1HDT Cylinder Head Performance Modifications

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IMG_1122.JPG I decided to perform some minor cylinder head porting and polishing when my engine was apart for a minor overhaul. Researching the forums and looking at common practices with high performance motorcycle and car engines I decided to do some basic cylinder head modifications. If you have any questions or comments pls post. Are there known porting or valve rework technics that help to make our trucks flow better?
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The exhaust port recieved the bulk of the work. Matching exh ports to exhaust manifold this resulted in a 3 mm larger port. Open up the bowel below the valve seat. The short side radius of the port is horrible and no easy solution it is just about a 90* turn.
A standard 3 angle valve job and thats about it.

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The intake ports in the head are a fairly good size but I am unfamiiar with this swirl port head design. Googled it a bit and it seems this similar to the vortec heads from GM.
Minor cleanup of the ports with alot of material removed from the inside diameter of the valve seat insert. The insert was creating a 1mm step right before the valve seat which causes turbulence of the intake air just before trying to enter the cylinder. I enlarged the inside diameter of the insert almost 2.5mm. The intake was finished off with a 5 angle valve job.IMG_1125.JPG

The intake manifold ports are considerably smaller than the ports on the head. I die ground a radius as large as a I dared because the manifold is paper thin. See pic of gaskets to view the difference
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Stock valves were ground back to spec and seats were cut using a Neway cutter set. I also back cut the valves.

The focus of the valve work was to improve low lift flow.

I am not an expert cylinder head builder. The work performed is what I thought was best for my application.
So far so good I am very happy with the way the Cruiser is running.
The 2H/12H-T/1HZ/1HD-T/1HD-FT Gturbo Alternative Tech Thread


I used information from David Vizard,s book
Developing Highly Functional Cylinder Heads for Performance Applications - Part 10
 
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bjowett

 
 
 
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Great posts.

The GM heads will offer some ideas... The Hino W Series engines also have the swirl port... and since the Cummins 4BT/6BT 12 valves engines are a likely copy or co-deleoped with the W (my speculation), they too have the swirl port. This is where we can hopefully find the best porting mods for our applications.
 
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Be careful deshrouding the intake valve as you can make it easier for intake reversion on the last bit of the intake valve opening when the piston is on its way up. This is especially true with low intake port velocities and longer duration. Both occur at low rpm which is a primary goal for most diesel guys.
I did think a little about this...
My thoughts....I think the 1HDT is tuned towards low speed running with little valve overlap and consevative valve timing for intake closing. I am sure I saw a published figure in a manual for valve timing. I would guess less than 25* after BDC for intake close which is very little piston travel. If there is reversion with stock ports then it makes sense that porting would increase the amount of reversion. I am interested in improving inlet flow into the cylinder and exhaust gases out...bulk flow.
The deshrouding will give a significant flow benefit when the intake valve is just opening.... the sooner you can get the gases moving the cylinder filling will be that much better. Gases are heavy and it takes time to get the flow moving or stopping. the deshrouding of the exhaust will have the same benefit for gases leaving the cylinder...start flow early in the valve lift cycle. this should provide more cfm of flow total.
This modification seems popular with professional tuners too. I plagerized the idea from Riverina Cylinder Heads facebook page. (See back a few posts) We have a turbo on our motors providing postive pressure to the intake pushing back against reversion. I am guessing Non-turbo engines would be more sensitive to reversion.
With deshrouding complete I am committed now.

in theory..... :worms:

:hmm: wish I could test.....i'll need a pressure transducer in the intake hooked to an oscilloscope.


https://musclecardiy.com/cylinder-heads/eliminating-cylinder-head-valve-shrouding-improved-performance-part-9/

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I performed the machine work with a wood router using carbide burrs as bits. Crude for sure.
 
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Reply moved from 1HDT Head Gasket Issues thread from @gerg

That's the problem with head porting. You can't measure power improvement easily even with a flow bench. I know when I port my heads I am continuously tempted to deshroud the intake valve....like constantly. I chose to work in the bowl and blend the grinds on the intake valve to improve flow up until it entered the cylinder. Deshrouding the exhaust valve is a no brainer. I based my porting off of low lift low rpm v8 engines that were focusing on building low end power. It's the only porting on an engine I've found that came close to running like a diesel.
 
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Ahh sorry. These threads overlap a bit.
It is all good. As mentioned earlier it is a bit of a black art and it is a good discussion for sure.
I am probably too reactive and just do things instead of posting my plan first and having a meaningful discussion. It will be interesting to see the effect ...if noticable at all.
I am also changing from a 9 blade exhaust turbine to 12 blade in an attempt to increase drive pressure at lower engine speeds. (More misplaced content)
It will be impossible to tell which change has the most effect.

Thanks again for the input.
 

gerg

 
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Don't sweat it about the discussion. The peanut gallery doesn't have much to add in the way of porting and it is a major black art, your right. I went with what I knew was a win win and tried to avoid the possible negatives.

Switching from a 9-12 blade will have a tremendous bennifical effect at least up to 3000rpm(guessing) as I trialed those combos on my td04 and found EGTs were lower, power was up and turbo spooled much faster and earlier in the rpm range. I measured my drive/ boost pressure and it too improved. I really think decreasing blades is really for high rpm goals and shifts your turbo up in the rpm range which is sort of the exact opposite of what we want.
 
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Don't sweat it about the discussion. The peanut gallery doesn't have much to add in the way of porting and it is a major black art, your right. I went with what I knew was a win win and tried to avoid the possible negatives.

Switching from a 9-12 blade will have a tremendous bennifical effect at least up to 3000rpm(guessing) as I trialed those combos on my td04 and found EGTs were lower, power was up and turbo spooled much faster and earlier in the rpm range. I measured my drive/ boost pressure and it too improved. I really think decreasing blades is really for high rpm goals and shifts your turbo up in the rpm range which is sort of the exact opposite of what we want.
Well that’s good news. It is very hard to find much on diesels comparing the two different blade counts. It seemed like my turbo was always a little behind, just about ready to spool up. As for reduced top end power it makes sense that the exhaust is more restricted with 12 blades and holds more back pressure when the motor is revving hard. The only time I rev it that hard is for videos.
I have the gtx style impeller 11blade on the compressor side. I see that Mamba now sells a 12 blade exhaust with a6blade compressor. Trying to get some top end back? :idea:.
Vicious circle...

MAMBA 12-6 Turbo FIT TOYOTA Land Cruiser 1HD-T / 1HD-FT 2.4" TD05H-18G w/ 7cm | eBay

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AHH now I am posting off topic. :doh:
 
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gerg

 
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As far as I know a 6+6 has more effecient flow at high pressure ratios vs say a 11 blade compressor. The 11 blade will have a wider effeciency map at mid pressure ratios and build boost sooner. So how much has always been the question for me. Have never seen or done a side by side comparison.

Don't look to a sales person to recommend a product. If you do, expect they will recommend their product. They are in the buisness of selling stuff, not making your engine perform. Trendy builds and fads always sell. That's why I only eat Diamond shreddies. I hate the old square ones.
 
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Don't look to a sales person to recommend a product. If you do, expect they will recommend their product. They are in the buisness of selling stuff, not making your engine perform. Trendy builds and fads always sell. That's why I only eat Diamond shreddies. I hate the old square ones.

WTF is a shreddie?

Mamba don't strike me as being sophisticated enough to be doing their own RnD
Maybe too harsh, but I reckon they are building what ricers want, and have realised that there is a market for selling the same stuff packaged for the diesel crowd, even if it is not ideal
 

gerg

 
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A shreddy is a special Weed trimmer made out of parts from small helicopters. We use them to cut blackberry bushes. Nast bushes but they have nice berries. You guys don't have shreddies?
 

gerg

 
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Haha. Nice. A shreddies is a square cereal flake. The new and improved one is diamond shaped, or a square turned slightly to resemble a diamond. I agree no r and d seems to accompany their vehicle recommendations and I doubt ther main customers are folks who buy old diesel trucks.
 
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WTF is a shreddie?

Mamba don't strike me as being sophisticated enough to be doing their own RnD
Maybe too harsh, but I reckon they are building what ricers want, and have realised that there is a market for selling the same stuff packaged for the diesel crowd, even if it is not ideal
When I researched the Mamba line of turbos a few years ago they were popular with the Audi crowd in Europe and JDM guys in various markets. Couldn’t find much bad press about reliability, although fitment issues seemed common.
R & D ..... I guess I am paying for that. Service is typical chinese. 3weeks to get an answer as to which 12 blade exhaust wheel fits my hybrid. I was so disgusted with that I ordered from Kinugawa. There wheel is Inconel 718 Mamba was 713C.
For the initial purchase price I am still pretty happy.
 
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