Question: plastigauge loose clearances on mains

[Rollus]

Hi guys,

I'm rebuilding my 7MGTE, here are the plastigauge results on main bearings:
(mm)

[TD] 0,050 [/TD][TD] 0,070 [/TD][TD] 0,053 [/TD][TD] 0,053 [/TD][TD] 0,070 [/TD][TD] 0,050 [/TD][TD] 0,050 [/TD]

TSRM specs in mm:

Std Min	Std Max	Grand Max
0,030	0,048	0,070

I use Clevite77 and ARP everywhere, torqued to ARP spec with ARP lube.

Here are rod bearing clearances FYI:

[TD] 0,038 [/TD][TD] 0,040 [/TD][TD] 0,043 [/TD][TD] 0,045 [/TD][TD] 0,045 [/TD][TD] 0,050 [/TD]

TSRM specs (mm):

Std Min	Std Max	Grand Max
0,021	0,053	0,07

The engine is a 7MGTE I'm building for 600whp (Wisecos, Eagle, MHG, etc..)

What do you think guys for the loose side of mains?

Thanks,

Reynald

 

[tmsperformance]

For 600whp those clearances are a tad on the tight side.
Those power levels
Mains: 0.065-0.070mm (0.00255-0.00275")
Rods: 0.060-0.065mm (0.00235-0.00255")
Some 5w60 or 10w60 and all should be golden. That's coming from my experiences.

 

[IJ.]

Ditto, I build my engines with Mid to High 2 thou clearance for above 500rwhp, don't buy into the "It's not a Chevy and needs to built tight" BULLSHIT

Again from practical experience gathered over 39+ years building engines.

 

[SeeUSmile]

Ehh where did you get your hands on genuine clevites!!!

anyway I believe IJ mentioned about running in the looser end clearances are fine for a power build as toyota's specs are pretty tight clearances.

 

[suprarx7nut]

Doesn't look too bad from my view. I'd run heavier oil than normal, but that may be preferred anyways if you're aiming for that kind of power. IJ would have some great real world insight. He's mentioned building 7M's with a little extra clearance, but I'm not sure how much you want to aim for.

 

[Rollus]

OK, thank you guys for your answers.

So 0,050~0,053 (2 thou) to 0,070 (2,7 thou) won't hurt my street/highway build?
The engine will see sustained revs and time to time pulls.

What about the unbalance between 0,050 and 0,070 bearings? Should I get OEM select fits for these two really loose or it doesn't matter?



@SeeUSmile, I got theses Mahle/Clevitte brand new bearings from Zumtizzle here on forums.

Edit: where did the 2 frst answers gone? (tmsperformance's & IJ's)

 

[tmsperformance]

you double posted here are the answers
http://www.supramania.com/forums/sh...uestion-plastigauge-loose-clearances-on-mains

 

[super51fan]

I would get select fit to try and reduce you clearance. IMO good luck.

 

[Rollus]

you double posted here are the answers
http://www.supramania.com/forums/sh...uestion-plastigauge-loose-clearances-on-mains

Oups (probably double posted with my smartphone), thank you

Could a mod merge both topics please?

 

[Rollus]

Hello guys, thanks for your answers.

So 0,050~0,053 (2 thou) to 0,070 (2,7 thou) won't hurt my street/highway build?
The engine will see sustained revs and time to time pulls.

What about the unbalance between 0,050 and 0,070 bearings? Should I get OEM select fits for these two really loose or it doesn't matter?

By mistake I double posted my question, here also: http://www.supramania.com/forums/sh...ing-main-bearings-some-loose-what-should-I-do (please, could a mod merge?)

 

[IJ.]

Tried swapping some shells around to see if you can open up the 050 or close down the 070?

In the old days I used to select fit shell using steel wool to polish off some material, clean thoroughly then remeasure.

Threads merged

 

[Rollus]

Thank you Ian

I fought about swapping shells, but then could "false round" happens?

 

[Rollus]

Tried swapping some shells around to see if you can open up the 050 or close down the 070?

In the old days I used to select fit shell using steel wool to polish off some material, clean thoroughly then remeasure.

Thank you Ian

I fought about swapping shells, but then could "false round" happens?

Sorry to bump Ian, but... bump.

 

[Tuner.87]

I took a high performance class in college. If you building a race engine they say you want .001 clearance per 1 inch of diameter. now running on the street you adjust some but that a good starting. Ive confirmed this with a couple other builders. example 2" diameter you want .002 oil clearance

 

[Rollus]

Thank you. So that mean for 60mm 0.060mm clearance. That sound good.

Now, what if I swap some shells to balance clearance? May I encounter false round?

Envoyé de mon Nexus 5 en utilisant Tapatalk

 

[Tuner.87]

Keep in mind that is a race engine setup

 

[IJ.]

Sorry to bump Ian, but... bump.

Nah we're only talking tenths Rey, in my LS build I used half a set of 5thou under to get where I wanted to be with the brand new Stroker Crank.

 

[Rollus]

Keep in mind that is a race engine setup

Yep, in a street car (won't see full throttle everytime)

Nah we're only talking tenths Rey, in my LS build I used half a set of 5thou under to get where I wanted to be with the brand new Stroker Crank.

Ok thanks.

I will take all advice and tell here how it turn. Thanks to all who helped.


Envoyé de mon Nexus 5 en utilisant Tapatalk

 

[super51fan]

If you really want to know you oil clearance you can't count on Plasti gauge. You should get a micrometer and at least snap gauges. An inside micrometer is even better than snap gauges. This way you can measure your crankshaft and the use snap gauges to measure the mains and rods with bearings installed. The difference is you oil clearance. BTW you can also check for roundness.

I think you should run stock specs for your set up. Good luck.

 

[IJ.]

If you really want to know you oil clearance you can't count on Plasti gauge. You should get a micrometer and at least snap gauges. An inside micrometer is even better than snap gauges. This way you can measure your crankshaft and the use snap gauges to measure the mains and rods with bearings installed. The difference is you oil clearance. BTW you can also check for roundness.

I think you should run stock specs for your set up. Good luck.

And why do you think that?