building engine questions.

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gixxer750

2jzget comingsoon!
Mar 30, 2005
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1.... About how hard should the valve springs be...? Pushing down with my palm onto the valve springs onto a bathroom scale, it's taking about 70 lbs to compress the stock springs. Does this sound right?

2. Anyone have pics of combustion chamber work that they or a machine shop has done(IE deburring)? I need to get an idea of what I can work on while I'm doing my head.

3 Anyone else priced valve stem seals from toyota...? Are they SUPPOSED to cost $175 for a set?

4 Should I get my head surfaced if I had it done 20k miles ago and the surface is still smooth with the exception of the ring a cometic leaves in the head? is that ring ok?

5. I kind of tried to do a hardness test on the head, dropping a plastic ball down a 6 inch length tube onto the head. The ball is bouncing up about 2.5 inches off the head the first bounce and about an inch the second bounce. Does this sound normal or does anyone have more information on this kind of test?
 
I

IJ.

Grumpy Old Man
Mar 30, 2005
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1.... About how hard should the valve springs be...? Pushing down with my palm onto the valve springs onto a bathroom scale, it's taking about 70 lbs to compress the stock springs. Does this sound right?

Ummm you need to use a proper valve spring tester to get an idea if they're sacked out or not as you need an accurate way of compressing them a set amount (the installed height take a reading then again at max lift)

2. Anyone have pics of combustion chamber work that they or a machine shop has done(IE deburring)? I need to get an idea of what I can work on while I'm doing my head.

Remove any sharp edges or dags, the 7M chambers aren't bad

3 Anyone else priced valve stem seals from toyota...? Are they SUPPOSED to cost $175 for a set?

Genuine Toyota seals are Viton rubber so expensive, see if you can find one of the kits that has a "Stone" head gasket and viton seals as they're the manufacturer for Toyota.

4 Should I get my head surfaced if I had it done 20k miles ago and the surface is still smooth with the exception of the ring a cometic leaves in the head? is that ring ok?

Can you "feel" the ring with a fingernail?

5. I kind of tried to do a hardness test on the head, dropping a plastic ball down a 6 inch length tube onto the head. The ball is bouncing up about 2.5 inches off the head the first bounce and about an inch the second bounce. Does this sound normal or does anyone have more information on this kind of test?

Ummm errrr ahhhh you're being serious here?
If so the "Hardness Tester" I described in another post uses a tiny metalic ball probably 3mm diameter and is a precision instrument
 
bigaaron

bigaaron

Supramania Contributor
Apr 12, 2005
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www.driftmotion.com
Ummm errrr ahhhh you're being serious here?
If so the "Hardness Tester" I described in another post uses a tiny metalic ball probably 3mm diameter and is a precision instrument[/QUOTE]

metal, plastic, whats the damn difference :icon_bigg
 
G

gixxer750

2jzget comingsoon!
Mar 30, 2005
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damn, I thought I read plastic ball.... I was just curious. I hate asking stupid questions, but I'm trying to get an idea here of what I need to do. I think they have a valve spring tester of sorts at the airport down the road. I'll check into that. Yes, I can feel the ring with a fingernail. I guess I let the machine shop take care of the head for me... I just didn't wanna spend that money I guess. Thats what I was going to use for a turbo. I guess I need to put that into the head to get a good solid long block for when I get the new turbo setup. I need to stop trying to be a cheap ass...lol
 
G

gixxer750

2jzget comingsoon!
Mar 30, 2005
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I know it.... I've spent so much on the block its starting to hurt my feelings. At this point I'm well over 3k in just the shortblock.

Should a cometic leave a ring in the head around the combustion chambers or do I have something bad going on. Its almost like a ring for a oring or something. Not real deep, but you can catch your fingernail in it.

I disassembled my head earlier. Should I buy new valves or do they really wear out if nothing is wrong with them. They have about 140k miles on the, and when you pull them out with a finger over the end of valve guide it pulls a vac on your finger and holds it.
 
I

IJ.

Grumpy Old Man
Mar 30, 2005
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Sounds like you've been lifting the head at some time and it's moving around a bit!

The Head shop will have the bore gauges to measure the guides.

As long as the valve stems don't have a wear ridge they should be fine but it's worth getting them measured to be sure.

An alternative if the guides are worn is thinwall bronze inserts I've used these in the past in other motors with great success.
 
G

gixxer750

2jzget comingsoon!
Mar 30, 2005
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the guides look beautiful. Hopefully they'll measure out that way. This engine has had synthetic since it was new in 88 best I can tell from the previous owners recipets. The valves don't have any wear on them, just carbon on the backs of the exhaust valves. know of any good ways to clean them? Of course I'll let my machinist check them.

What is the cause of lifting the head? I've been running a 57 trim at no more than 18 psi.... Then again, I did detonate a head gasket to death a while back because my tuner sucks.
 
I

IJ.

Grumpy Old Man
Mar 30, 2005
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It was probably the Detonation that did the damage.

May have lifted the head a touch then let it move around enough to make the rings.

Check the dowel pins and their holes in the head and deck.

The machine shop will clean the valves.
 
IHI-RHC7

IHI-RHC7

"The Boss"
Apr 1, 2005
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Nice, My dad is working at a Titanium manufacturing plant at the moment, and we're trying to figure out if any of the obsolete equipment would be capable of re-hardenizing the heads.
As we all know, toyota knows their metalurgy, so once I can find out th exact alloy used in our heads, we might be able to get the equipment to get rid of this banana head crap.
You'll notice in the TSRM that if a head is warped out of specification, the solution is to buy a new head. Basically, if it's been heated enough to be warped, then it's done.
We have about 6 high temp digital oven controlers that are accurate to 1/10 of a sec and 1/10 of a degree up to about 5000 degrees, so heating the heads accurately shouldn't be an issue, but finding the alloy is crucial to finding the proper cool down temp and timeframe. As well as any catalysts that might be needed.
Ian, do yo know where we could find the exact alloy of the head casting? It woul dbe nice to be able to save some heads...
 
IHI-RHC7

IHI-RHC7

"The Boss"
Apr 1, 2005
1,310
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The thing is that our heads are heat treated.
Straightening the head doesn't hurt it, but if it was warped, the heat treating was probably nullified by all of the heat involved in warping the head. By straightening it, you fixed the warped problem, but without a hardness tester, it's hard to say whether or not the head's hardness was jeopardized.
 
rakkasan

rakkasan

Currahee!!
Mar 31, 2005
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Fort Campbell, KY
bigaaron said:
If you had a head straightened, what is the worst thing that could happen?
Click to expand...

It *could* warp again at a much lower temp than the first time. Also, are the valve seats hardened inserts? I don't think they are, and that could cause trouble, too.

Just some thoughts.....
 
IHI-RHC7

IHI-RHC7

"The Boss"
Apr 1, 2005
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Plus if it is softened, the head won't seal against the gasket under high cyl pressure.
It's kind of like going from a stock piston to a forged piston only backwards.
A stock piston will hold up fine under a perfect tune, but one slip up under high boost and the motor's done. a forged piston is much stronger and can withstand a more ragged tune.
Same thing here, a hardened (factory) head will hold great and can withstand detonation to a point.
A softened head will just spit and sputter under even the mildest detonation. It ends up looking like someone threw some rice into the casting before the metal hardened. A treated head is much less susceptable (sp?) to detonation damage, and a soft head can even develope hot spots which cause detonation just by being so much softer.
 
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