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Opeler
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Discussion Starter #1
I thought I'd start a new thread on this project since the previous thread "Modern 2.5 - 2.7L Engine Build" was more information and idea gathering.

So I started with a 2.4L core engine from Charles and after much research and searching for parts this was the final recipe:

Lower End:
  • VW G60 H-beam racing rods: 136 mm length
  • KB 1745HC-5mm pistons: 97 mm bore. Pistons are dished for 5mm but was enlarged in diameter and depth to increase to about 11 cc. This was done on a lathe. Dishes are 0.08 deep.
  • stock 2.4L crank was offset ground to 48 mm journal size to match the VW rods and shoulders widened only a fraction of a mm to fit the rods. This allowed a 3mm increase in stroke and was super easy according to the machine shop.
  • crank was balanced, etc. by the machine shop (Ohio Crankshaft) and block assembled, all clearances checked. There was no interference anywhere including the piston skirts or block. This machine chop builds racing engines and the manager (Jeff) was unbelievably helpful and answered a million questions from me.

Top End:
  • Stock 2.4 Head cleaned, inspected, etc.
  • 1.88" ss intake valves
  • 1.60" ss exhaust valves
  • all new guides, seals, seats, springs, cups, retainers using SBC parts according to the shop manager. Seat pressure is 100 lbs and open pressure is 210 lbs. These specs came from recommendation from Bob and others. I really had no idea how to design this area but Jeff said this was no issue for them and was quite easy. It's good to have a good machine shop.
  • Cometic .040 MLS head gasket (still on the way)

I'll post some pictures of the final assembly along the way. Plan is to use my Sniper EFI setup on the engine and header with 2.5" exhaust.
 

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Opeler
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573 Posts
Discussion Starter #4
You bought another GT, right? This is going to be the more tame build, compared to a V6.
I actually have 4 GTs now plus the one my son and I are building. This engine will go into my 1970 Yellow GT I'm currently driving and replace the stock 1.9L engine. The V^ roadster is being completely rebuilt.......another project! Yes I have the disease really bad! o_O
 

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Opeler
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573 Posts
Discussion Starter #5
Here are some pictures of the block and head from the machine shop. The shop measured the head chamber volumes at 54 cc, and the deck clearance is 0.0065". Piston volumes are 11 cc.
 

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Very nice. I'm watching closely since since my plan is very similar. Will enjoy seeing how it works!
 

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Opeler
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573 Posts
Discussion Starter #9
Thanks guys! I really don't know how much power but the torque should be impressive (I'm hoping) due to it being a stroker motor.

Forgot to mention I selected a custom camshaft from Isky based on much advice from many on this forum but particularly Rally bob and Manta Rallier! Thanks you two!

Cam specs are:
H-373 Exhaust lobe with .435 lift and 262 adv (208 @ 0.05)
H-353 Intake lobe with .440 lift and 270 adv (214 @ 0.05)
LSA = 112, Intake lobe centerline at 110 degrees or essentially a 2 degree advance.

Hope this all works!
 

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Mike,
Before you install the MLS head gasket according to Cometic also for anyone else considering using the MLS head gasket, the two mating surfaces have to be 50ra or less (smoothness rating). I recently installed a Cometic, both the block and head were resurfaced at a 30 ra rating. I considered myself lucky because none of this was known to me, I found out after the fact it just so happened that the machine shop I used had just upgraded the shops equipment as the MLS gaskets have been becoming more popular these days.

Now if Bob or someone else has successfully ran the MLS gasket using rougher surfaces (I’ve heard 75ra is typical) then you may be fine. Hopefully your fine but the pictures look questionable that’s why I brought it up. HTH
 

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Opeler
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Discussion Starter #11
Copy and that and I did learn of that before working with the machine shop. They assured me their milling processes were in compliance with MLS gaskets.
 
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Pedal Smasher
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What did Isky charge you for the custom cam? I'm thinking of doing the same for my 2.4, but with larger valves.
 

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Opeler
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Discussion Starter #13
What did Isky charge you for the custom cam? I'm thinking of doing the same for my 2.4, but with larger valves.
Well after consulting with Mark and Bob and discussing that I wanted a streetable engine that would idle reasonably well we settled on those lobe profiles. They are fairly mild ramps up and down compared to more aggressive ramps which might promote valve floating or cam wear. This will be a high torquer low rpm motor as most stroked engines are.
 

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Here are some pictures of the block and head from the machine shop. The shop measured the head chamber volumes at 54 cc, and the deck clearance is 0.0065". Piston volumes are 11 cc.
Very impressive - never touched the inside of an engine but the more I look the more fascinated I am with a new clean engine, very cool..
 

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Opeler
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Discussion Starter #15
What did Isky charge you for the custom cam? I'm thinking of doing the same for my 2.4, but with larger valves.
$261 + shipping.
 
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Opeler
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Discussion Starter #16
So I need to order a gasket for the oil pan. I've installed the pickup tube along with the bracket support and all seems to clear just fine. My history has not been good with oil leaks on these Opel engines. They all seem to leak someplace or the other! What are the best tricks and sealants to use on these engines? Oil pan gaskets in particular!
 
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Pedal Smasher
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Thanks for the info. I expected it to cost more. I'm also interested in the best way to seal the oil pan against leaks. If I was to try without any advice, I would have done some high temp gasket maker on both sides of the gasket. Just enough to coat the gasket. This would make the gasket stick to both the block and the pan.
 

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Opel Rallier since 1977
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2,124 Posts
Copy and that and I did learn of that before working with the machine shop. They assured me their milling processes were in compliance with MLS gaskets.
Many/most shops are now doing the finer head surface finishes as standard practice, simply because so many modern engines are using MLS gaskets. The closeup pix of the head surface, showing the valves and chambers, looks like a modern, fine finish surface. But you should always touch upon this matter with the shop if you are using an MLS head gasket.
 

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Opel Rallier since 1977
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2,124 Posts
For the oil pan gaskets:
  • If using a steel pan gasket, put the side edges on a narrow board or piece of wood and, with the round end of small ball-peen hammer, hammer the flat areas around each bolt hole flat and level with the thin 'riser' line running along the edge.
  • Optional step: Pull the rear main cap and put a tiny dab of sealer between cap and block at the back edge and then retorque.
    • Make sure the rear main seal stays in place when torquing on the rear main cap, and the seal's outer surface to the block & cap is perfectly dry; no oil on the rear main seal's outer surface! I NEVER drive the rear seal in after the rear main cap is in place; the cap always is loose when inserting the rear main seal.
  • Apply super-thin skim coats of Permatex #2 or black RTV gasket maker on both side of all pan gaskets, including the end seals. (Or put it on the metal surfaces.) Use only enough to 'color' the surface; too much sealer will act as a lubricant, and the gaskets will shift out of place, and can start to spread and split with insufficient pressure on them. If you can wipe any of it off with your finger, do so as that means you had too much on there.
    • When using the gasket maker, snug all the bolts, then let it set 3 hours or so to let it set, and then do the final tightening.
  • Put a generous gob of sealer underneath and on top of each of the 4 corners, where the end gaskets meet the side gaskets. it ought to ooze out there when the pan is tightened in place
  • Tighten the bolts veeery gradually and evenly, a little at a time, and do it in a pattern to skip every other bolt, going around and around the pan. I end up going around 6 or 8 times, slowly drawing the pan into place. The objective is to draw down the pan evenly into place all around, and avoid tightening down any place too soon. Put the torque wrench aside for this, just use a rachet.
  • The limit of bolt torque is reached as soon as the side gaskets start to bulge out the least tiny bit at any bolt; that is enough! Continue torquing the other bolts around and around in the pattern until the side gaskets bulge the same tiny bit at each bolt.
Never had a pan gasket leak, even racing.
 

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Opel Rallier since 1977
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2,124 Posts
And Mike, I use skim coast of gasket sealer on every surface like timing cover gaskets, the front area of the head gasket, t'stat to head, and the valve cover gasket on the cover side only. Oil gallery plugs usually get a hardening type sealer (or pipe dope if it is threaded; better than teflon pipe tape).

BTW, IDK what timing cover you have and if the Cometic head gasket has the extra thickness of gasket material on the underside around the timing cover area or not that was on early head gaskets.
  • If it has that extra gasket material, and you have a later timing cover that has the top edge flush with the block deck, then that material needs to come off.
  • If that extra gasket material is NOT there, and you have an early timing cover that has a top edge that sets around 040" lower than the deck, then you have to use some black RTV gasket make in that area to fill that gap.
 
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