Opel GT Forum banner

1 - 16 of 16 Posts

·
U-2 Driver
Joined
·
126 Posts
Discussion Starter · #1 ·
Fellas,
I just bought some NOS 265 pistons off ebay, the price was right ($15.00 for 4) GM part number: 3734079. Now my questions are as follows:
1) Do these look like the ones others have used? I mean, are the valve reliefs in the right place, are they big enough? I am planning on having my head ('71 vintage 1.9) redone with 1.72 intakes and 1.5 ex, and "by the book" from rally bob's post on a good street recipe.
2) What is the best way to make sure that this combo will work out before I have my machinest begin hogging on the block?
3)I know that "green smurf" has done this conversion, with not so great results, I want to make sure that I have the right clearance with the valves and the pistons.

anyonw with expieience, please chime in. I have kept track of all my reciepts and plan on a "how to" if this works out. I do not want to deviate from R. bob's post becasue I think that he has completed this conversion many times. The only exception is that these pistons are NOT the custom venolias that he used.

muchas gracias
 

Attachments

·
Super Moderator
Joined
·
13,840 Posts
The 265 Chevy pistons don't have the valve reliefs in the exact correct location for an Opel, but unless you are using a fairly radical cam with those big valves, it won't be an issue at all.

One thing to consider is that the 265 Chevy pistons were a 2-year wonder, and have offset piston pins which were designed to improve power but at the expense of piston slap noise. They could be reversed to make them quiet like all Chevys small blocks built since '57.

Chevy pistons are typically sold as 'lefts' and 'rights'....so it helps to know what you have to begin with. With 4 valve reliefs they can reversed but the pin offset will change too. Just something to consider.

Bob
 

·
U-2 Driver
Joined
·
126 Posts
Discussion Starter · #3 ·
My machinist pointed that out. He noticed the offset right away, and I belive mine are offset for the driver's side deck. One last question that I did not post was, what kind of cam should I use since my head used HYD lifters. can I use the came techniques grind you recommended in your street combo with a hydraulic grind? Or can I simply get new SOLID lifters and use the cam you recommended in my '71 head? thanks fore the info, where is your paypal account so I can contribute?..........seriously

neal
 

·
Super Moderator
Joined
·
13,840 Posts
T-6 driver said:
can I use the came techniques grind you recommended in your street combo with a hydraulic grind? Or can I simply get new SOLID lifters and use the cam you recommended in my '71 head?
If you are refering to the F306 cam specs, it's only a solid profile. New lifters can still be gotten from overseas, you'd have to check with OGTS to see if they have inventory.

If you are set on using hydraulics, I seem to recall using a .412" lift hydraulic grind from Cam Techniques with a little less duration (240 @ .050"). You might have to notch the pistons slightly however with either profile, not for the depth as much as the valve locations.

Bob
 

·
Moderator
Joined
·
587 Posts
When I did my rebuild with the 265 pistons, I used hydraulic lifters with the "autocross" cam Bob used to sell at C&R. .430" lift, 224 Duration @.050" with 108 degrees lobe separation & 4 degrees advance cut in.

I used 1.84 & 1.50 valves. I remember having to notch the valve reliefs. But I believe, as Bob stated, it was more to make them a bit wider than deeper due to their location. Probably because of the cam specs I used.

It idles with a nice "lope" at about 1100 rpm & really takes off when the RPMs get above 3K. I'm definitely satisfied with the power. And with some "tweaking" of the 38 dges, I think it will run even better.

~Tom
 

·
Registered
Joined
·
214 Posts
Right now, there is no "simply" to getting solid lifters.

OGTS does not have any solid lifters. They have been on order for months. Kent, in Great Britain lists some. Maybe one of the blokes from o'er yonder can point you in the direction of a good source.

Or you could have your hydraulics resurfaced, and have solid end caps made. Bob may have those specs, or I think I saw them on a Dutch site a while back.

My fingers have been crossed for a few weeks now with regard to having a set sourced and sent...Inasmuch as I'd hate to do it, I'd sacrifice my wife's cat in a VooDoo ritual for a set right now. :D
 

·
Super Moderator
Joined
·
13,840 Posts
Scott McDonald said:
My fingers have been crossed for a few weeks now with regard to having a set sourced and sent...Inasmuch as I'd hate to do it, I'd sacrifice my wife's cat in a VooDoo ritual for a set right now. :D
Well, as long as you are willing to replace them when you get your order in, I have a set I could send you Scott. Sounds like you need them faster than I do right now.

Bob
 

·
U-2 Driver
Joined
·
126 Posts
Discussion Starter · #8 ·
Thanx for the info on the cam, Bob, can you recomend the HYD cam mentioned, or would you rather wait for the solid lifters and do the split profile cam that you recomended in the first place? This car will be my "friday" car and will not see much milage, but I would like it to keep up with the civics.
scott, dude, i am from ALVIN, I grew up in that area, my dad is a space contracter in that area, as soon as my airforce gig is up (16 years), I plan on moving back out there. I know of a few folks out your direction that have cars if you are looking for parts and such, let me know.
neal
 

·
OPEL-LESS!!!
Joined
·
2,116 Posts
the only problems i had with my 2.0 were the pistons were too tall (0.020 above the deck) and had to take them back out to be shaved, really easily avoided, just stupidity on my part to not check. i then got a mysterious "knock" in my motor, which probably in turn comes back to bad wrenching on my part.

had 600 miles on the motor and decided to try and race a S10 witha 4.3 liter and 5 speed. sure, good idea with stock head, solex, and fresh bottom end, and i must not have gotten into 3rd all the way as when i let the clutch out and laid into the throttle it spit outta 3rd and free-wound the motor, put it back in gear and kept going, all seemed well until the stop light, oil pressure was fluxuating with a nice little knock.

i know, kill me now but thats the real story behind that motor, tore it down and nothing was broken and all bearings looked great still, i just didnt get to pull the number 1 main cap and i still wonder if that was it.
 

·
U-2 Driver
Joined
·
126 Posts
Discussion Starter · #10 ·
Jared,
The only question I have for you is: did you trash the S-10 before you trashed the motor? Did you make us look good bro?

on a serious note, do you know if your block had been decked previously? Maybe that was why the pistons were sticking out the top by .020? Also, did you try and "mock" everything up prior? i think that I am going to go that route, on the advice of the machinist. Where did you get the fastners? My machinist says ARP might be the only way to go, I'm just looking for the best price. Just got a gasket set for $40, now I need a 2.0 head gasket, bolts and bearings and I should be good to gizzel!
 

·
Old Opeler
Joined
·
5,564 Posts
T-6 driver said:
Where did you get the fastners? My machinist says ARP might be the only way to go, I'm just looking for the best price. Just got a gasket set for $40, now I need a 2.0 head gasket, bolts and bearings and I should be good to gizzel!
ARP can no longer supply GT rod bolts - out of stock - but OGTS still lists Opel replacements as:
6067 Bolt, Connecting Rod: 1.9L @ $9.00 each
They also do 6068 76-91 2.0L Head Gaskets @ $58.80!
Try www.opelgtsource.com

I have discussed reuse of the original head bolts with Rally Bob and he has never seen a used one fail - but it is your risk to reuse them! The only replacement may be some "Ricer" ARP head studs but no idea what ones - let us know if you find something that fits. Likewise with main cap bolts/studs.....
That is why most people just reuse the originals - needs must :(
 

·
Opel Adventure # 77 NC
Joined
·
648 Posts
Jim,
This gasket is also on the OGTS site.

6136 HEAD GASKET
2.0L, European after market gasket, less expensive than factory gasket 6068. Twelve (12) bolt. $33.00

It has worked great for me.
Kevin
 

·
OPEL-LESS!!!
Joined
·
2,116 Posts
dont worry T-6, i made us look good, altho it didnt look good having that paticular chevy tow me back home, much rather chevy than dodge, or especially ford tho!!!

he turned the corner at the stop sign, took off haulin ass, i made my stop and at the end of 2nd gear my bumper was at his front wheel. after popping outta 3rd gear i fell back a little bit, about a car length, and ended up catching back up and barely getting around him. not bad for a 2 liter versus a 4.3 liter, over twice as big altho opel has the aerodynamic and weight advantages.

i used the stock fastners as nothing looked suspect, and the motor had been running before i rebuilt it, until my father had blown it up (ironic, this motors been blown twice). it spun a number one rod bearing. seems like so long ago i had that car (3 years ago, very first GT). anyway i did no mock up as rather than the pistons, everything was stock parts, and i have no knowlege of that motor, it could have been decked, i'm really not sure.
 

·
Opel Tinkerer and Rescuer
Joined
·
7,517 Posts
Got a Q for Bob.. I know an AMC piston was also a 2.0L Piston option.

I was told by the guy I bogh Bens Manta from that it was rebuilt with AMC pistons, and has big valves.. Although as stated before have yet to confirm because I don't want to tear the motor down.

But I can tell from the seat of my pants (And the fact with a 40DFAV, big exhaust and Bobs intake it runs sweet..) that it definately has some ass in the motor.

Anyway, just curious what those pistons were...

Charles
 

·
Super Moderator
Joined
·
1,802 Posts
GoinManta said:
Got a Q for Bob.. I know an AMC piston was also a 2.0L Piston option.
couple of odd-ball AMC piston options:

-66-71 225 v-6 pistons, 92.25mm std but oversizes are available, 1.835" compression height and .9398 pins, so same issues as 265 pistons, too tall and big pins

-79-90 232 or 258 inline-6, 95.25mm bore, 1.632" compression height and .9310" pins, so a lottle low in the hole and still a bit big on the rods, also odd D-shaped recess in the top of the piston

-68-71 350 v-8, 96.52mm bore, 1.805" compression height, .9398" pins, so same issues as the 265 pistons, but closer on deck height than the v-6 ones

-and lastly, in a wierd "what if" sort of way, theres the pistons for the 90-94 3.3l V-6 Eagle Vision motor, 93mm, 1.260" compression height, and .9009" pins. Might just work with small journal 350 chevy or chevy inline-6 5.7" rods if you had the small ends bushed down a bit and wanted a long rod motor to improve your rod/stroke ratio.

Just some AMC ideas, maybe none of them the one Bob mentioned even.
 

·
Opel Tinkerer and Rescuer
Joined
·
7,517 Posts
oldopelguy said:
-79-90 232 or 258 inline-6, 95.25mm bore, 1.632" compression height and .9310" pins, so a lottle low in the hole and still a bit big on the rods, also odd D-shaped recess in the top of the piston.
Cool, At least if its this one I can look down the sparkplug hole and check.

Speaking of checking, is there any way to test the flow and displacement of the motor without breaking it down? Which I may do anyway. Figured may not hurt to give the motor a once over before I drive it across country.

One of the main reasons I want to get the car ready for Carlilse is to be able to get it on the Dyno.

Charles
 
1 - 16 of 16 Posts
Top