Opel GT Forum banner

1 - 14 of 14 Posts

·
Member
Joined
·
115 Posts
Discussion Starter · #1 ·
GT engine questions

1. How do I determine what year my engine was manufactured?

2. The engine I am rebuilding has an aluminum oil pan. Another spare engine I have the oil pan is steel. Is one an after market replacement or was the type of oil pan used, specific to a particular year the engine was manufactured?

3. Recommended color and paint type for my engine? (Note: GT is silver in color)
 

·
OPEL-LESS!!!
Joined
·
2,116 Posts
look at the casting number behind the starter, the last 2 digits represent the year the block was manufactured.

if its a silver car, with silver engine compartment, i'd probably paint the engien the interior color of the car. if the engine compartment is black, body silver, do a silver engine in my opinion.

i like the cerama-kote engine paint products, they work well. theres another paint i really like, i'll have to go to the barn tomarrow and see what it is as i dont remember.
 

·
Member
Joined
·
115 Posts
Discussion Starter · #3 ·
Greensmurf20;
Thanks for the feedback. Any idea about the oil pans, aluminum vice steel?
 

·
Moderator
Joined
·
1,973 Posts
aluminium would probably be the way to go, you can tighten steel ones down easier and distort them, the aluminium ones are more ridgid.
 

·
Old Opeler
Joined
·
5,564 Posts
Ali vs Steel Pans

Ali is 'cool' ...... but Steel is 'tough'!

The ali pans are reputed to seal better to the block but can be easily cracked by over tightening or slaming into immobile objects.

The steel pans are more durable for "spirited" GT use.

Your choice .. if you lose your oil you loose your engine .. nuff said?


..Ali pans ARE "cool"
 

·
Banned
Joined
·
3,842 Posts
in my opinion the steel pans are great... for putting parts in. They normally leak without large quantities of silicone. I've never cracked an ali pan on install, how you could do it is beyond me. On the other hand I did break one on a manta off roading it. I had it welded back up without removal but if it were steel it would have ripped it to shreds. I won't use steel pans cuz I don't like leaks. Just my opinion
 

·
Registered
Joined
·
6,344 Posts
My two cents, on ali vs steel, either will do the job they were designed for, hold a quantity of oil as a reservoir for the oil pump and have a place for the oil to return to. Breaking the ali pan, or distorting the steel pan is caused by one thing, overtorquing. You can undimple/undistort a steel pan with a ball peen hammer and a piece of wood, you can fix a broken ali pan by heli-arcing it. So you won't have to fix either one, use a torque wrench. ;)
 

·
Registered
Joined
·
2,894 Posts
I just walked down to the shed to clean up and see what needs to be done before I can pull the brown one in. I checked the engine I got from "Bear" as Jared said "look at the casting number behind the starter, the last 2 digits represent the year the block was manufactured"
The engine block nos has Ja 70 stamped on it and is sporting an Ali pan, straight, not finned, as some of the others I have do. I guess my questions are, aside from pulling the head, is there any other way to tell if it has the "High compression" pistons? and since its already has the Ali pan, I can use one of the finned pans as was discussed in some of the previous posts. Thanks, Jarrell
 

·
Member
Joined
·
583 Posts
Steel vs. aluminum

The aluminum pans came on the GT's at least until 1970. Mine had an aluminum pan and it was stock. The aluminum vs. steel debate can rage for days, but here's a thought. You have differing expansion rates between the two metals. Over time this could cause leaks, as if an Opel needing help developing them. Whatever your choice, just ensure that you use the appropriate pickup for the pan.

Good luck.
 

·
OPEL-LESS!!!
Joined
·
2,116 Posts
some people say you can shine a light into the spark plug hole and look at the top of the piston to determine a dish or flat top, i've never done this. pull the valve cover off, and if the date on the head matches the date on the block, with correct lifters, then the matching set of pistons is probably being used. (solids and flatops were paired from factory as dish and hydraulic was paired from factory) if you have solid lifters in a head, and you do believe the engine hasnt been messed with, it probably has flat tops. looking at the piston its self is the only sure-fire way to know it has flat tops, as anybody could have changed them throughout the years. 70 and older had flat tops. my 71 GT made in 9-70 has all 70 casting dates, had a ali pan, but since it was a 71 model year car, it has dish pistons and hydraulic lifters, therefore casting dates cannot always be a "stamped in stone" rule, atleast for 71'(the change-over year). car only had 69 thousand miles origional miles and 2 owners before I, the 2nd owner having it since 76 and 8,000 miles, no engine work ever done until i had a hold of it.
 

·
OPEL-LESS!!!
Joined
·
2,116 Posts
P.S.: Finned ali pans are said to only come off from 71 Manta engines. may hold true as the one finned pan i had was a spare engine i got with my first GT, casting dates on block, head, timing cover, and dizzy were 71'.
 

·
Old Opeler
Joined
·
5,564 Posts
New Technology

One of those wizard firbe optic oizmos used by the medical profession to look inside people can be used to view the piston top through the spark plug hole ...... Just don't tell the Charge Nurse what you used it for whenyou take it back. ;)
 

·
Senior Contributor
Joined
·
903 Posts
greensmurf20 said:
some people say you can shine a light into the spark plug hole and look at the top of the piston to determine a dish or flat top,
A Stylus works perfectly for this and is reasonably priced. You can stick the light through the hole and still have enough room around the light to see the cylinder wall and top of the piston...

http://www.streamlight.com/stylus_specifications.htm

-Travis
 

·
Old Opeler
Joined
·
5,564 Posts
Bore Light

A bore light for looking up rifle barrels also works well. It looks much like the Stylus but the fibre optic bit sticks out the front longer and can go right down through the spark plug hole. Very inexpensive at a Gun shop.
 
1 - 14 of 14 Posts
Top