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can you use the 7mge or 7mgte pistons as well or are they too large?
Piston relief is different for the valves. 7M pistons accomodate the 24V setup. Remember, the 5M/6M is only 12V. Put the 7M pistons into a 5m or 6M, and depending on the space between the head & the block, and you may end up with a interference motor.... Not a good thing if the timing belt breaks.
 

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The dome on the 7M pistons is also matched for the combustion chambers on the 7M head. Using the 7M pistons with the 2-valve chamber design on the 5M head would be a huge mistake!
 

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rwhite said:
Well, I called a Toyota dealership and it looks like:
Crankshaft part number for 8/81 - 12/85 is 13411-45013 all the same

Piston part number for 8/81 - 8/84 is 13101-43041
8/84 - 12/85 is 13101-43051

Connecting Rod part number for 8/81 -1/84 is 13201-45010 and 13201-49015
1/84 - 12/85 is 13201-49026

Cylinder Head part number for 12/81 - 12/85 11101-49296 and 11101-43031

Of coarse the parts book has no technical info, but it seems the pistons and connecting rods are different before and after 84. If anyone has any tech info or corrections to this please let me know.
Sorry, I am kind of new to this. I helped a friend rebuild a 5mge and we were wondering what the causes of the differences in HP were as well. So, for example, you have an earlier 5m... to up the compression is it possible to just swap the earlier 5m parts for later 5m parts, or will this cause problems?
 

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Can't remember what the differences are between the rods, it's been awhile since I last saw the reason....

Pistons are well known & you would have found it using search... Since I'm in a peachy mood right now......

82 - "some" of the 84 motors (if you have a Automatic): Flat top pistons... 84 5-speeds - all 85 - 86 motors.... Raised domed pistons, which bumps up the compression.
 

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I don't have any "early" pistons or rods right now.I ave a core 85 5m,and a 7mgte that needs pistons,which I have,so no problem getting me to take it apart for measurements.
 

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Naw, screw the rods let's do the rockers and cam and valve measurements. Just stock so that shit is documented.

a head with:

1 the equivalent of a pumped up HLA or a spacer.
2 cam tower gaskets on and torqued.
3 cam degree wheel.
4 shit to make indexes or pointers

So whatever you think just to measure:

1 max valve lift
2 where does the tip of the lobe touch the lifter at max lift?
3 where is the end of the lifter touching the valve end?
4 what is the arc of the rocker arm from rest to max lift in degrees?
 

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Hi Kenny,

In your other thread you mentioned "About the rockers: I cannot remember where the information is but the rocker arm ratio is considered a "mean" or average ratio. In the TRD cams thread there was some confusion regarding the lift at the valve and the rocker ratio and the space the tower gaskets took up and their affect on measurements."

Both comments are absolutely correct.

I have been re-measuring both a stock cam profile and the TRD 272 Cam grind profiles both on the lobe and on a valve. I've been taking measurements every 1 camshaft degree on these measurements and plotting them using Microsoft Excel.

The rocker arm ratio varies continuously as the cam lobe tip sweeps over the contact patch of the rocker arm. In general, the ratio varies between 1.76 to 2.05. I say in general, because at the extreme ends of the arm, the ratio changes even more, but this is in the 0.006" or less lift range.

I have also taken a stock Toyota Cam Tower Gasket which measures 0.0265" thick when uncompressed and used it to re-measure valve lift on the stock exhaust cam (so far).

I don't want to go overboard because I haven't rechecked all the new measurements yet, but the difference in rocker ratio seems to be minor. Stock exhaust cam at max lift measures a rocker ratio of 1.8379:1 with no gasket, and 1.8164:1 with the gasket in place.

I suspect that the relatively minor change in valve lift and rocker ratio is due to the HLA compensating for the presence of the gasket. When pumped up the HLA moves the rocker closer to the cam lobe and partially compensates for the cam being farther from the valve.

I feel strongly that the mean rocker ratio is in the 1.7:1 range. My measurements indicate this and Shadbolt Cam's product book confirms this. I shall be interested in seeing other people's measurements of this.

In regards to finding exactly where on the rocker arm the cam lobe is at max lift, I don't think that you can observe this directly. The cam lobe is in the way. I think you must calculate it by measuring the cam lobe max lift, valve max lift, measuring from the fulcrum point at the HLA to the contact point on the valve tip, and go back where the rocker ratio indicates it should be.

By the way, I've been enjoying following this thread. The 5M-GE valve geometry is one of the more complex, and there isn't much good literature on the topic.

Different topic. I cc'd the intake runner volume in the head from the valve to the flange and I measured 80cc.

I realize that the cross sectional area is not actually measured by width by height, but I measured the head intake runner dimensions as length:76.2mm, diameter: 34.925mm, calculating a theoretical volume of 73.0122cc.

I talked to Dema Elgin of D. Elgin cams and he is not a fan of high valve lift. He thinks that 0.5" lift or higher is a waste of time because most heads just aren't efficient enough to support that high a flow. I think that time on a flow bench would be a good idea before planning on 0.6" valve lift. That high a lift may work, but it would probably be cheaper to first look at the flow capabilities before spending a lot of money on modifying the valve system.

I don't want to be negative, because first of all, I may well be wrong. Also, this thread is drawing a lot of attention on how to increase the efficiency of N/A motors which I think is cool.

Keep up the good work.

Dale Z

p.s. I'll post cam profiles and cam timing cards for the stock 5M-GE cam and for the TRD 272 cam grind when I've had a chance to recheck them.
 

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It was your work and others that inspired me to post. 'member in "Close Encounters...." when they were escaping detainment the three of them all had reproduced images from there mind's eye? But it was Richard Dreyfuss who had sculpted not painted and was able to reveal details? All of us are going to contribute whether we know it or not but the most progress will be made with the actual parts in front of us.

You and Dema are right and I am wrong. But I am right when I say Yamaha designed the head. I am right when I say it is purposely detuned. I am right when I say it has been benched because Yamaha did it. Certain clues led me to believe that the shapes Yamaha used were very clever. Now that you have posted the port ccs I think I can prove what I am saying. The relation to port volume and rpm range is secret. But you have revealed a key! Just for fun since you're at it: the distance perpendicular to the port floor from the greatest point exposed of the valve guide is the choke point. Have you measured that? I believe Yamaha has cleverly used this really as a high-velocity nozzle. The cross-sectional shape is nothing in particular but if you stare at the port, the guide AND the bend then nozzle exposes itself! Fuckin' brilliant and elegant! What happens in the widening of the bend is the atomization is improved while slowing because of the increased volume on the port just past the nozzle. Beautiful, if that designer is somewhere out there. All may find this ironic, but I am speechless.

In modeling the head's design the airflow modeling is based on bench data. But volute and nozzle shape is pure science, in no single domain. I based .600 on the stock valve spring free-to-bind. I have only modeled cams to .535 because that is where the airflow was .5 mach and starting to stall. With this occuring no increased benefit will be realized.

My guesses about the heads performance have to do with the comparisons I made of bore-to-stroke ratio, bore-to-valve ratio, rod-to-stroke ratio, mean piston speed, and weights of components.

If we're on the same page about rocker ratio I understand the entire cam profile is the mean. You have 360 measurements summed and divided by 360 and you get 1.7:1? That is interesting. Don't bother to post the cam cards just bring them with you on the first, just kidding.

Good work on the volume measurements. I'm thinking about throwing together a kit to do this to use ability repeatedly.
 

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Hi Kenny,

I have to be brief because I'm heading off to work AND Christmas shopping.

First, I don't want to give you the impression I am nay saying. I wrote my last post late at night and sometimes the tone comes out wrong. I find your theories very interesting and definitely believe it's worth exploring.

By "mean" rocker ratio, what I did was take all the measurements where there was any measurable lift above the base circle as measured on the cam lobe. I then took the same measurements on the valve over the same duration.

I took these numbers and put them in excel. I did a scatter graph with the data points connected. What I ended up with was a graph with the X-axis being rocker ratio and the Y-axis being camshaft degrees.

The period over which the mean is taken is the lobe open duration.

The ratio changes depending on the lobe lift. Near closed, the ratios are WAY different than the mean. This could certainly be measurement error.

These measurements at really low lift are obviously affected by the accuracy of my measurements. The Mitutoyo dial gauge that I used is limited in accuracy that I can get out of it.

But during the 0.050" lift through maximum lift back to 0.050" lift on the closing side of the lobe there is a very characteristic curve.

As I said before, I want to check my numbers first, but I'll try to put the excel data and graphs on a web site so you can see them.

I'll also try to take the measurements in the intake runner you mentioned. With the holidays coming up, I'm not sure I'll be doing it for the next week, but I will when possible.

In regard to your looking at bore/stroke ratio, rod/stroke ratio, Dema Elgin completely agrees with you. On his web site under "Camshafts" he says....

"The maximum piston speed of the engine is then limited by the resistance to gas flow of the engine and/or the stresses due to the inertia of the moving parts. You must be wondering why I'm talking about piston velocity during the first stroke.
FACT ONE: Volumetric efficiency is directly related to piston velocity"

I agree that modelling the variables that you are is key. Like I said before, keep up the good work.

Regards,

Dale Z
 

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I take your observations as encouragement. I just finished with my 8:00. I understand what you're saying about the ratio of the rockers I just think that the mean is the cam's entire rotation.

Your port volume information completes an equation involving why our engines torque and horsepower curves occur where they do. I can barely wait to start the math again. Shopping? Mercy on you.......
 

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Hello, I'm working on my 85 MKII, and i need a new crank shaft, but i have a 89 supra short block, will that crank fit on my 5m-ge engine?
 

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I have a 85 P-type, I need help figuring out why my car is blowing blue smoke and has little power on take off and also sputters at cruising around 45 up. I compression tested and wet tested the cylinders and no compression loss found so dont think I am leaking oil into cyliders and plugs dont show burning oil. I am thinking it might be fuel related do to I am going though alot of gas also. If there is anyone out there that knows any common concerns about this let me know please. Also I am looking for a manual trans for my car I have all the parts to convert from auto to manual just need a good trans.
 

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Is this Kenny form Olympia area? If it is this is Tony and I was wondering if you have a Manual trans for a MKII I have a 85 P-Type now. Let me know
 

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I need help figuring out why my car is blowing blue smoke
Need to be more specific......

A: Does it only do this when you accelerate from a stop, after it's been idling for awhile (valve stem seals)

OR:

B: Does it do this all of the time??? (usually rings).

Either one has been discussed before.
 

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My car blows blue smoke

Ok only does it from stop accelerating, and sitting at a stop for a minute or so. If I stop and then just go it doesnt do it. I also go though alot of gas like I am running realy rich and I am blowing out the excessive fuel when sitting at a idle. I also when the car warms up my idle is at 400 to 500 rpms but doesnt run bad at idle.
 

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Thanks Chris I will to the valve stem seals when I get a wild hair up my but. LOL. Also for some reason resently my cars exhaust smells like it is running lean but I still go though alot of fuel like I only get 19 to 20 mpm but then agian that could be valve issues also. One this I have been trying time my car and it tell me to jump the conector for timing advance the only concetor I can find that looks like the diagram is behind the battery but when I jump it and adjust the timing seems like I just retarted my timing to far. The car starts sputtering on accell and has no power, I returned the timing to the original possition and runs normal but I still have a very low idle like at 400 rpms is that normal.
 

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re: Measuring Compression Ratio

rwhite and others,

I'm measuring the compression ratio of my engine as it has custom forged pistons and a 7M crank and I'm not 100% sure what the compression ratio is? I am thinking about doing it a slightly different way though and wanted to get your opinion on it. Would it not be better to measure the compression ratio by bringing the engine to BDC, seal the piston to the cylinder with grease, put the head back on and bolt in place, fill the cylinder and combustion chamber through the spark plug port using your 70/30 mixture of ATF/water (and a graduated cylinder). Keep filling until the fluid reaches the level of the spark plug port, then stop and note amount used. Remove fluid (using a shop vac or similar), remove head, bring piston to TDC, regrease ring to wall joint, put back head and secure, and refill using same procedure as before. The difference of the two values should give you a fairly accurate number for the compression ratio. Now it won't give you as accurate a number for combustion chamber volume (depending on how far up the spark plug port you go), but it should give you a more accurate number due to the fact that your not adding and subtracting as many numbers. Sure it's a little more a pain in the butt (since the head isn't exactly light), but it seems to me the extra fuss might be worth it in the end? Any comments or views on this method? Thanks,

Sonny
 
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