Replacing head gasket B engine; any tips? (1 Viewer)

[arutgers]

This morning I noticed an obvious leak in the head gasket of my 1978 BJ40 (3.0 liter B engine); coolant was leaking out. When I replace the head gasket, are there other things I should do while the head is off anyway?

Ton

 

[Island Moose]

How many miles on the engine?

 

[arutgers]

I don't know, only 5 digits on the odometer ... My guess is 350,000 km (217,000 miles), but could also be 250,000 or 450,000 km (155,000 or 280,000 miles).

Ton

 

[mk1pickle]

when you replace the headgasket you should take the head to a machine shop and have it checked for trueness (flat) before bolting it back on, also checking the pre burner cups for any type of cracking is also recommended.. the burner cups tend to fail and fall into the cylinders, replacing them while the head is off is good insurance. also for about 30 bucks an injector have them rebuilt/ cleaned. does the engine suffer from high blowby? check the ridge at the top of the cylinder bore..

overall though definately check the pre burner cups

 

[arutgers]

Ok thanks, I will check those cups.
I do notice high blowby. What about that ridge at the top of the cylinder bore? Should it be or not be there?

Ton

 

[cruiser_guy]

You should also have the head magnafluxed to check for cracks. If it's anything like a 3B I'd bet it has cracks and the simple act of removing the head and replacing the gasket may cause enough of a disturbance to the cracks to cause problems.
I've taken 3-4 3B's apart and have yet to find one without a cracked head!!

 

[arutgers]

Thanx for the info, though I am not happy with the thought the head may be cracked. Well we'll see ...

Ton

 

[wesintl]

Well, If you get alot of blowby why not hone the cyl and rering it. You're half way there....

Check for truness, crackes and replace the precups if cracked.

HTH

 

[PressOn]

I just pulled my 3B head to replace the head gasket. Compression was good at ~400 psi, fuel economy was decent at 26 miles/gallon, oil analysis didn't flag anything but it was leaking oil bad and it had a little piston slap noise. With roughly 100,000 miles I wasn't expecting to find much wrong.......

One cracked piston skirt, a heat checked crank shaft, cracked head, 2 of 4 cracked precups later the engine is now finally being totally rebuilt. I suspect the PO ran it hard low on oil. Magnaflux was key for the head and crank shaft cracks.

I'm surprised that little engine was even running.

 

[arutgers]

One cracked piston skirt, a heat checked crank shaft, cracked head, 2 of 4 cracked precups later the engine is now finally being totally rebuilt. I suspect the PO ran it hard low on oil.

Anyone there with positive, cheerful, stimulating stories that make me look foreward joyfull to do this job ...?

 

[wesintl]

a 3b head weighs no where near as much as an F head or other 6cyl

No mess of emissions crap either

 

[lowenbrau]

Anyone there with positive, cheerful, stimulating stories that make me look foreward joyfull to do this job ...?

My buddy pulled the head off his BJ60 (c/w turbo) three Saturdays in a row. Got the re and re down to 2 hours flat. Its a cakewalk.

 

[Deny]

Anyone there with positive, cheerful, stimulating stories that make me look foreward joyfull to do this job ...?

When I pulled mine apart, I only did a visual check for cracks, and only found the precups cracked, so changed them, they were easy, bolted it back together with all new gaskets, and it's worked great ever since. I wouldn't worry.
Cheers,
Deny

 

[arutgers]

Thanks guys, that's the kind of peptalk I need (this is my first major engine repairjob ...).

Ton