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Search found 1402 matches

by digger
Sat Nov 21, 2020 8:30 pm
Forum: Engine Tech
Topic: Piston pin "end play" ? How much is ok ??
Replies: 18
Views: 702

Re: Piston pin "end play" ? How much is ok ??

MadBill wrote: Sat Nov 21, 2020 5:40 pm A single 1/8" one would do, but tricky to machine and it would have to be chamfered to lock the clips in place.. :-k
i'd want symmetry otherwise load transfer is skewed
by digger
Sat Nov 21, 2020 4:38 pm
Forum: Engine Tech
Topic: Piston pin "end play" ? How much is ok ??
Replies: 18
Views: 702

Re: Piston pin "end play" ? How much is ok ??

machine a couple spacers if you cant get a longer pin?
by digger
Thu Nov 19, 2020 3:59 pm
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2004

Re: Small cams on 106-108 LSA’s

it all depends on your goal for power band. when the duration is fairly mild the tighter LSA will make more at the bottom and middle but can lose a fair bit up top as the events are skewed that way. When the duration is higher the tradeoff is much smaller because of where the resultant events end up...
by digger
Tue Nov 17, 2020 12:31 am
Forum: Engine Tech
Topic: Shot Peening
Replies: 16
Views: 957

Re: Shot Peening

shot peening is a well proven process but like everything it comes down to the specification and process.
by digger
Thu Nov 12, 2020 3:30 pm
Forum: Engine Tech
Topic: I6 header or header(s)? 6-1 or 6-2
Replies: 23
Views: 3564

Re: I6 header or header(s)? 6-1 or 6-2

This may be application specific, but the best header commercially sold for my Jeep 4.0 is the arh 6:1. Here’s a pic of mine. It also uses the rotational firing mentioned by others. https://i.imgur.com/zPKcMUn.jpg The next best header is a 6:2:1 design and doesn’t make near the power the arh does. ...
by digger
Wed Nov 11, 2020 9:56 pm
Forum: Engine Tech
Topic: Cam experts
Replies: 11
Views: 999

Re: Cam experts

Aleksss, is this an older BMW? Does it have variable or fixed valve timing? VVT cams usually have pretty modest durations as the VVT changes timing on the fly. If older, I would check with Cat Cams in Europe. They make nice cams for european cars. See what their offerings are. Their website include...
by digger
Wed Nov 04, 2020 4:41 am
Forum: Engine Tech
Topic: Question about EFI cold start AFR
Replies: 54
Views: 1180

Re: Question about EFI cold start AFR

1 point richer than when upto temp. Ultimately give the engine what it wants. Indeed, that might be what it needs, but it depends on the engine. If the goal is to get the engine to be more powerful you could just as well increase the ignition timing. Doesn’t matter if you get power through timing o...
by digger
Wed Nov 04, 2020 3:00 am
Forum: Engine Tech
Topic: Question about EFI cold start AFR
Replies: 54
Views: 1180

Re: Question about EFI cold start AFR

1 point richer than when upto temp. Ultimately give the engine what it wants.
by digger
Wed Oct 28, 2020 10:43 pm
Forum: Engine Tech
Topic: duration @ .050"/ .200"
Replies: 29
Views: 2153

Re: duration @ .050"/ .200"

then you can run a simulation to see which the engine prefers for optimisation of VE at a specific rpm range if it’s not immediately apparent
by digger
Mon Oct 26, 2020 2:18 am
Forum: Engine Tech
Topic: Lowering octane
Replies: 19
Views: 834

Re: Lowering octane

I’d be more interested in finding out the other differences in the ingredients. The octane just went along for the ride
by digger
Fri Oct 23, 2020 12:07 am
Forum: Offtopic Forum
Topic: 1959 vs 2009 crash test
Replies: 3
Views: 156

Re: 1959 vs 2009 crash test

luckily they dont make em like they used to
by digger
Thu Oct 22, 2020 9:58 pm
Forum: Engine Tech
Topic: duration @ .050"/ .200"
Replies: 29
Views: 2153

Re: duration @ .050"/ .200"

A bit like asking how high is high, it depends. I'm known for being a deep searcher. :) Some great comments here: https://www.speed-talk.com/forum/viewtopic.php?t=12012 Mike Jones stated - "Since the .200" number changes with the design, and is not only a product of the required duration, but the r...
by digger
Sun Oct 18, 2020 11:19 pm
Forum: Engine Tech
Topic: Top piston ring gap - whats really required?
Replies: 34
Views: 1790

Re: Top piston ring gap - whats really required?

risk vs reward
by digger
Thu Oct 01, 2020 5:34 am
Forum: Engine Tech
Topic: IVC and cranking compression
Replies: 9
Views: 621

Re: IVC and cranking compression

As long as the intake valve closing point remains the same, does the cranking compression and general fuel octane compatibility stay about the same? I’m referring to street performance builds, not really all out racing applications Cranking compression will be fairly the similar. Fuel octane No, th...
by digger
Sun Sep 27, 2020 1:24 am
Forum: Engine Tech
Topic: Connecting Rod Tech.
Replies: 19
Views: 1030

Re: Connecting Rod Tech.

FEA can simulate anything you want Please explain input for crank rotation? The input is angular velocity or acceleration as well, you do a flexible body analysis with the crank, piston, pins modelled and the associated joints. Flex bodies using MBD or FE using non-linear material properties? :) To...