BJ74 overheating... leads to head or head gasket (real time surgery)

[Radd Cruisers]

Here we go... this little bucket of bolts has been pissing me off for a few weeks now with constant overheating. A new rad last night didn't solve it - so the off with his head!

So, grab a and some and follow along... hopefully I'll get this done in short time. And, hopefully it's the gasket.

Starting at 14:00 hours PDT - from Duncan BC Canada

~John

 

[ForealBoreal]

yikes! good luck!

 

[Radd Cruisers]

1 hour later... injection lines off, cooling system dumped, most coolant pipes off, air cleaner out....

 

[Radd Cruisers]

15:42 - two different friends stopped by. Howard to borrow one of my engine lifts and Ian to just have a chat. Progress is a little slow, but the intake is off and the rockers are out. Push rods are on the bench, power steering pump is tied back out of the way.

 

[Gun Runner 5]

I am glad I lived long enough to see the phrase "overheated" and have it be associated with a powerplant other than the 2L-TE
Not that you need it but good luck with your project.
.......1978HJ45

 

[Radd Cruisers]

Here we are... getting ready for lift off!

Overheating and head cracking may go hand in hand, but these little beasts rarely have head failures. Hopefully it's just the head gasket, but I've overheated this thing three times myself, and I'm sure Kyla did it a couple of times before I got the "there's a leak under the car the last time I used it" message/

The cooling system dumps as soon as you start pushing the boost up past about 12 (it goes to 16) and I'm really sure it's a gasket failure that's the cause.

Moments from finding out...


~John

 

[Radd Cruisers]

Okay, the head's off and it looks as though the failure is indeed the gasket. These things use composite gaskets from the factory, and the lack of cooling system maintenance it had during its life in Japan seems to be the culprit.

There areas near the water passages and close to the cylinders show signs of rusting, which leads to the gasket not adhering to the block properly. The combustion gases can then push past the gasket and into the water jacket.

It's really common that the JDMs that we see have horrifically poorly maintained cooling systems that are at least partially blocked with sediment from corrosion and overly mineralized water being used in the radiator. This vehicle is no exception, and after if arrived from Japan I did a system flush which lead to a leaking water pump - the dirt in the system has worn out the seals, but is also providing a seal itself. When one washes out the system, the sediment gets cleaned off somewhat and leaks occur. Also, freeing up sediment in the system can cause it to move through the system causing rapid wear of the seals in the water pump and blocking heaters cores and rad passages.

Here are some photos of the block and head.

I'm going to do a quickie gasket change and see if that's the solution. I'm not too far into this thing time wise to make it a nasty job. Certainly light years ahead of the 2LTE to work on as there's not timing belt to deal with.

~John

 

[Radd Cruisers]

Here are a few more photos - one of the three in the last sequence was of the head gasket itself. There is evidence of scrubbing of the cylinder sealing ring... this is usually from expansion and contraction from heating/cooling cycles. MLS (multi layer steel) gaskets were designed to reduce the effects of scrubbing when mixed metal engines are used as Aluminum and Iron have vastly different expansion and contraction properties. Also, Al - Al engines have a terrible time with gasket failures and MLS gaskets really help.


~John

 

[Lee777]

Thanks for the write up john, I've gives novices like me a chance to see how its done

Lee

 

[Radd Cruisers]

It's going back together now...

Here's your next update as we follow Coleman getting a new headgasket:

The block has been prepared by scraping off the old gasket material that was stuck behind. The areas where there was evidence of gasket failure were scraped and then prepared (sanded, really) with some 80 grit machinist's cloth. I focused on getting the surface rust off and baring clean iron so that the new gasket will seal to the surface properly. I also used a razor and went around the sleeves to remove the very slight build up of carbon that was there.

Then, I cleaned out the head bolt holes with a long air blower minding that debris didn't fly all over the place (covered with a rag while working). Then I went over the holes with some degreaser (Kleen Flo 313) that is naptha based to remove any junk that didn't come out with compressed air. I then blew the holes out again (actually a couple of time) to remove the degreaser. It's really critical that the holes are clean and dry before you go to put the head back on and the bolts in.

If there's liquid or debris in the holes you can ruin the threading or not achieve proper torque. I have seen more than one rookie destroy expensive headbolts or tear the threads out of a block (Cadillac North Star engine which is all aluminum) from not being careful about what they are doing. Repairing damaged threads in a block is not generally that difficult, but it's really stupid to create more work for yourself by having to dismantle the engine twice to fix something that didn't have to be a problem in the first place.

I then degreased the surface of the block and set the gasket in place to see if the fit was good. The 13BT uses the same gasket as the 3B - which I have in stock as a loose item . I also needed a turbo oil system gasket - found one in my misc. gasket bag .

More photos... and then on to cleaning the head up.

 

[Radd Cruisers]

Here are a few more before I go to town on the head...

 

[Radd Cruisers]

The head's back on, and the dinner bell has rung....

Last update for an hour or so. I have to go and get some dinner or my other half will be unhappy that I let it get cold...

The head is now back on. I added some sealant to a few areas around the water passages that I figured might be problematic.

Here's the photo essay of it:

 

[Radd Cruisers]

20:10

Cleaned up the head bolts that had a little surface rust on the and inspected them for integrity. They all looked good after I ran them on the soft wire wheel for a few seconds each.

Coated the bolts in a layer of light spray grease to provide the needed "light oil" for torquing into place. Made sure that there was some grease under the bolt head.

I then ran them into place, following the proper order, with my really gutless but quite quick 1/4" air ratchet.

Now that the head is down, and ready to be done up, I'm going for dinner.

More to follow when I get back.

 

[Radd Cruisers]

And the last of this round of photos:

 

[Hulsty]

Looking good! I've never noticed before but the block is one chunky unit compared to the gas motors I have worked on.

Some questions when you get time,

Does the 13BT suffer head gasket problems at high boost levels?

Your mentioned this vehicle runs 16psi boost, what rpm is this achieved at?

 

[Radd Cruisers]

Well, dinner's over and I'm back... will get to torquing the head down and answering some questions.

As for 13BT gasket failures - I don't think it's a problem with these engines. Running inadequate coolant is probably the cause of this failure. I run my at a minimum of 50/50 (tests to -36C). You could see the rust in the iron where it was causing the gasket not to adhere to the block.

As for boost, I don't have a pyro on this one but I'm sure it gets quite hot. I don't really pay too much attention to the revs that it makes that boost at. Being an automatic, I just let the trans do the shifting unless I'm pulling a hill and then I knock it down to third and let the Extreme Valve Body hold third with the converter locked up. At that point I'm sure it's doing 2400 or so... and it will easily max out the boost setting at those revs.

~John

21:25

 

[Radd Cruisers]

Head bolt torque is 87 ft lbs, so I'm going to bring it up in three stages...

Yikes, that's going to take a bit.

~john

 

[Radd Cruisers]

Head is torqued, injector tubes are in but not tightened down, power steering pump is back in - had some trouble getting the bolts all lined up, intake is down and torqued up, rockers are in and torqued down - still have to adjust them, turbo support bracket is done up - need to do up the oil supply/drain tube, exhaust is up and about to get torqued down.

Here are the latest photos....

 

[Radd Cruisers]

Here are the rest of this round's photos...

 

[Radd Cruisers]

One more... and then back to the wrenches...