To rebuild or not to rebuild? Thats the dilemma!

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3X00-Modified
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Re: To rebuild or not to rebuild? Thats the dilemma!

Postby 3X00-Modified » Thu Mar 06, 2014 8:40 am

I'm going to say it's the same push rod since the length never changed between the stamped 1.6 and roller 1.6, so if you can use stamped with factory push rods you should be able to do the same with these, but in order to make them work you need to at least cut the grooves in the heads for the pedestal, OR you can choose to grind the tooth off the pedestal and continue to use the pushrod guides(which could change needed push rod length)... BUT if you do not cut the notch in the head then there is nothing preventing these rocker posts from twisting and the rocker from falling off the valve... If you have the heads off then yeah this is something that can be done.

And you will actually gain more than 1-2hp because your going from a 1.5 stamped rocker ratio to 1.6. Unless you mean in comparison to the 1.6 stamped flavor.... In that case yeah maybe 1-2hp... but I wouldn't call it free if he doesn't have either rockers to use.



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Re: To rebuild or not to rebuild? Thats the dilemma!

Postby Rettax3 » Thu Mar 06, 2014 4:32 pm

Yes, I notched the heads for the pedestal tang, it seemed like the best way to do it. I was very nervous about them twisting without stronger guides, but it has never been a problem (at least, not yet :fool: ). I actually did the porting and the pedestal notching on the heads while they were on the engine, there are some old-school tricks to keeping the shavings out of the cylinders, and I just washed-down the block really well with carburetor-cleaner to get everything out of the cam/crank area before I continued to build it, but yeah, that was a back-assward way of doing it, but I hadn't planned on going that way at first, and didn't want to re-do the head-gaskets. :pardon:

Neither the 3400 push-rods nor the MPFI push-rods worked completely right for mine, as it is a 3400 block with the roller-cam/lifters and 3.1 MPFI heads. BUT, I was able to use six push-rods from each engine for correct lengths, so if you have both complete sets to use, you can hybrid the two together without buying anything else. I just don't remember which six from each engine I needed. :unknown:

I was referring to a 1-2 HP gain with roller-base vs pivot-ball, not 1.5 ratio vs 1.6 ratio, but good point. I would love to get my engine up on a dyno... :wink: And I meant that the power is free in that it doesn't cost any extra fuel to get it -it is all from increased efficiency. :good:


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
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To rebuild or not to rebuild? Thats the dilemma!

Postby zcylex » Thu Mar 06, 2014 10:28 pm

It took me a while to digest all that info you guys give me lol. On the other hand i was told i could make a hybrid by swaping in the topend from a3x00 engine onto my 2.8 found a little info on the web but most people that did it are on sites that now dont exist as well as them tutorials, if i were to go that way is it just a bolt on upgrade i know i need tuning and parts, all i know is i need a LIM, UIM and head s from a 3100/3400

Im not throwing everything that we have discussed away, its just that since getting an engine here is super expensive ~1800$-2000$ from the engine shipping and shipping to my contry)

Rettax3 i have 0 parts for my retta here i mean literally all i could find is a front crankshaft seal. Sedan,coupe, GM cars are not very popular here. Mostly pickup trucks are..


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Re: To rebuild or not to rebuild? Thats the dilemma!

Postby Rettax3 » Fri Mar 07, 2014 1:35 am

Sorry, I am not trying to throw useless info at you, it sounded like you were looking at buying replacement rockers, and I know the roller-base ones are nice and CAN be made to fit your 2.8's heads. I think my comment was meant more academically though, since it was being stated that you CAN'T use them. It is all good though, I give you credit for even trying to keep your 'retta running, let alone working at making it even better than stock like you are looking at doing. :good: Some of the GM iron-head 2.8/3.1 engine parts might fit your engine too, and might be easier for you to find since those engines were used in GM trucks, Jeeps, Isuzu SUVs, etc. Just a thought...


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26

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zcylex
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To rebuild or not to rebuild? Thats the dilemma!

Postby zcylex » Fri Mar 07, 2014 2:35 am

Don't worry you were trying to help i get that. Jeeps are rare here, then theres isuzu rodeo, and KB and thats basically it. Most big cars are either ford or nissan or toyota here, i literally had to google for isuzu suvs lol(didn't remember the rodeo) and 90% of them are diesel, so yeah parts are very hard to find . Plus it would be cheaper to get a
Cylinder head in the us than here mostly because of our devaluated currency. My retta is here because it was driven by granddads brother-in-law, he changed his 1969 chevy nova for the retta (sold the nova we couldn't do anything at the time :( ) and now when he tried to get rid off the retta we managed to get it from him. Anyways back on topic, what do you think about the top end swap on my 2.8, would it be worth it? Besides ecm what other things could give me problems? I was told to contact wot-tech and talk to some one to get a chip for a bigger cam.


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Re: To rebuild or not to rebuild? Thats the dilemma!

Postby themixer » Tue Mar 11, 2014 12:22 pm

hows this coming along?



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zcylex
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To rebuild or not to rebuild? Thats the dilemma!

Postby zcylex » Tue Mar 11, 2014 10:43 pm

Well im waiting for my compression tester to arrive, since mechanics here said "if the crankshaft feels hard to move its ok, if its loose then you need to rebuild " and i was like WTF? So i bought one at ebay. Then im going for the rebuild if required if not im just going to replase all gaskets and camshaft, lifters etc.. I know i might be putting too much money on the engine instead of swaping it but the thing is, someone offered me a completely rebuilt 3.1l and after shipping it would go up to 1800-2000$ lol (1100-1300 in shipping lol)


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