Changing Head

[Guest AWhite]

I have just bought a new head with large valves and a piper285 cam off ebay. It comes with a carb correctly jetted for this head.

 

Now I have never changed a head before but know a few things. I have been down to my local motor factors and purchased a head set. They said that i needed a set of head bolts but not knowing what type are on my car yet I declined especially as they were £30 for the set.

 

The head is going on a standard block. I will have a look at the Haynes Manual Tonight obviously but wondered if there was some tips/special procedure considering it has a hot cam in it.

 

Any advice appreciated guys.

 

[Mitch]

Bloody Hell, £30 a set, last ones i got were £9 from a local (to Jim) acccesory shop,

try another supplier, he's taking the P""s.

 

You will (may) depending on type fitted need to replace them, and for the price (normal price) i would do it.

 

as for set up, maybe a article on Jims site re ignition and altering the Dizzy to suit

 

HTH

Mitch

[Longboarder]

First I suggest you go to a different motor factor and buy new Torx style headbolts for the pinto which should cost about £12. Turn the engine so that number one cylinder is at Tdc. Follow the Haynes procedures which are clear for stripdown. As soon as the head is off put a smear of grease round the junction of the top of the pistons and the cylinder walls to stop gunge getting in and lightly smear the bore walls.

Unless the head has just been built you will have to strip down to clean chambers and ports, grind in valves, fit new valve stem seals. Worth checking to see that the head is OK for unleaded. If its an injection head with the pear shaped inlets it is. Otherwise look on the machined exhaust face by number 4 plug for P,PP,R,RR,L.

Make sure all gasket faces are clean and reassembly is the reverse.......The trick of grinding off the heads of two old head bolts, slotting their stems and putting them temporarily in the head to hold the gasket in place is a good one. The cam should be turned till the lobes on number 1 cylinder face up in a V shape and with the crank still at Nu 1 Tdc the head drops on with no issues.

Cam timing is as per Haynes if you have a standard pulley but I hope you get a vernier pulley. If you do then search this site or go to Burton Power where they describe cam timing in detail.

Good luck.

 

Nigel

[Guest AWhite]

Pic

[Guest AWhite]

"Unless the head has just been built you will have to strip down to clean chambers and ports, grind in valves, fit new valve stem seals."

 

The head is not new, how would i go about the above?

 

EDIT: Don't the valve stem seals come in the head set?

 

Thanks again.

[Longboarder]

Burton Power are here and there are some very good articles under Tech Support including cam timing with a vernier pulley.

I can't clearly see but the inlets look round in your picture. If so it's from a carburetted engine and you need to check the unleaded code letters. Overhauling a cylinder head is described in Haynes and is not hard. Yours may be OK to fit as it is if it has recently been rebuilt and is clean. Have you any more experienced Hoodie locals who can come round, drink your coffee and advise?

 

Nigel

 

ps The valve stem seals are in the set.

 

pps Leicester is a bit far for me to pop in.

Edited May 13, 2005 by Longboarder

[Guest AWhite]

Yeah my dad is also a hoodie. Will bounce head of him (not literally...well maybe).

 

Thanks for your help,

 

Andy

[Andy Spencer]

I live near Leicester as well (nr Ashby) so if its not too far could pop in sometime, bit busy this weekend working on mine but maybe next week.

 

PM me if you want. I did a top end rebuild last year.

 

Andy

[Guest AWhite]

Heads off. And guess what I tore the teeth out the cyl head bolts (spline type) on the last bolt! Managed to drill the head off after about 2 hours work. Sheesh what a ball ache.

[Snapperpaul]

Don't forget to renew the camshaft spray bar while its apart, only cheap and will prolong the camshaft life.

[Guest AWhite]

You know those jobs you wish you hadn't started.

 

Started taking the valves out to replace the valve seals and the valves ports are a bit mucky. So off to get a valve grinding tool and some carbowhotsit paste.

 

Had a look at a few vernier pulleys (it hasn't got one) bloody hell they are expensive!

 

Better be worth it at the end of this. For a start i'll keep the standard dizzy, and cam pulley. Will i still notice the difference from the smaller valved standard cammed head?

[Guest Guy]

If the valve seats are hardened then surly you don't grind the valves in as it removes the case hardening. Just like the case hardening on the cam shafts, it's only thin and once you break through it you get to the girls blouse metal underneath.

[Guest AWhite]

You don't actually grind the metal. Its like a plunger you stick it to the valve and grind away the carbon build up by turning the valve with some paste that comes in course and fine varieties that way it makes sure the valves seats properly when not open.....or so i'm told

 

[Longboarder]

The valve seat inserts are not surface hardened like a cam lobe but made of harder steel to resist valve recession. Ford machine them after fitting to put the correct face angle on and align them with the guide. They couldn't do this if the hardness was a surface property only. Mine were recut to three angle two years ago and there is no problem with recession. There may be a benefit in leaving the seats untouched in an unleaded head if they are in good condition to retain 'lead memory' but this must be rare these days.

 

Nigel

[Guest Guy]

Well that's okay then, I remember the issue from my old Honda VF750 but it must have been a cheap engine