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Hello,
I've been trying to search for info but haven't found anything that pertains to exactly my truck. I understand it has the jet valve head, that I think is cracked. I will remove it to be sure that it isn't a head gasket leak, but I want to make sure I can get the right head, before I start taking it apart.
That is my main question... What is the right head, and who makes the best one? since I want to put on a new head. I appreciate your advice!
Clearwater heads are well-regarded and used by many here. For the 4G54 they only have non-jetvalve heads with mechanical (manual/non-hydraulic-lifter) valve lash adjustment, both of which are preferable:
https://www.cylinder-heads.com/produ...81-86-no-core/
I'm still confused about heads. My G54b is the same as a 4G54? I thought they were different because of the nomenclature, but that is why I'm asking here as I know so little about this.
The Clearwater link says that head fits 81-86, but my truck is an 87.
4G54 and G54B are alternate designations for the same engine (G54 being the key portion). From what I can tell by the Haynes manual, seems like the G54B version may indicate jet valves and/or hydraulic lifters, which were added in a later revision. That's why Clearwater only lists their head for '81-86 models, but it should fit any 2.6L G54 variant.
I've been looking around at heads, and prices vary from under $400 on Amazon to the Clearwater $530. Are there differences that make one better than the other, or do they all come from China?
From what I can determine, I have the jet valve, hydraulic valve head, but it is still on the engine. It think that is what came stock in 1987. So you believe the new head from Clearwater is a bolt on?
Thanks
Be aware that there are differences between the mechanical vs hydraulic heads that make valvetrain parts non interchangeable. Rockers, rails and cams do not swap.
That is not good news since so far I've only seen mechanical heads for sale.
Am I relegated to trying to get mine welded/repaired? or trying to find a good used one? The success of accomplishing either doesn't seem likely from what I've read.
Thanks
There are pros and cons with going with a mechanical head. Pros - they are more resilient to heat cycles, are preferred from a performance perspective and they lack the jet valves which are known to cause issues (burning out, cracking the roofs of combustion chambers due to thermal expansion) Also the hydraulic adjusters are expensive to replace. Cons - being mechanical they will always create some valvetrain noise and the adjusters need to be set manually (not a big deal but there is a trick to it and it means throwing the book away...)
There are complete heads available but it will depend on what your budget is and how long you can wait to get one (I've seen complete heads for forklifts on AliExpress at reasonable prices if you can handle the shipping)
I thought AliExpress always dealt in volume. I probably don't want to wait longer than a couple of weeks to get into this project. I saw where O'reilly's had the head for about $850 complete, but the term complete can mean different things to different sellers. I had hoped to be able to buy a head that I can bolt on, or transfer over my parts, without mods, and without spending that much. With gaskets and new bolts, I will be over $1000, with O'reilly's. I'm looking for the best head design, but also a lower cost if possible, so I feel it is money well spent. At the same time having a parked non-running vehicle makes no sense either. Your advice is appreciated.
AilExpress will handle single orders but Alibaba deals with minimum orders. The best head design is the non jet valve M6 or M7 head. They have the hemispherical combustion chambers and the ports are bigger.
Is this M6, or M7 design something, I could buy that would bolt up without mods? I saw a head that made 4-600 HP for a little over 2k, that's interesting, but I'm not looking to change the Mukini carb that is on it now or anything else. My truck is an auto trans... I'm looking for good MPG and reliability, bolt on, and being retired, at the best price I can find it. Thanks
Highly dubious a mere head swap would "make" 4-600 HP when the stock carb'd engine was only 114 HP at most; more likely they just meant it was "good for" up to 4-600 HP, meaning it would hold up and flow well enough combined with all the other engine mods required to make that kind of power.
Yeah, I wouldn't think the bottom end would handle that kind of power very long. 114 HP is more than I will use.
I haven't found reference to type 6, or 7 heads yet, but I haven't delved into it much yet.
Thanks
Fun fact - the stock 4G54 bottom end will run 600 HP. The thing that strangles these engines is the cylinder heads, HKS made twin cam heads for the 4G54 and in NA form produced 276 HP as part of a full performance package (headers and twin Mikuni PHH carbs) They are rare as hell now. A freind and myself debated over whether or not an E30 twin cam head could be modded for the 2.6 block but it would take some assing to get the timing cover and chains to work...