2.4 Head and Block

[neuropel]

First let me say, Bolt Extractors ROCK!
The cheap, soft allen heads on my 2.4 easily stripped while using a hardened 10mm Allen on them. Next option was bolt extractors. If you don't have a set, go get them! They work awesome. I can't believe anyone would re-use those soft head bolts!

Upon first glance the internals look ok. I was surprised to see how big the stock(?) valves are in a 2.4 head. A quick measure with my cheap digital calipers shows the intakes at 1.78" and the exhausts at 1.58". Assuming the bottom end is ok (no scoring, etc. is evident on the walls, and there's not even that much of a ridge on them), I hope to just "freshen up" the stock stuff and go with it. I'm hoping the bearings are still ok! Apparently the 2.4 bearings are a bit tough to find?

The head will soon be on its way to the machine shop for 1.94" intake and 1.62" exhaust valves, per RallyBob's recommendations, with hardened exhaust seats. Anyone on the list running one of these engines in a manta? Figured I'd throw in a pic or two...

Todd

[GTJIM]

Those 'soft' head bolts are the modern torque-to-yield type that are completely non-reusable as they get stretched past their yield point when being tightened correctly - there is quite a procedure in tightening them involving angles of rotation rather than a specific torque.
They MUST be replaced every time the head is off.

[RallyBob]

Originally Posted by neuropel I was surprised to see how big the stock(?) valves are in a 2.4 head. A quick measure with my cheap digital calipers shows the intakes at 1.78" and the exhausts at 1.58".

They're actually 1.77" and 1.57", better get those calipers recalibrated!

I'm hoping the bearings are still ok! Apparently the 2.4 bearings are a bit tough to find?

Mains are the same as 1.5 > 2.2, the rod bearings are unique however. Cam bearings are the same as any 2.0/2.2 since about 1980. That was when they changed the oil passages in the head, and stopped using a grooved front journal on the camshafts. So never use a late 2.0, or 2.2/2.4 cam on an old 1.9 or you will stop all oiling to the valvetrain!

The head will soon be on its way to the machine shop for 1.94" intake and 1.62" exhaust valves, per RallyBob's recommendations, with hardened exhaust seats.

I would recommend a 1.60" exhaust valve for a 2.4 head. I only recommend the 1.625" exhaust valves on the poorer-flowing 2.2 exhaust ports.

[neuropel]

Originally Posted by RallyBob They're actually 1.77" and 1.57", better get those calipers recalibrated!

I'd say it's safe to assume there's easily 0.01" of carbon buildup on there...I'm amazed my cheapies got that close actually!

OK...1.94" intake and 1.6" exhaust it is. Do you only typically have hardened seats on the exhaust? Also, for the 1.6" valves in a 2.4 head how deep are the seats you usually use...7/32" perhaps? I don't want the shop to break through the water passages.

Thanks Bob!
Todd

[neuropel]

Got the head into the machine shop today, and was quoted $200 to cut the new oversize valve seats, install bronze phosphor guides and hardened exhaust seats. That was cheaper than I thought it'd be...sound about right? Only $25 to hot tank and magnaflux. Turns out there are three race shops all within 20 miles of my house! Must be all the mud-bogger guys in the area. If I could ever settle down and live in one area long enough, I'd know more about my surroundings!

The machinist had some questions I could not answer (no surprise there), but said he'd work through it. He was curious as to how much can be safely cut into the side wall of the combustion area? I told him I thought the bore size was 95mm(?), and that the 1.94" intake was a proven size for that head...upon hearing that he seemed cool with it. It must've looked close to him upon quick examination.

He's an older guy that's been in business for over 30 years. When we were discussing valves he said either he can get them or that some people find better pricing on the internet. He's ok with it either way. How refreshing! He keeps the guides and seats in his shop and is fine with me bringing in whatever valves I want to use.

He had engine projects in there ranging from mercedes to sprint cars, and even ATV engines. I was relieved to see more than just small block chevy stuff, though that was there too. He also does diesels. Two other guys brought in ricer 4 cyl heads while we were talking, so he obviously does a lot of import 4 cylinder stuff as well.

I ordered the valves today from Summit Racing...Manley Stainless Race-Flo 11522 intake and 11565 exhaust.

I'll post pics when I get it back, whenever that might be. He commented that every spring he's up to his neck with work from the local race guys and was now working on weekends to try to stay caught up.

Fingers crossed!
Todd K.

[neuropel]

Got a call from the shop today that my head was done! Since I was working from home, I was able to run out at lunch and pick it up. I stuck the new Manley valves in for the pic...

$240 for the machine work, hot tank, and magnafluxing thus far.

Bob, (or anyone else that knows)...is there any reason I can't use the 2.4 valves in a 1.9 head? Will they work with stock valve springs, guides, etc.? If so, it'd be a cheap way to quickly build up another head. Would the 1.57" exhaust valves need to be cut down? I've never heard of anyone doing this...just curious.

Todd

[RallyBob]

Originally Posted by neuropel Bob, (or anyone else that knows)...is there any reason I can't use the 2.4 valves in a 1.9 head? Will they work with stock valve springs, guides, etc.? If so, it'd be a cheap way to quickly build up another head. Would the 1.57" exhaust valves need to be cut down? I've never heard of anyone doing this...just curious.

Yes, it can be done. In fact I've done this with all the 'old' valves I've stripped from used 2.2 and 2.4 heads I've worked on over the years. I leave the intake valves 'as is', but cut the exhaust valves down to 1.5" for use in a 1.9 head. If it was a 2.0 head, I'd leave the exhaust valves at 1.57" since they need help in the exhaust flow department.

[GTJIM]

The 2.4 head looks right on - the opening up around the intake is spot on.
The edge of the bore dictates the amount that can be removed and the contour of the edge of the head gasket.

The 2.4 valve should go into a 1.9 head AOK as the standard upgrade in the old C&R Large Valve Kit days was 1.72" intake and 1.5" exhaust. So if you have to reface the 2.4 valves and reduce their diameter a wee bit to restore the height of the margin at the edge of the valve you will be right on the money. The 1.9 head will need to be opened up around the intake too - depending upon the gasket and the bore size used.

Nice One!

[neuropel]

How about spring rates between the 2.4 and the 1.9? Which springs would be best to use in the 1.9 head with 2.4 valves? This is cool!

Thanks again for the info...
Todd K.

[GTJIM]

I have a set of 2.4 aftermarket 'Pioneer' brand springs to use on my head with Opel 2.0 valves - have not checked the spring rate but both the exhaust and intake are like 1.9/2.0 intake springs so do need a spacer under the exhaust ones with the rotator removed. I will try to find a link to the pic of them on here somewhere ....

[neuropel]

A lot of water under the bridge since the last posting in this thread, but progress has been made in a lot of areas. Roller rockers are now fixed, head and intakes have been ported and fitted up for an ITB setup, and today I received the cam I'll be eventually using. I placed the pictures here just for future reference. The Extrudabody throttle body setup has been discussed elsewhere.

[RallyBob]

Don't forget, with the roller rocker arms, the valve lift on that cam will be .487" intake/.451" exhaust due to the higher rocker ratio.

[2 Fast 4 U]

this looks very nice

[madhatterpdc]

Okay, I'll bite, any updates to this motor?

[neuropel]

Unfortunately, no updates. I've had everything packed up since October waiting to move (new job). LOTS of work remaining to be done. I mainly just keep buying parts and storing them for that eventual "someday". The engine plans are complete, so at least I know what I will have. More recently I've been picking, planning and piecing my way through the fuel system that will be needed for the car, which for me is no small task and has involved a lot of learning about fuel pumps, fuel lines, and EFI systems. I have a Manta fuel tank modified for EFI and will be running (I think) an Aeromotive EFI pump with all braided lines and AN fittings.

Engine specs:
2.5L with ~10:1 pistons (from RallyBob)
Cam is from Cam Techniques (F313/F290-12)
.487" intake/.451" exhaust, 248 int/242 exh duration @ .050", 112 degree lobe separation angle.
It'll also be getting a set of Gregg's roller rockers that have been reworked by GTJim.

Tranny will be a Getrag 240, for as long as it lasts. The other big ticket item I need to find is a ZF or Quaife unit for the rearend. I just haven't been able to swallow that cost quite yet as I keep hoping to find a used one that can be rebuilt - rare as hens teeth.

It's all going into a 73 Manta Rallye with factory sunroof and AC. I have NO idea when the car will be done. As a matter of fact I have NO idea when the next step will be done - I only know I have bought a lot of parts and I'll be buying a LOT more before it's complete. In the meantime, I have my old trusty '74 Manta that I tinker with as time allows. I've also been collecting parts (more parts!) to swap it over to EFI using Bob's Nissan throttle body trick on the '75 Opel EFI manifold. I have the EFI setup left over from my 2.4, and apparently the fuel rail and injector setup will fit the 1.9 manifold. It will hopefully serve as a platform for me to get familiar with Megasquirt - but I'm relying on the 32/36 Weber will get me to Carlisle .

Todd K.

[RallyBob]

Originally Posted by neuropel I have a Manta fuel tank modified for EFI and will be running (I think) an Aeromotive EFI pump with all braided lines and AN fittings.

If you haven't purchased the pump yet, I ended up fitting an MSD EFI pump to Gregg's 1975 Sportwagon. With not much more than a piece of 1/2" thick rubber to isolate the pump body (it's only 1.865" OD), it fits quite nicely. I also enlarged the inlet fitting from 3/8" to 1/2". This pump feeds 43 gph, which is good for about 500 hp (overkill). Best part is it's only $95.

BUT, if you want dead-stock reliability and quiet running, you can't beat a Bosch pump. Most of the rally guys use Porsche pumps, but they're pricey....

Bob

[neuropel]

Originally Posted by RallyBob If you haven't purchased the pump yet, I ended up fitting an MSD EFI pump to Gregg's 1975 Sportwagon.

Bob, is this Gregg's yellow 2.5L Sportwagon? I didn't realize you had switched it over to EFI yet - last time I saw it it was running a Holley 500. I assume it's not running megasquirt but some other controller? Any idea on whether he's going to Carlisle?

Also, I've been assuming a 3/8" inlet would be fine - is this just typical "Legeristic overkill" or is it something I should plan? Umm...I think I'll be well within the 500HP limit.

Todd

[RallyBob]

Originally Posted by neuropel Bob, is this Gregg's yellow 2.5L Sportwagon?

Yup.

I didn't realize you had switched it over to EFI yet - last time I saw it it was running a Holley 500. I assume it's not running megasquirt but some other controller?

It *was* running a 500 Holley, but it was running so badly when he brought it down to my shop recently I decided that *now* was the time to switch to EFI. Unfortunately the more I looked at the car the more I realized the car needs an entire mechanical restoration. It has a broken a-arm, bad torque tube bushing, bad engine mounts, failing brakes, broken trans mount, dangling/leaking exhaust system, wiring is fubar'd beyond all hope, etc....I made a two page list of 'why the car is unsafe for the road'.

I really don't need another project, but even if I got the car running correctly someone would get hurt because the rest of the car simply cannot handle the power. In fact when I drove the car briefly, making left turns there was about a 2 second delay turning the wheel before the car turned left! The broken a-arm (inner bushing) was deflecting that much...

I replaced all the fuel lines this week, including the filler neck and the breather hoses. The breather hoses were so rotted I was able to 'remove' them by grabbing them with my hand and just pulling them off the car. The filler neck hose was barely any better. Scary stuff, 35-year old rubber parts!

I 'stole' the SDS (Simple Digital Systems) EFI from his turbo engine and got new 30 lb. injectors (high impedance). So I guess the Megasquirt will find its' way to the turbo engine, which is okay because I'd rather have ignition control anyway there.

Any idea on whether he's going to Carlisle?

I don't know if he's going to attend Carlisle or not. I decided I would stay home this year however. The car will not be ready for Carlisle anyway. I'm still receiving parts for it, my order sheet was huge. Today I'm starting on the header though.

Also, I've been assuming a 3/8" inlet would be fine - is this just typical "Legeristic overkill" or is it something I should plan? Umm...I think I'll be well within the 500HP limit. Todd

The stock fuel pickup is 1/2". So I simply matched the sending unit's outlet diameter. Saved making some odd adapters within an otherwise very tight bend.

His fuel pickup was nearly kinked shut anyway, as there was a piece of standard fuel line there, not pre-formed. It can't handle the tight bend, and under suction the fuel line collapses inwards, choking fuel flow. I made a radiused metal hard-line and connected it with straight sections of hose to the pump inlet. No restriction.

Bob