305 pistons/2.4 liter CIH conversion
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Here is my article which the posts are referring to.
http://clubs.hemmings.com/clubsites/oana/tech/24l.pdf
(MODERATOR's NOTE: Link is broken, see attached .pdf file)
All the information that you need to do the basic conversion is in the article, please don't ask me to supply additional info! If you need to arrive at a specific compression ratio or cam specs, sorry but you'll have to do the math yourself to figure it out. I have probably been asked 50 times for information about this conversion, and with the exception of one or two requests, all of the questions were already answered in the article. Just gotta read it! It is NOT my recommended method of enlarging an Opel engine these days, it is simply ONE of the ways it can be done.
Bob
http://clubs.hemmings.com/clubsites/oana/tech/24l.pdf
(MODERATOR's NOTE: Link is broken, see attached .pdf file)
All the information that you need to do the basic conversion is in the article, please don't ask me to supply additional info! If you need to arrive at a specific compression ratio or cam specs, sorry but you'll have to do the math yourself to figure it out. I have probably been asked 50 times for information about this conversion, and with the exception of one or two requests, all of the questions were already answered in the article. Just gotta read it! It is NOT my recommended method of enlarging an Opel engine these days, it is simply ONE of the ways it can be done.
Bob
Joined
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499 Posts
Hi,
I am nearing the end of the 1.9 to 2.4 conversion (I hope).
If you do go this route I do happen to have a lot of the parts that one might need to do this. Like dual springs, rings, titanium retainers, pistons, valves etc because most of the places I bought things sold the stuff in sets of eight so I have 4 of everything left over.
I will sell mine for exactly 1/2 of what I paid, which would be cost. However if you want to get your own that is all fine too. Here are the pistons that I am using and where to get them.
http://store.summitracing.com/partdetail.asp?part=8469
My valves are Chevy .184 and .150ies, rings molly, I think the springs are Chevy parts too. Email me if you want [email protected] .
On the other hand all the engine parts are at the machine shop except the crank which that should be coming soon from welding and offsetting way up in Detroit. If you wait a bit I will be able to tell you if this all works when undertaken by a clueless duffer like me and not a professional like Bob who knows what he is doing as it is second nature to him.
I guess it depends on who does it too. I am sure Rodgers Opel engineering could make you one up or OpelGTsource.
Having someone who doesn’t know Opels means you end up like me reading out of a manual and quoting posts from this board as you tell a machine shop “how to put in a cam” or “how to put a head” on because you will have too. The shop won’t like you reading to them out of a book “cause they know Chevy’s” and when they treat it like a Chevy they will put things together wrong. It is really tough to tell a professional to “watch out for spring float” if you have no idea what that is in the first place.
Unless you know what you are doing and know the Opel engine yourself (unlike me) you will have to visit your shop week in and week out till you make friends with them. Take them a case of beer and sit down and make them read Bob’s stuff and some of the posts here or from the yahoo group where they talk about what happens to engines that are not put together right…. Make sure the person you tell is the one who will be putting it together and not the kid in the back or better give the kid a copy of the stuff to read too cause there is a far better chance that a kid will read it. Give the kid one six pack if 21.
I am doing this way simply because (sadly) I am not overly affluent and it seems to be the most cost effective way of doing this. Just buying a 2.4 would be far easier but I think I will have an equally good engine with a ported head and welded up reground cannon intakes (finished today! Thanks again for the tip Bob) and dual Weber 40dcoes for less than the cost of a used 2.4 from Opel Gt Source. That said there are many parts that opelgtsource can get you that you don't have to buy eight of and I have gotten many things from them like rod bolts, gaskets sets, bearings etc.
This way is far cheaper monetarily but there is lots and lots more worry and if you are doing this one pay check at a time like me maybe the worry may not be worth the hassle.
If my engine works in real life and not just on paper I will gather up all the parts and receipts and sell them.
Calvin
I am nearing the end of the 1.9 to 2.4 conversion (I hope).
If you do go this route I do happen to have a lot of the parts that one might need to do this. Like dual springs, rings, titanium retainers, pistons, valves etc because most of the places I bought things sold the stuff in sets of eight so I have 4 of everything left over.
I will sell mine for exactly 1/2 of what I paid, which would be cost. However if you want to get your own that is all fine too. Here are the pistons that I am using and where to get them.
http://store.summitracing.com/partdetail.asp?part=8469
My valves are Chevy .184 and .150ies, rings molly, I think the springs are Chevy parts too. Email me if you want [email protected] .
On the other hand all the engine parts are at the machine shop except the crank which that should be coming soon from welding and offsetting way up in Detroit. If you wait a bit I will be able to tell you if this all works when undertaken by a clueless duffer like me and not a professional like Bob who knows what he is doing as it is second nature to him.
I guess it depends on who does it too. I am sure Rodgers Opel engineering could make you one up or OpelGTsource.
Having someone who doesn’t know Opels means you end up like me reading out of a manual and quoting posts from this board as you tell a machine shop “how to put in a cam” or “how to put a head” on because you will have too. The shop won’t like you reading to them out of a book “cause they know Chevy’s” and when they treat it like a Chevy they will put things together wrong. It is really tough to tell a professional to “watch out for spring float” if you have no idea what that is in the first place.
Unless you know what you are doing and know the Opel engine yourself (unlike me) you will have to visit your shop week in and week out till you make friends with them. Take them a case of beer and sit down and make them read Bob’s stuff and some of the posts here or from the yahoo group where they talk about what happens to engines that are not put together right…. Make sure the person you tell is the one who will be putting it together and not the kid in the back or better give the kid a copy of the stuff to read too cause there is a far better chance that a kid will read it. Give the kid one six pack if 21.
I am doing this way simply because (sadly) I am not overly affluent and it seems to be the most cost effective way of doing this. Just buying a 2.4 would be far easier but I think I will have an equally good engine with a ported head and welded up reground cannon intakes (finished today! Thanks again for the tip Bob) and dual Weber 40dcoes for less than the cost of a used 2.4 from Opel Gt Source. That said there are many parts that opelgtsource can get you that you don't have to buy eight of and I have gotten many things from them like rod bolts, gaskets sets, bearings etc.
This way is far cheaper monetarily but there is lots and lots more worry and if you are doing this one pay check at a time like me maybe the worry may not be worth the hassle.
If my engine works in real life and not just on paper I will gather up all the parts and receipts and sell them.
Calvin
Joined
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499 Posts
I am using stock rods as they are quite strong and the older stock ones are forged to boot. I had them cleaned up. The crank is out of the 1.9 and I sent it to “Crankshaft Craftsmen” in Detroit. That is the same place that Joe Van W. did his. You should be able to get it done for under $500 including shipping. When the crank comes back you will have to have your machine shop clean it up a bit and take a bit off the counterweights to make it fit, at least that is what Joe did. I will find out firsthand soon.
I have the same header showing in some of the posts here with the small collector: ( but that is what I have.
I have two 2.5 exhaust systems also. One is straight pipe the other is brand new and comes with a turbo muffler.
Read up on re-curving the distributor and/or maybe try to find a marine mechanic as the boat people have to do this sort of thing all the time. You have to do that in the car, as the motor will have to be running. Travis and Bob have posts on this. I am not that far along yet. I am busy explaining to the other half why I have to sand fenders, hoods and trunks deck lids in the dining room (no garage and ST Louis has had TWICE as much so as Denver or Milwaukee this year).
The other way to do this is get a 2.4 crank from Germany and the right size pistons from say Reise motor sport in Germany. That will set you back about $1900 Euros plus shipping but they just slap in no fuss no muss 1200 for the crank 700 for the pistons. Minor point the stock 2.4 crank weighs lots more than even a built up and reground 1.9. A lightened one will cost you say another 600.
Of course if you go that route you won’t have sweat bullets trying to make it work, which, everyone knows helps you bond to your car. You’re the guy going to toss it into the corner at “that” rate of speed what do you want in your car? The expensive Stock off the shelf from Irshmer/riese-Wal-Mart anything but a discount motorsport or the prudent and frugal good old fashioned red-blooded American we will take it apart build this the way GM should have from the get go ingenuity? (The patriotic speech with the puritanical frugal and prudent buzz words tossed in for good measure mollified the Mrs. Nothing like I am building an engine AND saving money speech.
Say if you have any ideas on how to explain lots and lots of orange dust in a dining room then I am ALL ears.
I have the same header showing in some of the posts here with the small collector: ( but that is what I have.
I have two 2.5 exhaust systems also. One is straight pipe the other is brand new and comes with a turbo muffler.
Read up on re-curving the distributor and/or maybe try to find a marine mechanic as the boat people have to do this sort of thing all the time. You have to do that in the car, as the motor will have to be running. Travis and Bob have posts on this. I am not that far along yet. I am busy explaining to the other half why I have to sand fenders, hoods and trunks deck lids in the dining room (no garage and ST Louis has had TWICE as much so as Denver or Milwaukee this year).
The other way to do this is get a 2.4 crank from Germany and the right size pistons from say Reise motor sport in Germany. That will set you back about $1900 Euros plus shipping but they just slap in no fuss no muss 1200 for the crank 700 for the pistons. Minor point the stock 2.4 crank weighs lots more than even a built up and reground 1.9. A lightened one will cost you say another 600.
Of course if you go that route you won’t have sweat bullets trying to make it work, which, everyone knows helps you bond to your car. You’re the guy going to toss it into the corner at “that” rate of speed what do you want in your car? The expensive Stock off the shelf from Irshmer/riese-Wal-Mart anything but a discount motorsport or the prudent and frugal good old fashioned red-blooded American we will take it apart build this the way GM should have from the get go ingenuity? (The patriotic speech with the puritanical frugal and prudent buzz words tossed in for good measure mollified the Mrs. Nothing like I am building an engine AND saving money speech.
Say if you have any ideas on how to explain lots and lots of orange dust in a dining room then I am ALL ears.
Joined
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499 Posts
Hey You are close!!! Southern Il where? I live close to where the old areana was in St Louis. [email protected]
Mine will end up the '72 light metalic green or maybe opel yellow. In will be going in to be painted in the next week or two.
calvin
Mine will end up the '72 light metalic green or maybe opel yellow. In will be going in to be painted in the next week or two.
calvin
Joined
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15,429 Posts
A factory Opel 2.4 also has different rods, so you'd need those too. They have a different pin diameter, are full-floating, and are longer than the 1.9's. So figure in a set of rods, plus some extra grinding in the 1.9 block to clear the 2.4 crank's counterweights. Oh, and the 2.4 rod bearings are different too, and MUCH more expensive. Probably another $500 Euros for the rods and bearings.calvin said:
Bob
Edit: Sorry, I only realized what I said after the fact, you need to grind the block to clear the RODS, not the counterweights. The 2.4's extra stroke throws the rods much further out to the side, and they will hit the main oil galley protrusion.
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