i want something stiff...

Level 7 User Joined: 27 Feb 2004 Posts: 243

tried using JB weld today to decrease the port size on the inlet manifold before i move onto the head, but the problem is that its like honey. its fine once it sets hard, but before it sets it runs everywhere, so u cant "place it" properly. anybody no of a product that will be stiffer before curing, like metal putty of sorts?

jimbo

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

Jimbo, get some plastercine and continue to use the JB weld.

Where did you get the stuff? Nowhere supplies it anymore!

Level 7 User Joined: 27 Feb 2004 Posts: 243

wats plastercine gunna do?

i used summat called super steel. exaclty the same as JB weld, but available from motorworld n places like that.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

Plastercine, you stuff it into the valve seats so it doesn't run out. Then have it so the floors level and pour it in. Then grind off the rest.

Whos inlet manifold is that in your sig? Its crap, forgot to mention that when you 1st put it up.

Level 7 User Joined: 27 Feb 2004 Posts: 243

thats a b16 inelt manifold. was gunna do sumthin like that for the valver with these samller ports eventually. some decent sized inlet runners with v stacks n stuff

jimbo

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

I take it you cannot see the fundamental error with that manifold? It would be ten times worse with any form of forced induction.

If the side with the throttle plate is no1 and the other end is number 4 then 1 will be getting less air in than 4.

The plenum is parrellel, it should taper down towards the end to ensure equal flow.

How much money are you all goign to pay me for my informed input? lol

Do you get what I mean about the plastercine? poke it up so the seats totally hidden then fill it as you would. Remember to round up the edges into the walls.

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

think he wants something with the consistency of plasticine that he can "mould" to the side of the ports...not something runny that wont stay on the sides, as he wants to bring the sides in...not the top and bottom so much. like a body filler feel, that you can sculpt before it goes off...would car body filler do it?once its gone off its pretty solid.

Level 7 User Joined: 27 Feb 2004 Posts: 243

the manifold design ive nocked up is tapered, so cyl 4 is got some decent air flow, tho the standard manifold dusnt work on a tapered design.

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

are u sure it'll be ok when the head gets hot, and the aluminium expands more than the epxoy??

u wouldnt want it 2 seperate and start bouncing round the engine!!

not thought about TIG welding?? altough localised heating maybe a problem.........

think wot (I mean what really) chris means is make a "pocket" using the plastercine around where u want 2 add material. then fill the pocket with epoxy and wait till it cures

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

chris, do u not mean 4 will be getting less flow??

surely this will only be at part throttle positions (or snap acceleratio) tho, where there is physically more mass of air between 4 and the butterfly (restriction) to undergoe a pressure change---therefore greater time----therefore less air per induction stroke. the taper will help this by speeding up gasflow towards 4.

but at wot (I mean what really) when there isnt really any restriction at the butterfly, flow should be equal to all four providing the volume of the plenum is sufficient.

jimbo, are u making all runners the same length??
wot (I mean what really) lengths are u going to tune to?

Level 7 User Joined: 27 Feb 2004 Posts: 243

the runners wud be tuned to watever length i cn fit in the engine bay! lol wud be about 8-9inches from back of the valve. 45mm diamter pipe. ideally id like a taper on the runners, but cus renault used the worlds largest inlet ports, id need pipe work of like 80mm diameter lol.

but at the moment im thinking of saving it, until i can shrink the ports properly, remove the head, valves tec, get it all done properly, then build a manifold from there.

Level 7 User Joined: 27 Feb 2004 Posts: 243

ok, last night i tried using somehting different on one of the manifold ports. i decided to use exhasut system putty. sounds absurd but so far its set like stone, is easily sandable, and wud obviously take the heat all the engine can throw at it. ive tried chipping it away from the ally of the manifold, but its welded itself to it pretty well - so im thinking it mite withstand a serious vacuum? hmmmm

jimbo

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Until it gives way under heavy airflow @ 7500rpm and blows up your bottom end well and truelly, if it got past the valves! lol

You got any pics?

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

i was thinkin lastnight also.......to test whether any of these materials will take the heat/changes in expansion (and not come off), find an area of the of the head that is exposed in the engine bay. clean it up, and slap a dolop of the stuff on. take the car 4 a good 'ol blast till the engine is proper hot, and see whether it has stayed in contact/not cracked etc. etc.
its crued but at least it'll give u some idea as to whether it will stay in contact.

Retroholic Joined: 12 Feb 2004 Posts: 5685

Two words, superglue and tissue, YKIMS

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

JB weld will be fine, if done properly it won't fall off etc, its also very similar to aluminium in expansion terms.

Add it in rows jimbo, don't try to slap it all on at once.

The ren manifold isn't tapered because its more than large enough plenum wise.

If you look at my saab pics in the pics section eyou will see the saab tapered inlet manifold.

Peopel have used bodyfilla to do the ports but I wouldn't be confident on how long it lasts.

Exchaust paste, in my experience this tends to break apart and not like heat either.

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Yeah exhaust paste that has been gleefully plastered all over the joint on my system is all cracked etc.. although that could be down to wear and tear with being under the car..

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

get the head off and stand it on end then can fill/work on one side of the ports at a time...i couldnt be arsed tho....but i do have that spare head remember

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

Chris H wrote:

If you look at my saab pics in the pics section eyou will see the saab tapered inlet manifold.

what pics?

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

here

except it doesn't show it, its actually rounded under at the opposite end of the throttle plate.

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Isn’t that just the most magnificent plank of wood you have ever seen?