Jump to content
DatsSully

L20b rebuild, coolant leaking out the head

Recommended Posts

Okay so I've been putting this car together slowly for the past 3 years where the car fought me every step of the way with stupid little shit that kept holding me back but I finally get it to the point where I can fire it up. I fill her up with oil, then I go to fill the radiator up with water so i don't ruin anything on startup(If it starts at all). Sure enough f'ing Murphy's law'd once again, as I fill it up with water I hear this trickling noise so I look up and there's water leaking out the coolant passages from under the head out onto the side of the block(Sorry no pics or video, I immediately took the head off to check it out). 

 

I just "rebuilt" this engine before swapping it in, I had replaced the timing chain, head gasket and swapped a few parts I knew were working off my old engine onto it. The head bolts were on there nice and snug(I broke a craftsman ratchet trying loosen them before I switched to a breaker bar haha). I thought it might be that I didn't put these 6 or 8 dowels that were in the l18 but they were too small to fit in the passages and it didn't look like they were supposed to have dowels int those ports. I also checked and and cleaned the surfaces and nothing seemed warped or damaged. I did notice that the coolant holes in the head are slightly smaller than the ones in the block so maybe that's the issue.

 

I couldn't find any issues similar to this in searching, maybe someone knows something that could help me, I'm going to put the head back on soon and hope it works if not.

Share this post


Link to post

Two dowels in block to position cylinder head; did you use those?

 

 

Did you use a torque wrench to tighten head bolts evenly?

  • Like 1

Share this post


Link to post

Not enough info.
 
 

as i fill it up with water I hear this trickling noise so I look up and there's water leaking out the coolant passages from under the head out onto the side of the block(Sorry no pics or video, I immediately took the head off to check it out).



Which side??????? If the manifold side it's probably they are not tightened down evenly and water is leaking out the two coolant passeges to the intake.. Are these stock intake and exhaust manifolds or are you running a header???? Headers have a thinner flange and the bolt tightens unevenly.


 

The head bolts were on there nice and snug(I broke a craftsman ratchet trying loosen them before I switched to a breaker bar haha).



Broke wrench loosening the head bolts???? This begs the question... how were they tightened?? Did you use a torque wrench or might you have over tightened them????


 

I thought it might be that I didn't put these 6 or 8 dowels that were in the l18 but they were too small to fit in the passages and it didn't look like they were supposed to have dowels int those ports.



Two questions on this... what engine are we talking about here? What 6 or 8 'dowels'??????? There are only two alignment 'dowels' between the block and the head.

 

I also checked and and cleaned the surfaces and nothing seemed warped or damaged. I did notice that the coolant holes in the head are slightly smaller than the ones in the block so maybe that's the issue.



 
Seemed.... isn't enough a warped head is not obvious to the eye. The maximum allowable amount of warp on an L head is 0.004" that's the thickness of 3 sheets of writing paper.
[]

 

 

 

  • Like 1

Share this post


Link to post

The two dowels that are meant to be there are there. I tightened the headbolts with a torque wrench to spec awhile ago. I have I think 8 dowels and I was pretty sure they were in the block on my l18 I could be wrong since I didn't label the bag and I did all that 2 years ago. I took a new metal yard stick and check the clearance with a feeler gauge and it checked out. Maybe the head bolts just got a little loose after awhile, maybe once I redo it it won't leak? I had done everything by the book, the head did have some build up on it but I didn't think it would cause such a problem.

Share this post


Link to post

Is it running out on the intake side? What head do you have? If it has the water passages from the head to the intake it could be that the intake was not tight enough. 

A couple pics would be very helpful. 

Lets see those mating surfaces. 

Share this post


Link to post

These dowels? where are they located? I'm not understanding what you mean about them. There are only TWO alignment dowels on the L series. They each look like a piece of 1/2" copper water pipe and fit into two slightly larger diameter head bolt holes and align the head over the cylinders. Nothing else should be between the head and the block but the gasket.

 

 

 

 

Again.... What side is the leak on?

  • Like 1

Share this post


Link to post

intake tight?

 

I cant see where you can hear the lak then its a big open cavity somewhere.  Manifold water passage tight? the hose to the intake if you have a water heated manifold. 710s might be different.

 

 

I also never heard of 6 dowls. Theres only 2 in the head for lighning that up then the intake exhaust bolts anf the lower bolts have the washers that apply even pressure to the intake and exhaust at the same time

 

 

noway the headgasket is not sealed that bad!!!!!!!!!!!!!!

  • Like 1

Share this post


Link to post

I don't know what engine he has, I asked. Said he swapped it in, mentions L18 but not what went in. His profile car mentioned doesn't say the year.

 

L18s (had water cooled intakes) were only installed on the '74 710..... all others were L20B with U67 heads without  the water cooled intakes. If a '74 and you put a later '75-'77 L20B without the water cooled intake the  water return line under the carb has to be sealed off. This is why I ask questions because not enough info is included.

Share this post


Link to post

I've had people swear that they propperly cleaned all the old gasket from the surfaces, only to find that they didn't......

I went in, using a proper gasket scraper, and got all of the old gasket off, installed a new gasket, and everything sealed back up just fine.

Share this post


Link to post

I don't know what engine he has, I asked. Said he swapped it in, mentions L18 but not what went in. His profile car mentioned doesn't say the year.

 

L18s (had water cooled intakes) were only installed on the '74 710..... all others were L20B with U67 heads without  the water cooled intakes. If a '74 and you put a later '75-'77 L20B without the water cooled intake the  water return line under the carb has to be sealed off. This is why I ask questions because not enough info is included.

 

Sorry it's been awhile since I've tried to troubleshoot on here, the motor I swapped in is an L20b with an A87 head, I'm using stock 74' 710 manifolds with a weber 32/36 conversion. The leak was between the block and the head, coming out both the passenger and drivers side.

 

Haha I worked on it when I had time between school and work, mixed with inexperience. I have no idea where the dowels are from at this point and yeah the head bolts have washer and all that.

 

I'm going to re-torque everything with the new clean surfaces and see if that solves the problem. 

  • Like 1

Share this post


Link to post

The reason why there might b some confusion in helping u out is because u mentioned L18 on ur post. Btw, did u torque it down in sequence, per book?

  • Like 1

Share this post


Link to post

Got it back together and tested it again, now it's just coming out the intake ports, the intake gasket I have installed is pretty shitty so that's probably the problem. 

Share this post


Link to post

Got it back together and tested it again, now it's just coming out the intake ports, the intake gasket I have installed is pretty shitty so that's probably the problem. 

You better damn well hope that the water is NOT coming you of the intake ports.  Do you mean between the intake ports.  You are really light on info, the "8 dowels" that you mention, are they the alignment dowels for the cam towers?  You may be a newbie from New Hampshire, theses guys are trying to help you.  If you think you know everything, you do not or you wouldn't be asking these questions.  Quit your haha's and pay attention.  Most of them are more tolerant than I am.  Better wear your tin undies and be ready for an a$$ whippin' if you don't listen.

  • Like 1

Share this post


Link to post

If water from between head and block then something is crushed in there that shouldn't be there.

 

The block to head alignment dowels look like this...

s-l225.jpg

  • Like 2

Share this post


Link to post

go ez. took 2 trys on my 1st head gasket.

 

I forgot about the cam dowels. then anything can happen on this one. Cam can snap!!!!!!!

 

The dowels are from my disassembled L18, I never took the cam towers off the L20b that I swapped in

 

If water from between head and block then something is crushed in there that shouldn't be there.

 

The block to head alignment dowels look like this...

s-l225.jpg

 

Those are in and the headgasket seems to be sealed now, the leak is now coming from the coolant passages that lead to the intake manifold.

Share this post


Link to post

The bottom four studs have large thick washers that bridge across the bottoms of both the intake and the exhaust flanges and clamps them both. They are hard to get at and tighten properly.

  • Like 1

Share this post


Link to post

A very common mistake is made during the cleaning process. People seem to think it's ok to use a high speed  die grinder with a Roloc scotch brite disc to clean the gasket surfaces. If you did this to clean the intake manfold surfaces, you may want to remove the manifolds and start over with a square block of wood wrapped with emery cloth (sand paper will work). Use WD40 as a lubricant while sanding.

 

Clean it off with acetone, lacquer thinner or carb cleaner on a towel.

 

For assembly, add a small ring of orange high temp RTV around the water ports (both sides of the gasket) and then assemble the manifolds.

 

Another thing you may want to consider is to swap out the four bolts on the underside with studs. This will allow more torque without the worry of pulling a thread out of the head.

  • Like 3

Share this post


Link to post

Also, the thick washers are mildly cone shaped on on one side, the cone points toward the manifold.

  • Like 3

Share this post


Link to post

Thanks for the help guys, so the leak was coming from the manifold, didn't realize there was those other spots for bolts, that leak stopped after putting some washers and bolts on there. Then I had to switch the coolant line the runs across the front of the engine so that the thermostat and the intake can hook up their outlets, the one on the engine was just for the therm outlet. Doesn't leak now but I have to figure out whats keeping it from turning over(Probably just some starter fluid down the barrels in the morning will do the trick). The only thing holding me back here was my lack of knowledge, it's the little things that get me since I bit off alot for a newbie(Auto to manual swap and engine swap at the same time) so thanks again.

 

Also I cleaned the gasket areas with a razor blade very carefully.

Share this post


Link to post

maybe plugs are wet now.

 

ck for spark at the end of the center coil wire!!!!!!

then see if gas is squirting in the carb when you cycle the gas.

 

if you have them both then ck the lvalve lash and the timming of the distributor

 

 

really you need to get this fucking running before declaring victory on this as it heats up it still may leak

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

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.

Loading...

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.