38 replies to this topic

[yel327]

Stuck a camera down the spark plug holes and exhaust ports today. Bores look good, can still see the obvious honing cross hatching. There is some scale in the exhaust ports and sitting on the top of the valves. Turning the camera head around I can see some minor surface rust scale on the bits of combustion chamber that don't have carbon on them. Some minor surface rust on the valve caps too that are near the breather but the other side was clean as a whistle (I took that rocker off).

 

So I think for the small amount of work involved I'll take the heads off and give the valves a lap with some grinding paste and give the ports a good clean, maybe put some new springs in while the valves are out (I have a couple of sets of new springs here that I'll never use). Plenty of VRS gaskets spare so it's only my labour. I might compression test it first though after blowing out the exhaust ports, and after first blowing some air down the plug holes of the cylinders that the exhaust valves are open to try and blast out any crap.

[rodomo]

So I think for the small amount of work involved I'll take the heads off and give the valves a lap with some grinding paste and give the ports a good clean

Wow!...…………...You're as old skool as me?...………….cept the bit about the fancy camera

[skap]

LS is the answer. Only read half ya question... maybe a quarter 😂

[yel327]

Wow!...…………...You're as old skool as me?...………….cept the bit about the fancy camera

 

Is valve lapping old school? I thought that was what everyone did? Camera isn't fancy, just a Jaycar thing. Takes photos but haven't got that to work as yet. 
 

[yel327]

LS is the answer. Only read half ya question... maybe a quarter 😂

 

Too small for me unless I went for an LS3, but who wants an LS is a Holden anyway? Nowhere as cool or desirable as a big SBC or a BBC and costs a lot more to fit and Engineer. I'll leave that to beer drinking millennials! I want an engine and a car as old as I am! Born in the 60's and born as a Chevrolet in the USA, not modern GM powertrain stuff made in Canada or Mexico.
 

[rodomo]

Is valve lapping old school? I thought that was what everyone did?

Lol...……...try buying the lapping sticks with the suckers attached.

[yel327]

Lol...……...try buying the lapping sticks with the suckers attached.

Don’t have to, already have them. It is what I use.

[rodomo]

I tried to buy some 15yrs ago as mine had perished

[caterham2]

Lol...……...try buying the lapping sticks with the suckers attached.

Best source is as a Briggs and Stratton service part. You get 3 suckers of different sizes plus a real nifty stick to drive them. Any mower shop should be able to get for you.

[rodomo]

Thanks! It's a lost art...……………..If you can call it that?

 

I still have a near full tube of bearing blue I have to use.

[caterham2]

Thanks! It's a lost art...……………..If you can call it that?

 

I still have a near full tube of bearing blue I have to use.

Ah! Bearing blue, yes I remember.

[yel327]

Wow, time has got away. I thought I'd be less busy during Covid but had more on.

 

Finally getting back to this car. Decided I couldn't be bothered trying to resurrect this 283 and bought this low hour Mercury Marine 5.0L engine. Was in a fresh water system (heat exchanger) setup, clean as a whistle inside. Guy that had it pulled the heads and sump off to check it out and put new ones back on. Bore is good, valves all good. Has about 170psi compression across the board and was running on engine stand a few weeks ago.

 

It's a 1991 230hp 4BBL 5.0LX traditional (LH) rotation engine. Flat tappet engine, roller cams not until about 1998 in these. These are 9.3:1, same cam as a HK-HQ 307-350, 1.88/1.5 valves. Just a standard torquey engine as they run the same 3.48" stroke as a SBC and Holden 350. The good thing about a Marine engine is it doesn't come out of a car bringing emissions requirements with it. Gets treated like a crate engine.

 

It'll be a good engine to get the car going, engineered and registered. I'm just going to remove the Quadrajet, HEI and all the front stuff other than the harmonic balancer. Fit the Holley Sniper & Hyperspark plus the serpentine drive setup. Will allow me to get it all running, and onto the trailer to get the exhaust done, without having to worry about hurting a new engine. I'll also be able to run the standard TH350 behind it, and later on swap it all out with the 377 and heavy duty TH350C.

 

Just have to buy a 153 tooth flex plate and starter for it as these come standard with a 168 tooth flex plate. And sort out the dipstick that works with a Corvette 2.5" ramshorn and doesn't foul on the brake booster as it has a driver side dipstick. I was hoping the one on it would work but it hits the Ramshorn. I'll also try and get a non-filler rocker cover as it has a pair of the same side on it, I think Mercury Marine do that standard.

 

 5.0 -1.jpg   216.46K   4 downloads

 5.0 -2.jpg   216.97K   3 downloads

Edited by yel327, 13 June 2023 - 08:27 AM.

[RallyRed]

Never would have thought of a boat eng. for a car. Good work.

Edited by RallyRed, 13 June 2023 - 08:58 AM.

[yel327]

GM kept building them up until about 2013 for Marine use. They still build GenII 350 for the same application. They are in no way a Chev engine, just happen to bolt in where an older SBC engine fitted other than for the flex plate difference due to the one piece rear main. Remember GMH used to build 308/5.0L engines for years for marine use in Australia. They used to supply new HT-HG style 350 engines as well. They kept producing the final HQ/HJ (1974) spec 5.0L for years for sale for use in boats, came as the pre-canister pollution spec engine. They probably kept doing it right up until the end of the carbureted 5.0L. I always wondered why so many 7043284 Quadrajets kept turning up with late 70's date codes, in theory these should have stopped about 9/74 for local use (they did continue on export HX and HZ). I thought originally they must have been export carbs but no manual ones ever turned up locally, and they should have if the auto ones did. It was for those marine application 5.0L engines.