Feedback from Loctite is that the head was likely commercially "porosity sealed" using Loctite Resinol RTC. It is an anaerobic sealant that has varying resistance to different chemicals. Mechanical cleaning will not affect it, and cleaning the scale out of the water jacket with oxalic acid solution will not be a problem. It can handle room temperature caustic, but running in a hot tank at pH 12 and just under a slow simmer for a few hours may be a drama.
So wire wheeling it planned to get the paint off, and some petrol and nailbrush/toothbrush to clean up any oil.
Cheers,
Harv
Harv's Repco HighPower crossflow head thread
Re: Harv's Repco HighPower crossflow head thread
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
Re: Harv's Repco HighPower crossflow head thread
The valve spring saga is not getting any easier.
I purchased the ET G1260 retainers, and swapped them for the aluminium ones. The fit was like night and day – no longer sloppy from where the ally had been flogged out over time. Some measurements of valve spring installed height were now in order. I will need about 80lb closed spring pressure on the exhaust side, and 110lb on the inlet side (which fights boost pressure). The closed spring pressures can be a little more than this, aiming for no more than 350lb of open pressure (400lb is where cam lobes are likely to start to get wiped).
Measuring installed spring height is normally done with the valve, retainers and collets in place, but no spring. With the valve held shut by your fingers, a digital vernier is used to measure from the retainer top down to the spring seat. This uses the little steel bar that pops out of the end of the vernier when you open it (depth measurement). By subtracting the thickness of the retainer, you get a measurement of the springs height when installed.
This is fiddly, as you are trying to measure to a relatively small spring seat and it is easy to have the vernier tilted. I find when I take 3 or 4 measurements that I get variance, most likely from my inept handling of the vernier. If this was a standard motor (where installed height is known, just being checked) then I could get away with it. With the Repco head I need to be more careful, as there is a fair chance this thing has been played with more than once.
A better way to measure the installed height is to use a thimble micrometer. These are two metal pipes that are threaded together, which you install instead of the valve spring. As you wind them apart a scale appears on the side, which tells you the thimble height. Pretty neat. The Repco head has very low installed heights, so the normal off-the-shelf ones won’t do. I managed to find one though from 4 Piston Racing that will measure from 1.30-1.75 inches. Bought it, and waited a while for it to arrive from the US. Company sent the wrong part, and then waited again for the right one (if anyone needs an oil seal installer for a B20 engine let me know).
With my fancy purple thimble micrometer in place and the new ET G1260 retainers in play I went to measure installed height. This is where I realised that the micrometer needs to be much, much shorter than the installed height. Valve in, micrometer over the stem, slide retainer on and DOWN heaps to get clearance to put in the collets. You guessed it… my fancy new purple micrometer was still too long and I could not get the collets in. Put the micrometer in the naughty corner and got the vernier out again. Lots of measurement (and dropped collets) gave me installed heights of 1.31” on the inlet and 1.35” on the exhaust. That’s really, really short. Some conversation with spring suppliers showed that I would not get a spring at that height.
Borrowed two different retainers from a gentleman (with thanks) and measured again. By this stage I am getting really good at picking up fumbled collets. Measured up the first collet, and sure enough the micrometer still won’t fit. Some vernier work later shows 1.25” on the inlet and 1.33” on the exhaust. Dammit… worse than the ET G1260 retainers. On to the second set of borrowed retainers. This is looking more hopeful, as FINALLY the thimble micrometer will fit under the retainer. I get 1.29” on the inlet and 1.35” on the exhaust. Still no better than the ETG1260's.
Back to the spring suppliers again, and still waaaaay too short. Double check with another Repco head, and that gentleman is running 1.41” inlet and 1.42” exhaust. I’m 100 thou or so too small. Not much of a fan of the idea of milling the valve seats deeper… it would be just my luck to strike water. My overall valve lengths look OK (1.63” or so installed height to the tip, the same as the other gentleman’s), but mebbe my collet grooves are machined lower on the stem.
More thinking to do.
Cheers,
Harv
I purchased the ET G1260 retainers, and swapped them for the aluminium ones. The fit was like night and day – no longer sloppy from where the ally had been flogged out over time. Some measurements of valve spring installed height were now in order. I will need about 80lb closed spring pressure on the exhaust side, and 110lb on the inlet side (which fights boost pressure). The closed spring pressures can be a little more than this, aiming for no more than 350lb of open pressure (400lb is where cam lobes are likely to start to get wiped).
Measuring installed spring height is normally done with the valve, retainers and collets in place, but no spring. With the valve held shut by your fingers, a digital vernier is used to measure from the retainer top down to the spring seat. This uses the little steel bar that pops out of the end of the vernier when you open it (depth measurement). By subtracting the thickness of the retainer, you get a measurement of the springs height when installed.
- measuring installed height with verniers.jpg (671.69 KiB) Viewed 286 times
This is fiddly, as you are trying to measure to a relatively small spring seat and it is easy to have the vernier tilted. I find when I take 3 or 4 measurements that I get variance, most likely from my inept handling of the vernier. If this was a standard motor (where installed height is known, just being checked) then I could get away with it. With the Repco head I need to be more careful, as there is a fair chance this thing has been played with more than once.
A better way to measure the installed height is to use a thimble micrometer. These are two metal pipes that are threaded together, which you install instead of the valve spring. As you wind them apart a scale appears on the side, which tells you the thimble height. Pretty neat. The Repco head has very low installed heights, so the normal off-the-shelf ones won’t do. I managed to find one though from 4 Piston Racing that will measure from 1.30-1.75 inches. Bought it, and waited a while for it to arrive from the US. Company sent the wrong part, and then waited again for the right one (if anyone needs an oil seal installer for a B20 engine let me know).
- thimble micrometer - closed.jpg (608.28 KiB) Viewed 286 times
- thimble micrometer - open.jpg (549.47 KiB) Viewed 286 times
- thimble micrometer installed.jpg (775.42 KiB) Viewed 286 times
With my fancy purple thimble micrometer in place and the new ET G1260 retainers in play I went to measure installed height. This is where I realised that the micrometer needs to be much, much shorter than the installed height. Valve in, micrometer over the stem, slide retainer on and DOWN heaps to get clearance to put in the collets. You guessed it… my fancy new purple micrometer was still too long and I could not get the collets in. Put the micrometer in the naughty corner and got the vernier out again. Lots of measurement (and dropped collets) gave me installed heights of 1.31” on the inlet and 1.35” on the exhaust. That’s really, really short. Some conversation with spring suppliers showed that I would not get a spring at that height.
Borrowed two different retainers from a gentleman (with thanks) and measured again. By this stage I am getting really good at picking up fumbled collets. Measured up the first collet, and sure enough the micrometer still won’t fit. Some vernier work later shows 1.25” on the inlet and 1.33” on the exhaust. Dammit… worse than the ET G1260 retainers. On to the second set of borrowed retainers. This is looking more hopeful, as FINALLY the thimble micrometer will fit under the retainer. I get 1.29” on the inlet and 1.35” on the exhaust. Still no better than the ETG1260's.
Back to the spring suppliers again, and still waaaaay too short. Double check with another Repco head, and that gentleman is running 1.41” inlet and 1.42” exhaust. I’m 100 thou or so too small. Not much of a fan of the idea of milling the valve seats deeper… it would be just my luck to strike water. My overall valve lengths look OK (1.63” or so installed height to the tip, the same as the other gentleman’s), but mebbe my collet grooves are machined lower on the stem.
More thinking to do.
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
Re: Harv's Repco HighPower crossflow head thread
After much measuring, borrowed retainers, purchased stuff and thinking, I believe I have a viable valve train for my Repco head… just.
The setup uses Crow 4038 springs, 4134 collets (which increase installed height by 50 thou) and 11717 retainers (which increase installed height by 100 thou). With this setup I get 105lb on the closed inlet valve (close to the target 110lb to help the inlet valve close against the blower pressure), 292lb on the open inlet valve (target no higher than 300lb to stop it wiping cam lobes) and 35 thou left to valve bind (normal target is 50 thou). For the exhausts I get 90lb closed (perfect), 290lb open (highish, but under 300lb) and 42 thou to bind.
The numbers are promising, but do not have too much leeway in them. At 7500rpm things go kablooie pretty badly if I hit spring bind. The springs will need careful spring selection from the dozen I have (not all springs bind at the same height, and they vary pretty significantly in height) and shimming to achieve the results (there is 60 thou variance in spring seat heights). My rough-as-guts measuring is not up to this level of care, so if I use this valve train setup I will get a pro shop (probably HSD) to do the final check and assembly.
I still have one more option to pursue, curtesy of discussion with the lumpy humpy crowd. This option uses Harley V-Rod springs (Ferrea S10096). The spring specs look great, but it will all boil down to installed height. Sadly, the springs are a funky dimension that will not allow any of the five types of retainer I have to be used. The V-Rods have their own retainer (yay!) which is a Ferrea E11041. I would normally jump in, buy a retainer and recheck for installed height. Unfortunately, this is made for a 6mm valve stem, and the Repco head has 11/32” stems which is 8.7(ish)mm (d’Oh!). Can't just drill them out, as they have a high-tolerance angled surface to seat the collets. So not a simple solution. Will talk again to the lumpy humpy guys and see what retainer is used (suspect it will be something like a Crow retainer that is machined down).
It would have been a lot easier just to give this to a pro shop and ask them to go-fix. More expensive that way, and I would not learn too much. At least this way I will understand the setup, and where it is pushing the limits. That should help me trouble shoot it once it gets run in anger.
Cheers,
Harv
The setup uses Crow 4038 springs, 4134 collets (which increase installed height by 50 thou) and 11717 retainers (which increase installed height by 100 thou). With this setup I get 105lb on the closed inlet valve (close to the target 110lb to help the inlet valve close against the blower pressure), 292lb on the open inlet valve (target no higher than 300lb to stop it wiping cam lobes) and 35 thou left to valve bind (normal target is 50 thou). For the exhausts I get 90lb closed (perfect), 290lb open (highish, but under 300lb) and 42 thou to bind.
The numbers are promising, but do not have too much leeway in them. At 7500rpm things go kablooie pretty badly if I hit spring bind. The springs will need careful spring selection from the dozen I have (not all springs bind at the same height, and they vary pretty significantly in height) and shimming to achieve the results (there is 60 thou variance in spring seat heights). My rough-as-guts measuring is not up to this level of care, so if I use this valve train setup I will get a pro shop (probably HSD) to do the final check and assembly.
I still have one more option to pursue, curtesy of discussion with the lumpy humpy crowd. This option uses Harley V-Rod springs (Ferrea S10096). The spring specs look great, but it will all boil down to installed height. Sadly, the springs are a funky dimension that will not allow any of the five types of retainer I have to be used. The V-Rods have their own retainer (yay!) which is a Ferrea E11041. I would normally jump in, buy a retainer and recheck for installed height. Unfortunately, this is made for a 6mm valve stem, and the Repco head has 11/32” stems which is 8.7(ish)mm (d’Oh!). Can't just drill them out, as they have a high-tolerance angled surface to seat the collets. So not a simple solution. Will talk again to the lumpy humpy guys and see what retainer is used (suspect it will be something like a Crow retainer that is machined down).
It would have been a lot easier just to give this to a pro shop and ask them to go-fix. More expensive that way, and I would not learn too much. At least this way I will understand the setup, and where it is pushing the limits. That should help me trouble shoot it once it gets run in anger.
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
Re: Harv's Repco HighPower crossflow head thread
Admire your dedication to the cause good sir 
When you're faced with an unpleasant task that you really don't want to do, sometimes you just have to dig deep down inside and somehow find the patience to wait for someone else to do it for you.
Foundation member #61 of FB/EK Holden club of W.A.
Foundation member #61 of FB/EK Holden club of W.A.
Re: Harv's Repco HighPower crossflow head thread
I don't know how you find room in your head for all the good stuff you know Harv. Mine is clogged up with so much nonsense.
Sent from my SM-G781B using Tapatalk
Sent from my SM-G781B using Tapatalk
getting my FB ute on the road
EK van on rotisserie
EK van on rotisserie
Re: Harv's Repco HighPower crossflow head thread
Brilliant read Harv - keep it coming. Glad you didn’t hand it off to a shop as now we all learn at the same time 