Rod shortening as an alternative to a thicker headgasket
- Thread starter JimR
- Start date
No 
Even the stock bolts and rods are huge if you compare them to say a SBC.
Any failures I've seen are a result of RK.
(anyone that steps up to 500+ addresses this before it becomes an issue but I suspect built correctly it's a non issue)
Even the stock bolts and rods are huge if you compare them to say a SBC.
Any failures I've seen are a result of RK.
(anyone that steps up to 500+ addresses this before it becomes an issue but I suspect built correctly it's a non issue)
Those were my thoughts as well. I talked to Reg Reimer here in Calgary and he has never had a broken bolt. So I've decided not to get the rods resized afterall. This lets me use toyota bearings, and not worry about any rod clearance issues after the resize operation.
Apparently there's something like 60 thou valve to piston clearance? So I don't have to worry about this becoming an interference motor if I put a 1.2mm gasket on there, and I can have a little more compression to boot.
Apparently there's something like 60 thou valve to piston clearance? So I don't have to worry about this becoming an interference motor if I put a 1.2mm gasket on there, and I can have a little more compression to boot.
IJ.;954164 said:
They are at the machine shop. I will doublecheck as soon as I get them back. However, everything I have mic'd so far is perfect! lol it's kinda freaky sometimes. For example, the oil pump. The gears had ZERO wear on them.
It's a 140,000km car with religious maintenance all it's life.
LOL not surprised on the pump
(it lives in Oil)
Usually just being run/unbolted is enough to egg the BE's.
(it lives in Oil)
Usually just being run/unbolted is enough to egg the BE's.
I dropped by the machine shop today and had a long discussion with the machinist. He's quite knowledgable, and I learnt a lot! We checked out two of the rods using a dial gauge set up on a machine which showed in ten thousanths, and the big ends were out-of-round by about one thou each. So you were quite right!
The final result is that I am definately getting these things resized and shortened, and they are putting in the ARP rod bolts as well. Might as well do it all!
The final result is that I am definately getting these things resized and shortened, and they are putting in the ARP rod bolts as well. Might as well do it all!
No, actually you quite enjoy it! LOL
Anyway, I've been thinking about this over the past few days, and in the meantime I've read several threads about people simply pulling the pistons/rods out of the motor, say to do a ring or bearing replacement. They just put them back in when they were done. After that, I haven't heard much. No re-rodknock threads popped up that I found.
So, it makes me wonder. Toyota doesn't list the rods as un-reusable, and since they don't recommend resizing (according to Reg), are there some other mitigating factors involved here that make a mildly warped big-end "just work" when it's put back in?
FYI this is hypothetical for my particular case... my rods are already resized. I'm just trying to figure out what advice to give to other people doing this.
Anyway, I've been thinking about this over the past few days, and in the meantime I've read several threads about people simply pulling the pistons/rods out of the motor, say to do a ring or bearing replacement. They just put them back in when they were done. After that, I haven't heard much. No re-rodknock threads popped up that I found.
So, it makes me wonder. Toyota doesn't list the rods as un-reusable, and since they don't recommend resizing (according to Reg), are there some other mitigating factors involved here that make a mildly warped big-end "just work" when it's put back in?
FYI this is hypothetical for my particular case... my rods are already resized. I'm just trying to figure out what advice to give to other people doing this.
Yep you can get away with it
will it be optimal ... no
The danger is at high output you run a risk of picking up some bearing material where the out of round reduces clearence and causes a rub point/hot spot then RK is seconds/minutes away.
Genuine Clevite 77's aren't anything like round installed but where they're egg shaped is to promote the Oil wedge a bit like a wave at the beach.
will it be optimal ... no
The danger is at high output you run a risk of picking up some bearing material where the out of round reduces clearence and causes a rub point/hot spot then RK is seconds/minutes away.
Genuine Clevite 77's aren't anything like round installed but where they're egg shaped is to promote the Oil wedge a bit like a wave at the beach.
Right.
From what I understand, our fluid-film journal bearings are made slightly thicker in the middle than at the ends. This helps provide immediate lubrication on cold startup by letting a tiny bit of oil rest between the bearing and journal on shutdown. Plus you need that oil wedge you mentioned.
So if I take this assumption and apply it to the numbers in my TSRM, the Mark 2 rod bearing lists a size of 1.496mm to 1.500mm . My assumption is that the smaller number will be at the ends, and the bigger number in the middle of the bearing. I need to check this...
From what I understand, our fluid-film journal bearings are made slightly thicker in the middle than at the ends. This helps provide immediate lubrication on cold startup by letting a tiny bit of oil rest between the bearing and journal on shutdown. Plus you need that oil wedge you mentioned.
So if I take this assumption and apply it to the numbers in my TSRM, the Mark 2 rod bearing lists a size of 1.496mm to 1.500mm . My assumption is that the smaller number will be at the ends, and the bigger number in the middle of the bearing. I need to check this...
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