Summer engine build idea...

[bgdowski]

Im planning on pulling my motor out this summer and was looking for some feedback from the engine gods of OpelGT.com... Here is what i was thinking of doing:

-Block skimmed to ensure flat surface.
-Boring block to fit 2.0L pistons from OGTS.
-Fitting 2.0L from OGTS. #6132
-2.0l rings from OGTS. #6140
-new rod and main bearings, obviously
-.430" lift, 268 duration or .430" lift, 284 duration camshaft (i dont know if mine is solid lifter or hydraulic. Remind me how i can tell)
-valve job (stock replacement valves put in)
-New lifters and cam bearings

Im not worried about a rough idle, gas mileage, or octane use with this motor. I am building it with the intent to drive it every day, but be able to open it up on the street when needed and track it a little.

I have a Weber 32/36 on it already and a pointsless ignition system. My goal is 150hp, do you think that is obtainable with these engine modifications? What do you suggest i do to reach my goal, or get close... This is a budget minded build, so nothing to radical. I have decent mechanical skills aswell, and am not afraid to do head work with the right guidance.

[First opel 1981]

There is a thread or two here with mods that you can make to your intake manifold. Try those as well.
As long as you are at it, see if you can have the head ported a little.
Add a header and you might have less problem finding that 150HP.

[bgdowski]

Im looking for feedback on internals for now, I would like to know how the will work with eachother, and if i can improve on my plans. I only want to pull the motor once, and can mess around with manifolds later on in the game.

[yellaopelgt]

If you skim the block.....you just messed with the cam timing. Not a huge deal,been done plenty of times.But you need an adjustable cam gear depending on how much is taken off. I would just say as long as you are going with new valves....get biguns! The concept it to make this motor breath better right? Any restrictions along the way pretty much kill the effort if it isnt done all the way through the motor.

IE. header,ported intake efforts wont do you much if its choked down at the valves. NOT to say it WONT help completely...just that you're grabbing for small gains everywhere.
While on the same note as far as getting lil ponies, an electric fuel pump and fan,lighten the flywheel,s-10 clutch,bigger(2") exhaust system, re-jet the Weber,and many other mods will get you up to the desired HP.(and keep it drivable) Its not cheap.......trust me,I KNOW!!! But while 150HP isnt a crazy goal...its not a walk in the park either.

Its a big snowball effect.....

[bgdowski]

Originally Posted by yellaopelgt If you skim the block.....you just messed with the cam timing. Not a huge deal,been done plenty of times.But you need an adjustable cam gear depending on how much is taken off. I would just say as long as you are going with new valves....get biguns! The concept it to make this motor breath better right? Any restrictions along the way pretty much kill the effort if it isnt done all the way through the motor. IE. header,ported intake efforts wont do you much if its choked down at the valves. NOT to say it WONT help completely...just that you're grabbing for small gains everywhere. While on the same note as far as getting lil ponies, an electric fuel pump and fan,lighten the flywheel,s-10 clutch,bigger(2") exhaust system, re-jet the Weber,and many other mods will get you up to the desired HP.(and keep it drivable) Its not cheap.......trust me,I KNOW!!! But while 150HP isnt a crazy goal...its not a walk in the park either. Its a big snowball effect.....

Haha i realize its a big snowball, and that one mod requires a million supporting mods. I would just like to get internals out of the way so that i can work on the more "bolt-on modifications" if you will while i am at college. I read about shaving the block messing with the timing, and i wanted to stay away from that but the machinist said he wanted to do it mearly to true up the head, he seemed fairly insistent on it. I suppose i can convince him otherwise. Would you mind expanding on the larger valves, and what goes into it? Ive read on the forums but it seems like greek to me, and like i began reading a book half way through, instead of cover to cover. Any step by steps on what goes into larger valves out there that i havent stumbled upon?

[opelwasp]

If you do all that work and not the valves you are just wasting your money. The most bang for the buck in an engine comes from the head(I've heard it said 75% of the total gains). If it breaths better it will go faster have more power and be funner to drive. Just over boring the pistons won't do much. You can put the biggest pistons you can find in there but if you can't get the air out more efficiently, then what's the point. Bigger valves are a must. Also DO NOT reuse the original valves, because the can break off and destroy your freshly rebuilt engine(ask me how I know this). If you are going to get the head redone anyways then you might as well get the bigger valves. The machining will cost you the same.

[yellaopelgt]

I just want add a little bit of advice here.......if the machinst you are dealing with has never worked on an Opel motor(may,may not have IDK) DONT let him tell you how to do anything!!! While granted,he's the one doing the work,this isnt your fathers run of the mill chevy 350. The overzealous machinist trying to tack on a few extra $$ has caused more damage than good on more than one occassion. Do the research,bring him copies of the measurements/tolerances you are after,and stick to the plan. Dont let him deviate from this. Its your money and your motor.Basically........measure twice,cut once. IF even that.

[bgdowski]

Originally Posted by opelwasp Also DO NOT reuse the original valves.

I wasnt planning on reusing my original valves. How do i go about having larger valves fitted, and what valves do i use?

Would it be smarter to use the 2.0l pistons or just 1.9l high compression?

[oldopelguy]

First off, if you're planning on replacing the lifters then it doesn't matter what you have, buy solids or hydraulics to match your new cam and you will be fine.

Secondly, swapping the head in the car, even on a GT, is certainly possible without dropping the motor. It's no fun, but it's do-able. If your current head is working fine, there's no reason to not use it as-is and put the car back together with a fresh short-block and start driving it. Then buy an extra head to do the porting, valves, cam, lifters and whatever to and plan on swapping it in one weekend. This buys you a couple of things, the first being time to get the work done while you still enjoy the car and it's not drying out or rusting somewhere due to neglect. The second thing you gain is a way to spread the costs out as you can afford them, which might mean you can spring for more or better parts in the short block now and have a better engine overall when you're done.

As to that short block, the 2.0 pistons are a good place to start, along with their matching rings, but if you can find/afford aftermarket forged ones with a little higher compression ratio there's nothing wrong with them either. Swapping out pistons means you should get the rotating assembly balanced as well, and if you're going to have it balanced you should ensure you are using the earlier, stronger, forged connecting rods just in case. Maybe cosider having the counter-weights knife-edged while they are balancing if you want this to be an all-out motor. Spring for new rod bolts too, if you can find/afford them. Obviously new bearings are a must, don't skimp and make sure your machinist does a good job on the crank for them.

While you're in there, and having stuff balanced you might as well do a new clutch, either the uprated Opel stuff OGTS sells or the S-10 clutch conversion, maybe even one of the aluminum flywheels with the conversion. If you don't want to drop the egine again, why would you want to crawl under for a clutch?

Pay special attention to the timing cover when you have the engine work done. Have them clean it with the block and then take it home to give it some attention by hand cleaning out passages and making sure the relief detents are all clean and working. Consider a new oil pump gears and cover, and if you can't find the cover you'll want to get a piece of glass and some sandpaper and spend some time loving it up 'til it's nice and smooth. Add a new timing chain, with a master link, when you put the works back together and you'll be set.

Then, once the motor is back together ad installed in the car, come back and educate yourself on porting and big valves and such and get that work done while you have fun driving the car. At that point the bottom end will be stronger than you could possibly break breathing through the stock head, so you'll never have to worry about it. It won't be making it's ultimate power potential, yet, but it'll be ready for it, and you'll be driving the car so you won't lose interest and give up.

My $.02 worth.

[opelwasp]

OGTS sells 2.0L valves and 2.2/2.4L valves. I would recommend the 2.0L valves for your engine size. They have the same stem diameter so they will fit fine. When the machinist cuts in the new seats he will cut them in to fit whatever size that will fit the valve. So you supply the valves and he does the work.

[hrcollinsjr]

Originally Posted by opelwasp OGTS sells 2.0L valves and 2.2/2.4L valves. I would recommend the 2.0L valves for your engine size. They have the same stem diameter so they will fit fine. When the machinist cuts in the new seats he will cut them in to fit whatever size that will fit the valve. So you supply the valves and he does the work.

Check to see if your local machine shop has the reamers for the Opel valve stems as they are odd sized compared to everything else it seems. I'm lucky in the fact that the machine I use once did Opel engines for the local circle track racers and one of them bought the proper sized reamer for Opel valves because they were required to run stock sized valves.

OldOpelGuy gave you several valid reasons for building a solid bottom end, one that you can build on later but enjoy today!

If you deck the block or shave the head slightly then you effect the cam timing. You can compensate for this to some degree by having the cam ground with some advance "built in". Ideally an adjustable cam pulley probably would be better.

You just missed OGTS's sale on 2.0L pistons and valves. It ended Dec. 31. You should have received a flyer.

Good luck,

Harold

[opelnut10]

Originally Posted by bgdowski I wasnt planning on reusing my original valves. How do i go about having larger valves fitted, and what valves do i use? Would it be smarter to use the 2.0l pistons or just 1.9l high compression?

The 2.0 valves are the least problem money wise and ease of installation. While the machinist is cutting the seats for the larger valves have the hardened seats installed for the use of unleaded gas, also if the machinist does a lot of head work he should have a "bowl hog" to blend the top of the valve pocket around the guide that helps flow. If you use a hyd. cam then using a .030 shim under the stock (new) valve springs will give you better seat pressure on the springs and will not get into a coil bind problem. Valve size and cam timing can make a bigger improvment for the money than anything else on a street engine, flat top pistons are about all you can run on pump gas (usually 9:0 or 9.5 to 1) and getting the engine to breath better will help it a lot. 150 HP is not do able with a 32/36 Weber and a street exhaust system but certainly 130-135 is a realistic number and will make the car fun to drive.

[RallyBob]

Originally Posted by bgdowski Im planning on pulling my motor out this summer and was looking for some feedback from the engine gods of OpelGT.com... Here is what i was thinking of doing: -Block skimmed to ensure flat surface. -Boring block to fit 2.0L pistons from OGTS. -Fitting 2.0L from OGTS. #6132 -2.0l rings from OGTS. #6140 -new rod and main bearings, obviously -.430" lift, 268 duration or .430" lift, 284 duration camshaft (i dont know if mine is solid lifter or hydraulic. Remind me how i can tell) -valve job (stock replacement valves put in) -New lifters and cam bearings Im not worried about a rough idle, gas mileage, or octane use with this motor. I am building it with the intent to drive it every day, but be able to open it up on the street when needed and track it a little. I have a Weber 32/36 on it already and a pointsless ignition system. My goal is 150hp, do you think that is obtainable with these engine modifications? What do you suggest i do to reach my goal, or get close... This is a budget minded build, so nothing to radical. I have decent mechanical skills aswell, and am not afraid to do head work with the right guidance.

As the others have said, these components would not yield 150 hp. A bone-stock 2.0E engine makes 110 ps (metric HP, about 108 SAE net HP), and that is based on the 2.0 block with higher compression, plus the higher flowing 2.0 head with bigger valves, the 2.0 EFI system (which outflows your 32/36 Weber), and a better flowing exhaust manifold and system. At best, even with the larger cam you propose, I think 95-100 hp is all you'd see with a stock head (and valve sizes) and unported intake manifold. That is appreciably more than a stock 1.9, however tame it may sound!

150 hp is achievable, but you'd need higher compression still, an appreciably modified big valve head, a fairly large cam, 38 DGAS Weber/Holley 2-bbl/or EFI intake, ported intake if you are using a carburetor, and a good custom exhaust system. And the appropriate tuning, primarily to the distributor curve and to the carburetor (it would have to be modified internally to work with the bigger cam). Cost of such an engine would be about $4500 or more, unless you did everything yourself (porting, assembly and tuning).

There are some nice running engine combinations that myself and others have posted specs of on this site, it would be justifyable to spend a few hours with the search option and reading up on some of these modifications to get a good feel about what is involved with building a true 150 hp engine, or even 125 hp.

Good luck!
Bob

[Redskinsjbs]

Originally Posted by RallyBob At best, even with the larger cam you propose, I think 95-100 hp is all you'd see with a stock head (and valve sizes) and unported intake manifold. That is appreciably more than a stock 1.9, however tame it may sound! Good luck! Bob

I thought that the stock 1.9 already made ~100 hp?

[Viny Charb]

1968-1970 about 80 hp , 1971-1973 smog engines more like 65hp. The Opel tech books are exaggerated as far as 1.9l outputs.

[Viny Charb]

Hey on the subject of engine builds, valve size. etc...... here's one for bob or who ever else. A cheap way to go as far as the most bang for buck big valve 1.9 head set up that I've read about 45mm intakes (from 2.2l), and 36mm exhaust (from 2.0l). Would there been any more benefit to buying 2.2l (40mm) exhaust valves and machining them down to 38mm as to match the chevy 1.5 exhaust valves set up 0n the 1.72-1.5 and 1.85-1.5 inch valves. Basically my question is, if I would build my 1.9l into a 2.0 with bigger valves from opel is there really a point to going a few steps further and doing a 45-38mm valves compared to just using stock 2.0L exhaust valves????

[newman27]

Originally Posted by Redskinsjbs I thought that the stock 1.9 already made ~100 hp?

Period review articles of the GT indicate 102 HP @ 5,400 RPM for a stock 1.9L engine with the high compression pistons. However, I assumed Bob was referring to horse power at the wheels (BHP).

[bgdowski]

Thanks for all the advice guys, im learning alot and will continue to look for other peoples set ups on the site. Any specific links to buildups i should reference?

So my plan has been modified to first doing the bottom end... (Having the crank balanced and knife-edged, ensuring i have forged pistons, bore for 2.0l pistons, along with rings and bearings.) Depending on income, i may lighten the flywheel and do the s-10 clutch also. Ill also jet my 32/36 to run better with the internals.

While i am at school i will slowly build up a head from a core off of ebay, or the community with a port and polish from Bob's tutorial, 2.0l valves, hardened seats, solid lifters, and a fairly radical cam. I will also work on a full exhaust (which will most likely happen this summer) and getting a Weber 38, electronic fuel pump, electric fan, etc.

Does that sound like a better idea?

[yellaopelgt]

I think you should be happy with that set-up.
Put some thought into sway bars,good shocks,bushings,better brakes.....All this adds up into a nice lil street-car that really sticks to the road. Honestly....a motor pushing 150 HP is starting to stress out other driveline components anyway. These cars are so light and nimble that even a small HP increase is pretty noticable.
JMO

[opelwasp]

Knife-edging the crank will cost you a bundle. It is very labor intensive and the shop is going to charge you dearly for it. Get a crank scraper it will be much cheaper and accomplish the same results for your application.

[opelnut10]

Originally Posted by bgdowski Thanks for all the advice guys, im learning alot and will continue to look for other peoples set ups on the site. Any specific links to buildups i should reference? So my plan has been modified to first doing the bottom end... (Having the crank balanced and knife-edged, ensuring i have forged pistons, bore for 2.0l pistons, along with rings and bearings.) Depending on income, i may lighten the flywheel and do the s-10 clutch also. Ill also jet my 32/36 to run better with the internals. While i am at school i will slowly build up a head from a core off of ebay, or the community with a port and polish from Bob's tutorial, 2.0l valves, hardened seats, solid lifters, and a fairly radical cam. I will also work on a full exhaust (which will most likely happen this summer) and getting a Weber 38, electronic fuel pump, electric fan, etc. Does that sound like a better idea?

Knife edging the crank is a waste of time and money, far better to lighten the crank by cutting down the counterweights and balance. Forged pistons is something else you can do without unless you are going to super charge, turbo charge or run NOS. You will need to run the early forged rods (pre 74) with new rod bolts. When looking for a head try to find a 10 bolt 4 bearing head for a core and use the matching front cover. You might want to give some thought about getting a better brake system to stop this thing after you make it quicker as the stock brakes are barely enough to stop a stock 103HP GT.

[oldopelguy]

Originally Posted by opelnut10 Knife edging the crank is a waste of time and money, far better to lighten the crank by cutting down the counterweights and balance.

If you're going to cut weight off the crankshaft, why would you do it any way other than to end up with a knife-edged crank? Were you just thinking about cutting 1/4" off the whole outside edge of the counter-weight? Seems silly to me, but I guess to each his own.

[wrench459]

Humm aren't ya'll doing the same thing only from different angles?
Removing any metal from the rotating mass of the crank will improve the performance of the engine.
But at what cost? for a street engine its not cost effective for the very small amount of increase in horse power..

[hrcollinsjr]

Originally Posted by wrench459 Humm aren't ya'll doing the same thing only from different angles? Removing any metal from the rotating mass of the crank will improve the performance of the engine. But at what cost? for a street engine its not cost effective for the very small amount of increase in horse power..

Does removing weight from the crank increase horsepower? Then go with a lighter flywheel to, that will also increase horsepower.

How about this reducing the weight helps with acceleration. Correct? Horsepower can/is gained by reducing windage. There are several ways to do this from some type of mechanism to scrape the oil off of the crank, to coatings, to shaping the counterbalance weights into a tear drop shape, etc. I believe Jeff Denton even went so far as to plumb an outside oil drain from his head (engine ) to the oil pan to prevent any loss that might occur from it draining back onto the crank underneath.

Harold

[Gordy]

If you want a car that's FUN to drive, put the sbc valves in and get the head worked! I've had stock valve jobs done with hardened seats put in at a cost of about $350. (includes inspections, cam bearings etc.)
The last head I had reworked, I printed out Bob Legere's text on using sbc valves and the unshrouding process, took it along with my head to a performance speed and machine shop, and yes it was $900 (included all the parts), checked the valve clearance, cut the 2.0 pistons, and with your other tweeks you will have a red hot Opel!