G54B cylinder head variation question

[strong79]

Hello all, great site. I have a 79 sport. It had a bad head so I ordered a new Non-jet valve head from autopartswarehouse.com. good price, but different from the Jet-valve head I, m wanting to replace. The new head has an extra cam journal in the rear and a smaller hole in the front by the cam pulley. Should I use this head if I can pick up a valve cover that will fit, or are the cams different on non-jet vs. Jet valve heads. Thanks for any help.

[strong79]

I think the head I ordered was for a hydraulic lifter valvetrain. I noticed there were some engines produced 79-82 that were equipped with them (according to my manual). So, I guess I'm returning the head and attempting to find another that will work for me.

[strong79]

I meant to post pics...but in my frustration I spaced it. Already boxed up new head to send back. I'll try to post pics of putting it back together.

[pennyman1]

if this is a complete head you can use it with the later valve cover and a cam plug that fits in the extra cam journal. The differences in the heads are mainly where the vent ports are located on each model head. Hydraulic lash heads came out in early 1984 and on all 85 on motors. Mechanical rockers can be used on the hydraulic heads with the cam and possibly valve swapout depending on cam lift and dished or flattop pistons. A 1979 2.6 has dished pistons, so the lift issue is not a problem. At some point I need to create a sticky to show the differences to make this easier to understand. Get the valve cover gasket set for an 85 up 2.6 for the right gasket and rubber bits - don't send it back, the mechanical one will be the same issue with the vent ports.

[strong79]

Thanks for the reply. I contacted the warehouse that sold me the head. Their website inaccurately listed it as fitting D50, but turns out its a montero head. I believe I could make it work with the valve cover and gasket kit/cam plug set you recommended. I guess a guy can make just about anything work with enough money invested:). Anyway, I got a line on a local guy with a complete head thats all correct. His asking price is a bit steep (250). I going to look at it this evening. Might be the easiest route. And autopartswarehouse is not gonna charge me anything to return the head because the initially said it would fit.

[Mandle]

Not trying to thread jack here, but I'd like to request (beg) that you do start that sticky Pennyman.... My local machinist tried dumbing this down for me too much and now I'm confused. He said there is 2 versions of the 2.6 (an "old" one and a "new" one) and that they don't have interchangeable heads because the displacement is different. He runs so many different projects its possible he's confused with another motor, but he had me all worried on my 1st gen because I had an aftermarket head on a G54b that wasn't stock to the year/make/model of my truck...
I'd still like this cleared up to this day! haha.

[pennyman1]

To help with the confusion - he is correct that there are 2 head designs - an early head with manual adjustors and the motor has dished pistons (8.2 to1), and a later design with a higher dome, hydraulic lash adjustors, and the motor has flattop pistons and higher compression (9.0 to 1). The non jet heads are usually of the later design, although there are some early non jet heads that were either caravan heads, or canadian heads. The heads are interchangeable, the difference is a drop of 1/2 to 3/4 of a point of compression between using a later head on the earier motor and the original head. Once I have my non jet head at the house with my 1st gen head, I will put the sticky together - that will be this week. As long as its a 2.6 head, it will work - the problems start when you change over the hydraulic 1.5 arm with the 1.6 arm from a 3.0 motor, then try to run a high lift or long duration cam with a flattop piston - it gets ugly fast.

[Mandle]

Ah that makes sense. So the heads are interchangeable and his worries were for nothing. Understood. Thanks for clearing that up! I don't have access to a 3.0 (yet) so I can push that worry aside for now =-D

[strong79]

I bought a complete used head from a local guy that my brother knows. He used to own two 79 d50s but sold them off with most of his parts. He showed me what he said was a 79 2.6 head (I believe him) and said it should be the same head thats on my d50 (he should know...he used to own it!) But low and behold, he had the same head that I bought online (the one the parts warehouse said was for a montero) He was surprised when I told him my head was different. I offered to just buy the valvetrain, cam and cover to use on the new one, but he didnt want to split up the deal. Said it is an aftermarket cam and something about a guy named Jim Baker. Anyway, bought the whole deal. I'm bolting it on tomorrow.

[strong79]

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[pennyman1]

you got a hell of a deal - that John Baker cam was designed for these trucks back in the day, and will accept weber carbs, headers and exhaust mods with great results. You just went from fixing the motor to making a major improvement in one shot. The cam was also known as a Mikuni Muscle cam, ground by Mikuni for John Baker when he raced these trucks off road. That cam could be bought from John Baker separate or with the complete head. Let us know how it runs after you get it back together. Does the other head he had have the same cam in it?

[strong79]

My old head is stock. When he told me about the cam I wanted to buy it. I wanted to bolt the valvetrain onto the new head I ordered to get rid of the jet valves. Sometime later I will order the jet delete plugs.

[BradMph]

You might want have that distributor curved at a special auto shop that does that work. It will benefit the cam to have the distributor come on when the cam does with advancing the time curve. It should give you some more RPMs too! Pretty important to have them matched. You should try and get the cam's lobe settings and other info. Timing set, valve adjustment, etc etc.

[strong79]

Thanks Bradmph. I'll look around for some info. In the meantime I'll give it a couple degrees on the timing advance and see how it runs. Im anxious to get started but waiting for headgasket. Hopefully this afternoon or early tomorrow.

[pennyman1]

the specs for that cam should have you run timing at 10 btdc as a starting point - I used to have the specs on both the early and later 2.6 cams, but I have no idea where they went - maybe ragragtimetime still has the sheets from his...

[Mandle]

Pennyman: I've been following this thread and your last couple replies have got me wondering.... is there anything about these trucks that you do not know? You took Jim Baker and recognized the racer John Baker (a connection I failed to make) and understood the history of it! Do you obsess over Geronimo that much or have you just had him long enough to acquire all this knowledge over the years?

[pennyman1]

yes to both - 34 years is a long time to have a vehicle. There are still things I learn about these truck on here, and I try to help with what I know - there is too much that would be lost otherwise. I am also the same way with coin op games - I have friends that call me all the time on games they are working on, and most times I can talk them through the problem without seeing the machine. It's cool and a curse at the same time.

[noahwins]

Pinball? I'm a pinball nut, Theater of Magic era and earlier.

I remember a thread where someone posted a blurry picture of a camper shell on a 1st Gen from about 20 feet away and Encyclopedia Brown popped in and gave the manufacturer and model, but was disappointed in himself because he couldn't remember which city in Arizona the company was based in in 1983. LOL

[pennyman1]

been fixing them since 1978, and playing them years before that. Wedge head Gottliebs were the kings of EM pinballs until the mid 70s when the digital solid state pins from Bally, Stern, and Williams came out. Gottlieb farmed out their design to Rockwell and the result was horrible and they never recovered. Still love playing them and fixing them - glad that pinball is making a major resurgance. If you ever get to Vegas, look up the Pinball Museum - great place with many unique games from all eras to play. I have a standing invite to stop in and help fix games anytime I am in town. The owner Tim Arnold is a great guy - he has been on American Restorations many times working on their games and having games restored by them.

[noahwins]

A guy I used to play with in high school got really deep into it, looked him up and he scored something absurd like 50+ billion on Johnny Mnemonic at a tourney at the Pinball HOF. Cayle George.

We have the Pinball Museum in Alameda and Playland Not At The Beach in El Cerrito but pinball is dying out here. Sad, always liked pins more than video games.

I was never a tourney caliber player but I'd like to get an old busted Theater of Magic or Whirlwind some day and learn how to fix them. Love that Williams action and snap.

Anyway, sorry to derail, back OT.

[strong79]

Well, I spent the last three days unable to work on my d50 due to an unreliable lower back and crazy spasms. Today I hobbled out to the shop and started putting things together. I'm excited to get my new head with the Baker cam bolted on. after some cleaning and polishing it was time to bolt the intake manifold to the head...The bolt patterns are different. New head has a staggered bolt intake and the head I removed has the studs directly above and below the intake ports. I've verified the block is 2.6l. I'm wondering if someone previously bolted on a 2.0 head and thats whats causing me the trouble I've been having with this thing. Exhaust ports match up. I'll post some pics. I'm also planning to post a variety of pics in the new member intro section since I still haven't done so.

[strong79]

12504here is my intake that was on the truck.12505This is the new head with the staggered studs12506The old junk head.12507The sad state of affairs in my shop.12508Shot a quick coat of paint on the new valvecover to match the exterior.

[strong79]

I was looking around the site for info.http://www.mightyram50.net/vbulletin/showthread.php/1501-Latrine/page2 This guys valve cover looks like mine in the pic. His problems sound similar also with the head I.D. and such. My block is stamped g54b. Looked for the vin decoder on wiki, couldn't find it. I'm over the old head. Just need to get an intake for my baker head, make sure the headbolts are the right length and bolt 'er up.

[BradMph]

Strong79, are you sure the old head isn't a modified 2.0 head? . I think there have been people who used 2.0 heads on the 2.6 engine. That new head looks like the fuel pump hole is not in the center like the old head is also.




G52 2.0L 1995cc. 78-83 Head On A G54B 2.6L


. If you have a manual, take a look and compare your them possibly.



12509

[strong79]

I have a Haynes manual that isnt really specific. The diagrams on the head show different fuel pumps for the 2.0 vs. 2.6. My fuel pump Fits in both heads (even though I'm planning to convert to electric for the weber) I guess my best course of action from here (I wish the heads were stamped with ID #s) is to just move ahead with the new head. I know it will fit the block. I'll need to ensure the proper headbolt size (I saw somewhere there's a kit to replace headbolts with studs, but I'm thinking it's probably pretty pricey), measure the cam to crank sprockets and hope they are the same distance/diameter so I can use the new chain I just bought, and pick up a wrecking yard 2.6 intake manifold. Is it right that 84-87 caravan intake interchanges?
Thanks for stickin with me through this. That old head has sure given me the runaround. There's not a lot of parts support out there for these old trucks.

[strong79]

Another look in the haynes book and it looks like the 2.0 intake ports are paired with the fuel pump in the center. Mine are evenly spaced with the pump between holes 1 and 2. I believe they are both 2.6 heads. My truck is a 79 and I thought I saw somewhere on here that they had some mid-year changes that first year. I'm in WA state, so I wouldn't rule out Canadian stuff, but it had the jet-valves, so probably not from there.

[pennyman1]

The intakes are different from 84 on - that is why the old manifold doesn't line up with the newer style heads. The g52b truck heads and g54b truck heads from 79 - 82 will interchange with no issues. The issues in the swap thread had to do with using a 4g52 automotive head on a g54b truck motor - the differences were due to the different requirements for emissions between trucks and cars at the time. A caravan manifold should work since you are putting a Weber on it, but some fittings may be in different places because it was for a front drive application, and the emissions issues.

[strong79]

Thanks Pennyman1. I will be familiar with every bit of my truck soon. Thats a good thing. I expect much better performance out of it when I finally get it all back together. That old head was in such poor shape and my linkage for the secondary butterfly was unhooked due to a tang that didnt hold the nut on the end. I was thinking about popping the exhaust manifold apart to check the cat and see if it's fallen apart. Does it increase flow to pull that out? I would like to put a header on it eventually, but workin with what I got now.

[pennyman1]

it cant hurt - if you can, get the element out in one piece. That is the old style cats that have a lot of platinum and other precious metals - it is worth a lot to cash in regardless of condition. If you want the best header, get the DG header on this site - pricey but the best there is. Pacesetter is a cheep header that is not built for the daily use of a truck - it is a horsepower header at high revs above the power - DG is built for max power at motor torque peak. It was patterned off of the Doug Thorley tri-y header with improvements. That cam and the weber with the right header will make that truck scream in a good way.

[strong79]

Well I got myself an 85 intake and after some cleaning and minor mods (cut out the inner support at mounting base) bolted it back together a few days ago. Converted to electric fuel pump and did a low idle carb tune. It really scoots now! It does have some hesitation at 3500-4000 rpm, but only with the secondary open and pulling hard. I plan to go through the carb in the next couple weeks, but for now Im back to commuting in it. Thanks for the responses. The next time I have some time off work when its still light outside, I plan to get some pics and post them.

[83sapporo]

I picked up an unknown remanufactured long block and found out today that the head/cam are different than my previous Sapporo /Starion head. What is wording me out is the block doesn't have the access plate for the balance shaft on the intake side. I have a Oregan cam in my old head and when I pulled the cam from the reman head the journals were way bigger. 1/8in or so larger diameter journals. It's a jet valve head with hydro adjusters. The guy died a few years ago but it was bought for a Raider that it never made it into.

What the heck do I have here?

[geezer101]

Hi and welcome to mightyram. The old mechanical lifter head has different specs to the hydraulic head - the components aren't cross compatible. The Astron I engine you have didn't have a removable side cover. The updated engine is referred to as an Astron II and also uses a different intake stud pattern that is compatible with 3 intake set ups - carb'd, a single injector ECI, and MPI in countries outside of the US.

[83sapporo]

My Starion had a hydraulic head being it was an '87, this '83 Sapporo (US model) is mechanical. Cams for sure interchange because I had to put an old Starion cam in the Sapporo to get it running when I bought it.

I still have to pull the studs from one of the old heads for the new engine but the intake bolt pattern looks to be identical. I'm confused to why the cam journals are so different when these heads are almost identical aside from mechanical and hydraulic lifters but both being jet valve heads. I want to use my Oregon cam :confused:

[geezer101]

Hmm. Weird. I know the mechanical and hydraulic cams are different and don't interchange.

[83sapporo]

Found out why I was stumped. Remanufactured head = oversized cam journals. Noticed you can just buy cams with bigger journals so the head can be be repaired. Need to bring a micrometer home tomorrow and see what size over it is so I can buy another cam to then have it reground :bang:

For anyone searching for the info, no you CANNOT swap hydraulic/mechanical rocker cams. Valves stick up further in the mechanical rocker head. took me a few minutes of staring at both heads searching for a difference.

[pennyman1]

you may also be able to have a set of cam bearings made to make up the difference between the head and cam you want to use, if you can find a shop that can do it. If you swap the valves, you can swap the cams to match the rockers.