Buying Extractors-

[altezzaclub]

OK, the head has been off for a couple of weeks now. The first job was to open up the inlet ports to suit the Lynx manifold, which went well, then the engineer machined valves & seats, took 15thou off it and most important, got it sparkling clean!

 

Now to match the extractors. The one-piece Durapro manifold gasket was offset to one side (it fits on the inlet manifold locating pins, so it can't move around) so I hit the offending holes with a small grinding wheel in a drill. They came out OK, but it shouldn't have needed to be done if the manufacturers took some care.

 

Some careful marking of the extractors found the best-fit position for them (they do walk around on the bolts) but it was clear the end pipes were too low. This was obvious when I put a straight-edge across all four pipes. The straight-edge (a bit of thick-wall aluminium section) was perfect along the head ports, but over 2mm off on cyl 1 & 4 on the extractors The steel plate they are welded onto is straight, but the end holes are cut in the wrong place.

 

The photo shows them after I'd already started work on them, I only got the camera out after I got pissed off enough to write a topic on it!

 

Another half an hour with a grinder and a file slowly sorted them out. Take a straight-edge with you when you go buying extractors!

 

Next was bolting it up to the head, and surprise surprise, the welds obscure the nut placement so the nuts can't be done up tight! So next job is to grind the welds back until a spring washer can sit there, which is after a cup of coffee now! That's labelled 'A'.

 

You can also see the flange thickness difference between the inlet and extractors, so I'll have to pack the thinner one of the manifolds or it will not be clamped tight. That's labelled 'B'

 

..and talking of stupid engineering and poor execution, the brass circle in the inlet (labelled 'C') is where the brake booster pipe was mounted, completely obscuring the top nut on the inlet. You had to take the little pipe out every time you wanted to undo the manifold nut, AND you couldn't swing a spanner on the pipe because the manifold nut was in the way! That's been transferred into the thick manifold flange out of the way.

 

This is all 2-hand gear, so what sort of quality are people building into their cars?

[rob83ke70]

about the same quality as some motor mechanics workmanship obviously.....

 

My extractors weren't quite right, and my porting job was a bit more rushed and not as neat as yours either.

 

when the ke55 engine comes apart I *might* pull the head off and tweak it some more, I wasn't overly happy with that cylinder head and the ports need to be matched up properly, some time and experience is a wonderful thing for doing that job. I love it how I work on cars at work, and work on cars at home, and the two jobs rarely seem like the same thing.

 

I should really really be working on cars on weekends too and I just haven't been motivated to do anything on weekends :wink: which is really really unusual for me.

 

Robert.

[tojo2]

How large were the ports in the lynx manifold on head side ?

[altezzaclub]

30mm.

 

The head was about 27mm.

[KEI069]

Unfortunatly, the problem with most extractors these days is that they are built

to be replacements for cracked or damaged exhaust manifolds, not for

the performance aspect so much. The pacemaker extractors used to be about

the only decent set on the market but due to lack of interest, production was stopped

a few years ago.

So unless you have the extractors made the qaulity is not the greatest.

 

Cheers Justin

[altezzaclub]

hmm.. I hadn't thought of that- I did notice the performance advertising was all aimed at Holden and Ford, while the most common Toyota extractors were for 4WDs, Landcruisers etc.

 

Part of owning a 'rolla I suppose, buy somethig and then have to modify it to do the job it was designed for..

[tojo2]

30mm.

 

The head was about 27mm.

 

 

Cheers

[philbey]

yeh I had my ports opened to match my lynx, about 30-31mm.

[TRD ke70]

Now to match the extractors.

 

This is a common mistake, port matching the extractors isn't a good idea.

The extractor should be larger than the port or you can create reversion.

 

This is where the exhaust gases at low speed stop and get drawn back into the cylinder under valve overlap.

By having a larger extractor, the exhaust gases, when they try too reverse encounter a restriction.

 

If you have access to any David Vizard books, he covers it in there.

he explains it better than i ever will.

 

Works very well with larger cams, most of the time can make the engine come on cam a lot sooner, also can give a smoother idle.

Teddy can vouch for that, was done to his 7k which has a large cam and it idles nice.

All I done was grind a 45 degree angle on it, it only has to be enough to create a restriction for the gases if they reverse.

Also our rally engine had this done and it idled like a road car, it has a massive cam.

 

Oh, yes i have had all the same problems with extractors, it just must be something you have to live with.

[altezzaclub]

: sigh :.... So its back with the grinder until they're a couple of mm bigger all round then?

 

At least one face is bigger already, the mis-aligned one!

 

 

...and I can see all the guys who want a loping idle hogging out the exhaust ports in the head to create reversion waves and get it to sound like a bridgeport rotary! :D

Edited January 19, 2010 by altezzaclub