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Search found 232 matches

by 4vpc
Mon Sep 16, 2019 12:56 pm
Forum: Engine Tech
Topic: Recommend me stone grits
Replies: 14
Views: 844

Re: Recommend me stone grits

Thanks for posting Glen. As a Pro you will probably look at the crosshatch and tell whether it is 45' or not, but as someone starting out how would you measure it?
by 4vpc
Fri Sep 13, 2019 7:25 pm
Forum: Engine Tech
Topic: Subaru EJ25 combustion chamber to do / not to do
Replies: 61
Views: 5613

Re: Subaru EJ25 combustion chamber to do / not to do

I don't know if you're still doing your research on this or came to any conclusions, but i've recently been looking at Duratec engines and their crown designs mirror the what I called 'satellite dish' type bowl which Saab were using back in the day (see pic back there). I'm quite confident that is ...
by 4vpc
Thu Sep 12, 2019 6:25 pm
Forum: Engine Tech
Topic: 2618 Piston Street Use Longevity
Replies: 131
Views: 20948

Re: 2618 Piston Street Use Longevity

Why would you need a forged piston when this new cast alloy is 2.5 times stronger than the old type?
For all we know it may be in use by several companies already....
by 4vpc
Thu Sep 12, 2019 5:39 am
Forum: Engine Tech
Topic: Subaru EJ25 combustion chamber to do / not to do
Replies: 61
Views: 5613

Re: Subaru EJ25 combustion chamber to do / not to do

I don't know if you're still doing your research on this or came to any conclusions, but i've recently been looking at Duratec engines and their crown designs mirror the what I called 'satellite dish' type bowl which Saab were using back in the day (see pic back there). I'm quite confident that is t...
by 4vpc
Thu Sep 12, 2019 5:17 am
Forum: Engine Tech
Topic: accurately measuring port cross section area
Replies: 26
Views: 966

Re: accurately measuring port cross section area

I like that gadget, thanks for posting. You wouldn't stand much chance of getting a solder ring around the min csa of a 4v port though. Although on that note what i've recently started doing is hacking up old molds which I don't need anymore into small bits and putting them in a new port along with ...
by 4vpc
Thu Sep 12, 2019 5:10 am
Forum: Engine Tech
Topic: 2618 Piston Street Use Longevity
Replies: 131
Views: 20948

Re: 2618 Piston Street Use Longevity

If you can get your hands on a forged OE Honda F20C piston then I would recommend it, you'll learn lots with a straight edge and simple measuring tools and that's a design that is now 17yrs out of date. Top ringland is barrel shaped and looking on top of the crown you'll notice it's oval too. Bore ...
by 4vpc
Thu Sep 12, 2019 4:46 am
Forum: Engine Tech
Topic: Theory of 4 valve poly quad cylinder heads.
Replies: 90
Views: 2427

Re: Theory of 4 valve poly quad cylinder heads.

You don't want swirl in a gasoline spark ignition engine. If you're seeing combustion efficiency improvements with the introduction of swirl then the system simply didn't have enough charge motion to begin with. Tumble is what you want in a gasoline SI engine. High swirl rates produce fuel/air sepa...
by 4vpc
Thu Sep 12, 2019 4:04 am
Forum: Engine Tech
Topic: Torque To Yield
Replies: 30
Views: 835

Re: Torque To Yield

Mazda always say use new bolts on their Duratec range, but in the real world mechanics just re-use them and they run fine.
At the other end of the scale the guys at the top say that using ARP on the bottom end distorts the mains meaning they have to be honed true.
by 4vpc
Wed Sep 11, 2019 4:23 am
Forum: Engine Tech
Topic: Theory of 4 valve poly quad cylinder heads.
Replies: 90
Views: 2427

Re: Theory of 4 valve poly quad cylinder heads.

You don't want swirl in a gasoline spark ignition engine. If you're seeing combustion efficiency improvements with the introduction of swirl then the system simply didn't have enough charge motion to begin with. Tumble is what you want in a gasoline SI engine. High swirl rates produce fuel/air sepa...
by 4vpc
Tue Sep 10, 2019 8:01 pm
Forum: Engine Tech
Topic: Theory of 4 valve poly quad cylinder heads.
Replies: 90
Views: 2427

Re: Theory of 4 valve poly quad cylinder heads.

ptuomov wrote:
Tue Sep 10, 2019 7:33 pm
Stuff
On a similar note where can I find your turbo squish pad thread? I think you started one or something similar. I came across something of vague interest the other day, but don't know whether it was noted there or not.
by 4vpc
Tue Sep 10, 2019 7:56 pm
Forum: Engine Tech
Topic: Finally figured out how to move some air on these heads...
Replies: 14
Views: 1082

Re: Finally figured out how to move some air on these heads...

The eternal question; does CFM really matter to power output?
by 4vpc
Tue Sep 10, 2019 7:38 pm
Forum: Engine Tech
Topic: Theory of 4 valve poly quad cylinder heads.
Replies: 90
Views: 2427

Re: Theory of 4 valve poly quad cylinder heads.

You need to buy and read his book then you won't have to guess or assume, it's not expensive. I think it's a bit cheap to post up pictures from it. The car featured with Polyquad was a Mitsubishi Evo with VVT. I think the idea will have come from an existing design and I did rebuild a 16v Renault di...
by 4vpc
Sun Aug 25, 2019 6:55 pm
Forum: Engine Tech
Topic: pressed in pins (rod temperature)
Replies: 35
Views: 1175

Re: pressed in pins (rod temperature)

I use a Goodson rod heater set to 450 degrees, and a special marker that melts at 450 degrees to verify the temp. Oven has a temp setting, but the marker just backs it up. My big deal is that if the heating of the rod leaves a blue mark, my opinion is that the properties of the metal has been chang...
by 4vpc
Fri Aug 16, 2019 7:04 pm
Forum: Engine Tech
Topic: Custom vs Catalog Cams
Replies: 204
Views: 8656

Re: Custom vs Catalog Cams

A big factor is if it's a mainstream engine or not. You could spend days looking through sbc and Ford cam choices online till you get dizzy. Other stuff,, not so much For engines without much selection available that makes sense. I'm curious what makes a person stop looking at the catalogs and orde...
by 4vpc
Fri Aug 09, 2019 7:24 am
Forum: Engine Tech
Topic: Silicone sleeve for grinder
Replies: 11
Views: 484

Re: Silicone sleeve for grinder

https://www.impacto.ca/products/orthex-tool-wrap/ Yes, that leads me to some gloves as well: https://www.impacto.ca/products/blackmaxx-blade/ It's a fine line between keeping that dexterity you need whilst getting the protection too. It is an electric grinder, will have a measure of the diameter la...