Bad head gasket?

Ok I have an 85 FJ600. Now I have built this thing pretty much from scrap metal to where it is now.

I have a pretty good mechanical back ground so lets assume I know what i'm doing before asking me basic level questions. So to fast forward and give some background this was in someone's yard. as in just laying there. one cylinder had a lot of rust intrusion and I had to have the valve seats ground because of the cavitation to the seats.

Measured everything and everything ended up coming into spec. There's one spot on the cylinders that is close to spec but still under for straightness. I don't think that's the problem but i'm not going to say its not. I want to say block straightness was .0012 and I ended up with like .010. I did this last year and stepped away for a while since it pissed me off massively. Anyway.........

So yesterday I pulled the engine since it only put out roughly 80psi equally across all cyl's. Won't fire clearly. I did a leak down before this and got roughly 90 to 95% leakage through the piston rings. Figure I did something stupid. Rings aren't lined up, piston to cyl measure is good but here's some stuff I've never seen before.

Pulled the head and there is assembly oil coating the surface of the new gasket. Take the gasket off and more oil all over the surface of the cylinder jugs. Now I had all of this clean before assembly. I have new oil seals on the ends as well. Base gasket is dry. So clearly its blowing from the cylinders across into the timing chain area where I felt the air coming out of the valve cover when I did my leak down test.

Its an aftermarket gasket but my question is, is it possible the new gasket didn't crush correctly and it blew the compression through the stamped steel seams and that's what up. I've never seen this happening and before I go and buy a new gasket I wanted to have a few of you engine builders tell me I did something else wrong. I also considered my one weird spot on the head of the cylinders to be a problem but being under spec I don't think that's it. And yes i'm thinking of taking it to the machine shop to have it decked now.

I can upload pictures if needed. I was certainly expecting piston to wall clearance too much since I realized the other day I have a set of FJ pistons that I have no idea why I have.

 

Heres my findings yesterday. I also put wd40 in the cylinders so that's the brownish color.

 

I just put the straight edge back on the cylinders and the more I think about it I really shouldn't be able to see any light with a flash light anywhere. I could also feel a very small tip when I laid it in a cross pattern from 1-4. between 1 and 2 there is a very small gap but there's something there. but since the compression loss is across the board is it a combo of an untrue surface and a gasket? As said I've never experienced a problem like this. I don't have new rings but they measured fine as well from what I can recall. I don't think I had any gaps that were bad. I'm going to get my mic's and bore gauge from work tomorrow and measure everything again. I have a Yamaha shop manual for the engine so I don't think any of the specs given are typo's. I probably just missed something obvious besides the cylinders which i'll take to the machine shop. to be honest i'm not sure why I didn't before. Probably because this bike has far exceeded its value and I probably tried to skip out. As said this has also gone on 3 years with buying a new house, having a baby, switching jobs. Never really had a ton at once to start and finish.

 

Who makes the gasket set that you bought? There are several that do not actually fit correctly, even though they claim to.

 

I have no idea. Some chinese kit on ebay. Everything seems to fit great but i was considering buying yamaha head gasket. I think im going to make sure both surfaces get decked and use an oem gasket.

I looked earlier and theres a few questionable low spot. Nothing that really made me stare but enough i didnt like.

 

I strongly suspect that is the problem.
Start a conversation with Chacal. He only sells what fits and works.

 

If $ permits also get oe oil seals.

Gary H.

 

Double post deleted.

Gary H.

 

It may permit now. I have all winter to get it to run. I travel about 30 miles to work again so it would be nice to have that 50mpg and 45 minute relax cruise again.

I still want a damn buell though!

 

So lol.... cylinder 4 sleeve is above the others. Causing a .008" gap between 3 and the end of the block. .05" in the middle and naturally ending at 0 at cyl 1.

How the hell did it move?

Measured pistons, ring gap, and cylinder borea. Everything is fine there. Im guessing the giant hole is causing most of this. The head in the center has a low spot but its about .002" but im pretty sure i can wetsand that with a 2x4

 

Glad you found it.

Gary H.

 

Well, I'll be ***** ! How would that happen ?

 

i have no idea. Been that way since i picked it up my guess. i never dropped it and even if i did that would be a hard hit to move the sleeve

 

So, how do you solve that? Heat the block and press it with a hydraulic press?

 

I reckon so. At one point I was going to take my block to the local auto machine shop to get a liner changed and that's what they proposed.
Interestly I now recall that on my spare 600 block the ally has been peened (?) with what looked like a centre punch over the liner in a few places- not so on my spare 550 block

 

Im almost not sure what to do. Goong to take it my machine shop. I dont know how hot it needs to be. We have a 20 ton press here but im a little nervous to attempt such a thing.

If it goes bad it goes bad. Ill just try to find a good set of jugs and measure them out.

 

I could probably set the press up fine but i would be worried first about warping the surface or cracking the cylinder block.

Since its .008" kinda hoping they can grind that off without that affecting anything.

 

On dirt bikes we used to put the jug in a oven and drop ice in the bore and smack it with a block of wood.
The're not in there as tight as you think.

 

As plolock said, they aren't all that tight. They are made to be a slight interference fit to. Inimitable distortion during assembly. LockTite makes a sleeve retention liquid that helps out, but you'd need to drop the sleeve all the way out to use it. Just hear it, wack it back into place and lightly peen the head to help it stay in place. Finish with a oil stone to remove any high spots from the preening.

 

How hot should i get that little guy? And would a dead blow be good enough. Ive got 3 and the biggest is 54oz i think.

 

I only ask since its aluminum. Im guessing around 375 or 400? Bake for 15 minutes and tap it down?

 

From memory, like 40 years ago.
350/400 for about 30 minutes.
Then we wrapped it in a rag to keep it hot
And wiped ice cubes in it till the sizzle stopped. Used a piece of 4X4 to hit it. On the end grain about 18 inches long.
On yours I'd support it somehow, don't want to knock the others out while hitting that one in.
Try giving it a smack cold just might go right down

 

I'm thinking 400 degrees plus the ice for the sleeve. Mainly because the block will get pretty close to 400 degrees during normal running anyway.

 

was just gonna say that I had a cylinder head leak on a newly rebuilt engine , after pulling the head again I found one of the locating dowels had not seated correctly
thus it was slightly cocked and crushed, causing the leak.
I also used the "cheap?" gasket set off ebay ,with no trouble
stu

 

I

I think that would work

 

Cool, ill try this weekend when wife is gone. Im thinking incan set up a stand with my vice. Take it out, run to the garage which is on the other side of the wall, ice it and smack that dude.

Ill post my beating update. Stay tuned.