engine rebuild tips

[gtkid2]

i have a complete/ running 1.9 pulled from a '70 opel. any tips for rebuilding? I'm on a tight budget and have a list of about $300 worth of rebuild parts like gaskets etc... any tips

[RallyBob]

i have a complete/ running 1.9 pulled from a '70 opel. any tips for rebuilding? I'm on a tight budget and have a list of about $300 worth of rebuild parts like gaskets etc... any tips

Well, you can't actually 'rebuild' for $300. You can re-gasket, inspect, etc., but that's about it. I just cleaned up (machine shop washed all parts, polished the crank journals, and honed the block) a used 2.2 and got a gasket set. It cost me $240 so far...gaskets $110, machine shop services $130.

A minor overhaul would include gaskets, rings, bearings, and a valve job at least. Again, over $300.

A true rebuild would cost $1500-$1800. Including (but not limited to) new pistons, rings, recon'd rods, bore block, turn crank, new bearings, new oil pump, new timing chain, new cam, new lifters, new valves, new springs, valve job, hardened seats, milled head and decked block, new valve guides, etc. But it would truly run like a new engine at that point.

If the engine you have is in good shape.... compression read reasonably high, doesn't smoke, etc.... then I'd simply wash it and replace the gaskets and seals.

[OriginalOpelGTOwner]

Good morning Bob. Question for you. If a 1.9L low compression engine is running 17 - 18 mm of Hg at idle with a steady vacuun gauge needle and compression test results are 130, 130, 130, 120 would this be considered reasonable good condition or ready for a ring job? No smoke except sometimes on start up.

[RallyBob]

Good morning Bob. Question for you. If a 1.9L low compression engine is running 17 - 18 mm of Hg at idle with a steady vacuun gauge needle and compression test results are 130, 130, 130, 120 would this be considered reasonable good condition or ready for a ring job? No smoke except sometimes on start up.

I can't comment on that specific vacuum reading as my gauge reads in inches..but in that case 20-22 inches of vacuum is typical for a good running stocker.

Compression numbers sound very good for a low compression engine. Low compression is the one cylinder might simply mean it's time for a valve job. But I'd say the engine has plenty of life left in it.

Start-up smoke is likely just exhaust guides and valve seals.

[OriginalOpelGTOwner]

Thanks Bob. My vacuum gauge measures in inches of Hg as well. I have no idea why I typed mm of Hg.

[RallyBob]

Thanks Bob. My vacuum gauge measures in inches of Hg as well. I have no idea why I typed mm of Hg.

No problem. It amazes me sometimes at the fact we still use Imperial measuring units. Metric really is easier, and all but 4 countries in the world use it. Funny how we as a nation seem to universally embrace new technologies at the drop of a hat (computers/phones/TV) but are scared of counting by units of ten...

BTW, a bump of the ignition timing and a fine tune of the carburetor and I'll bet you're right at 20-21" with that engine.

[First opel 1981]

i have a complete/ running 1.9 pulled from a '70 opel. any tips for rebuilding? I'm on a tight budget and have a list of about $300 worth of rebuild parts like gaskets etc... any tips

Here's my 2 cents on a $300 freshening.

Pick up a gasket set from AutoZone for under $100. The part number can be found in this website if you look for it (I was too lazy to look for it for you).
Now, take the engine apart and check the crank bearings for wear. If there is ANY wear, have the crank ground.
Buy NEW bearings for the crank. If it's not worn, then the new stock bearings will give you more life. Make sure to plastigauge the bearings when you put them back in.
Check the cylinder walls for a lip. If it has a significant lip, you are done thinking of staying under $300. If the lip is modest then you "can" keep the pistons where they are. Don't remove them if you are not going to replace the rings.
For the head. Remove the rockers and lifters. Mark each place where each lifter and rocker came from and then pull the camshaft to inspect it. You need to make sure all the lobes are intact. If they are worn, then you are done thinking of a $300 job. If the lobes are good, then you "can" put the cam back in and reuse the lifters on the lobes they came from. If a lifter goes, it probably won't hurt the rest of a stock engine so it's pretty safe to reuse them.
Make sure to replace the valve seals. This will help get rid of the oil smoke at startup. The valve seals are included in the gasket set.
Check the timing chain to make sure it's not stretched. If it is, get another one. Check the timing chain follower for wear. If its worn out, get another one.
While the engine is out and apart, clean it very well both inside and out. This will help you find leaks if and when they develop.

Reassemble engine. Use a GOOD quality oil and possibly an additive for extra lubrication. Change oil regularly.

The cost of this freshening will be inder $300. Gasket set will be under $100. Bearings can be had for under $100 for the mains and rods. You WILL have to shop to find bearings for that price because most parts stores aren't going to have Opel GT in their computer anymore. Getting a crank ground can be under $100 if you ask around. The timing tensioner and chain can put you over the $300 but not by much.

My opinion is the crankshaft is the part you want to protect the most. If you lose a rod, the damage will be catastrophic. Any other parts could fail and not "kill" an engine.

Just my opinion guys and gals.

[Paul]

I'll add a bit to the above post...

When tearing apart the engine, I like to use the bag and tag method. Zip-loc freezer bags work great because you can write on the outside and it ususlly won't rub off and items don't fall out... So as you remove the rocker nut, place the entire assembly in the bag: nut, washer, rocker arm and lifter. Then identify contents as #1 Intake... you get the idea.

The cylinder walls on Opel blocks are dang near bullet proof. Unless something bad has happened, normal wear will not leave a ridge. Many times you will still be able to see the original cross-hatching. If compression is good, leave well enough alone.

Crank polishing if done carefully only removes a few tenth's, grinding removes thousandth's. If there is no scoring on the journals, a couple of tenth's can be polished off and then standard size bearing can purchased. When grinding, it usually means going undersize on bearings, like .010, .020 or .030 and bearings to match. AND..., when grinding undersize, the rear main has to be paid special attention to get the thrush bearing gound properly.

Edit:....Oh, and to be clear... I mean polishing at the crank grinding shop, not polishing by emory cloth by hand...

GL

[First opel 1981]

Adding something I forgot...

When putting the engine back together with a new head gasket, make sure to modify the head gasket with the two 3/8 inch holes as described in this thread http://www.opelgt.com/forums/opel-ti...st-valves.html
Call it insurance against a cracked head.

[gtkid2]

sweet thanks! Yea I checked the engine and everything seems within tolerances and specifications... I just wanted to do a little freshening-up for around 300 before it went back in... thanks!

[yellaopelgt]

Since no one so far has mentioned this....dont forget to check the tolerances in the oil pump cover and gears.Might as well take a peek at the ball and spring too....Integral part of an engine that shouldnt be overlooked. As well as priming the system before starting up.Good luck!
Joe

[Mike Preble]

And to add my two cents into this, I have found over the years that if you just do a valve job on an engine and leave the original rings in place you may soon be doing the rings. As an engine gets old, everything in it gets old. As you all know after years of wear and tear things weaken. If you do a valve job and seal up the top of the engine the compression gases want to go somewhere. The rings are weak and this tends to allow some of the gas to escape past them giving you a lower compression reading. Creating a good, tight seal around the valves and the gases want to go the path of least resistance, the weakened rings. This will accelerate the wearing down of the rings.

Opel engines are very tough but will only last so long. If you are tearing down the engine to do a needed valve job just think about new rings. Even if you don't need to over bore the block it might be wise to think about replacing the same size rings. I know that you will have a larger ring gap but it will possibly still be within specs. But the rings will be new.

Again, just my two cents worth. And all the gaskets are new.

Mike