strange starting problem

[Beau]

Unfortunately not, however the guy I spoke to test it for leaks by sealing the head and then submerging it in water. He then pressurizes the head and looks for air bubbles. It's a pretty bulletproof method I think...

The plan was to initially tighten it down, but not to torque spec, just tight. Once warm I would re-tight it further. Shayne, yeah it's a pretty old school approach but it works. And like you said, I have nothing to lose. I'm quite looking forward to seeing how it goes. Will definitely take pics for you guys.

 

[StarCruiser]

Good luck holding and tightening bolts down when it's up to temperature…

 

[Shayne]

Welding mask and gloves with a long extension on your socket . I have no doubts about the theory or the practical Beau what made me laugh is using the kitchen oven i can just imagine the mrs saying that roast doesn't smell right

 

[clivehorridge]

Roast cruiser head, with garnish... Yummy!

 

[Beau]

First I need to see if it fits!

 

[Beau]

Update time! So...

Head was warped 0.40mm at worst, mostly in the middle of the head, a lot when it comes down to warping. Toyota specifies to replace the head if warped more than 0.15mm.

Attempt 1 - Used 30mm steel - Bolted the two middle bolts down and torqued to 80 ft pounds - Used 0.20mm shims. No success, steel was taking most of the force and was warping.

Attempt 2 - Same steel, used 0.50mm shims instead - Same thing!

Attempt 3 - Cut out another 30mm steel sheet and doubled it up. 60mm thick now. Bolted it up with the 0.50mm shims and 120 ft pounds - Success, somewhat, it moved 0.05mm in. Maximum warpage now 0.35mm. Even with 60mm thick steel it was still warping and taking the force instead of putting the force on the actual head.

Attempt 4 - Used the two steels, and also some 4mm large steel box section! 80 ft pounds torque on the bolts. - Success - I couldn't believe it! Remaining warpage is now under 0.10mm. Within spec to bolt back on but I'm going to sand it flat and use a slightly thicker gasket.




Glass table top with 100 grit sand paper. Will finish off with something finer like 600.


Not too bad.



Where the gasket sealed around the compression area, there is a slight lip on the head, enough to feel with my finger nail. Do you guys think this will be a problem when bolting back down and sealing properly? If so I can sand down a bit more, but would rather remove as little material as possible. Head is now under 0.05mm warpage.

 

[Beau]

Oven procedure was fairly simple...

I torqued the bolts down prior to entering the oven, because it was too tight and somewhat dangerous to get to the bolts in the oven (I tried).... Placed the head in the oven and gradually rose the temp in increments. 250F, 300F, 375F, 425F and then for 4 hours at 475F. Once the 4 hours was done, oven switched off and head left in oven to cool back to room temp. This took nearly an entire day! Then removed the head from the oven, and carefully unbolted the head and re-checked with a straight edge.

Overall, I'm pretty pleased with the results - Look forward to the rebuild now... I bet a lot of heads get thrown away because they are warped beyond spec.

 

[Shayne]

well done for trying and bravo on your success I don't know about the lip but i would have thought that's why we have gaskets , nothings perfect if you get what i'm saying .

 

[Sag]

Good job there and saved a lot of brass at same time,like Shayne said gasket should be OK to sort the lip out but sure someone with more experience will come along and let you know.

 

[BobMurphy]

The standard head tightening sequence is here - i.e. middle to ends.

I would be tempted to give the centre bolts the full 180 degrees on the second pass and give the outer bolts 90 deg and 90 deg on the second and third passes - pausing to let the gasket settle between each.

Just a thought.

Others may disagree .

Bob.

 

[Beau]

The standard head tightening sequence is here - i.e. middle to ends.

I would be tempted to give the centre bolts the full 180 degrees on the second pass and give the outer bolts 90 deg and 90 deg on the second and third passes - pausing to let the gasket settle between each.

Just a thought.

Others may disagree .

Bob.

Any particular reason why you'd give the centre bolts there 180 on the second run, instead of doing it in 90 degree stages like the manual suggest?

Also I remember in one of your old threads when doing a head job, you used a gasket sealant. Did you use the sealant on both sides of the gasket or only the side against the head? I imagine you spread the sealant very thinly on the gasket?

 

[BobMurphy]

I thought it might help to pull the head flat - as it has a tendency to lift in the centre. I may be completely wrong of course.

I put a thin smear of sealant on both sides of the gasket (careful not to block the oil hole at the back or the camshaft may be starved). Mine has been fine since I did that.

It will be very interesting to see if your head straightening trick produces a permanent fix - impressive stuff.

Bob.

 

[Shayne]

I was thinking Bob's 180 method would be to help the gasket spread , whether its solid or liquid the excess has to go somewhere when it's compressed .

 

[Beau]

ah I seee! I'll have to have a think about that and decide. If I had the slightest warpage in the middle of the head (low spot) then I think that might be a good idea, but with a perfectly flat head, I'm thinking equal stages may be best.

Any specific kind of sealant you use?

Shayne, yeah that was my thought too. It's 50/50 with using any sealant. A lot of people say the gasket should seal it all. It actually has some kind of composite seal on it. That black stuff that gets compressed into the head. But I see the sense in using sealant when you have low spots within the head. Mine's flat, but I'm sure there will be low spots that's hard to detect. So with that said, I'm leaning more towards using some kind of sealant. I know Volvo's use a Aerobic gasket sealant on there gaskets. You use a roller brush and roll it on.

 

[Shayne]

Copper spray seems to be popular in America ? big engines there me thinks .

 

[BobMurphy]

Any specific kind of sealant you use?

A lot of people say the gasket should seal it all. It actually has some kind of composite seal on it. That black stuff that gets compressed into the head. But I see the sense in using sealant when you have low spots within the head.

I wasn't worried about the head as it was a new 'Roughtrax' one - it was the etching around the top of the block I was worried about. Stripping the engine down and getting the block re-faced was a step too far .

I used a clear, red 'Car Plan' non-setting sealant. it was quite thin and went on well. I've not been able to get any more of it so now use "V-tech red RTV silicone Instant Gasket Maker". I haven't used that on a cylinder head yet - just on Transfer Box joints.

"Blue Hylomar" would be OK. There was a rumour that production was stopping so I stocked-up at an Autojumble. The rumour seems to be false, thankfully, as I use it a lot.

Bob.

 

[Beau]

hmm I'll have to do some research on that! Been busy gasket matching/porting the head and intake. Turbo porting next me think, more on that later hehe

 

[Shayne]

A 3" turbo back exhaust is what you need Beau all the steroids in the world won't make a horse run when its tethered on a choke chain .

 

[Beau]

A 3" turbo back exhaust is what you need Beau all the steroids in the world won't make a horse run when its tethered on a choke chain .

Exhaust is on the list Shayne (among a long list of other stuff), but whilst the head and turbo is out I thought why not

 

[Beau]

Update time! Pics below show the porting work I did. Nothing professional, it was my first ever time doing something like this, I reckon it's good enough. Got the the head built and stuck on. I used some copper spray on the gasket. Product looks good, I hope it works well too! Also removed the throttle valve and got rid of the EGR pipe work all together.

So she starts and sounds normal which is a good sign. However, the starting process still takes about 7-10 seconds of cranking. I'm really lost. Here's a video. You can hear it starting to catch a few seconds in and then finally she starts. https://youtu.be/LmKczIGZg5c

Not visibly pressurizing the coolant system, and revs really freely and nice. Didn't get a chance to take her for a test drive. Will probably do another compression and leak down test to see if I have any compression issues.