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Search found 616 matches

by Tom68
Mon Dec 05, 2022 1:02 am
Forum: Engine Tech
Topic: Full vs 100 percent synthetic oil
Replies: 2
Views: 140

Re: Full vs 100 percent synthetic oil

The overwhelming majority of synthetic oils are group III based, including many high end racing oils. There's no sense in using group IV, at 6x the cost, when group III/III+ gives similar or better results. Not forgetting most users don't even need the group 3 if they have everything working right ...
by Tom68
Sat Dec 03, 2022 6:20 pm
Forum: Engine Tech
Topic: Burn patterns on piston and chamber
Replies: 47
Views: 1004

Re: Burn patterns on piston and chamber

20221203_182359.jpg20221203_180151.jpg Curious on what to look for and which direction one should take when looking at burn patterns. Spark plug wetting seems to be a issue for a lot of early OEM type cylinder heads. The fuel used here was MS109 I am interested in opinions on what guys think is hap...
by Tom68
Sat Dec 03, 2022 3:15 pm
Forum: Engine Tech
Topic: 350ci 470HP Peak at 6000RPM
Replies: 86
Views: 2739

Re: 350ci 470HP Peak at 6000RPM

skinny z wrote: Fri Dec 02, 2022 9:57 pm
Those stacks always bring me back to the CanAm series with the BBC 427's.

427.jpg

The vid below is a dyno test of that.

https://youtu.be/v6dMJ5L6G2c
Up and down from 742 to 749 indicated from 6000 to 7000.
Dyno Testing - 1973 McLaren Can-Am Big Block Chevy.mp4_snapshot_01.20.865.jpg
by Tom68
Sat Dec 03, 2022 6:44 am
Forum: Engine Tech
Topic: Cold valve lash settings - tighter or looser?
Replies: 23
Views: 939

Re: Cold valve lash settings - tighter or looser?

So the consensus is: Steel : lash gets tighter when hot Aluminum: lash gets wider when hot Right? Frank Cam suppliers publish the information. When Honda Dirt Bikes were having all the intake valve recession issues they'd be running fine for the day. The next day when the engine was cold, they woul...
by Tom68
Fri Dec 02, 2022 10:16 pm
Forum: Engine Tech
Topic: 350 Uneven Cranking & Won't Stay Running After Break In
Replies: 37
Views: 1149

Re: 350 Uneven Cranking & Won't Stay Running After Break In

Congrats on getting the engine running right. On Hyd cams I only use 0 lash plus 1/8 turn down as almost every Hyd cam I ever ran with most lifters at 3/4 turn down went into lifter pump up at high RPM. Not sure how my BBC will be next year with my Hyd roller cam, might have to experiment with thos...
by Tom68
Fri Dec 02, 2022 9:44 pm
Forum: Engine Tech
Topic: 350ci 470HP Peak at 6000RPM
Replies: 86
Views: 2739

Re: 350ci 470HP Peak at 6000RPM

210 216 112 cam 5.7 Hemi, 6" extensions on speedmaster stacked injection, peaked just over 450 at 6,000.

We definitely miss out on single carb manifold connected engines, a dual plane would have made his test more interesting.
5.7 6000rpm.jpg


https://youtu.be/G_DZSvJiFaA
by Tom68
Fri Dec 02, 2022 2:11 pm
Forum: Engine Tech
Topic: 350 Uneven Cranking & Won't Stay Running After Break In
Replies: 37
Views: 1149

Re: 350 Uneven Cranking & Won't Stay Running After Break In

If you had them that tight you should still be checking for bent valves.

Check out Weingartners video on bent valves that still seal.
by Tom68
Fri Dec 02, 2022 2:01 am
Forum: Engine Tech
Topic: Intake Manifold Porting Show ‘n Tell
Replies: 200
Views: 5001

Re: Intake Manifold Porting Show ‘n Tell

Ever play with a divider down the middle? Which picked up 7kw on the V10 but didn't work on the V8, it says they divided the front cylinders on the V8 and encouraged interference on the rear, or something to that effect. Flat plane crank anyways no doubt. http://www.f1-forecast.com/pdf/F1-Files/Hon...
by Tom68
Thu Dec 01, 2022 1:40 am
Forum: Engine Tech
Topic: How will you go faster?
Replies: 289
Views: 6739

Re: How will you go faster?

tuffxf wrote: Wed Nov 30, 2022 7:38 pm This whole post is almost a sales pitch for selling data loggers.

Cheers
Is that what's going on !!!!

I thought I was in the some parallel universe where Horsepower is totally irrelevant and all motor racing is conducted standing around benches torquing.
by Tom68
Thu Dec 01, 2022 1:24 am
Forum: Engine Tech
Topic: 350 Uneven Cranking & Won't Stay Running After Break In
Replies: 37
Views: 1149

Re: 350 Uneven Cranking & Won't Stay Running After Break In

Don't do a leak down on all cylinders, too much messing around. Crank it over with the rocker covers off and watch that all valves have full travel. If no... you stuffed a cam or there's no oil getting to your lifters....fix it. If yes... Compression test all cylinders. If major variations...get wor...
by Tom68
Wed Nov 30, 2022 5:51 pm
Forum: Engine Tech
Topic: 350 Uneven Cranking & Won't Stay Running After Break In
Replies: 37
Views: 1149

Re: 350 Uneven Cranking & Won't Stay Running After Break In

Seem to be doing the valve lash and dizzy install the hard way.

Split the firing order for lash adjusting.

Air coming out number 1 plug hole is on the way to TDC.
Or just check number 6 rockers are rocking for number 1 TDC.
by Tom68
Wed Nov 30, 2022 5:44 pm
Forum: Engine Tech
Topic: Benefits of 4-port water bypass on a SBC?
Replies: 173
Views: 10904

Re: Benefits of 4-port water bypass on a SBC?

I don't see how increasing flow will decrease pressure. The opposite will occur. The restrictions in the engine are the coolant passages where they cross over from block to head via the head gasket. Either the hole in the block, the head or the gasket will be the smallest area & this regulates the ...
by Tom68
Wed Nov 30, 2022 1:01 am
Forum: Engine Tech
Topic: How will you go faster?
Replies: 289
Views: 6739

Re: How will you go faster?

David Redszus wrote: Tue Nov 29, 2022 1:26 pm By now we should all be able to agree that the acceleration curve, in each gear, tracks to the torque curve not the horsepower curve. And that peak torque or peak horsepower have little or no contribution.
OH WOW.
by Tom68
Wed Nov 30, 2022 12:39 am
Forum: Engine Tech
Topic: Trick Flow 175cc "Double hump" heads.
Replies: 24
Views: 3943

Re: Trick Flow 175cc "Double hump" heads.

I've used them, they were ok, I just prefer a production fuelie head myself for the money spent. How come? Do the aftermarket heads have some kind of significant shortcomings? Or is there a really blatant visual tell that's easy to spot if you're familiar with Chevy engines? Or something else? I'll...
by Tom68
Tue Nov 29, 2022 5:04 pm
Forum: Engine Tech
Topic: Cubic inch horsepower at given RPM
Replies: 13
Views: 639

Re: Cubic inch horsepower at given RPM

Is there a calculation or calculator or rule that would dictate an RPM difference where peak horsepower/torque would happen in the RPM range based off of a difference in cubic inches? Example: 496 chevy with matching parts has peak power at 6300. 468 chevy with matching parts has peak power at 6800...