Another cylinder head questioin

sicarumba · Post by **sicarumba** » Wed Apr 11, 2012 2:23 pm

Hello all

I have a 3.5 RV8 from a P5B, circa 1970 ish (rope seals and all). It's in bits right now and I am slowly reassembling it. I was given some cylinder heads this week with the intention of using the rocker shaft assemblies on my original heads, since the shafts show no wear at all and my original ones were shot. Having read several other threads on here I am now considering ditching my heads in favour of the new ones, given that a) they appear to be better in every way and b) will have hardened valve seats for that additional peace of mind running on unleaded.

They have casting number HRC 2210 which according to the sticky on this forum makes them early 90s EFi heads. The page suggests they have been machined by Rover to use composite head gaskets. Does this mean they will bolt straight on to my P5B block using a composite gasket with no modifications required? Are all HRC 2210 heads like this or are there differences? Am I likely to experience any issues doing this, or should I just stick to my original heads and use a tin gasket?

A point of note, the engine is to be used in a V8 trike so I am not desperate to squeeze maximum power from it. I like the idea of using a composite gasket but have spent so long cleaning and fettling and measuring things I don't want to take on any more trouble if possible.

Thanks in advance,
Simon

kiwicar · Post by **kiwicar** » Wed Apr 11, 2012 2:49 pm

Hi
Go with the newer heads, they are heaps better, you can as you say use them with composite gaskets without further skimming. I would still shim the rocker pillars to set the preload correctly on the tappets, but nothing else to do for them to work.
If you can find the time a quick clean up of the castings would be worthwhile, just to remove the casting marks and any sudden transitions from machining to casting, it will just make pick-up crisper and it will be easier to set up the engine but just a clean up.
Best regards
Mike

sicarumba · Post by **sicarumba** » Wed Apr 11, 2012 6:03 pm

Hi Mike

Thanks for the reply. Just wanted to confirm my understanding was correct, there aren't tin gasket and composite gasket varieties of the HRC 2210 and I can go ahead and order some composite ones without having to get the heads machined.

Next question, looking at the Real Steel website there seems to only be one type of composite gasket for the 3.5 engine, but flicking through ebay there seem to be early and late types on offer, some being 10 bolt and some 14. My new heads are 14 holes but I have read on here it's advisable to leave the 4 bolts at the exhaust manifold side out and only use 10 bolts. Is this correct? And can I therefore get a later 10 bolt gasket from any engine size RV8 for this application?

ChrisJC · Post by **ChrisJC** » Wed Apr 11, 2012 6:17 pm

The composite type heads can be checked by taking these measurements:

You might want to check that the ancillary fixing locations are OK for your application. I don't think they ever moved any, just added more over the years.

Go for 10bolts, all composite engines only used 10 bolts. Just ignore the extra holes. Up to you whether you prefer the earlier torque-them-up type bolts, or the single use stretch bolts.

There are two bore sizes, 3.5" and 3.7". The 3.5" bore what used on the 3.5l engines, 3.7" bore on 3.9, 4.0, 4.2, 4.6. Therefore you should make sure you get a composite gasket with the right bore size.

Chris.

sicarumba · Post by **sicarumba** » Thu Apr 12, 2012 6:44 pm

Thanks Chris

I measured one of the heads as shown in the diagram, and my A and B measurements appear to be about 2mm longer than shown. Does this mean they pre-date the composite gaskets and are intended for use with tin?

I used a vernier caliper tool and measured to the red lines :

kiwicar · Post by **kiwicar** » Fri Apr 13, 2012 9:36 am

Hi
They sound like heads for tin gaskets. . . plus a bit,

78 thou extra? I would still use them, get them skimmed.
They are much better heads (oh did I mention that earlier).
Best regards
Mike

ChrisJC · Post by **ChrisJC** » Fri Apr 13, 2012 11:52 am

Agree with Mike. Just get them skimmed down to the measurements on the drawing, and use composite gaskets.

Chris.

DEVONMAN · Post by **DEVONMAN** » Fri Apr 13, 2012 12:06 pm

Something is not right here. 2mm error is unlikely even though it's a Rover.

Check again and make sure the vernier is at zero.

Or the safe way is to compare your old and new heads, if they are the same then it's for a tin gasket.

Regards Denis

sicarumba · Post by **sicarumba** » Fri Apr 13, 2012 4:43 pm

Thank you for the further updates.

I compared the old and "new" heads as suggested and it looks as though they may be for tin gaskets :

So I guess a bit of skimming is on the cards.

kiwicar · Post by **kiwicar** » Fri Apr 13, 2012 9:10 pm

Hi
yup looks like tin gasket ones. Strip them, give them a scrub with "fairy power spray" then shove them in the dish washer and they will come up all shiney and the chap who skims them for you will think you a loverly person.
Best regards
Mike