- Thread starter
- #301
I will let you know soon....
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12H-T performance Build (1 Viewer)
- Thread starter gbentink
- Start date
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Any more news?????????
bumped
- Thread starter
- #304
Long time with nothing on this thread.
Update: Release of some earlier secret info
In the stroker engine a mate built we used 1HDT Pistons, offset machined the combustion chamber to suit 12HT and stroked the crank by welding and offset grinding it using stock rods. Compression height in 1HDT piston ~ 6mm lower than 12HT.
I had my doubts about welding up the crank which is why I didt proceed really. Anyway, it broke. Rane etrrifically when running, so with a custom crank these could be taken to 4.9L, but needs a good crank.
All was not lost, the engine didnt suffer any additional danage, so we had new conrods made in 4340. See photo below that has there rods - 1HDT (short one), std 12HT and the custom 12HT rod made 5.5mm longer than stock to use the 1HDT pistons.
The rods are in fact modified Duramax Upgrade rods good for over 100hp/ea in a Duramax. They are in fact LIGHTER than the stock 12HT rods lol!
The mod takes the 12HT from 3.98L to 4.35L.
The engine is running but there is a problem with the injection system!!! When thats sorted I will fit one of my turbos and should be happy days. Since my mate has had a few issues he will be running it for a while with ~ 110rwkw until he is sure all the bugs are out. then he will lean on it - currently installed in a HDJ81! Yes, he pulled the 1HDT to put in the modded 12HT!
I had 2 sets of rods made, so one set is in my hot little hands - just need to know when and where to use them.....
I think I will start a new thread!
Update: Release of some earlier secret info
In the stroker engine a mate built we used 1HDT Pistons, offset machined the combustion chamber to suit 12HT and stroked the crank by welding and offset grinding it using stock rods. Compression height in 1HDT piston ~ 6mm lower than 12HT.
I had my doubts about welding up the crank which is why I didt proceed really. Anyway, it broke. Rane etrrifically when running, so with a custom crank these could be taken to 4.9L, but needs a good crank.
All was not lost, the engine didnt suffer any additional danage, so we had new conrods made in 4340. See photo below that has there rods - 1HDT (short one), std 12HT and the custom 12HT rod made 5.5mm longer than stock to use the 1HDT pistons.
The rods are in fact modified Duramax Upgrade rods good for over 100hp/ea in a Duramax. They are in fact LIGHTER than the stock 12HT rods lol!
The mod takes the 12HT from 3.98L to 4.35L.
The engine is running but there is a problem with the injection system!!! When thats sorted I will fit one of my turbos and should be happy days. Since my mate has had a few issues he will be running it for a while with ~ 110rwkw until he is sure all the bugs are out. then he will lean on it - currently installed in a HDJ81! Yes, he pulled the 1HDT to put in the modded 12HT!
I had 2 sets of rods made, so one set is in my hot little hands - just need to know when and where to use them.....
I think I will start a new thread!
How much different in weigh for custom cod and std cod?
- Thread starter
- #306
How much different in weigh for custom cod and std cod?
Whats with the rolleyes? Seems like your favourite!
You really think I am going to take my time and measure and record it for you based on that?
Yup! Is my favourite engine. 12HT best, I'm with this engine. Well, the weigh is not just for me only. I don't demand for that. OK! You can weigh the rod and keep it to yourself, don't show to me/us. Is for your own data record and knowledge also, right?
- Thread starter
- #308
@ Wongtsenhim,
I didnt mention the weight because I didnt really care too much as long as it was in the ballpark for balancing with crank and piston and the engine isnt a big revver anyway. Since the balancing is performed by another company, it is academic. I only mentioned the weight because looking at the chrome moly rod you would think it was much heavier, but it isnt.
Maybe I misunderstood the rolleye's - in Australia that would be quite insulting and not what you want to do to someone while at the same time expecting from them a favour. Also, When I said it is your favourite, I didnt mean engine favourite, I meant using the "rolleye's", which you also used when asking another question in another thread.
Anyway, its way OT now. I might measure when I get a chance and am happy to post the weight, its not a secret.
I didnt mention the weight because I didnt really care too much as long as it was in the ballpark for balancing with crank and piston and the engine isnt a big revver anyway. Since the balancing is performed by another company, it is academic. I only mentioned the weight because looking at the chrome moly rod you would think it was much heavier, but it isnt.
Maybe I misunderstood the rolleye's - in Australia that would be quite insulting and not what you want to do to someone while at the same time expecting from them a favour. Also, When I said it is your favourite, I didnt mean engine favourite, I meant using the "rolleye's", which you also used when asking another question in another thread.
Anyway, its way OT now. I might measure when I get a chance and am happy to post the weight, its not a secret.
- Thread starter
- #310
So for all you people rebuilding your 12HT, maybe someone knows of a relatively inexpensive rod manufacturer and build with 10% more capacity
There is a manufacturer in Thailand that produces custom MLS head gaskets for a reasonable price. We didnt use them only because the locally made headgasket was available in 1 week and this company is so busy that they are 5 weeks out after order.
The 3B valves are longer than 12HT but have the same stem diameter. So they were cut down and had the collet groove remachined in place. If I can get a photo I will post it.
One thing I have some misgivings about is the stem diamater on these engines (12HT/3B/13BT etc) - huge! Being over built is one thing but if there isnt any great benefit... its a waste. I used Nissan TD42 valves in a 12HT engine I built previously for this reason and it is a fair reduction in moving mass. Much easier this time though just to go for the 3B valves.
There is a manufacturer in Thailand that produces custom MLS head gaskets for a reasonable price. We didnt use them only because the locally made headgasket was available in 1 week and this company is so busy that they are 5 weeks out after order.
The 3B valves are longer than 12HT but have the same stem diameter. So they were cut down and had the collet groove remachined in place. If I can get a photo I will post it.
One thing I have some misgivings about is the stem diamater on these engines (12HT/3B/13BT etc) - huge! Being over built is one thing but if there isnt any great benefit... its a waste. I used Nissan TD42 valves in a 12HT engine I built previously for this reason and it is a fair reduction in moving mass. Much easier this time though just to go for the 3B valves.
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What is the difference in diameter between those and the 3B's? Is it quite a bit?
g
g
- Thread starter
- #312
I *think* the std 12HT valves are 35mm and the 3B something like 40-42mm. It was a while ago and I cant remember.... There is room for a little larger than stock valves in the std 91mm bore of 12HT and the 3B valve used all of this up and also the extra 2mm radius afforded by over boring from 91 to 95mm
intercooler for 12ht
Hi,
just wondering which road I should go down with installing an intercooler on a 12ht. top mount like in tapage cruiser tencha, or a front mount ? lots easier to install a top mount. just wondering what is the difference in performance? Any ideas.
cheers
Hi,
just wondering which road I should go down with installing an intercooler on a 12ht. top mount like in tapage cruiser tencha, or a front mount ? lots easier to install a top mount. just wondering what is the difference in performance? Any ideas.
cheers
Tapage
Club 4X4 Panamá
In my humble opinion frount mounted will always be better .. if you have room for that .. why I choose then top mounted .. here in Panamá AC it's an important add to my Cruisers .. and I would not sacrifice air flow to condensor with front mounted intercooler ..
