't screw something up.

 

20180324_182434-1 - Copy.jpg

20180324_182609-1 - Copy.jpg

20180316_163134-1 - Copy.jpg


John
94 S4

Share this post


Link to post
Share on other sites

Looks OK to me but of course I dont have the perspective from photos.   Why not run a compression test to rule out mechanical damage?    You could also pull plug leads in order to see if you have an issue with a single cylinder?    

Share this post


Link to post
Share on other sites

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.


John
94 S4

Share this post


Link to post
Share on other sites

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?


John
94 S4

Share this post


Link to post
Share on other sites

I'd be double-checking valve clearances first!


British Ambassador to Florida, New York, Denmark and Newfoundland.  And Sweden.

Share this post


Link to post
Share on other sites

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.


John
94 S4

Share this post


Link to post
Share on other sites

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.

  • Thanks 1

Margate Exotics.

Share this post


Link to post
Share on other sites
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. :thumbup:

Edited by jonwat

Cheers,

John W

http://jonwatkins.co.uk

Share this post


Link to post
Share on other sites

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.


John
94 S4

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

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!


John
94 S4

Share this post


Link to post
Share on other sites

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.


British Ambassador to Florida, New York, Denmark and Newfoundland.  And Sweden.

Share this post


Link to post
Share on other sites

:thumbsup::thumbsup::thumbsup:

Enjoy your upcoming driving :D


88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

For forum issues, please contact the Moderators

Share this post


Link to post
Share on other sites

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!

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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 by Techspy
  • Like 1

John
94 S4

Share this post


Link to post
Share on other sites

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!

Share this post


Link to post
Share on other sites

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.


British Ambassador to Florida, New York, Denmark and Newfoundland.  And Sweden.

Share this post


Link to post
Share on other sites
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.:ermm:

Share this post


Link to post
Share on other sites

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!


British Ambassador to Florida, New York, Denmark and Newfoundland.  And Sweden.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...